Academic literature on the topic 'Cotton Molecular genetics'
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Journal articles on the topic "Cotton Molecular genetics"
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Farahani, Farah, Masoud Sheidai, and Fahimeh Koohdar. "Genetic finger printing of cotton cultivars by ISSR molecular markers." Genetika 50, no. 2 (2018): 627–34. http://dx.doi.org/10.2298/gensr1802627f.
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Gossypium hirsutum is one of the main tetraploid cotton species that is cultivated throughout the world. Due to continuous selection of cotton cultivars for specific agronomic traits, the genetic variability within the cultivars decrease that lead to genetic erosion. To tackle the problem of reduced genetic variability, we should track all available genetic diversity within cotton germplasm and use them for inter-specific and intra-specific hybridization and produce new elite cotton cultivars. Therefore, the present study used ISSR molecular markers to illustrate genetic variability in 13 tetraploid cotton genotypes (Gossypium hirsutum L.) and to categorize these genotypes based on genetic affinity. 65 cotton plants were studied. The results identified private bands in the studied genotypes, while Network and STRUCTURE analyses of molecular data obtained grouped the genotypes with genetic affinity together. Some of the genotypes differed in their genetic content from the others; therefore, studying the genetic and agronomic variability within available cultivars is very important and produced data to broaden the gene pool for planning further hybridization in cotton.
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Grover, Corrinne E., Mengqiao Pan, Daojun Yuan, Mark A. Arick, Guanjing Hu, Logan Brase, David M. Stelly, et al. "The Gossypium longicalyx Genome as a Resource for Cotton Breeding and Evolution." G3: Genes|Genomes|Genetics 10, no. 5 (March 2, 2020): 1457–67. http://dx.doi.org/10.1534/g3.120.401050.
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Cotton is an important crop that has made significant gains in production over the last century. Emerging pests such as the reniform nematode have threatened cotton production. The rare African diploid species Gossypium longicalyx is a wild species that has been used as an important source of reniform nematode immunity. While mapping and breeding efforts have made some strides in transferring this immunity to the cultivated polyploid species, the complexities of interploidal transfer combined with substantial linkage drag have inhibited progress in this area. Moreover, this species shares its most recent common ancestor with the cultivated A-genome diploid cottons, thereby providing insight into the evolution of long, spinnable fiber. Here we report a newly generated de novo genome assembly of G. longicalyx. This high-quality genome leveraged a combination of PacBio long-read technology, Hi-C chromatin conformation capture, and BioNano optical mapping to achieve a chromosome level assembly. The utility of the G. longicalyx genome for understanding reniform immunity and fiber evolution is discussed.
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Andres, Ryan J., Daryl T. Bowman, Don C. Jones, and Vasu Kuraparthy. "Major Leaf Shapes of Cotton: Genetics and Agronomic Effects in Crop Production." Journal of Cotton Science 20, no. 4 (2016): 330–40. http://dx.doi.org/10.56454/mnrs4737.
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There exist four major leaf shape alleles in tetraploid cotton: normal, sub-okra/Sea-Island, okra, and super-okra. This allelic series has long served as a model genetic locus both in cotton and the broader leaf development research community. Over the years, numerous studies have attributed various production advantages to specific leaf shapes. The objective of this study was to provide a comprehensive review of this literature in order to provide a definitive report on the true benefits of these leaf shapes. In addition, a history of the genetic dissection of the major leaf shape locus was compiled. Leaf shape was found to have consistent effects on boll rot resistance, earliness, flowering rate, chemical spray penetration, lint trash, and yield. Reported effects on various insect resistances, photosynthetic rate, water use efficiency, and fiber quality were not consistent across studies. An ideal cotton cultivar would produce normal leaves up until the point canopy closure is obtained and then it would switch over to an open canopy of okra or super okra. Major leaf shapes of Upland cotton are a multiple allelic series of a single incompletely dominant genetic locus L-D1 on chromosome 15-D1 (Chr15). Genetic analysis studies have precisely mapped the major effect leaf shape genes in cotton and deciphered the causal nucleotide and gene expression changes leading to leaf shape phenotypic diversity in cotton. Recent advances in understanding the molecular processes underlying leaf shape phenotypic changes could help open new avenues for developing cotton cultivars with ideal leaf shape and could enhance sustainable and profitable cotton production.
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Ji, Yuanfu, Dwaine A. Raska, M. Nurul Islam-Faridi, Charles F. Crane, Michael S. Zwick, Robert E. Hanson, H. James Price, David M. Stelly, and Thomas D. McKnight. "Use of meiotic FISH for identification of a new monosome in Gossypium hirsutum L." Genome 40, no. 1 (February 1, 1997): 34–40. http://dx.doi.org/10.1139/g97-005.
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The extensive use of molecular cytogenetics in human genetics and clinical diagnostics indicates that analogous applications in plants are highly feasible. One sort of application would be the identification of new aneuploids, which traditionally involves either direct karyotypic identification, which is feasible in only a few plant species, or tests with markers (cytogenetic, genetic, or molecular), which require sexual hybridization and at least one subsequent seed or plant generation. We have used meiotic fluorescence in situ hybridization (FISH) to analyze a new monosome of cotton (Gossypium hirsutum L., 2n = 4x = 52, 2(AD)1) that had a phenotype which seemed to be distinct from monosomes in the Cotton Cytogenetic Collection. Painting with A2-genome DNA revealed the monosome's D-subgenome origin. DAPI–PI staining showed that the monosome carries a major NOR, delimiting it to the major NOR-bearing chromosomes of the D-subgenome, i.e., 16 or 23. Dual-color FISH with 5S and 18S–28S rDNAs indicated that the monosome contains separate major clusters of each of these two tandemly repeated rDNA elements, thus delimiting the monosome to chromosome 23, for which the Cotton Cytogenetic Collection has previously been devoid of any sort of deficiency. Of the 26 chromosomes in the cotton genome, the Collection now provides coverage for 16 (70%) in the form of monosomy, and 20 (77%) in the form of monosomy and (or) telosomy. Use of molecular cytogenetic methods to identify a new plant aneuploid in cotton exemplifies the fact that a physicochemical karyotypic chromosome identification system is not required a priori for application of new molecular cytogenetic methods, thus indicating their potential applicability to nearly all plant species.Key words: fluorescence in situ hybridization, monosome, aneuploid, Gossypium hirsutum.
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Becerra Lopez-Lavalle, L. A., B. Matheson, and C. L. Brubaker. "A genetic map of an Australian wild Gossypium C genome and assignment of homoeologies with tetraploid cultivated cotton." Genome 54, no. 9 (September 2011): 779–94. http://dx.doi.org/10.1139/g11-037.
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Genetic diversity for traits such as fibre quality or disease resistance to microorganisms is limited in the elite cotton germplasm; consequently, cotton breeders are looking for novel alleles in the secondary or even in the tertiary gene pools. The wild Australian Gossypium species (tertiary gene pool) represent an alternative source of novel alleles. However, to use these species efficiently, enabling tools are required. Chromosome-specific molecular markers are particularly useful tools to track the transmission of this exotic genetic material into the cultivated cotton during introgression. In this study, we report the construction of a genetic linkage map of the Australian wild C-genome species Gossypium sturtianum. The map, based on an F2 population of 114 individuals, contains 291 AFLP loci. The map spans 1697 cM with an average distance of 5.8 cM between markers. To associate C-genome chromosomes with the A and D subgenomes of cultivated cotton, 29 SSR and RFLP–STS markers were assigned to chromosomes using cultivated cotton mapped marker information. Polymorphisms were revealed by 51 AFLP primer combinations and 38 RFLP–STS and 115 SSR cotton mapped markers. The utility of transferring RFLP–STS and SSR cotton mapped markers to other Gossypium species shows the usefulness of a comparative approach as a source of markers and for aligning the genetic map of G. sturtianum with the cultivated species in the future. This also indicates that the overall structure of the G. sturtianum linkage groups is similar to that of the A and D subgenomes of cotton at the gross structural level. Applications of the map for the Australia wild C-genome species and cotton breeding are discussed.
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Ahmed, Haris, Mian Faisal Nazir, Zhoe Pan, Wenfang Gong, Muhammad Shahid Iqbal, Shoupu He, and Xiongming Du. "Genotyping by Sequencing Revealed QTL Hotspots for Trichome-Based Plant Defense in Gossypium hirsutum." Genes 11, no. 4 (March 28, 2020): 368. http://dx.doi.org/10.3390/genes11040368.
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Cotton possesses certain physical features, including leaf and stem trichomes that help plants deter damage caused by insect pests, and to some extent, from abiotic factors as well. Among those features, trichomes (pubescence) hold a special place as a first line of defense and a managemental tool against sucking insect pests of cotton. Different insect pests of cotton (whiteflies, aphids, jassids, and boll weevil) severely damage the yield and quality of the crop. Likewise, whiteflies, aphids, jassids, and other insect pests are considered as potential carriers for cotton leaf curl viruses and other diseases. Genotyping by sequencing (GBS) study was conducted to understand and explore the genomic regions governing hairy (Pubescence) leaves and stem phenotypes. A total of 224 individuals developed from an intraspecific cross (densely haired cotton (Liaoyang duomao mian) × hairless cotton (Zong 128)) and characterized phenotypically for leaf and stem pubescence in different environments. Here we identify and report significant QTLs (quantitative trait loci) associated with leaf and stem pubescence, and the response of plant under pest (aphid) infestation. Further, we identified putative genes colocalized on chromosome A06 governing mechanism for trichome development and host–pest interaction. Our study provides a comprehensive insight into genetic architecture that can be employed to improve molecular marker-assisted breeding programs aimed at developing biotic (insect pests) resilient cotton cultivars.
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Zheng, Juyun, Zeliang Zhang, Yajun Liang, Zhaolong Gong, Nala Zhang, Allah Ditta, Zhiwei Sang, Junduo Wang, and Xueyuan Li. "Whole Transcriptome Sequencing Reveals Drought Resistance-Related Genes in Upland Cotton." Genes 13, no. 7 (June 27, 2022): 1159. http://dx.doi.org/10.3390/genes13071159.
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China, particularly the cotton-growing province of Xinjiang, is experiencing acute agricultural water shortages, stifling the expansion of the cotton sector. Discovering drought resistance genes in cotton and generating high-quality, drought-resistant cotton varieties through molecular breeding procedures are therefore critical to the cotton industry’s success. The drought-resistant cotton variety Xinluzhong No. 82 and the drought-sensitive cotton variety Kexin No. 1 were utilised in this study to uncover a batch of drought-resistant candidate genes using whole transcriptome sequencing. The following are the key research findings: A competing endogenous RNA network (ceRNA) was built using complete transcriptional sequencing to screen the core genes in the core pathway, and two drought-related candidate genes were discovered. It was found that γ-aminobutyric acid aminotransferase (GhGABA-T, Gohir.A11G156000) was upregulated at 0 h vs. 12 h and downregulated at 12 h vs. 24 h. L-Aspartate oxidase (GhAO, Gohir.A07G220600) was downregulated at 0 h vs. 12 h and upregulated at 12 h vs. 24 h. GABA-T is analogous to a pyridoxal phosphate-dependent transferase superfamily protein (POP2) in Arabidopsis thaliana and influences plant drought resistance by controlling γ-aminobutyric acid (GABA) concentration. The analogue of GhAO in A. thaliana is involved in the early steps of nicotinamide adenine dinucleotide (NAD) production as well as in plant antioxidant responses. This study revealed that gene expression regulatory networks can be used for rapid screening of reliable drought resistance genes and then utilised to validate gene function.
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Smith, W. E. "Therese Cotton." Biospectroscopy 5, no. 1 (1999): 1–2. http://dx.doi.org/10.1002/(sici)1520-6343(1999)5:1<1::aid-bspy1>3.0.co;2-6.
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Grover, Corrinne E., Mi-Jeong Yoo, Meng Lin, Matthew D. Murphy, David B. Harker, Robert L. Byers, Alexander E. Lipka, et al. "Genetic Analysis of the Transition from Wild to Domesticated Cotton (Gossypium hirsutum L.)." G3: Genes|Genomes|Genetics 10, no. 2 (December 16, 2019): 731–54. http://dx.doi.org/10.1534/g3.119.400909.
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The evolution and domestication of cotton is of great interest from both economic and evolutionary standpoints. Although many genetic and genomic resources have been generated for cotton, the genetic underpinnings of the transition from wild to domesticated cotton remain poorly known. Here we generated an intraspecific QTL mapping population specifically targeting domesticated cotton phenotypes. We used 466 F2 individuals derived from an intraspecific cross between the wild Gossypium hirsutum var. yucatanense (TX2094) and the elite cultivar G. hirsutum cv. Acala Maxxa, in two environments, to identify 120 QTL associated with phenotypic changes under domestication. While the number of QTL recovered in each subpopulation was similar, only 22 QTL were considered coincident (i.e., shared) between the two locations, eight of which shared peak markers. Although approximately half of QTL were located in the A-subgenome, many key fiber QTL were detected in the D-subgenome, which was derived from a species with unspinnable fiber. We found that many QTL are environment-specific, with few shared between the two environments, indicating that QTL associated with G. hirsutum domestication are genomically clustered but environmentally labile. Possible candidate genes were recovered and are discussed in the context of the phenotype. We conclude that the evolutionary forces that shape intraspecific divergence and domestication in cotton are complex, and that phenotypic transformations likely involved multiple interacting and environmentally responsive factors.
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Li, Shengmei, Shiwei Geng, Bo Pang, Jieyin Zhao, Yajie Huang, Cun Rui, Jinxin Cui, Yang Jiao, Ru Zhang, and Wenwei Gao. "Revealing Genetic Differences in Fiber Elongation between the Offspring of Sea Island Cotton and Upland Cotton Backcross Populations Based on Transcriptome and Weighted Gene Coexpression Networks." Genes 13, no. 6 (May 26, 2022): 954. http://dx.doi.org/10.3390/genes13060954.
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Fiber length is an important indicator of cotton fiber quality, and the time and rate of cotton fiber cell elongation are key factors in determining the fiber length of mature cotton. To gain insight into the differences in fiber elongation mechanisms in the offspring of backcross populations of Sea Island cotton Xinhai 16 and land cotton Line 9, we selected two groups with significant differences in fiber length (long-fiber group L and short-fiber group S) at different fiber development stages 0, 5, 10 and 15 days post-anthesis (DPA) for transcriptome comparison. A total of 171.74 Gb of clean data was obtained by RNA-seq, and eight genes were randomly selected for qPCR validation. Data analysis identified 6055 differentially expressed genes (DEGs) between two groups of fibers, L and S, in four developmental periods, and gene ontology (GO) term analysis revealed that these DEGs were associated mainly with microtubule driving, reactive oxygen species, plant cell wall biosynthesis, and glycosyl compound hydrolase activity. Kyoto encyclopedia of genes and genomes (KEGG) pathway analysis indicated that plant hormone signaling, mitogen-activated protein kinase (MAPK) signaling, and starch and sucrose metabolism pathways were associated with fiber elongation. Subsequently, a sustained upregulation expression pattern, profile 19, was identified and analyzed using short time-series expression miner (STEM). An analysis of the weighted gene coexpression network module uncovered 21 genes closely related to fiber development, mainly involved in functions such as cell wall relaxation, microtubule formation, and cytoskeletal structure of the cell wall. This study helps to enhance the understanding of the Sea Island–Upland backcross population and identifies key genes for cotton fiber development, and these findings will provide a basis for future research on the molecular mechanisms of fiber length formation in cotton populations.
Dissertations / Theses on the topic "Cotton Molecular genetics"
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Local, Andrea. "Cloning of Carbonic Anhydrase from Cotton (Gossypium hirsutum L.)." Thesis, University of North Texas, 1998. https://digital.library.unt.edu/ark:/67531/metadc279044/.
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Carbonic anhydrase is a ubiquitous zinc-metalloenzyme that catalyzes the interconversion of carbon dioxide and carbonate and has been found to play a wide range of roles in animals, plants and bacteria. Cotton genomic and cDNA libraries were screened for the plastidial isoform of carbonic anhydrase. The nucleotide sequences of two 1.2 Kb partial cDNA clones were determined. These clones exhibit high homology to carbonic anhydrases from other dicot plants and possess all the expected peptide motifs. For example, serine and threonine rich chloroplastic targeting peptide and conserved zinc binding residues are both present. These clones were utilized to isolate two carbonic anhydrase genes that were shown to encode different isoforms by PCR and RFLP analysis.
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Nampaisansuk, Mongkol. "Molecular cloning and analysis of the genes for cotton palmitoyl-acyl carrier protein thioesterase (PATE) and Δ-12 fatty acid desaturase (FAD2-3) and construction of sense and anti-sense PATE plasmid vectors for altering oilseed composition of transgenic cotton plants." Thesis, University of North Texas, 2002. https://digital.library.unt.edu/ark:/67531/metadc3123/.
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A cotton PATE cDNA clone has a 1.7-kb insert with an coding region for 410 amino acids, lacking codons for the three N-terminal amino acids. The predicted amino acid sequence of the PATE preprotein has a characteristic stromal-targeting domain and a 63% identity to the Arabidopsis FatB1 thioesterase sequence. A cotton genomic clone containing a 17.4-kb DNA segment was found to encompass a palmitoyl-ACP thioesterase (FatB1) gene. The gene spans 3.6 kb with six exons and five introns. The six exons are identical in nucleotide sequence to the open reading frame of the corresponding cDNA, and would encode a preprotein of 413 amino acids. The preprotein is identified as a FatB thioesterase from its deduced amino acid sequence similarity to those of other FatB thioesterase preproteins. A 5'-flanking region of 914 bp was sequenced, with the potential promoter/enhancer elements including basic helix-loop-helix elements (E box). Alkaline blot hybridization of cotton genomic DNA suggests the presence at least two FatB1 thioesterase genes in cotton. Four plasmid constructs for both constitutive and seed-specific anti-sense RNA suppression and gene-transgene co- suppression of PATE gene expression were successfully generated. Two overlapping cotton genomic clones were found to encompass a Δ-12 fatty acid desaturase (FAD2-3) gene. The continuous FAD2-3 coding region is 1,155 bp and would encode a protein of 384 amino acids. The FAD2-3 gene has one large intron of 2,967 bp entirely within its 5'-untranslated region. Several potential promoter/enhancer elements, including several light responsive motifs occur in the 5'-flanking region. Yeast cells transformed with a plasmid construct containing the cotton FAD2-3 coding region accumulate an appreciable amount of linoleic acid (18:2), not normally present in wild-type yeast cells, indicating that the gene encodes a functional FAD2 enzyme.
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Pavinato, Vitor Antonio Corrêa. "Variabilidade e estrutura genética de populações de Alabama argillacea (Hüeb.) (Lepidoptera: Noctuidae) no Brasil: subsídios para o manejo da resistência à toxina Cry1Ac em algodão geneticamente modificado." Universidade de São Paulo, 2010. http://www.teses.usp.br/teses/disponiveis/11/11146/tde-17032010-141038/.
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Algodão geneticamente modificado que expressa a toxina Cry1Ac de Bacillus thuringiensis Berliner tem sido plantado no Brasil desde 2006. Entre as pragas-alvo da tecnologia, Alabama argillacea (Hüeb.) é uma espécie monófoga e apresenta alto potencial de risco de evolução da resistência. Para a implantação de um programa de manejo da resistência de A. argillacea à toxina Cry1Ac no Brasil, os principais objetivos do trabalho foram: a) estabelecer a linhas-básicas de suscetibilidade à toxina Cry1Ac em populações de A. argillacea e definir concentrações diagnósticas para o monitoramento da resistência e b) isolar e caracterizar locos microssatélites para avaliar a variabilidade e estruturação genética de populações de A. argillacea no Brasil. As linhas-básicas de suscetibilidade foram estimadas por meio de bioensaio de imersão de discos de folhas em soluções contendo a toxina Cry1Ac para populações de A. argillacea coletadas nos estados da Bahia, Goiás, Mato Grosso e Mato Grosso do Sul, durante as safras agrícolas de 2008 e 2009. Foram isolados e caracterizados dez locos microssatélites. Para avaliar a variabilidade genética foram estimadas as heterozigosidades observadas e esperadas. Para o estudo da estruturação genética foram estimadas as estatísticas F e feita a análise de agrupamento (distância de Nei) e análise Bayesiana. Baseado na estimativa da CL50 foram encontradas variações naturais de até seis vezes na suscetibilidade à toxina Cry1Ac entre as populações testadas. A partir da análise conjunta dos dados de concentração-mortalidade das populações testadas, foram definidas as concentrações diagnósticas de 10 e 32 µg de Cry1Ac/ml de água para futuros programas de monitoramento da resistência. O número médio de alelos por loco foi de 7,1 (variando de dois a 23 alelos). As heterozigosidades observada e esperada médias foram de 0,532 e 0,329. O índice de fixação intrapopulacional médio (f FIS) foi de 0,268, com variação entre os locos de -0,008 a 0,736. O índice de fixação da espécie (FIS) estimado através da análise de variância foi de 0,244 (IC 95% de 0,093 a 0,418). O valor de FST estimado foi de 0,036 (IC 95% de 0,007 a 0,080). Esse valor de FST não diferiu significativamente de zero, indicando a ausência de estruturação genética. Contudo foi detectado certo grau de endogamia intrapopulacional. A estruturação espacial da variabilidade genética não foi detectada, pois as populações avaliadas apresentaram uma coesão que é mantida pela alta taxa de migração (6,7 migrantes por geração). Entretanto, foi identificada indícios de estruturação genética determinada pelo tempo, uma vez que tanto o agrupamento baseado em distâncias genéticas quanto à análise Bayesiana identificaram grupos que são formados por populações coletadas em safras agrícolas diferentes. As causas ligadas a essa mudança na variabilidade genética não puderam ser identificadas, entretanto pode se inferir que possivelmente causas naturais ou práticas de manejo estejam determinando eventos de gargalo genético. Devido ao intenso fluxo gênico entre populações de A. argillacea no Brasil, estratégias de manejo da resistência devem ser implantadas no âmbito nacional.Genetically modified cotton expressing Cry1Ac toxin of Bacillus thuringiensis Berliner has been planted in Brazil since 2006. Among target pests of this technology, Alabama argillacea (Hüeb.) is a monophagous species and offers a high potential risk of resistance evolution. In order to implement a resistance management program of A. argillacea to Cry1Ac toxin in Brazil, the objectives of this research were: a) to establish baseline susceptibility to Cry1Ac toxin in A. argillacea populations and define diagnostic concentrations for resistance monitoring and b) to isolate and characterize microsatellite loci to evaluate the variability and genetic structure of A. argillacea populations in Brazil. The baseline susceptibility data were estimated with leaf-disc bioassays by dipping into different concentration of Cry1Ac solution. Populations of A. argillacea were collected in Bahia, Goiás, Mato Grosso and Mato Grosso do Sul States, during 2008 and 2009 cotton-growing seasons. Ten microsatellite loci were isolated and characterized. The genetic variability was evaluated estimating observed and expected heterozygosities. For the studied of genetic structure, the F statistics was estimated, and Cluster analysis (Nei´s distance) and Bayesian analysis were performed. Based on estimation of LC50, natural variation up to 6-fold was detected in the susceptibility to Cry1Ac among tested populations. Based on analysis of concentration-mortality data by combining all populations, diagnostic concentrations of 10 and 32 µg of Cry1Ac/ml of water were defined for monitoring resistance. The mean number of alleles per loci was 7.1 (varying from 2 to 23 alleles). The observed and expected heterozigosities was 0,523 e 0, 395. The mean intrapopulation fixation index (f FIS) 0,268, varying from -0.008 to 0.736 between loci. The species fixation index (FIS) estimated by analysis of variance was 0.244(95% CI of 0.093 to 0.418). The estimated value of FST was 0.036 (95% CI of 0.007 to 0.080). The FST value was not significantly different from zero, indicating absence of genetic structure However, some degree of intrapopulational inbreeding was detected. Spatial structure of genetic variability was not detected because tested populations showed cohesion kept by high migration rate (6.7 migrants per generation). However, evidence of genetic structure across time was detected by Cluster analysis of genetic distance as well as by Bayesian analysis with group formation by population collection seasons. Factors affecting changes in genetic variability were not identified; however, natural factors or management practices may be determining some genetic bottleneck events. Due to intense gene flow among A. argillacea populations in Brazil, resistance management strategies must be implemented in a national basis.
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Martinelli, Samuel. "Suscetibilidade a deltametrina e variabilidade molecular em populações de Spodoptera frugiperda (Lepidoptera: Noctuidae) coletadas nas culturas do algodoão e milho no Brasil." Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/11/11146/tde-20062006-125453/.
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Com a crescente expansão de cultivos agrícolas no Brasil, tem sido bastante comum o sistema de produção de algodão e milho em uma mesma região. Como uma possível conseqüência deste sistema de cultivo, os problemas com Spodoptera frugiperda (J. E. Smith) têm aumentado nestas duas culturas nos últimos anos. Assim, para o estabelecimento de um manejo mais efetivo desta praga, foi levantada a hipótese de que as mesmas populações de S. frugiperda atacam as culturas do algodão e milho em uma determinada região. Para testar esta hipótese, foram realizados os seguintes estudos: 1) a avaliação a suscetibilidade ao piretróide deltametrina em populações de S. frugiperda, e 2) a estimativa da similaridade e da estrutura genética em populações de S. frugiperda com o uso de marcadores moleculares RAPD e AFLP. A avaliação da suscetibilidade a deltametrina das populações de S. frugiperda foi realizada mediante bioensaio de aplicação tópica. Além disso, foi avaliada a resposta à seleção com deltametrina em uma população de S. frugiperda em condições de laboratório. As populações de S. frugiperda coletadas na cultura do algodão foram significativamente menos suscetíveis a deltametrina do que as populações coletadas no milho. Estes resultados poderiam ser entendidos como uma conseqüência da pré-seleção de indivíduos resistentes a deltametrina A população de S. frugiperda selecionada em laboratório apresentou uma razão de resistência a deltametrina de ≈14 vezes. Pela técnica de RAPD, os dendrogramas (Simple Matching e Jaccard) classificaram as populações da praga em grupos proximamente relacionados com a região geográfica de coleta dos insetos. Não foi identificado nenhum ramo capaz de separar e associar as populações de S. frugiperda a nenhuma das duas plantas hospedeiras avaliadas. Estes resultados sugeriram que as populações da praga em algodão e milho em uma determinada região do Brasil apresentam um nível significativo de fluxo gênico. Os resultados da técnica AFLP foram organizados em um dendrograma UPGMA (índice de Jaccard), o qual também não classificou as populações da praga em grupos relacionados às plantas nas quais os insetos foram coletados. Não foi detectada correlação significativa entre a dissimilaridade genética e distância geográfica nas populações testadas. Foi detectada variação molecular entre as populações da praga atribuída à origem geográfica dos insetos. A análise molecular de variância indicou que 7% da variação molecular total poderiam ser atribuídos à divisão das populações de S. frugiperda em grupos de insetos coletados no Brasil e na Argentina. Além disso, foi detectado 0% de variação genética, e um valor de fluxo gênico Nm=1,32 entre os grupos de populações da praga coletadas nas culturas do algodão e do milho. Assim, as infestações de S. frugiperda que ocorrem em campos de milho e algodão podem ser consideradas como subunidades potencialmente intercruzantes de uma mesma população. Portanto, conclui-se que há necessidade de um planejamento bastante estratégico nos plantios de algodão e de milho, no delineamento de programas de manejo de S. frugiperda no Brasil.Due to the expansion of the cultivated areas in Brazil, it has been very common to find the cultivation of cotton and maize in the same region. As a potential consequence to this cultivation system, the problems with Spodoptera frugiperda (J.E. Smith) have increased for the last years at both crops. In order to provide elements to the establishment of a more effective management of this pest it was hypothesized that the same populations of S. frugiperda attack the cotton and maize crops in Brazil. To test this hypothesis the following studies were conducted: 1) the evaluation the susceptibility to the pyrethroid deltamethrin in S. frugiperda populations and 2) the assessment of the molecular variability and genetic structure in S. frugiperda populations by using RAPD and AFLP molecular markers. The evaluation of the susceptibility to deltamethrin in S. frugiperda populations was conducted by using topical application bioassays. Furthermore, the response of this pest to the selection pressure with the insecticide was evaluated under laboratory conditions. The insect populations collected in the cotton crop were significantly less susceptible to deltamethrin than the ones collected in the maize crop. These results might be consequence of a pre-selection of deltamethrin-resistant individuals. The deltamethrin-resistant population selected under laboratory conditions had the resistance ratio of ≈14 fold. The dendrograms obtained by using RAPD markers (Simple Matching and Jaccard) classified the populations into clusters related to the geographical origin of the samples. Any branch of the dendrograms underpinned a molecular association of S. frugiperda with neither of the two host plants. These results suggested the existence of considerable gene flow between cotton and maize populations of S. frugiperda collected at the same region in Brazil. The AFLP results were organized in a UPGMA dendrogram (Jaccard index) which also did not classify the populations of S. frugiperda into clusters related to the host plant in which the insects were collected. It was not found a significant correlation between genetic dissimilarity and geographical distances. It was detected genetic variation attributable to the geographical origin of the populations. The analysis of molecular variance highlighted 7% of the variation due to the division of the S. frugiperda populations into Brazilian and Argentine groups. Also, no molecular variation (0%) and a gene flow rate equal to Nm=1.32 were estimated between fall armyworm group of populations collected at maize and cotton fields in Brazil. The same populations of S. frugiperda infest cotton and maize crops in Brazil and could be considered as interbreeding subunits of the same population. Therefore, there is a need of strategic action plans to the planting of cotton and maize crops for designing of management programs of S. frugiperda in Brazil.
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An, Chuanfu. "SNP CHARACTERIZAITON AND GENETIC AND MOLECULAR ANALYSIS OF MUTANTS AFFECTING FIBER DEVELOPMENT IN COTTON." MSSTATE, 2008. http://sun.library.msstate.edu/ETD-db/theses/available/etd-03302008-191842/.
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Cotton (Gossypium spp.) is the worlds leading textile fiber crop, and an important source of oil and protein. Insufficient candidate gene derived-markers suitable for genetic mapping and limited information on genes that control economically important traits are the major impediments to the genetic improvement of Upland cotton (G. hirsutum L.). The objectives of this study were to develop a SNP marker discovery strategy in tetraploid cotton species, SNP characterization and marker development from fiber initiation and elongation related genes, chromosomal assignment of these genes by SNP marker-based deletion analysis or linkage mapping, and genetic and molecular analysis of mutants affecting cotton fiber development. Phylogenetic grouping and comparision to At- and Dt-genome putative ancestral diploid species of allotetraploid cotton facilitated differentiation between genome specific polymorphisms (GSPs) and marker-suitable locus-specific polymorphisms (LSPs). By employing this strategry, a total of 222 and 108 SNPs were identified and the average frequency of SNP was 2.35% and 1.30% in six EXPANSIN A genes and six MYB genes, respectively. Both gene families showed independent and incongruent evolution in the two subgenomes and a faster evolution rate in Dt-genome than that in At-genome. SNPs were concordantly mapped to different chromsomes, which confirmed their value as candidate gene marker and indicated the reliability of SNP discovery stragey. QTL mapping by two F2 populations developed from fiber mutants detected major QTL which explain 62.8-87.1% of the phenotypic variation for lint percentage or lint index in the vicinity of BNL3482-138 on chromosome 26. Single marker regression analyses indicated STV79-108, which was located to the long arm of chromosome 12 (the known location of N1 and perhaps n2 loci), also had significant association (R2 % value 15.4-30.6) with lint percentage, lint index, embryo protein percentage and micronaire. Additional QTL and significant markers associated with other seed and fiber traits were detected on different chromosomes. Inheritance analysis indicated that both genetic models N1N1n2n2 and n2n2li3lisub>3 could lead to the fiberless phenotype. The observation of fuzzless-short lint phenotype indicated fiber initiation and elongation were controlled by different mechanisms. The penetrance of Li2 gene expression was observed in this study.
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Klingler, John Paul. "Phenotypic and molecular-genetic analysis of resistance to Aphis gossypii (cotton-melon aphid) in Cucumis melo (melon)." Diss., The University of Arizona, 1999. http://hdl.handle.net/10150/283992.
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Aphis gossypii Glover (cotton-melon aphid) is a major pest of agriculture worldwide. Cucumis melo L. (melon) possesses monogenic resistance to this aphid, and is a good model for the study of aphid resistance mechanisms in plants. This dissertation presents analyses of the effects of the resistance gene on A. gossypii, and of the gene's effects on biochemical and molecular-genetic properties of melon plants. Nearly isogenic lines (NILs) of melon, either resistant or susceptible to A. gossypii, were compared for their influence on aphid life history traits and feeding behavior. The resistance trait delayed development, increased mortality, and markedly decreased reproduction of aphids confined to leaves of resistant plants. Aphids on resistant plants salivated into phloem sieve elements significantly longer, and were less likely to begin sap ingestion after salivation, suggesting that the resistance factor acts within phloem sieve elements. Biochemical properties of callose synthase were compared between NILs to test the hypothesis that callose deposition plays a role in the resistance mechanism. No differences were detected between resistant and susceptible melon genotypes with respect to callose synthase subunit abundance or in vitro enzyme activity. Sixty-four F₃ families from a melon mapping population were tested for aphid resistance to place the resistance locus on a genetic map of the melon genome. Four molecular markers were found to be linked to the aphid resistance phenotype. The name Agr ( Aphis gossypii resistance) is proposed for this locus. The closest flanking markers were positioned at 4.3 and 7.0 cM from Agr. Evidence suggests Agr might be a member of the nucleotide binding site-leucine-rich repeat (NBS-LRR) family of plant resistance genes, which are known to cluster in plant genomes. Melon genomic DNA sequences homologous to this gene family were isolated to test the hypothesis that Agr is an NBS-LRR homolog. Two of these sequences were tested for genetic linkage to Agr in a population of F₂ plants segregating for the resistance trait. DNA gel blot analysis determined that one sequence, NBS-2, is approximately 2.7 cM distant from Agr, which suggests Agr resides in a cluster of NBS-LRR homologs and could be a member of this gene family.
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Bhoora, Raksha. "Molecular characterisation of Eucalyptus grandis PGIP." Diss., University of Pretoria, 2003. http://hdl.handle.net/2263/24370.
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Coniothyrium zuluense is the causal agent of a serious Eucalyptus stem canker disease in South Africa (Wingfield et al., 1997). Eucalypts are the most important hardwood plantations in the world, and in South Africa these hardwoods occupy approximately 1.5 million hectares of plantation area, an area that is soon to be increased by an additional 600 000 hectares. As exotics, Eucalyptus plantations are constantly exposed to infection by fungal pathogens such as C. zuluense, which by secreting cell-¬wall degrading enzymes contribute to the degradation of plant cell walls and subsequent reduction and in the quality of timber produced. This ultimately affects the South African paper, pulp and timber industries. Selection of resistant clones through traditional breeding methods is the most common method currently employed in overcoming the problem of fungal infection. The genetic manipulation of Eucalyptus trees for enhanced resistance to fungal diseases is an alternative to the time-consuming and tedious approach of conventional breeding. The identification of several antifungal proteins, particularly polygalacturonase-inhibiting proteins (PGIPs) from various plant species including Eucalyptus, lead to the hypothesis that over-expression of these proteins could potentially reduce pathogen attack. However, prior to the expression of PGIPs in plants, isolation and molecular characterization of these genes are required. The aims of this study were therefore (l) to clone and characterize the complete Eucalyptus grandis pgip gene, (2) to transform Nicotiana tabacum (tobacco) plants with the E. grandis pgip gene and (3) to test for inhibition of C. zuluense PGs by PGIPs extracted from transgenic tobacco plants. This forms the first step towards the generation of E. grandis clones that are more disease tolerant. A review of the role of fungal endopolygalacturonases and polygalacturonase¬inhibitors in plant-pathogen interactions are presented in chapter I. Strategies employed to isolate and characterize pgip genes from a range of plant species are highlighted and the importance ofPGIPs in disease resistance is discussed. In chapter 2, the molecular cloning and characterization of the E. grandis pgip gene is discussed. The work presented in this chapter is a follow up on work previously conducted by Chimwamurombe (2001). Previously, a partial Eucalyptus pgip gene sequence was obtained with the use of degenerate oligonucleotide primers. In this study, the complete Eucalyptus pgip gene was obtained through the employment of genome walking strategies. Transformation of Nicotiana tabacum cv LA Burley plants with the Eucalyptus pgip gene and the molecular characterization of transgenic tobacco plants is discussed in chapter 3. The transformation and expression of foreign genes in tobacco plants is a well-established protocol, making tobacco the most appropriate candidate plant for assessing the functionality of the plant transformation construct. The production of endopolygalacturonases from virulent C. zuluense isolates and the subsequent PGIP assays conducted to determine levels of PG inhibition are included in this chapter. This thesis consists of three independent chapters representing studies on the molecular characterization of an E. grandis pgip gene and focusing on the potential for inhibition of PGs produced by C. zuluense by Eucalyptus PGIP extracted from transgenic tobacco plants. Repetition of certain aspects in the individual chapters has been unavoidable and the thesis is presented following a uniform style.Dissertation (MSc)--University of Pretoria, 2003.
Genetics
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RIBEIRO, Carla Sibere Nogueira. "Caracterização in situ, molecular e morfológica de acessos de Gossypium do Estado de Pernambuco." Universidade Federal Rural de Pernambuco, 2008. http://www.tede2.ufrpe.br:8080/tede2/handle/tede2/6197.
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Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq
Cotton (G. hirsutum L.) has the most important natural textile fiber in the world. The Gossypium remainders in Pernambuco state are in risk of disappearing due to ecological and agricultural process. The study of species in situ, about they genetic and morphological characteristics gives support in order to find and implement preservation options. The aims of this work was characterize the genetic variability of G. hirsutum e G. barbadense accesses of Sertão, Agreste and Zona da Mata of Pernambuco state by morphological and molecular marks. On the in situ study were evaluated 82 accesses in the 29 counties during expedition in 2005 and 2006 by interview and observation about morphological and phenological characters, and condition of conservation. The identified plants uses were: medical, ornamental and for confection of lamp wick. The genetic erosion risk observed were: change and loss of cultural human habit, animal pastry and environmental depredate. In the molecular study was used fifteen pair of microssatelites primers in order to evaluate the allelic frequency, genetic diversity and genetic distance by Nei statistical. The average of heterozygosis expected (He) that correspond the genetic diversity was 0.321, it was biggest for upland cotton (0.481). For the three studied biomes on the Sertão and the Agreste where predominate of the upland cottonthe He had highest value, 0.548 e 0.444, respectively. The average of inbreeding index was 0.806, highest for G. barbadense (0.968). Cluster shoed an interspecific hybrid between G. barbadense and G. hirsutum (PE 0553). On the morphological characterization ex situ were evaluated 38 morphological characters and nine fiber characters of 72 Gossypium accesses PE0553 (G. barbadense), PE0516 (upland cotton) and PE0524 (moco cotton) were the most morphological divergent and showedmore variability for studied characters. The majority of accesses of three types of cotton shoed good index for fiber being what herbaceous cotton were better about fiber uniformity, reflectance, resistance and percentage of fiber. The information obtained on morphological and molecular cauterization Gossypium genus on Pernambuco state showed high genetic diversity that should be conserving in order gives genes to breeding programs.
O algodoeiro (G. hirsutum L.) possui a mais importante fibra têxtil natural no mundo. Os remanescentes de Gossypium no Estado de Pernambuco correm sérios riscos de desaparecerem em decorrência de fatores ecológicos e agrícolas. O estudo das espécies in situ, em relação suas características genéticas e morfológicas, contribui potencialmente à implantação de medidas de manejo e preservação de espécies naturalizadas. O presente trabalho teve por objetivo caracterizar a variabilidade genética de acessos de G.hirsutum e G. barbadense do Agreste, Sertão e Zona da Mata do Estado de Pernambuco, por meio de marcadores morfológicos e moleculares. No estudo in situ, avaliou-se os 82 acessos durante expedições em 29 municípios nos anos 2005 e 2006, investigando-se por entrevistas e observações, sobre caracteres morfológicos, fenológicos e de conservação. Os usos das plantas identificados foram: medicinal, asséptico, ornamental e confecção de pavios de lamparina. Os riscos de erosão genética constatados foram: mudança e abandono de hábitos culturais, pastejo e depredação do ambiente. Na análise molecular, utilizou-se quinze pares de primers microssatélites para avaliar freqüências alélicas, diversidade genética e distância entreos genótipos pelas estatísticas de Nei. A heterozigosidade média esperada (He), que correspondem a diversidade genética, foi 0,321, sendo mais alta para o algodoeiro mocó (0,481). Considerando-se os três biomas estudados, no Sertão e no Agreste, locais em que predominou algodoeiro mocó, tiveram os maior valore de He, 0,548 e 0,444, respectivamente. O coeficiente de endogamia média foi de 0,806, tendo sido mais elevado em G. barbadense (0,968). O agrupamento revelou um híbrido interespecífico entre G. barbadense e G. hirsutum (PE 0553). Na caracterização morfológica ex situ, avaliou-se 38 caracteres morfológicos e nove caracteres de fibra, de 72 acessos de Gossypium. Dos três tipos de algodoeiros caracterizados, constatouse maior diversidade morfológica nos acessos de algodoeiro mocó. Os acessos PE0553 (G. barbadense), PE0516 (algodoeiro herbáceo) e PE0524 (algodoeiro mocó) foram os mais divergentes morfologicamente, apresentando maior variabilidade nos descritores avaliados. A maioria dos acessos dos três tipos de algodoeiros revelaram índices satisfatórios de características intrínsecas de fibra, sendo que os algodoeiros herbáceos foram superiores em relação ao índice de uniformidade de fibra, reflectância,resistência e percentagem de fibra. As informações obtidas na caracterização molecular e morfológica mostraram elevada diversidade genética nos acessos de Gossypium, no Estado de Pernambuco, que deve ser conservada para servir de fonte de genes para os programas de melhoramento genético.
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Lima, Leonardo Henrique Guedes de Morais. "Qualidade fisiol?gica de sementes de gen?tipos de algodoeiro sob estresse salino." Universidade Federal do Rio Grande do Norte, 2007. http://repositorio.ufrn.br:8080/jspui/handle/123456789/16775.
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Previous issue date: 2007-02-28The germination of cotton seeds and the seedlings emergency are generally delayed and reduced by the salinity. Although the cotton is considered a tolerant culture, it can suffer substantial reductions in regarding its growth and production when exposed to salinity condition. The aims of this study went evaluate the effect of the saline stress in the germination phase to four cotton genotypes (BRS Rubi, BRS Safira, BRS 201 and CNPA 187 8H), using different osmotic potentials generated with increment of sodium chloride (NaCl). The saline stress was simulated using NaCl aqueous solutions in the potentials: 0.0 (Control); -0.2; -0.4; -0.6; -0.8 and -1.0 MPa. The treatments were monitored by means of tests for analysis of seeds, germination, first counting, speed germination index, length of shoot, radicle length, dry weigth of embrionic axis and shoot/radicle ratio. The tests for germination, first counting and index of germination speed were accomplished using 50 seeds for repetition and for the study of length of shoot, radicle length, dry weigth of embrionic axis and shoot/radicle ratio were used 20 seeds by repetition. For both tests four repetitions were accomplished by genotype for each one of the potentials. The seeds of each repetition were involved in papers Germitest humidified with NaCl solution corresponding to the potential. The repetitions of both tests were maintained in a germinator with saturated humidity. The analysis were initiate four days after the induction of the saline stress. The evaluations of the first three variables analyzed were accomplished daily; the seeds were remove and counted when its germinated. For the length tests just the repetitions corresponding to the potential of NaCl 0,0 MPa were analysis 4 days after the beginning of the induction of the saline stress. The analysis of the repetitions of the potentials -0,2 and -0,4 and of the potentials -0,6, -0,8 and -1,0 MPa they were accomplished with 12 and 20 days, respectively. For accomplishment of the analisis of this test the shoot of the 20 plantules of each repetition was separate from the radicle and both parts were measured. The statistical analyses were performed using the GENMOD and GLM procedures of the SAS. For the variable germination, the cultivates CNPA 187 8H and BRS Safira stood out for the potential -0.8 MPa, with averages of 89% and 81%, respectively. The test of speed germination index to cultivate BRS Safira presented the largest averages for the two higher saline potentials. It was observed that the increase of the saline potential reduces the germination percentage and speed germination index. For each day of evaluation it was verified that the increase of the saline potential causes a reduction of the length both of the shoot and of the radicle. The radicle tends to grow more than the shoot until the potential -0,4 MPa
A germina??o de sementes de algod?o e a emerg?ncia de pl?ntulas s?o geralmente retardadas e reduzidas pela salinidade. Embora o algod?o seja considerado uma cultura tolerante, pode sofrer redu??es substanciais no seu crescimento e na produ??o quando exposta ? condi??o de salinidade. O objetivo deste estudo foi avaliar o efeito do estresse salino na fase de germina??o em quatro gen?tipos de algod?o (BRS Rubi, BRS Safira, BRS 201 e CNPA 187 8H), empregando-se diferentes potenciais osm?ticos, gerados com acr?scimo de cloreto de s?dio (NaCl). O estresse salino foi simulado, utilizando-se solu??es aquosas de NaCl nos potenciais 0,0; -0,2; -0,4; -0,6; -0,8 e -1,0 MPa. Os tratamentos foram monitorados por meio de testes para an?lise de sementes: germina??o, primeira contagem, ?ndice de velocidade de germina??o (IVG), comprimento de parte a?rea, comprimento de rad?cula, peso seco de eixo embrion?rio e rela??o rad?cula/parte a?rea. Os testes para germina??o, primeira contagem e IVG foram realizados utilizando-se 50 sementes por repeti??o; para o estudo de comprimento de parte a?rea, comprimento de rad?cula, peso seco de eixo embrion?rio e rela??o rad?cula/parte a?rea, foram utilizadas 20 sementes por repeti??o. Para ambos os testes, foram realizadas quatro repeti??es por gen?tipo para cada um dos potenciais. As sementes de cada repeti??o foram envolvidas em pap?is Germitest umedecidos com a solu??o de NaCl correspondente ao potencial. As repeti??es de ambos os testes foram conduzidas em germinador e a umidade mantida ao ponto de satura??o. As leituras das tr?s primeiras vari?veis analisadas foram iniciadas quatro dias ap?s a indu??o do estresse salino. As avalia??es foram realizadas diariamente; as sementes foram retiradas e contabilizadas ? medida que ocorria a germina??o. Para os testes de comprimento, apenas as repeti??es correspondentes ao potencial de NaCl 0,0 MPa foram lidas, quatro dias ap?s o in?cio da indu??o do estresse. As leituras das repeti??es dos potenciais -0,2 e -0,4 e dos potenciais -0,6, -0,8 e -1,0 MPa foram realizadas, respectivamente, aos 12? e 20? dias. Para a realiza??o das leituras deste teste, a parte a?rea das 20 plantas de cada repeti??o foi separada da rad?cula e ambas mensuradas. As an?lises estat?sticas foram efetuadas, utilizando-se os procedimentos GENMOD e GLM do SAS. Para a vari?vel germina??o, as cultivares CNPA 187 8H e BRS Safira destacaram-se para o potencial -0,8 MPa, com m?dias de 89% e 81%, respectivamente. Foi observado que o aumento do potencial salino reduziu a porcentagem do IVG. Para cada dia de avalia??o, verificou-se que o aumento do potencial salino provoca uma redu??o do comprimento da parte a?rea e da rad?cula. A rad?cula tende a crescer mais que a parte a?rea at? o potencial -0,4 MPa
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Albernaz, Karina Cordeiro. "Suscetibilidade à proteína Cry1Ac e estrutura genética em populações de Heliothis virescens (Fabricius) (Lepidoptera: Noctuidae) no Brasil." Universidade de São Paulo, 2011. http://www.teses.usp.br/teses/disponiveis/11/11146/tde-24052011-090014/.
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Heliothis virescens (Fabricius) é uma das pragas-alvo do algodão geneticamente modificado que expressa a proteína Cry1Ac de Bacillus thuringiensis Berliner (Bt). Estudos sobre a suscetibilidade de H. virescens à proteína Cry1Ac e sobre a estrutura genética e padrões de fluxo gênico nas escalas locais e regionais desse inseto são fundamentais para a implementação de programas de Manejo da Resistência de Insetos (MRI) no Brasil. Dessa forma, os principais objetivos do trabalho foram: (a) avaliar a suscetibilidade à proteína Cry1Ac em populações de H. virescens coletadas nas principais regiões produtoras de algodão no Brasil (Bahia, Goiás, Mato Grosso e Mato Grosso do Sul) durante as safras agrícolas 2007/08 e 2008/09; e (b) avaliar a variabilidade genética e fluxo gênico de populações de H. virescens provenientes das culturas de algodão (safras 2007/08, 2008/09 e 2009/10) e de soja (safra 2009/10) utilizando sequências de DNA mitocondrial (DNAmit). As linhas-básica de suscetibilidade à proteína Cry1Ac foram estabelecidas mediante o uso de lagartas neonatas, por meio de bioensaios de incorporação das diferentes concentrações da proteína em dieta artificial. Para avaliar a variabilidade genética e o fluxo gênico entre populações de H. virescens utilizou-se sequências de DNAmit das subunidades I e II da citocromo oxidase COI e COII e a subunidade 6 da desidrogenase dinucleotídica da adenina nicotinamida nad6. As CLs50 estimadas variaram de 0,18 a 0,66 µg de Cry1Ac/mL de dieta para as populações coletadas na safra 2007/08 (variação de 3,7 vezes). Da mesma forma, as concentrações efetivas médias para a inibição do desenvolvimento larval (CE50) variaram de 0,0053 a 0,0161 µg de Cry1Ac/mL dieta (variação de 3,0 vezes). A partir da análise conjunta dos dados de concentração-mortalidade de todas as populações avaliadas, foram definidas e validadas as concentrações diagnósticas de 3,1 e 5,6 µg de Cry1Ac/mL de dieta para programas de monitoramento da resistência de H. virescens à proteína Cry1Ac no Brasil. Baseadas em análises de agrupamento (Neighbor-Joining e Análise de Componentes Principais) e Bayesiana (Structure) foram verificadas uma baixa estruturação entre as populações de H. virescens de diferentes regiões, bem como para aquelas coletadas em plantas hospedeiras diferentes. As análises de AMOVA também indicaram baixa estruturação genética entre as populações de H. virescens estudadas independente da cultura (Fst= 0,019) ou escala geográfica (Fst= 0,012), sugerindo um nível significativo de fluxo gênico. Em média, a distância genética entre as amostras foi de 0,1%. Uma rede de haplótipos obtida com os dados combinados resultou em 35 haplótipos, com quatro haplótipos únicos presentes somente nas amostras coletadas em soja. A principal característica dessa rede é a forma de estrela na distribuição dos haplótipos, bem como a ocorrência de muitos alelos em baixa frequência. Esse tipo de rede é característico de populações que passaram por uma recente expansão populacional e, de fato, a história demográfica de H. virescens, baseada no teste de distribuição da diferença genética par-a-par entre haplótipos (distribuição de Mismatch) e nos resultados negativos nos testes de neutralidade seletiva indicam também um episódio de expansão populacional recente. As informações obtidas no presente trabalho serão fundamentais para o acompanhamento da efetividade das estratégias de manejo da resistência de H. virescens à proteína Cry1Ac no Brasil.The tobacco budworm, Heliothis virescens (Fabricius), is one of target pests of genetically modified cotton expressing Cry1Ac insecticidal protein derived from Bacillus thuringiensis Berliner. Studies on susceptibility of H. virescens to Cry1Ac and the genetic structure and gene flow patterns at local and regional levels are crucial for establishing an Insect Resistance Management (IRM) program for Bt cotton in Brazil. Thus, the objectives of this study were (a) to evaluate the susceptibility of field-collected populations of H. virescens to Cry1Ac from major cotton-growing regions in Brazil (Bahia, Goiás, Mato Grosso and Mato Grosso do Sul) in the cropping seasons of 2007/08 and 2008/09; and (b) to evaluate the genetic variability and gene flow among H. virescens populations from cotton (2007/08, 2008/09 and 2009/10 cropping seasons) and soybean (2009/10 cropping season) with mitochondrial DNA markers. Baseline susceptibility data to Cry1Ac protein were estimated with neonate larvae thereby using diet incorporation bioassays. Genetic variation and gene flow among H. virescens populations were evaluated by using mitDNA sequences of cytochrome oxidase subunities I and II COI e COII and the subunity 6 of dinucleotide dehydrogenase of adenine nicotinamide nad6. The estimated LC50 values varied from 0.18 to 0.66 µg of Cry1Ac/mL of diet among the 2007/08 populations (3.7 fold variation). Similarly, the EC50 values based on growth inhibition ranged from 0.0053 to 0.0161 µg of Cry1Ac/mL of diet for the 2007/08 populations (3.0 fold variation). A joint analysis of the mortality data across all tested populations was used to develop candidate diagnostic concentrations for future monitoring programs. The proposed diagnostic concentrations of 3.1 and 5.6 µg of Cry1Ac/mL of diet were validated against field-collected populations from 2008/09 and will form the basis for future resistance monitoring programs with H. virescens. Based on cluster analysis (Neighbor-Joining and Principal Coordinate Analysis) and Bayesian analysis (Structure), a low structure was detected among H. virescens populations either by regions or host plants. AMOVA analysis also indicated low genetic structure among H. virescens populations across crops (Fst= 0.019) or geographic scale (Fst= 0.012), suggesting a significant gene flow. The mean genetic distance among samples was 0.1%. The haplotype network obtained with joint data resulted in 35 haplotypes, with four unique haplotypes present only in samples collected from soybean crop. The major characteristics of the haplotype network were the star-like pattern and the occurrence of many alleles at low frequencies. This type of network is typical for populations that passed through a recent population expansion and, in fact, the demographic history of H. virescens, based on distribution test of pair-wise genetic difference among haplotypes (Mismatch distribution) and negative results from tests of selective neutrality also indicate an episode of a recent population expansion.
Book chapters on the topic "Cotton Molecular genetics"
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Konan, N’Guessan Olivier, Jean-Pierre Baudoin, Angélique D’Hont, and Guy Mergeai. "Bridging Classical and Molecular Cytogenetics of Gossypium." In Genetics and Genomics of Cotton, 257–81. New York, NY: Springer US, 2009. http://dx.doi.org/10.1007/978-0-387-70810-2_11.
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Wright, Robert J., Chen Niu, and Bay Nguyen. "Bridging Classical and Molecular Genetics of Cotton Disease Resistance." In Genetics and Genomics of Cotton, 313–36. New York, NY: Springer US, 2009. http://dx.doi.org/10.1007/978-0-387-70810-2_13.
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Liu, Qing, Surinder Singh, Kent Chapman, and Allan Green. "Bridging Traditional and Molecular Genetics in Modifying Cottonseed Oil." In Genetics and Genomics of Cotton, 353–82. New York, NY: Springer US, 2009. http://dx.doi.org/10.1007/978-0-387-70810-2_15.
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Chee, Peng W., and B. Todd Campbell. "Bridging Classical and Molecular Genetics of Cotton Fiber Quality and Development." In Genetics and Genomics of Cotton, 283–311. New York, NY: Springer US, 2009. http://dx.doi.org/10.1007/978-0-387-70810-2_12.
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Saranga, Yehoshua, Andrew H. Paterson, and Avishag Levi. "Bridging Classical and Molecular Genetics of Abiotic Stress Resistance in Cotton." In Genetics and Genomics of Cotton, 337–52. New York, NY: Springer US, 2009. http://dx.doi.org/10.1007/978-0-387-70810-2_14.
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Paterson, Andrew H. "Molecular genetic map of cotton." In Advances in Cellular and Molecular Biology of Plants, 239–53. Dordrecht: Springer Netherlands, 2001. http://dx.doi.org/10.1007/978-94-015-9815-6_14.
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Zhang, Baohong. "Agrobacterium-Mediated Genetic Transformation of Cotton." In Methods in Molecular Biology, 19–33. New York, NY: Springer New York, 2018. http://dx.doi.org/10.1007/978-1-4939-8952-2_2.
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Boopathi, N. Manikanda, Selvam Sathish, Ponnaikoundar Kavitha, Ponnusami Dachinamoorthy, and Rajasekar Ravikesavan. "Molecular Breeding for Genetic Improvement of Cotton (Gossypium spp.)." In Advances in Plant Breeding Strategies: Breeding, Biotechnology and Molecular Tools, 613–45. Cham: Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-22521-0_21.
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Miao, Weiguo, and Jingsheng Wang. "Genetic Transformation of Cotton with a Harpin-Encoding Gene hpaXoo Confers an Enhanced Defense Response Against Verticillium dahliae Kleb." In Methods in Molecular Biology, 223–46. Totowa, NJ: Humana Press, 2012. http://dx.doi.org/10.1007/978-1-62703-212-4_19.
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Miao, Weiguo, and Jingsheng Wang. "Genetic Transformation of Cotton with the Harpin-Encoding Gene hpaXoo of Xanthomonas oryzae pv. oryzae and Evaluation of Resistance Against Verticillium Wilt." In Methods in Molecular Biology, 257–80. New York, NY: Springer New York, 2018. http://dx.doi.org/10.1007/978-1-4939-8952-2_22.
Full textConference papers on the topic "Cotton Molecular genetics"
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"Molecular analysis of BC1F1 and BC2F1 cotton hybrids using SSR markers." In Plant Genetics, Genomics, Bioinformatics, and Biotechnology. Novosibirsk ICG SB RAS 2021, 2021. http://dx.doi.org/10.18699/plantgen2021-022.
Full textReports on the topic "Cotton Molecular genetics"
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Barg, Rivka, Kendal D. Hirschi, Avner Silber, Gozal Ben-Hayyim, Yechiam Salts, and Marla Binzel. Combining Elevated Levels of Membrane Fatty Acid Desaturation and Vacuolar H+ -pyrophosphatase Activity for Improved Drought Tolerance. United States Department of Agriculture, December 2012. http://dx.doi.org/10.32747/2012.7613877.bard.
Full textAbstract:
Background to the topic: In previous works we have shown that Arabidopsis and tomato over-expressing H+-pyrophosphatase show increased tolerance to drought imposed by withholding irrigation of young plants in pots (Park et al. 2005). In addition, young tobacco plants over-expressing fatty acid desaturase 3 (OEX-FAD3) also showed increasing tolerance to drought stress (Zhang et al 2005), and similarly OEX-FAD3 young tomato plants (unpublished data from ARO), hence raising the possibility that pyramiding the two could further improve drought tolerance in tomato. Based on these findings the specific objects originally set were: 1. To analyze the impact of pyramiding transgenes for enhanced fatty acid desaturation and for elevated H+-PPase activity on tomato yielding under water deficit stress conditions. 2. To elucidate the biochemical relationship between elevated desaturation of the membrane lipids and the activities of selected vacuolar transporters in the context of drought responses. 3. To explore the S. pennellii introgression lines as alternative genetic sources for drought tolerance related to enhanced fatty acid desaturation and/or H+-PPase activity. 4. Since OEX-FAD3 increases the levels of linolenic acid which is the precursor of various oxylipins including the stress hormone Jasmonate. (JA), study of the effect of this transgene on tolerance to herbivore pests was added as additional goal. The Major conclusions, solutions, and achievements are: (1) The facts that ectopic over-expression of vacuolarH+-PPases (in line OEX-AVP1) does not change the fatty acid profile compared to the parental MoneyMaker (MM) line and that elevated level of FA desaturation (by OEX-FAD3) does not change the activity of either H+-PPase, H+-ATPaseor Ca2+ /H+ antiport, indicate that the observed increased drought tolerance reported before for increase FA desaturation in tobacco plants and increased H+PPase in tomato plants involves different mechanisms. (2) After generating hybrid lines bringing to a common genetic background (i.e. F1 hybrids between line MP-1 and MM) each of the two transgenes separately and the two transgenes together the effect of various drought stress regimes including recovery from a short and longer duration of complete water withhold as well as performance under chronic stresses imposed by reducing water supply to 75-25% of the control irrigation regime could be studied. Under all the tested conditions in Israel, for well established plants grown in 3L pots or larger, none of the transgenic lines exhibited a reproducible significantly better drought tolerance compare to the parental lines. Still, examining the performance of these hybrids under the growth practices followed in the USA is called for. (3) Young seedlings of none of the identified introgression lines including the S. pennellii homologs of two of the H+-PPase genes and one of the FAD7 genes performed better than line M82 upon irrigation withhold. However, differences in the general canopy structures between the IL lines and M82 might mask such differences if existing. (4). Over-expression of FAD3 in the background of line MP-1 was found to confer significant tolerance to three important pest insects in tomato: Bordered Straw (Heliothis peltigera), Egyptian cotton leafworm (Spodoptera littoralis) and Western Flower Thrips (Frankliniella occidentalis). Implications: Although the original hypothesis that pyramiding these two trasgenes could improve drought tolerance was not supported, the unexpected positive impact on herbivore deterring, as well as the changes in dynamics of JA biosynthesis in response to wounding and the profound changes in expression of wound response genes calls for deciphering the exact linolenic acid derived signaling molecule mediating this response. This will further facilitate breeding for herbivore pest and mechanical stress tolerance based on this pathway.