Project description:Sea-island cotton (Gossypium barbadense L.) has superior fiber quality properties such as length, fineness and strength, while Upland cotton (Gossypium hirsutum L.) is characterized by high yield. To reveal features of Upland cotton and Sea-island cotton fiber cells, differential genes expression profiles during fiber cell elongation and in secondary wall deposits were established using cDNA microarray technology. This research provides a valuable genomic resource to deepen our understanding of the molecular mechanisms of cotton fiber development, and may ultimately lead to improvements in cotton fiber quality and yield.
Project description:Sea-island cotton (Gossypium barbadense L.) has superior fiber quality properties such as length, fineness and strength, while Upland cotton (Gossypium hirsutum L.) is characterized by high yield. To reveal features of Upland cotton and Sea-island cotton fiber cells, differential genes expression profiles during fiber cell elongation and in secondary wall deposits were established using cDNA microarray technology. This research provides a valuable genomic resource to deepen our understanding of the molecular mechanisms of cotton fiber development, and may ultimately lead to improvements in cotton fiber quality and yield. 15 samples were prepared for microarray slides hybridized with three biological replicate samples including a swap-dye experiment for each growth stage. Each spot had a repeat in the microarray slideM-oM-<M-^Ltherefore, data for six replicate experiments performed with biologically independent samples.
Project description:In order to study gene expression at the genomic level during elongation and secondary cell wall synthesis of upland cotton fiber, oligonucleotide microarrays were employed. RNA was isolated from fibers in 7 different time points beginning prior to peak fiber expansion, continuing through termination of fiber expansion and ending at peak cellulose synthesis (5, 8, 10, 14, 17, 21, and 24dpa). The arrays contained ~25,000 oligonucleotides representing ~12,200 genes designed from a fiber EST database during peak cell expansion. Dynamic changes in gene expression were analyzed in a developmental context to identify stage-specific biological processes and pathways likely to be crucial to cell polar elongation or cellulose biosynthesis and secondary cell wall biogenesis. Genes with significant changes in expression relative to any preceding time point were identified (moderated t-statistics, adjusted p-value <0.05) for each developmental time point with an expected false discovery rate for multiple testing <5%
Project description:To gain novel insights into the molecular mechanisms of fiber secondary cell wall development, fiber transcriptomes of the immature fiber mutant (im) with defective secondary cell wall development and its near-isogenic line, TM-1 (wild-type) were compared using cDNA microarray technology. The expression profiling was performed at 5 developmental time points: 13, 16, 19, 22, and 25dpa. Secondary cell wall development related genes were identified by differentially expressed gene analysis. And these genes could be used as potential candidate genes for manipulation to improve fiber quality. Cotton plants were grown under field condition. Flowers were tagged and cotton bolls were collected during Fiber development stages. Total RNA was isolated from fiber bearing ovules of wild-type, TM-1 and immature fiber mutant (im) collected at various (13, 16, 19, 22 and 25 dpa) fiber development stages. A total of 15 hybridizations with three biological replicates including a swap-dye experiment for each fiber developmental stage were employed.
Project description:In order to study gene expression at the genomic level during elongation and secondary cell wall synthesis of upland cotton fiber, oligonucleotide microarrays were employed. RNA was isolated from fibers in 7 different time points beginning prior to peak fiber expansion, continuing through termination of fiber expansion and ending at peak cellulose synthesis (5, 8, 10, 14, 17, 21, and 24dpa). The arrays contained ~25,000 oligonucleotides representing ~12,200 genes designed from a fiber EST database during peak cell expansion. Dynamic changes in gene expression were analyzed in a developmental context to identify stage-specific biological processes and pathways likely to be crucial to cell polar elongation or cellulose biosynthesis and secondary cell wall biogenesis. Genes with significant changes in expression relative to any preceding time point were identified (moderated t-statistics, adjusted p-value <0.05) for each developmental time point with an expected false discovery rate for multiple testing <5% A bi-directional double-loop experimental design was adopted for the microarray analysis (Kerr and Churchill, 2001; Glonek, 2004) to analyze all possible significant changes in gene expression between any two developmental time points,. The double loop design guarantees that the two time points before and after each individual time point will have direct comparisons with multiple paths available to compare any two points. Self-hybridization control experiments between independent RNA isolations for each developmental stage demonstrated a high degree of reproducibility
Project description:Sea Island cotton (Gossypium barbadense) is the source of the world’s finest fiber-quality cotton, yet relatively little is understood about the genetic variation among diverse germplasm, the genes underlying important traits, and the effects of pedigree selection. Here, we resequenced 336 G. barbadense accessions and identified 16 million SNPs. Phylogenetic and population structure analyses revealed two major gene pools and a third admixed subgroup derived from geographical dissemination and interbreeding. We conducted a genome-wide association study (GWAS) of 15 traits including fiber quality, yield, disease resistance, maturity, and plant architecture. The highest number of associated loci was for fiber quality, followed by disease resistance and yield. Using gene expression analyses and VIGS transgenic experiments we confirmed the role of five candidate genes regulating four key traits, i.e., disease resistance, fiber length, fiber strength, and lint percentage. Geographical and temporal considerations demonstrate selection for the superior fiber quality (fiber length and fiber strength), and high lint-percentage in improving G. barbadense in China. Pedigree selection breeding wholly increased Fusarium wilt disease resistance, and separately improved fiber-quality and yield. Our work provides a foundation for understanding genomic variation in and selective breeding of Sea Island cotton.
Project description:We performed a comparative genomics approach between im mutant and TM-1 in order to understand the function of im gene reducing the degree of fiber cell wall development. We compared transcriptome profiles of developing fibers (10, 17, and 28 days post anthesis (DPA)) between two NILs using Affymetrix cotton array chip containing 21,854 transcripts.
Project description:Cotton is one of the most commercially important Fiber crops in the world and used as a source for natural textile Fiber and cottonseed oil. The fuzzless-lintless ovules of cotton mutants are ideal source for identifying genes involved in Fiber development by comparing with Fiber bearing ovules of wild-type. To decipher molecular mechanisms involved in Fiber cell development, transcriptome analysis has been carried out by comparing G. hirsutum cv. MCU5 (wild-type) with its fuzzless-lintless mutant (MUT). Cotton bolls were collected at Fiber initiation (0 dpa/days post anthesis), elongation (5, 10 and 15 dpa) and secondary cell wall synthesis stage (20 dpa) and gene expression profiles were analyzed in wild-type and MUT using Affymetrix cotton GeneChip Genome array.