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Journal articles on the topic 'Host resistance in plants'
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1
Dixon, G. R. "Interactions of soil nutrient environment, pathogenesis and host resistance." Plant Protection Science 38, SI 1 - 6th Conf EFPP 2002 (January 1, 2002): S87—S94. http://dx.doi.org/10.17221/10326-pps.
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Host plants and soil borne pathogens that attack them exist within an ecological matrix populated by numerous microbial species that may influence the access of pathogenesis. These events are moderated by physical and chemical components of the soil. The impact of inorganic and organic nutrients on pathogenesis and the development of host resistance are discussed in this review using two host – pathogen combinations as examples. Calcium, boron, nitrogen and pH have been demonstrated to affect the processes of resting spore germination, host invasion and colonisation in the Plasmodiophora brassicae-Brassica combination that results in clubroot disease. Organic nutrients that have associated biostimulant properties have been demonstrated to influence the development of Pythium ultimum-Brassica combination that results in damping-off disease. This latter combination is affected by the presence of antagonistic microbial flora as demonstrated by increased ATP, extra-cellular enzyme and siderophore production. In both examples there are indications of the manner by which host resistance to pathogenesis may be enhanced by changes to the nutrient status surrounding host plants. These effects are discussed in relation to the development of integrated control strategies that permit disease control with minimal environmental impact.
2
Gammelgård, E., M. L. Mohan, R. A. Andersson, and J. P. T. Valkonen. "Host gene expression at an early stage of virus resistance induction." Plant Protection Science 38, SI 2 - 6th Conf EFPP 2002 (December 31, 2017): 502–3. http://dx.doi.org/10.17221/10535-pps.
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Suppression subtractive hybridization (SSH) was carried out to detect genes differentially expressed in plants expressing resistance to systemic infection with Potato virus A (PVA), genus Potyvirus. Differential screening has up to now revealed 19 putative differentially expressed genes. Nothern blot hybridization has confirmed the differential expression of seven genes. Three of them were only induced by the virus, but four genes were also wound-induced.
3
Pink, D. A. C., and P. Hand. "Plant resistance and strategies for breeding resistant varieties." Plant Protection Science 38, SI 1 - 6th Conf EFPP 2002 (January 1, 2002): S9—S14. http://dx.doi.org/10.17221/10310-pps.
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An explanation of the ‘boom-bust’ cycle of resistance breeding was provided by the gene-for-gene relationship between a pathogen and its host. Despite this understanding, most R genes continued to be deployed singly and resistance has been ephemeral. The reasons for breeding ‘single R gene’ varieties are discussed. Alternative strategies for the deployment of R genes and the use of quantitative race non-specific resistance have been advocated in order to obtain durable resistance. The feasibility of both of these approaches is discussed taking into account the impact of technologies such as plant transformation and marker-assisted selection. A change in focus from durability of the plant phenotype to that of the crop phenotype is advocated.
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Gill, Upinder S., Seonghee Lee, and Kirankumar S. Mysore. "Host Versus Nonhost Resistance: Distinct Wars with Similar Arsenals." Phytopathology® 105, no. 5 (May 2015): 580–87. http://dx.doi.org/10.1094/phyto-11-14-0298-rvw.
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Plants face several challenges by bacterial, fungal, oomycete, and viral pathogens during their life cycle. In order to defend against these biotic stresses, plants possess a dynamic, innate, natural immune system that efficiently detects potential pathogens and initiates a resistance response in the form of basal resistance and/or resistance (R)-gene-mediated defense, which is often associated with a hypersensitive response. Depending upon the nature of plant–pathogen interactions, plants generally have two main defense mechanisms, host resistance and nonhost resistance. Host resistance is generally controlled by single R genes and less durable compared with nonhost resistance. In contrast, nonhost resistance is believed to be a multi-gene trait and more durable. In this review, we describe the mechanisms of host and nonhost resistance against fungal and bacterial plant pathogens. In addition, we also attempt to compare host and nonhost resistance responses to identify similarities and differences, and their practical applications in crop improvement.
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Hafez, Yaser M. "A Pivotal Role of Reactive Oxygen Species in Non-Host Resistance Mechanisms in Legume and Cereal Plants to the Incompatible Pathogens." International Journal of Phytopathology 4, no. 1 (May 2, 2015): 43–53. http://dx.doi.org/10.33687/phytopath.004.01.1176.
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Most of plants under normal conditions are resistant to most of the incompatible pathogens (viral, fungal and bacterial infections). This is called ״non-host resistance (NHR) phenomenon״. Till now it is not clear the non-host resistance mechanisms. As a result of inoculation of legume (pea and soybean) and cereal (barley and wheat) plants with compatible and incompatible pathogens, strong resistance symptoms were observed in the non-host/incompatible pathogen combinations as compared with host/compatible pathogen combinations which showed severe infection (susceptibility). Levels of reactive oxygen species (ROS) mainly hydrogen peroxide (H2O2) and superoxide (O2.-) were significantly increased early 6, 12, 24 and 36 hours after inoculation (hai) in the non-host plants as compared with host plants. Interestingly enough that the activities of the antioxidant enzymes such as catalase (CAT), dehydroascorbate reductase (DHAR) and peroxidase (POX) were not significantly increased at the same early time 6 - 36 hai in the non-host plants. However, these enzymes were significantly increased later on 48, 72 and 96 dai in the non-host plants as compared with host plants. It seems that early accumulation of H2O2 and O2.- could have a dual roles, first role is inhibiting or killing the pathogens early in the non-host plants, second immunization of the non-host plants by stimulating the activities of the antioxidant enzymes later on which thereby, neutralize the harmful effect of ROS and consequently suppressing disease symptoms. The author recommends giving more attention to these new mechanisms of non-host resistance particularly in relation to ROS levels and antioxidant activities which are very important for plant breeders and useful for finding alternative control strategies as well.
6
Kovalenko, A. G., T. D. Grabina, L. V. Kolesnik, L. F. Didenko, L. T. Oleschenko, Z. M. Olevinskaya, and T. A. Telegeeva. "Virus Resistance Induced with Mannan Sulphates in Hypersensitive Host Plants." Journal of Phytopathology 137, no. 2 (February 1993): 133–47. http://dx.doi.org/10.1111/j.1439-0434.1993.tb01333.x.
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Lou, Y., and I. T. Baldwin. "Manduca sexta recognition and resistance among allopolyploid Nicotiana host plants." Proceedings of the National Academy of Sciences 100, Supplement 2 (October 6, 2003): 14581–86. http://dx.doi.org/10.1073/pnas.2135348100.
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Klingeman, W. E., F. Chen, H. J. Kim, and P. C. Flanagan. "Feeding Preferences of Dogwood Sawfly Larvae Indicate Resistance in Cornus." Journal of Environmental Horticulture 25, no. 3 (September 1, 2007): 134–38. http://dx.doi.org/10.24266/0738-2898-25.3.134.
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Abstract Dogwood sawfly (Macremphytus tarsatus Say) is a native, phytophagous insect that relies on Cornus sp. host plants for larval development. Feeding injury by dogwood sawflies is primarily aesthetic and seldom results in host plant death. Still, native and non-native dogwoods have not been evaluated for susceptibility to larval feeding by this aesthetically damaging wasp. Ten species or cultivars of dogwoods that are either naturalized native plants or economically significant landscape plants were assayed for host suitability to dogwood sawfly larvae in no-choice and choice experiments. Flowering, kousa and corneliancherry dogwoods were consistently ranked among the least susceptible host plants while ‘Sibirica’ tatarian, gray, and ‘Flaviramea’ golden-twig dogwoods were highly preferred hosts. Preliminary GC/MS comparisons of foliar metabolite extracts from all 10 species have identified five peaks of interest that varied between resistant and susceptible hosts. These results suggest that certain chemical constituents in foliage of dogwood species may be important predictors of host palatability. More research is needed to confirm this hypothesis before crossbreeding for sawfly resistance can proceed.
9
Chen, Yu, and Dennis A. Halterman. "Phenotypic Characterization of Potato Late Blight Resistance Mediated by the Broad-Spectrum Resistance Gene RB." Phytopathology® 101, no. 2 (February 2011): 263–70. http://dx.doi.org/10.1094/phyto-04-10-0119.
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The potato gene RB, cloned from the wild potato species Solanum bulbocastanum, confers partial resistance to late blight, caused by the oomycete pathogen Phytophthora infestans. In order to better characterize this partial resistance phenotype, we have compared host resistance responses mediated by RB with those mediated by the S. demissum-derived R gene R9, which confers immunity to P. infestans carrying the corresponding avirulence gene avrR9. We found that both RB and R9 genes were capable of eliciting a hypersensitive cell death response (HR). However, in RB plants, the pathogen escaped HR lesions and continued to grow beyond the inoculation sites. We also found that callose deposition was negatively correlated with resistance levels in tested plants. Transcription patterns of pathogenesis-related (PR) genes PR-1 basic, PR-2 acidic, and PR-5 indicated that P. infestans inoculation induced transcription of these defense-related genes regardless of the host genotype; however, transcription was reduced in both the susceptible and partially resistant plants later in the infection process but remained elevated in the immune host. Most interestingly, transcription of the HR-associated gene Hin1 was suppressed in both Katahdin and RB-transgenic Katahdin but not in R9 4 days after inoculation. Together, this suggests that suppression of certain defense-related genes may allow P. infestans to spread beyond the site of infection in the partially resistant host despite elicitation of hypersensitive cell death.
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Rousseau, Elsa, Mélanie Bonneault, Frédéric Fabre, Benoît Moury, Ludovic Mailleret, and Frédéric Grognard. "Virus epidemics, plant-controlled population bottlenecks and the durability of plant resistance." Philosophical Transactions of the Royal Society B: Biological Sciences 374, no. 1775 (May 6, 2019): 20180263. http://dx.doi.org/10.1098/rstb.2018.0263.
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Plant qualitative resistances to viruses are natural exhaustible resources that can be impaired by the emergence of resistance-breaking (RB) virus variants. Mathematical modelling can help determine optimal strategies for resistance durability by a rational deployment of resistance in agroecosystems. Here, we propose an innovative approach, built up from our previous empirical studies, based on plant cultivars combining qualitative resistance with quantitative resistance narrowing population bottlenecks exerted on viruses during host-to-host transmission and/or within-host infection. Narrow bottlenecks are expected to slow down virus adaptation to plant qualitative resistance. To study the effect of bottleneck size on yield, we developed a stochastic epidemic model with mixtures of susceptible and resistant plants, relying on continuous-time Markov chain processes. Overall, narrow bottlenecks are beneficial when the fitness cost of RB virus variants in susceptible plants is intermediate. In such cases, they could provide up to 95 additional percentage points of yield compared with deploying a qualitative resistance alone. As we have shown in previous works that virus population bottlenecks are at least partly heritable plant traits, our results suggest that breeding and deploying plant varieties exposing virus populations to narrowed bottlenecks will increase yield and delay the emergence of RB variants. This article is part of the theme issue ‘Modelling infectious disease outbreaks in humans, animals and plants: approaches and important themes’. This issue is linked with the subsequent theme issue ‘Modelling infectious disease outbreaks in humans, animals and plants: epidemic forecasting and control’.
11
Burdon, J. J., and P. H. Thrall. "Resistance variation in natural plant populations." Plant Protection Science 38, SI 1 - 6th Conf EFPP 2002 (January 1, 2002): S145—S150. http://dx.doi.org/10.17221/10342-pps.
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The general outcomes of long-term trajectories of coevolutionary interactions between specific hosts and pathogens are<br />set by the interaction of their life histories. However, within those outcomes the speed of co-evolutionary responses and<br />the extent of their expression in the resistance/virulence structure of wild plant and pathogen populations respectively,<br />are highly variable characters changing from place-to-place and time-to-time as a result of the interaction of host and<br />pathogen with the physical environment. As a consequence, understanding of the role of diseases in the evolution of their<br />hosts requires approaches that simultaneously deal with host and pathogen structures over multiple populations within a<br />metapopulation framework.
12
Venisse, J. S., J. P. Paulin, and M. N. Brisset. "MECHANISMS UNDERLYING DISEASE AND RESISTANCE IN HOST PLANTS OF FIRE BLIGHT." Acta Horticulturae, no. 590 (November 2002): 467–68. http://dx.doi.org/10.17660/actahortic.2002.590.72.
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Gracen, Vernon E., and W. D. Guthrie. "Host plant resistance for insect control in some important crop plants." Critical Reviews in Plant Sciences 4, no. 3 (January 1986): 277–91. http://dx.doi.org/10.1080/07352688609382227.
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NÜRNBERGER, THORSTEN, and VOLKER LIPKA. "Non-host resistance in plants: new insights into an old phenomenon." Molecular Plant Pathology 6, no. 3 (May 2005): 335–45. http://dx.doi.org/10.1111/j.1364-3703.2005.00279.x.
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Hu, Luyang, Jiansu Wang, Chong Yang, Faisal Islam, Harro Bouwmeester, Stéphane Muños, and Weijun Zhou. "The Effect of Virulence and Resistance Mechanisms on the Interactions between Parasitic Plants and Their Hosts." International Journal of Molecular Sciences 21, no. 23 (November 27, 2020): 9013. http://dx.doi.org/10.3390/ijms21239013.
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Parasitic plants have a unique heterotrophic lifestyle based on the extraction of water and nutrients from host plants. Some parasitic plant species, particularly those of the family Orobanchaceae, attack crops and cause substantial yield losses. The breeding of resistant crop varieties is an inexpensive way to control parasitic weeds, but often does not provide a long-lasting solution because the parasites rapidly evolve to overcome resistance. Understanding mechanisms underlying naturally occurring parasitic plant resistance is of great interest and could help to develop methods to control parasitic plants. In this review, we describe the virulence mechanisms of parasitic plants and resistance mechanisms in their hosts, focusing on obligate root parasites of the genera Orobanche and Striga. We noticed that the resistance (R) genes in the host genome often encode proteins with nucleotide-binding and leucine-rich repeat domains (NLR proteins), hence we proposed a mechanism by which host plants use NLR proteins to activate downstream resistance gene expression. We speculated how parasitic plants and their hosts co-evolved and discussed what drives the evolution of virulence effectors in parasitic plants by considering concepts from similar studies of plant–microbe interaction. Most previous studies have focused on the host rather than the parasite, so we also provided an updated summary of genomic resources for parasitic plants and parasitic genes for further research to test our hypotheses. Finally, we discussed new approaches such as CRISPR/Cas9-mediated genome editing and RNAi silencing that can provide deeper insight into the intriguing life cycle of parasitic plants and could potentially contribute to the development of novel strategies for controlling parasitic weeds, thereby enhancing crop productivity and food security globally.
16
Hasan, Jakir, Swati Megha, and Habibur Rahman. "Clubroot in Brassica: recent advances in genomics, breeding, and disease management." Genome 64, no. 8 (August 2021): 735–60. http://dx.doi.org/10.1139/gen-2020-0089.
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Clubroot disease, caused by Plasmodiophora brassicae, affects Brassica oilseed and vegetable production worldwide. This review is focused on various aspects of clubroot disease and its management, including understanding the pathogen and resistance in the host plants. Advances in genetics, molecular biology techniques, and omics research have helped to identify several major loci, QTL, and genes from the Brassica genomes involved in the control of clubroot resistance. Transcriptomic studies have helped to extend our understanding of the mechanism of infection by the pathogen and the molecular basis of resistance/susceptibility in the host plants. A comprehensive understanding of the clubroot disease and host resistance would allow developing a better strategy by integrating the genetic resistance with cultural practices to manage this disease from a long-term perspective.
17
Hu, Lanxi, and Li Yang. "Time to Fight: Molecular Mechanisms of Age-Related Resistance." Phytopathology® 109, no. 9 (September 2019): 1500–1508. http://dx.doi.org/10.1094/phyto-11-18-0443-rvw.
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Plant age is a crucial factor in determining the outcome of a host−pathogen interaction. In successive developmental stages throughout their life cycles, plants face dynamic changes in biotic and abiotic conditions that create distinct ecological niches for host−pathogen interactions. As an adaptive strategy, plants have evolved intrinsic regulatory networks that integrate developmental signals with those from pathogen perception and defense activation. As a result, amplitude and timing of defense responses are optimized, so as to balance the cost and benefit of immunity activation. A general term “age-related resistance” refers to a gain of disease resistance against a certain pathogen when plants reach a relatively mature stage. Age-related resistance is a common observation on fruits, vegetables, and row crops for their resistance against viruses, bacteria, fungi, oomycetes pathogens, and insects. This review focuses on the recent advances in understanding the molecular mechanisms of how plants coordinate developmental timing and immune response.
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Taggar, Gaurav Kumar, and Ranjit Singh Gill. "Host plant resistance in Vigna sp. towards whitefly, Bemisia tabaci (Gennadius): a review." Entomologia Generalis 36, no. 1 (July 1, 2016): 1–24. http://dx.doi.org/10.1127/entomologia/2016/0184.
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Heath, Michèle C. "Signal exchange between higher plants and rust fungi." Canadian Journal of Botany 73, S1 (December 31, 1995): 616–23. http://dx.doi.org/10.1139/b95-303.
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The rust fungi appear to have evolved a sophisticated complex of molecular interactions with their host plants that govern both plant resistance and susceptibility. It is suggested that many of these interactions relate to the maintenance and effective exploitation of biotrophy, and that host specificity and the obligacy of parasitism are a consequence of the resulting interactive molecular control of plant and fungal activities. For the dikaryon, plant signals are required for locating stomata and the formation of infection structures, haustorial mother cells, and haustoria. Host susceptibility to both the monokaryon and the dikaryon appears to involve the suppression of defensive secretory processes, the induction of cellular alterations in invaded cells, and, for the dikaryon at least, changes in nutrient translocation. Parasite-specific resistance involves cultivar-specific fungal signals (elicitors) of defense responses such as cell death and callose deposition. The nature of, and evidence for, the signals involved in these interactions are reviewed. Key words: biotrophy, elicitors, rust fungi, signal exchange.
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Morroni, Marco, Jeremy R. Thompson, and Mark Tepfer. "Twenty Years of Transgenic Plants Resistant to Cucumber mosaic virus." Molecular Plant-Microbe Interactions® 21, no. 6 (June 2008): 675–84. http://dx.doi.org/10.1094/mpmi-21-6-0675.
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Plant genetic engineering has promised researchers improved speed and flexibility with regard to the introduction of new traits into cultivated crops. A variety of approaches have been applied to produce virus-resistant transgenic plants, some of which have proven to be remarkably successful. Studies on transgenic resistance to Cucumber mosaic virus probably have been the most intense of any plant virus. Several effective strategies based on pathogen-derived resistance have been identified; namely, resistance mediated by the viral coat protein, the viral replicase, and post-transcriptional gene silencing. Techniques using non-pathogen-derived resistance strategies, some of which could offer broader resistance, generally have proven to be much less effective. Not only do the results obtained so far provide a useful guide to help focus on future strategies, but they also suggest that there are a number of possible mechanisms involved in conferring these resistances. Further detailed studies on the interplay between viral transgene-derived molecules and their host are needed in order to elucidate the mechanisms of resistance and pathogenicity.
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Shin, Ryoung, Jeong Mee Park, Jong-Min An, and Kyung-Hee Paek. "Ectopic Expression of Tsi1 in Transgenic Hot Pepper Plants Enhances Host Resistance to Viral, Bacterial, and Oomycete Pathogens." Molecular Plant-Microbe Interactions® 15, no. 10 (October 2002): 983–89. http://dx.doi.org/10.1094/mpmi.2002.15.10.983.
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In many plants, including hot pepper plants, productivity is greatly affected by pathogen attack. We reported previously that tobacco stress-induced gene 1 (Tsi1) may play an important role in regulating stress responsive genes and pathogenesis-related (PR) genes. In this study, we demonstrated that overexpression of Tsi1 gene in transgenic hot pepper plants induced constitutive expression of several PR genes in the absence of stress or pathogen treatment. The transgenic hot pepper plants expressing Tsi1 exhibited resistance to Pepper mild mottle virus (PMMV) and Cucumber mosaic virus (CMV). Furthermore, these transgenic plants showed increased resistance to a bacterial pathogen, Xanthomonas campestris pv. vesicatoria and also an oomycete pathogen, Phytophthora capsici. These results suggested that ectopic expression of Tsi1 in transgenic hot pepper plants enhanced the resistance of the plants to various pathogens, including viruses, bacteria, and oomycete. These results suggest that using transcriptional regulatory protein genes may contribute to developing broad-spectrum resistance in crop plants.
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Uma, Battepati, T. Swaroopa Rani, and Appa Rao Podile. "Warriors at the gate that never sleep: Non-host resistance in plants." Journal of Plant Physiology 168, no. 18 (December 2011): 2141–52. http://dx.doi.org/10.1016/j.jplph.2011.09.005.
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Merdan, A., H. Abdel-Rahman, and A. Soliman. "On the influence of host plants on insect resistance to bacterial diseases." Zeitschrift für Angewandte Entomologie 78, no. 1-4 (August 26, 2009): 280–85. http://dx.doi.org/10.1111/j.1439-0418.1975.tb04181.x.
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Pitman, Andrew R., Robert W. Jackson, John W. Mansfield, Victor Kaitell, Richard Thwaites, and Dawn L. Arnold. "Exposure to Host Resistance Mechanisms Drives Evolution of Bacterial Virulence in Plants." Current Biology 15, no. 24 (December 2005): 2230–35. http://dx.doi.org/10.1016/j.cub.2005.10.074.
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Singh, Khushwant, Chris Dardick, and Jiban Kumar Kundu. "RNAi-Mediated Resistance Against Viruses in Perennial Fruit Plants." Plants 8, no. 10 (September 22, 2019): 359. http://dx.doi.org/10.3390/plants8100359.
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Small RNAs (sRNAs) are 20–30-nucleotide-long, regulatory, noncoding RNAs that induce silencing of target genes at the transcriptional and posttranscriptional levels. They are key components for cellular functions during plant development, hormone signaling, and stress responses. Generated from the cleavage of double-stranded RNAs (dsRNAs) or RNAs with hairpin structures by Dicer-like proteins (DCLs), they are loaded onto Argonaute (AGO) protein complexes to induce gene silencing of their complementary targets by promoting messenger RNA (mRNA) cleavage or degradation, translation inhibition, DNA methylation, and/or histone modifications. This mechanism of regulating RNA activity, collectively referred to as RNA interference (RNAi), which is an evolutionarily conserved process in eukaryotes. Plant RNAi pathways play a fundamental role in plant immunity against viruses and have been exploited via genetic engineering to control disease. Plant viruses of RNA origin that contain double-stranded RNA are targeted by the RNA-silencing machinery to produce virus-derived small RNAs (vsRNAs). Some vsRNAs serve as an effector to repress host immunity by capturing host RNAi pathways. High-throughput sequencing (HTS) strategies have been used to identify endogenous sRNA profiles, the “sRNAome”, and analyze expression in various perennial plants. Therefore, the review examines the current knowledge of sRNAs in perennial plants and fruits, describes the development and implementation of RNA interference (RNAi) in providing resistance against economically important viruses, and explores sRNA targets that are important in regulating a variety of biological processes.
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Kasuga, Takao, Katherine J. Hayden, Catherine A. Eyre, Peter J. P. Croucher, Shannon Schechter, Jessica W. Wright, and Matteo Garbelotto. "Innate Resistance and Phosphite Treatment Affect Both the Pathogen’s and Host’s Transcriptomes in the Tanoak-Phytophthora ramorum Pathosystem." Journal of Fungi 7, no. 3 (March 9, 2021): 198. http://dx.doi.org/10.3390/jof7030198.
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Phosphites have been used to control Sudden Oak Death; however, their precise mode of action is not fully understood. To study the mechanism of action of phosphites, we conducted an inoculation experiment on two open-pollinated tanoak families, previously found to be partially resistant. Stems of treatment group individuals were sprayed with phosphite, and seven days later, distal leaves were inoculated with the Sudden Oak Death pathogen Phytophthora ramorum. Leaves from treated and untreated control plants were harvested before and seven days after inoculation, and transcriptomes of both host and pathogen were analyzed. We found that tanoak families differed in the presence of innate resistance (resistance displayed by untreated tanoak) and in the response to phosphite treatment. A set of expressed genes associated with innate resistance was found to overlap with an expressed gene set for phosphite-induced resistance. This observation may indicate that phosphite treatment increases the resistance of susceptible host plants. In addition, genes of the pathogen involved in detoxification were upregulated in phosphite-treated plants compared to phosphite-untreated plants. In summary, our RNA-Seq analysis supports a two-fold mode of action of phosphites, including a direct toxic effect on P. ramorum and an indirect enhancement of resistance in the tanoak host.
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Tateda, Chika, Kazue Obara, Yoshiko Abe, Reiko Sekine, Syuuichi Nekoduka, Takashi Hikage, Masahiro Nishihara, Ken-Taro Sekine, and Koki Fujisaki. "The Host Stomatal Density Determines Resistance to Septoria gentianae in Japanese Gentian." Molecular Plant-Microbe Interactions® 32, no. 4 (April 2019): 428–36. http://dx.doi.org/10.1094/mpmi-05-18-0114-r.
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Plant stomata represent the main battlefield for host plants and the pathogens that enter plant tissues via stomata. Septoria spp., a group of ascomycete fungi, use host plant stomata for invasion and cause serious damage to agricultural plants. There is no evidence, however, showing the involvement of stomata in defense systems against Septoria infection. In this study, we isolated Septoria gentianae 20-35 (Sg20-35) from Gentiana triflora showing gentian leaf blight disease symptoms in the field. Establishment of an infection system using gentian plants cultured in vitro enabled us to observe the Sg20-35 infection process and estimate its virulence in several gentian cultivars or lines. Sg20-35 also entered gentian tissues via stomata and showed increased virulence in G. triflora compared with G. scabra and their interspecific hybrid. Notably, the susceptibility of gentian cultivars to Sg20-35 was associated with their stomatal density on the adaxial but not abaxial leaf surface. Treatment of EPIDERMAL PATTERNING FACTOR-LIKE 9 (EPFL9/STOMAGEN) peptides, a small secreted peptide controlling stomatal density in Arabidopsis thaliana, increased stomatal density on the adaxial side of gentian leaves as well. Consequently, treated plants showed enhanced susceptibility to Sg20-35. These results indicate that stomatal density on the adaxial leaf surface is one of the major factors determining the susceptibility of gentian cultivars to S. gentianae and suggest that stomatal density control may represent an effective strategy to confer Septoria resistance.
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Mudge, Kenneth W., Kent S. Diebolt, and Thomas H. Whitlow. "Ectomycorrhizal Effect on Host Plant Response to Drought Stress." Journal of Environmental Horticulture 5, no. 4 (December 1, 1987): 183–87. http://dx.doi.org/10.24266/0738-2898-5.4.183.
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Ectomycorrhizal symbiosis affects the water relations and drought resistance of woody landscape trees and shrubs in the families Pinaceae, Fagaceae, Betulaceae, and others. It has frequently been observed that host plants mycorrhizal with drought-adapted fungi exhibit improved growth and survival during drought and more rapid recovery after rewatering than non-mycorrhizal plants or plants mycorrhizal with fungi not adapted to dry sites. Relatively few studies have addressed the effect of mycorrhizae on the physiological response of host plants to drought stress. It is suggested that some fungi confer drought tolerance to their host, while others confer drought avoidance. Possible mechanisms by which mycorrhizae influence host water relations are discussed.
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Dodds, Peter N., Ann-Maree Catanzariti, Greg J. Lawrence, and Jeffrey G. Ellis. "Avirulence proteins of rust fungi: penetrating the host - haustorium barrier." Australian Journal of Agricultural Research 58, no. 6 (2007): 512. http://dx.doi.org/10.1071/ar07055.
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The continued deployment of resistance genes in Australian wheat varieties plays a crucial role in the prevention of crop losses as a result of rust infection. Resistance genes in plants act as an immune system by recognising specific components of the rust pathogen, encoded by avirulence (Avr) genes, and initiating defence responses. Recent advances in the model rust species, Melampsora lini, which infects cultivated flax (Linum usitatissimum), has led to the identification of several avirulence genes. These encode secreted proteins that are expressed in haustoria, specialised rust structures that penetrate the host cell wall. The AvrL567, AvrM, AvrP4, and AvrP123 proteins are recognised when expressed intracellularly in resistant plants, and the AvrL567 proteins interact directly with the corresponding L5 and L6 cytoplasmic resistance proteins. These observations imply that rusts deliver a range of small effector proteins directly into the plant cytoplasm, which are likely to perform key functions in facilitating pathogen infection. The plants’ resistance protein system has evolved to recognise the presence of these effectors during infection. Selection imposed by host resistance genes has led to the diversification of flax rust Avr genes to escape recognition. Nevertheless, virulent strains of flax rust retain variant forms of the Avr genes, suggesting that they have a positive fitness value to the pathogen. This knowledge is now being applied to develop screens for avirulence and pathogenicity-related proteins from important rust pathogens of wheat.
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Lapidot, Moshe, Michael Friedmann, Meir Pilowsky, Rachel Ben-Joseph, and Shlomo Cohen. "Effect of Host Plant Resistance to Tomato yellow leaf curl virus (TYLCV) on Virus Acquisition and Transmission by Its Whitefly Vector." Phytopathology® 91, no. 12 (December 2001): 1209–13. http://dx.doi.org/10.1094/phyto.2001.91.12.1209.
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The effect that Tomato yellow leaf curl virus (TYLCV)-infected resistant tomato plants may have on virus epidemiology was studied. Four tomato genotypes that exhibit different levels of viral resistance, ranging from fully susceptible to highly resistant, served as TYLCV-infected source plants. Viral acquisition and transmission rates by white-flies following feeding on the different source plants were evaluated. TYLCV transmission rate by whiteflies that had fed on infected source plants 21 days postinoculation (DPI), shortly after the appearance of TYLCV symptoms, was negatively correlated with the level of resistance displayed by the source plant. Therefore, the higher the resistance, the lower the transmission rate. In addition, TYLCV DNA accumulation was shown to be lower in the resistant source plants compared with the susceptible plants. Whitefly survival rate, following feeding on source plants 21 DPI, was similar for all the cultivars tested. Significant differences in whitefly survival were found, however, following feeding on the infected source plants at 35 DPI; here, whitefly survival rate increased with higher levels of resistance displayed by the source plant. At 35 DPI, the susceptible plants had developed severe TYLCV disease symptoms, and transmission rates from these plants were the lowest, presumably due to the poor condition of these plants. Transmission rates from source plants displaying a medium level of resistance level were highest, with rates declining following feeding on source plants displaying higher levels of TYLCV resistance. TYLCV DNA accumulation in whiteflies following feeding on infected source plants at both 21 and 35 DPI was directly correlated with viral DNA accumulation in source plants. Results show that, in essence, the higher the resistance expressed, the less suitable the plant was as a viral source. Consequently, following acquisition from a highly resistant plant, TYLCV transmission by whiteflies will be less efficient.
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Martelli, G. P. "A critical appraisal of non conventional resistance to plant viruses." Plant Protection Science 38, SI 1 - 6th Conf EFPP 2002 (January 1, 2002): S15—S20. http://dx.doi.org/10.17221/10311-pps.
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Among natural resistance mechanisms to plant pathogens, cultivar resistance has been extensively used in plant breeding to introduce what can be defined as “conventional” resistance to a number of them, including viruses. The necessity of overcoming the constraints of genetic incompatibility, so as to widen the range of possibile use of genetic control of infectious agents, has propitiated the utilization of biotechnological procedures, whereby “non conventional” or transgenic resistance was developed. Transgenic resistance to plant viruses encompasses the identification, cloning and tranferring into the recipient host of single viral genes, which gives rise to what is known as “pathogen-derived resistance” (PDR). Of the hypothesized mechanisms underlying expression of PDR, post-transcriptional gene silencing has been most extensively investigated in recent years. Despite of the success that virus-resistant cropping of transgenic plants begins to enjoy, in Europe there is still a widespread sentiment against agricultural biotechnologies and the use of genetically modified plants in particular. Yet, experimental evidence is accumulating that, in the case of PDR, the feared risks associated with genetic trasformation are minimal, if not negligible
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Schroeder, P., W. Wilsey, A. Shelton, and E. Earle. "Sinapis Albaibrassica Oleracea Somatic Hybrids for Host Plant Resistance Against Cabbage Maggot, 1994." Arthropod Management Tests 20, no. 1 (January 1, 1995): 365. http://dx.doi.org/10.1093/amt/20.1.365.
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Abstract Cuttings from somatic hybrids of Sinapis alba (Cornell accession Alt 543) and Brassica oleracea (rapid cycling) and parents were investigated in the greenhouse for resistance to larval feeding and adult oviposition by cabbage maggot (CM). Five weeks after the cuttings were rooted, they were infested with 20 CM eggs in a completely randomized test and checked 4 weeks later for numbers and weight of CM pupae. Additional plants were confined in cages with 20 CM adults (10 male and 10 female) in completely randomized trials with choice (three plants per cage) and no-choice (individual caged plants) oviposition tests and checked 4 days later for numbers of CM eggs. The choice test was replicated 3 times and the no-choice test was replicated 6 times.
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Nagata*, Russell, Gregg Nuessly, and Heather McAuslane. "Host Plant Resistance in Valmaine Cos Lettuce to the Banded Cucumber Beetle." HortScience 39, no. 4 (July 2004): 765D—765. http://dx.doi.org/10.21273/hortsci.39.4.765d.
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Host plant resistance is a key element in a viable integrated pest management plan. Resistance to plant feeding was observed on Valmaine cos lettuce, Lactuca sativa L. to the banded cucumber beetle (BCB), Diabotica balteata (LeConte). In no-choice feeding evaluations, adult BCB contained on three week old Valmaine plants gained less weight, died and fed less than individuals contained on susceptible Tall Guzmaine cos lettuce. Individual female BCB held on Valmaine plants also did not have egg development as in those individual held on Tall Guzmaine. Based on weight gain and feeding damage F1, F2, and F3 segregation data indicates that the resistance factor is recessive in inheritance and controlled by more that one gene.
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Escudero-Martinez, Carmen, Daniel J. Leybourne, and Jorunn I. B. Bos. "Plant resistance in different cell layers affects aphid probing and feeding behaviour during non-host and poor-host interactions." Bulletin of Entomological Research 111, no. 1 (June 16, 2020): 31–38. http://dx.doi.org/10.1017/s0007485320000231.
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AbstractAphids are phloem-feeding insects that cause economic losses to crops globally. Whilst aphid interactions with susceptible plants and partially resistant genotypes have been well characterized, the interactions between aphids and non-host species are not well understood. Unravelling these non-host interactions can identify the mechanisms which contribute to plant resistance. Using contrasting aphid-host plant systems, including the broad host range pest Myzus persicae (host: Arabidopsis; poor-host: barley) and the cereal pest Rhopalosiphum padi (host: barley; non-host: Arabidopsis), we conducted a range of physiological experiments and compared aphid settling and probing behaviour on a host plant vs either a non-host or poor-host. In choice experiments, we observed that around 10% of aphids selected a non-host or poor-host plant species after 24 h. Using the Electrical Penetration Graph technique, we showed that feeding and probing behaviours differ during non-host and poor-host interactions when compared with a host interaction. In the Arabidopsis non-host interaction with the cereal pest R. padi aphids were unable to reach and feed on the phloem, with resistance likely residing in the mesophyll cell layer. In the barley poor-host interaction with M. persicae, resistance is likely phloem-based as phloem ingestion was reduced compared with the host interaction. Overall, our data suggest that plant resistance to aphids in non-host and poor-host interactions with these aphid species likely resides in different plant cell layers. Future work will take into account specific cell layers where resistances are based to dissect the underlying mechanisms and gain a better understanding of how we may improve crop resistance to aphids.
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Yuan, Erliang, Hongyu Yan, Jing Gao, Huijuan Guo, Feng Ge, and Yucheng Sun. "Increases in Genistein in Medicago sativa Confer Resistance against the Pisum Host Race of Acyrthosiphon pisum." Insects 10, no. 4 (April 1, 2019): 97. http://dx.doi.org/10.3390/insects10040097.
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Interspecific interaction with host plants have important consequences for the host race formation of herbivorous insects. Plant secondary metabolites, particularly those that are involved in host races specializing on plants, warrant the theory of host specialization. Acyrthosiphon pisum comprises various host races that adapt to different Fabaceae plants, which provides an ideal system for determining the behavioral and physiological mechanisms underlying host-adaptive diversification. The current study evaluated the effects of host transfer on population fitness, feeding behavior and the transcriptome-wide gene expression of the two host races of A. pisum, one of which was originally from Medicago sativa and the other from Pisum sativum. The results showed that the Pisum host race of A. pisum had a lower population abundance and feeding efficiency than the Medicago host race in terms of a longer penetration time and shorter duration times of phloem ingestion when fed on M. sativa. In contrast, few differences were found in the population abundance and feeding behavior of A. pisum between the two host races when fed on P. sativum. Meanwhile, of the nine candidate phenolic compounds, only genistein was significantly affected by aphid infestation; higher levels of genistein were detected in M. sativa after feeding by the Pisum host race, but these levels were reduced relative to uninfested controls after feeding by the Medicago host race, which suggested that genistein may be involved in the specialization of the aphid host race on M. sativa. Further exogenous application of genistein in artificial diets showed that the increase in genistein reduced the survival rate of the Pisum host race but had little effect on that of the Medicago host race. The transcriptomic profiles indicated that the transcripts of six genes with functions related to detoxification were up-regulated in the Pisum host race relative to the Medicago host race of A. pisum. These results suggested that the inducible plant phenolics and associated metabolic process in aphids resulted in their differential adaptations to their Fabaceae host.
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Timko, Michael P., Kan Huang, and Karolina E. Lis. "Host Resistance and Parasite Virulence in Striga–Host Plant Interactions: A Shifting Balance of Power." Weed Science 60, no. 2 (June 2012): 307–15. http://dx.doi.org/10.1614/ws-d-11-00039.1.
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The witchweeds, members of the genus Striga, are noxious and persistent pests in farmers' fields and serious constraints to crop productivity throughout Africa, India, and Southeast Asia. Among the primary hosts for Striga are the major cereals (maize, sorghum, rice, and millet) and grain legumes (cowpea) that are important food staples worldwide. The negative impact of parasitic plants on crop productivity increases globally each year, and their potential for affecting domestic agriculture looms larger as the movement of seed resources expands on a global scale. At the present time there is a limited understanding of how Striga and other parasitic plants select a suitable host and overcome the innate defense responses of the host in order to complete their life-cycle. In the grasses most reported resistance to Striga appears to be polygenic with a large genotype by environment interaction. In contrast, resistance to S. gesnerioides in cowpea is conferred by single dominant genes functioning in a race-specific manner suggesting that a gene-for-gene mechanism similar to effector-triggered immunity (ETI) described in other host–pathogen interactions is likely operating in these parasite-host associations. A hallmark of ETI is the direct or indirect recognition of parasite-derived avirulence (Avr) factors and other effectors that interfere with plant innate immunity by host sensors (or R proteins) leading to activation of defense responses. The recent cloning and functional characterization of a race-specific R gene from cowpea encoding a canonical coiled-coil (CC)-nucleotide binding site (NBS)-leucine-rich repeat (LRR) type R-protein opens the door for further exploration of the mechanism of host resistance and provides a focal point for studies aimed at uncovering the molecular and genetic factors underlying parasite virulence and host selection. The potential for the development of novel strategies for parasite control and eradication based on parasite virulence factors is discussed.
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Mou, Beiquan, and Yong-Biao Liu. "Host Plant Resistance to Leafminers in Lettuce." Journal of the American Society for Horticultural Science 129, no. 3 (May 2004): 383–88. http://dx.doi.org/10.21273/jashs.129.3.0383.
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Leafminer (Liriomyza spp.) is a major insect pest of many important agricultural crops including lettuce (Lactuca sativa L.). The goals of this study were to evaluate lettuce genotypes for resistance to leafminers and to estimate the heritabilities of leafminer-resistant traits in the field, to examine the association among different resistant traits, and to study the mechanism of leafminer resistance in lettuce. Seventy-eight lettuce accessions and 232 F2 plants of crosses were evaluated for leafminer stings and the production of pupae and flies in the field in 2001 and 2002, and resistant genotypes were subjected to no-choice test. Wild species (Lactuca serriola L., L. saligna L., and L. virosa L.) had significantly fewer stings than cultivated lettuces. Among cultivated lettuces, sting densities were lowest on leaf lettuce and highest on romaine types. The sting results from the field were highly correlated with the results from insect cages (r = 0.770 and 0.756 for 2001 and 2002 tests, respectively), suggesting that a cage test can be used to screen for resistance in the field. Broad-sense heritability estimates for stings per unit leaf area in the field were 81.6% and 67.4% for 2001 and 2002 tests, respectively. The number of pupae produced per plant or per leaf was moderately correlated with sting density but was not correlated with leaf weight. Results suggest that both antixenosis and antibiosis exist in lettuce germplasm and resistant genotypes from choice tests remain resistant under no-choice conditions. These findings suggest that genetic improvement of cultivated lettuce for leafminer resistance is feasible.
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Gallois, Jean-Luc, Benoît Moury, and Sylvie German-Retana. "Role of the Genetic Background in Resistance to Plant Viruses." International Journal of Molecular Sciences 19, no. 10 (September 20, 2018): 2856. http://dx.doi.org/10.3390/ijms19102856.
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In view of major economic problems caused by viruses, the development of genetically resistant crops is critical for breeders but remains limited by the evolution of resistance-breaking virus mutants. During the plant breeding process, the introgression of traits from Crop Wild Relatives results in a dramatic change of the genetic background that can alter the resistance efficiency or durability. Here, we conducted a meta-analysis on 19 Quantitative Trait Locus (QTL) studies of resistance to viruses in plants. Frequent epistatic effects between resistance genes indicate that a large part of the resistance phenotype, conferred by a given QTL, depends on the genetic background. We next reviewed the different resistance mechanisms in plants to survey at which stage the genetic background could impact resistance or durability. We propose that the genetic background may impair effector-triggered dominant resistances at several stages by tinkering the NB-LRR (Nucleotide Binding-Leucine-Rich Repeats) response pathway. In contrast, effects on recessive resistances by loss-of-susceptibility—such as eIF4E-based resistances—are more likely to rely on gene redundancy among the multigene family of host susceptibility factors. Finally, we show how the genetic background is likely to shape the evolution of resistance-breaking isolates and propose how to take this into account in order to breed plants with increased resistance durability to viruses.
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Tellier, Aurélien, and James K. M. Brown. "The Relationship of Host-Mediated Induced Resistance to Polymorphism in Gene-for-Gene Relationships." Phytopathology® 98, no. 1 (January 2008): 128–36. http://dx.doi.org/10.1094/phyto-98-1-0128.
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Gene-for-gene relationships are a common feature of plant-parasite interactions. Polymorphism at host resistance and parasite avirulence loci is maintained if there is negative, direct frequency-dependent selection on alleles of either gene. More specifically, selection of this kind is generated when the disease is polycyclic with frequent auto-infection. When an incompatible interaction occurs between a resistant host and an avirulent parasite, systemic defenses are triggered, rendering the plant more resistant to a later attack by another parasite. However, induced resistance (IR) incurs a fitness cost to the plant. Here, the effect of IR on polymorphism in gene-for-gene interactions is investigated. First, in an infinite population model in which parasites have two generations per host generation, increasing the fitness cost of IR increases selection for susceptible plants at low disease severity, while increasing the effectiveness of IR against further parasite attacks enhances selection for resistant plants at high disease severity. This reduces the possibility of polymorphism being maintained in host and parasite populations. In finite population models, the number of plants varies over time as a function of the disease burden of the population. Polymorphism in gene-for-gene relationships is then more stable at high disease prevalence and severity if IR reactions are more costly when there is competition for resources between plants.
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Ors, M., B. Randoux, A. Siah, G. Couleaud, C. Maumené, K. Sahmer, P. Reignault, P. Halama, and S. Selim. "A Plant Nutrient- and Microbial Protein-Based Resistance Inducer Elicits Wheat Cultivar-Dependent Resistance Against Zymoseptoria tritici." Phytopathology® 109, no. 12 (December 2019): 2033–45. http://dx.doi.org/10.1094/phyto-03-19-0075-r.
Full textAbstract:
The induction of plant defense mechanisms by resistance inducers is an attractive and innovative alternative to reduce the use of fungicides on wheat against Zymoseptoria tritici, the responsible agent of Septoria tritici blotch (STB). Under controlled conditions, we investigated the resistance induction in three wheat cultivars with different susceptible levels to STB as a response to a treatment with a sulfur, manganese sulfate, and protein-based resistance inducer (NECTAR Céréales). While no direct antigermination effect of the product was observed in planta, more than 50% reduction of both symptoms and sporulation were recorded on the three tested cultivars. However, an impact of the wheat genotype on resistance induction was highlighted, which affects host penetration, cell colonization, and the production of cell-wall degrading enzymes by the fungus. Moreover, in the most susceptible cultivar Alixan, the product upregulated POX2, PAL, PR1, and GLUC gene expression in both noninoculated and inoculated plants and CHIT2 in noninoculated plants only. In contrast, defense responses induced in Altigo, the most resistant cultivar, seem to be more specifically mediated by the phenylpropanoid pathway in noninoculated as well as inoculated plants, since PAL and CHS were most specifically upregulated in this cultivar. In Premio, the moderate resistant cultivar, NECTAR Céréales elicits mainly the octadecanoid pathway, via LOX and AOS induction in noninoculated plants. We concluded that this complex resistance-inducing product protects wheat against Z. tritici by stimulating the cultivar-dependent plant defense mechanisms.
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Nechols, James R., Ashley R. Hough, David C. Margolies, John R. Ruberson, Brian P. McCornack, Brett K. Sandercock, and Leigh Murray. "Effect of Temperature on Plant Resistance to Arthropod Pests." Environmental Entomology 49, no. 3 (April 13, 2020): 537–45. http://dx.doi.org/10.1093/ee/nvaa033.
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Abstract Temperature has a strong influence on the development, survival, and fecundity of herbivorous arthropods, and it plays a key role in regulating the growth and development of their host plants. In addition, temperature affects the production of plant secondary chemicals as well as structural characteristics used for defense against herbivores. Thus, temperature has potentially important implications for host plant resistance. Because temperature directly impacts arthropod pests, both positively and negatively, distinguishing direct effects from indirect effects mediated through host plants poses a challenge for researchers and practitioners. A more comprehensive understanding of how temperature affects plant resistance specifically, and arthropod pests in general, would lead to better predictions of pest populations, and more effective use of plant resistance as a management tactic. Therefore, the goals of this paper are to 1) review and update knowledge about temperature effects on plant resistance, 2) evaluate alternative experimental approaches for separating direct from plant-mediated indirect effects of temperature on pests, including benefits and limitations of each approach, and 3) offer recommendations for future research.
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Dodds, Peter, and Peter Thrall. "Recognition events and host–pathogen co-evolution in gene-for-gene resistance to flax rust." Functional Plant Biology 36, no. 5 (2009): 395. http://dx.doi.org/10.1071/fp08320.
Full textAbstract:
The outcome of infection of individual plants by pathogenic organisms is governed by complex interactions between the host and pathogen. These interactions are the result of long-term co-evolutionary processes involving selection and counterselection between plants and their pathogens. These processes are ongoing, and occur at many spatio-temporal scales, including genes and gene products, cellular interactions within host individuals, and the dynamics of host and pathogen populations. However, there are few systems in which host–pathogen interactions have been studied across these broad scales. In this review, we focus on research to elucidate the structure and function of plant resistance and pathogen virulence genes in the flax-flax rust interaction, and also highlight complementary co-evolutionary studies of a related wild plant–pathogen interaction. The confluence of these approaches is beginning to shed new light on host–pathogen molecular co-evolution in natural environments.
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Romero, A. M., and D. F. Ritchie. "Systemic Acquired Resistance Delays Race Shifts to Major Resistance Genes in Bell Pepper." Phytopathology® 94, no. 12 (December 2004): 1376–82. http://dx.doi.org/10.1094/phyto.2004.94.12.1376.
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The lack of durability of host plant disease resistance is a major problem in disease control. Genotype-specific resistance that involves major resistance (R) genes is especially prone to failure. The compatible (i.e., disease) host-pathogen interaction with systemic acquired resistance (SAR) has been studied extensively, but the incompatible (i.e., resistant) interaction less so. Using the pepper-bacterial spot (causal agent, Xanthomonas axonopodis pv. vesicatoria) pathosystem, we examined the effect of SAR in reducing the occurrence of race-change mutants that defeat R genes in laboratory, greenhouse, and field experiments. Pepper plants carrying one or more R genes were sprayed with the plant defense activator acibenzolar-S-methyl (ASM) and challenged with incompatible strains of the pathogen. In the greenhouse, disease lesions first were observed 3 weeks after inoculation. ASM-treated plants carrying a major R gene had significantly fewer lesions caused by both the incompatible (i.e., hypersensitive) and compatible (i.e., disease) responses than occurred on nonsprayed plants. Bacteria isolated from the disease lesions were confirmed to be race-change mutants. In field experiments, there was a delay in the detection of race-change mutants and a reduction in disease severity. Decreased disease severity was associated with a reduction in the number of race-change mutants and the suppression of disease caused by the race-change mutants. This suggests a possible mechanism related to a decrease in the pathogen population size, which subsequently reduces the number of race-change mutants for the selection pressure of R genes. Thus, inducers of SAR are potentially useful for increasing the durability of genotype-specific resistance conferred by major R genes.
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Maris, P. C., N. N. Joosten, D. Peters, and R. W. Goldbach. "Thrips Resistance in Pepper and Its Consequences for the Acquisition and Inoculation of Tomato spotted wilt virus by the Western Flower Thrips." Phytopathology® 93, no. 1 (January 2003): 96–101. http://dx.doi.org/10.1094/phyto.2003.93.1.96.
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Different levels of thrips resistance were found in seven Capsicum accessions. Based on the level of feeding damage, host preference, and host suitability for reproduction, a thrips susceptible and a resistant accession were selected to study their performance as Tomato spotted wilt virus (TSWV) sources and targets during thrips-mediated virus transmission. Vector resistance did not affect the virus acquisition efficiency in a broad range of acquisition access periods. Inoculation efficiency was also not affected in short inoculation periods, but was significantly lower on plants of the thrips resistant accession during longer inoculation access periods. Under the experimental conditions used, the results obtained show that transmission of TSWV is little affected by vector resistance. However, due to a lower reproduction rate on resistant plants and a lower preference of thrips for these plants, beneficial effects of vector resistance might be expected under field conditions.
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Pagán, Israel, and Fernando García-Arenal. "Tolerance of Plants to Pathogens: A Unifying View." Annual Review of Phytopathology 58, no. 1 (August 25, 2020): 77–96. http://dx.doi.org/10.1146/annurev-phyto-010820-012749.
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Increasing evidence indicates that tolerance is a host defense strategy against pathogens as widespread and successful as resistance. Since the concept of tolerance was proposed more than a century ago, it has been in continuous evolution. In parallel, our understanding of its mechanistic bases and its consequences for host and pathogen interactions, ecology, and evolution has grown. This review aims at summarizing the conceptual changes in the meaning of tolerance inside and outside the field of phytopathology, emphasizing difficulties in demonstrating and quantifying this trait. We also discuss evidence of tolerance and current knowledge on its genetic regulation, mechanisms, and role in host–pathogen coevolution, highlighting common patterns across hosts and pathogens. We hope that this comprehensive review attracts more plant pathologists to the study of this key plant defense response.
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Harris, M. O., T. P. Freeman, J. A. Moore, K. G. Anderson, S. A. Payne, K. M. Anderson, and O. Rohfritsch. "H-Gene-Mediated Resistance to Hessian Fly Exhibits Features of Penetration Resistance to Fungi." Phytopathology® 100, no. 3 (March 2010): 279–89. http://dx.doi.org/10.1094/phyto-100-3-0279.
Full textAbstract:
Features shared by host-specific phytophagous insects and biotrophic plant pathogens include gene-for-gene interactions and the ability to induce susceptibility in plants. The Hessian fly shows both. To protect against Hessian fly, grasses have H genes. Avirulent larvae die on H-gene-containing resistant plants but the cause of death is not known. Imaging techniques were used to examine epidermal cells at larval attack sites, comparing four resistant wheat genotypes (H6, H9, H13, and H26) to a susceptible genotype. Present in both resistant and susceptible plants attacked by larvae were small holes in the tangential cell wall, with the size of the holes (0.1 μm in diameter) matching that of the larval mandible. Absent from attacked resistant plants were signs of induced susceptibility, including nutritive tissue and ruptured cell walls. Present in attacked resistant plants were signs of induced resistance, including cell death and fortification of the cell wall. Both presumably limit larval access to food, because the larva feeds on the leaf surface by sucking up liquids released from ruptured cells. Resistance was associated with several subcellular responses, including elaboration of the endoplasmic reticulum–Golgi complex and associated vesicles. Similar responses are observed in plant resistance to fungi, suggesting that “vesicle-associated penetration resistance” also functions against insects.
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Panchal, Balaji M., and Manvendra S. Kachole. "Rearing of Chilo partellus (Swinhoe) (Lepidoptera: Pyralidae) on artificial diet and its use in resistance screening." South Asian Journal of Experimental Biology 2, no. 4 (September 26, 2012): 190–95. http://dx.doi.org/10.38150/sajeb.2(4).p190-195.
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Chilo partellus is considered to be among the most damaging pests of sorghum crop throughout the world. Insects are reared in the laboratory on artificial diets for various purposes, namely for biological control, host and nonâ€host plant resistance and development of new artificial diets. The growth and development of Sorghum bicolor, C. partellus (Lepidoptera: Pyralidae) on six host plants and non host plants (five plant gum extracts and six tuber extracts PIs) was compared in the laboratory. Insect larval growth was significantly faster on 30% casein with 70% Zea mays in artificial diet. There was a significant variation in larval mortality, malformed pupae andpupal weights. 80% larval mortality was observed in Acacia leucophloea PIs containing diet, and 70 and 60% larval mortality in Ipomoea batatas and Mangifera indica PIâ€containing diet fed, respectively.
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Fernández-Falcón, Marino, Andres A. Borges, and Andres Borges-Pérez. "Induced resistance to Fusarium wilt of banana by exogenous applications of indoleacetic acid." Phytoprotection 84, no. 3 (June 15, 2004): 149–53. http://dx.doi.org/10.7202/008492ar.
Full textAbstract:
Fusarium wilt of banana (Panama disease), caused by Fusarium oxysporum f.sp. cubense, is a soilborne systemic disease which occludes host vascular system. We report here two experiments on resistance induction with banana plants (cv. Dwarf Cavendish) carried out in glass greenhouse with different indoleacetic acid treatments, which are capable of inducing resistance to Panama disease. The results obtained in these experiments suggest that the exogenous application of indoleacetic acid to banana plants induce resistance to Panama disease and that the resistance induction is more effective when performed using low doses and frequent applications. This work seems to confirm the role played by indoleacetic acid according to Beckman’s models as, one of the major defence factors of the host plant in vascular wilt diseases.
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Lutova, Ludmila A., and Galina M. Shumilina. "Metabolites of plants and their role in resistance to phytopathogens." Ecological genetics 1, no. 1 (January 15, 2003): 47–58. http://dx.doi.org/10.17816/ecogen1047-58.
Full textAbstract:
Plant disease resistance is a complex reaction where biochemical peculiarities play a major role. The review is focused on two strategies of improvement of plant resistance to some groups of pathogens. The first strategy is based on a dependence of pathogens on certain plant compounds, i.e. sterols. The lack of these metabolites in a host plant repress pathogen development and reproduction. Here we present modern data on sterol metabolism and their functions in plants as well as description of known plant sterol mutants. The other way to improve plant resistance is to stimulate biosynthesis of secondary metabolites with antimicrobial activity. The roles of phytoalexins and steroid glycoalcoloids in the development of plant resistance is described here on certain examples
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Hettenhausen, Christian, Juan Li, Huifu Zhuang, Huanhuan Sun, Yuxing Xu, Jinfeng Qi, Jingxiong Zhang, et al. "Stem parasitic plant Cuscuta australis (dodder) transfers herbivory-induced signals among plants." Proceedings of the National Academy of Sciences 114, no. 32 (July 24, 2017): E6703—E6709. http://dx.doi.org/10.1073/pnas.1704536114.
Full textAbstract:
Cuscuta spp. (i.e., dodders) are stem parasites that naturally graft to their host plants to extract water and nutrients; multiple adjacent hosts are often parasitized by one or more Cuscuta plants simultaneously, forming connected plant clusters. Metabolites, proteins, and mRNAs are known to be transferred from hosts to Cuscuta, and Cuscuta bridges even facilitate host-to-host virus movement. Whether Cuscuta bridges transmit ecologically meaningful signals remains unknown. Here we show that, when host plants are connected by Cuscuta bridges, systemic herbivory signals are transmitted from attacked plants to unattacked plants, as revealed by the large transcriptomic changes in the attacked local leaves, undamaged systemic leaves of the attacked plants, and leaves of unattacked but connected hosts. The interplant signaling is largely dependent on the jasmonic acid pathway of the damaged local plants, and can be found among conspecific or heterospecific hosts of different families. Importantly, herbivore attack of one host plant elevates defensive metabolites in the other systemic Cuscuta bridge-connected hosts, resulting in enhanced resistance against insects even in several consecutively Cuscuta-connected host plants over long distances (> 100 cm). By facilitating plant-to-plant signaling, Cuscuta provides an information-based means of countering the resource-based fitness costs to their hosts.