Gene expression in cotton stems and roots accumulating starch
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ABSTRACT: Cotton (Gossypium hirsutum L) is an important crop world wide that provides fiber for the textile industry. Cotton is a perennial plant that stores starch in stems and roots to provide carbohydrates for growth in subsequent seasons. These reserves are not available to produce seed and fiber when cotton is usually grown as an annual crop. Analysis of developing cotton plants indicated that starch levels peaked about the time of first anthesis then began to decline. An earlier peak of levels of starch was occasionally observed and in some greenhouse-grown samples starch increased 2 week after first bloom. Microarray analyses compared gene expression in tissues containing low levels of starch with tissues rapidly accumulating starch. Statistical analysis of differentially expressed genes indicated increased expression among genes associated with carbohydrate metabolism, transcription activity and the proteasome. Genes associated with starch synthesis, starch degradation, sucrose metabolism, hexose metabolism, raffinose synthesis and trehalose synthesis increased in expression in starch accumulating tissues. The anticipated changes in these sugars were largely confirmed by measuring soluble sugars in relevant tissues. We propose that altering expressions of genes and pathways identified in this work could be used to more efficiently mobilize stored carbohydrate to fiber production. Keywords: starch accumulating, stem, root
Project description:Cotton (Gossypium hirsutum L) is an important crop world wide that provides fiber for the textile industry. Cotton is a perennial plant that stores starch in stems and roots to provide carbohydrates for growth in subsequent seasons. These reserves are not available to produce seed and fiber when cotton is usually grown as an annual crop. Analysis of developing cotton plants indicated that starch levels peaked about the time of first anthesis then began to decline. An earlier peak of levels of starch was occasionally observed and in some greenhouse-grown samples starch increased 2 week after first bloom. Microarray analyses compared gene expression in tissues containing low levels of starch with tissues rapidly accumulating starch. Statistical analysis of differentially expressed genes indicated increased expression among genes associated with carbohydrate metabolism, transcription activity and the proteasome. Genes associated with starch synthesis, starch degradation, sucrose metabolism, hexose metabolism, raffinose synthesis and trehalose synthesis increased in expression in starch accumulating tissues. The anticipated changes in these sugars were largely confirmed by measuring soluble sugars in relevant tissues. We propose that altering expressions of genes and pathways identified in this work could be used to more efficiently mobilize stored carbohydrate to fiber production. Keywords: starch accumulating, stem, root Genes expression was compared between cotton stems that were low in starch and accumulating starch. Gene expression was also compared between cotton roots that were low in starch and accumulating starch. A total of three microarrays were used. One dye swap was used. Material from the field were harvested 2 weeks apart. Greenhouse grown material were planted at two week intervals and harvested at the same time. NOTE that the channel representing the low starch material only gave about half of the total signal than the high starch samples. QPCR of 9 genes confirmed differential expression of 8 of them. QPCR also confirmed similar expression of two genes not predicted to be differentially expressed by the microarray analysis. Therefore no correction was made for the apparent difference in the hybridization of high and low starch samples.
Project description:Global gene expression was compared between roots of cotton plants (variety Sicot 71) flooded for 4 hours and roots of unflooded cotton plants. Global gene expression was also compared between leaves of cotton plants (variety Sicot 71) flooded for 24 hours and leaves of unflooded cotton plants. Waterlogging stress causes yield reductions in cotton (Gossypium hirsutum L.). A major component of waterlogging stress is the lack of oxygen available to submerged tissues. While changes in expressed protein, gene transcription and metabolite levels have been studied in response to low oxygen stress, little research has been done on molecular responses to waterlogging in cotton. We assessed cotton growth responses to waterlogging and assayed global gene transcription responses in root and leaf cotton tissues of partially submerged plants. Waterlogging causes significant reductions in stem elongation, shoot mass, root mass, and leaf number. At the global gene expression level waterlogging significantly alters the expression of 1012 genes (4.2% of genes assayed) in root tissue as early as 4h after flooding. Many of these genes are associated with cell wall modification and growth pathways, glycolysis, fermentation, mitochondrial electron transport and nitrogen metabolism. Waterlogging of plant roots also altered global leaf gene expression, significantly changing the expression of 1305 genes (5.4% of genes assayed) after 24h of flooding. Genes associated with cell wall growth and modification, tetrapyrrole synthesis, hormone response, starch metabolism and nitrogen metabolism were affected in leaf tissues of waterlogged plants. Implications of these results for the development of waterlogging tolerant cotton are discussed. Keywords: Stress Response
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.
Project description:Cotton is the most important economic crop that provides natural fibre and by-products such as oil and protein. The global gene expression could provide insight into the biological processes underlying growth and development, which involving suites of genes expressed with temporal and spatial controls by regulatory networks. Improvement of cotton fiber in yield and quality is the main goal for molecular breeding, but many previous research have been largely focused on identifying genes only in fibres, so that we ignore seed which may play an important role in the development of fibers. In this study, we constructed and systematically analyzed twenty-one strand-specific RNA-Seq libraries on Gossypium hirsutum L. covering different tissues, organs and development stages, of which approximately 970 million reads were generated. In total, 5,6754 transcripts derived from 2,9541 unigenes were obtained to provide a global view of gene expression for cotton development. Hierarchical clustering of transcriptional profiles suggests that transcriptomes among tissues or organs corresponded well to their developmental relatedness. The organ (tissue)-specific gene expressions were investigated efficiently and provided further insight into the dynamic programming of the transcriptome, in particularly for coordinating development between fiber cell and seed (ovule). We identified series of transcription factors and seed-specific genes, which as the candidate genes should help elucidate key mechanisms and regulatory networks that underlie fiber and seed development. This report identified comprehensive transcriptome changes in different stage of cotton development and will serves as a valuable genome-wide transcriptome resource for cotton breeding. Examination of transcriptome of cotton
Project description:This study was initiated with the objective of identifying the anther/tapetum specific promoters from cotton floral buds. Cotton is an important commercial crop. Hybrid cotton varieties are developed to obtain improved yield and fiber quality. Most of the hybrid seed production in cotton is carried out by hand emasculation, which requires large amount of manpower, resulting in high cost of hybrid seed. We are developing barnase-barstar based male sterility system, which would be a better alternative for hybrid development. The tapetum specific promoters are main requirement for such a system. The study was thus carried out to identify genes expressed in the anthers. Cotton bud sizes were correlated with tapetum development. RNA was isolated from following tissues: • Anther tissues from buds at pre-meiotic stage of development (Tapetum absent) • Buds without anther tissues at pre-meiotic stage of development • Anther tissues from buds during meiosis (Tapetum present) • Buds without anther tissues during meiosis • Anther tissues from buds at post-meiotic stage of development (Tapetum degenerated) • Buds without anther tissues at post-meiotic stage of development • Leaf tissues • Seedling 5 days after germination Biotin labeled cRNA was hybridized on Affymertix cotton Genechip Genome array following Affymetrix protocols. Three biological replicates were maintained.
Project description:Global gene expression was compared between roots of cotton plants (variety Sicot 71) flooded for 4 hours and roots of unflooded cotton plants. Global gene expression was also compared between leaves of cotton plants (variety Sicot 71) flooded for 24 hours and leaves of unflooded cotton plants. Waterlogging stress causes yield reductions in cotton (Gossypium hirsutum L.). A major component of waterlogging stress is the lack of oxygen available to submerged tissues. While changes in expressed protein, gene transcription and metabolite levels have been studied in response to low oxygen stress, little research has been done on molecular responses to waterlogging in cotton. We assessed cotton growth responses to waterlogging and assayed global gene transcription responses in root and leaf cotton tissues of partially submerged plants. Waterlogging causes significant reductions in stem elongation, shoot mass, root mass, and leaf number. At the global gene expression level waterlogging significantly alters the expression of 1012 genes (4.2% of genes assayed) in root tissue as early as 4h after flooding. Many of these genes are associated with cell wall modification and growth pathways, glycolysis, fermentation, mitochondrial electron transport and nitrogen metabolism. Waterlogging of plant roots also altered global leaf gene expression, significantly changing the expression of 1305 genes (5.4% of genes assayed) after 24h of flooding. Genes associated with cell wall growth and modification, tetrapyrrole synthesis, hormone response, starch metabolism and nitrogen metabolism were affected in leaf tissues of waterlogged plants. Implications of these results for the development of waterlogging tolerant cotton are discussed. Keywords: Stress Response Plants of cotton cultivar Sicot 71 were grown to the two-leaf stage in tubs. For stress treatments plants were either watered as normal or flooded with water to completely submerge the root system. At four and twenty-four hours post-flooding samples of root or leaf tissue were taken from control and flooded plants. Total RNA was extracted from each tissue sample and assayed on cotton Affymetrix chips. Two biological replications were used for each comparison.
Project description:Cotton (Gossypium hirsutum L.), a crucial global fiber and oil seed crop, faces a diverse biotic and abiotic stresses. Among these, temperature stress strongly influence its growth, prompting adaptive physiological, biochemical and molecular changes. In this study, we explored the proteomic changes underscoring the heat stress tolerance in the leaves of two locally developed cotton genotypes, i.e., heat tolerant (GH-Hamaliya Htol) and heat susceptible (CIM-789 Hsus), guided by morpho-physiological and biochemical analysis. These genotypes were sown at two different temperatures, control (35ºC) and stress (45ºC) in glass house, in randomized complete block design (RCBD) in three replications. At the flowering stage, a label-free quantitative shotgun proteomics of cotton leaves revealed the differential expression of 701 and 1270 proteins in the tolerant and susceptible genotype compared to the control, respectively. Physiological and biochemical analysis showed that the heat-tolerant genotype responded uniquely to stress by maintaining the net photosynthetic rate (Pn)( 25.2-17.5µmolCO2m-2S-1), chlorophyll (8.5-7.8mg/g FW), and proline contents (4.9-7.4 µmole/g) compared to control, supported by the upregulation of many proteins involved in several pathways including photosynthesis, oxidoreductase activity, response to stresses, translation, transporter activities as well asprotein and carbohydrate metabolic processes. In contrast, the distinctive pattern of protein downregulation involved in stress response, oxidoreductase activity, and carbohydrate metabolism was observed in susceptible plants. Thus, in this study, the specific proteins that increased in abundance under heat stress tolerance mechanism can be used as markers in future for producing the heat tolerant cotton genotypes without compromising the yield.
Project description:In this study, β-carotene concentrations in cassava storage roots were enhanced by co-expression of transgenes for deoxyxylulose-5-phosphate synthase (DXS) and bacterial phytoene synthase (crtB), mediated by the patatin type-1 promoter. Storage roots harvested from field-grown plants accumulated carotenoids to ≤50 μg/g DW, a 15- to 20-fold increase relative to roots from non-transgenic plants. Approximately 85-90% of these carotenoids accumulated as all-trans-β-carotene, the most nutritionally efficacious carotenoid. β-carotene-accumulating storage roots displayed delayed onset of post-harvest physiological deterioration, a major constraint limiting utilization of cassava products. Significant metabolite changes were detected in β-carotene enhanced storage roots. Most significantly, an inverse correlation was observed between β-carotene and dry matter contents, with reductions of 50% to 60% of dry matter content in the highest carotenoid accumulating storage roots of different cultivars. Further analysis confirmed concomitant reduction in starch content, and increased levels of total fatty acids, triacylglycerols, soluble sugars, and abscisic acid. Irish potato engineered to co-express DXS and crtB displayed a similar correlation between β-carotene accumulation, reduced dry matter and starch content, and elevated oil and soluble sugars in tubers. Transcriptome analyses revealed reduced expression of starch biosynthetic genes, ADP-glucose pyrophosphorylase genes, in transgenic, carotene-accumulating cassava roots relative to non-transgenic roots. These findings highlight unintended metabolic consequences of provitamin A biofortification of starch-rich organs and point to strategies for redirecting metabolic flux to restore starch production.
Project description:Cotton fibers are seed trichomes, and their development undergoes a series of rapid and dynamic changes from fiber cell initiation, elongation to primary and secondary wall biosynthesis and fiber maturation. Previous studies showed that cotton homologues encoding putative MYB transcription factors and phytohormone responsive factors were induced during early stages of ovule and fiber development. Many of these factors are targets of microRNAs (miRNAs). miRNAs are ~21 nucleotide (nt) RNA molecules derived from non-coding endogenous genes and mediate target regulation by mRNA degradation or translational repression. Here we show that among ~4-million reads of small RNAs derived from the fiber and non-fiber tissues, the 24-nt small RNAs were most abundant and were highly enriched in ovules and fiber-bearing ovules relative to leaves. A total of 28 putative miRNAs families, including 25 conserved and 3 novel miRNAs were identified in at least one of the cotton tissues examined. Thirty-two pre-miRNA hairpins representing 19 unique families were detected in Cotton Gene Indices version 9 (CGI9) using mirCheck. Sequencing, miRNA microarray, and small RNA blot analyses showed that many of these miRNAs differentially accumulated during ovule and fiber development. The cotton miRNAs examined triggered target cleavage in the same predicted sites of the cotton targets in ovules and fibers as that of the orthologous target genes in Arabidopsis. Targets of the potential new cotton miRNAs matched the previously characterized ESTs derived from cotton ovules and fibers. The miRNA targets including those encoding auxin response factors were differentially expressed during fiber development. We suggest that both conserved and new miRNAs play an important role in the rapid and dynamic process of fiber and ovule development in cotton.