Project description:Cotton premature leaf senescence often occurred with an increasing frequency in many cotton growing areas and caused serious reduction in yield and quality of cotton has been one of the impontant factors that restrict severely the production of cotton.Our laboratory studies showed chilling stress is the key factor that induced A. alternatia infection, caused Alternaria disease and then lead to cotton leaf senescence, but the molecular mechanism of cotton premature leaf senscence is still unclear. We used microarrays to study molecular mechanism of chilling stress causing Alternaria alternata infection and leading to cotton leaf senescence and find the key genes during this process.
Project description:Cotton premature leaf senescence often occurred with an increasing frequency in many cotton growing areas and caused serious reduction in yield and quality of cotton has been one of the impontant factors that restrict severely the production of cotton.Our laboratory studies showed chilling stress is the key factor that induced A. alternatia infection, caused Alternaria disease and then lead to cotton leaf senescence, but the molecular mechanism of cotton premature leaf senscence is still unclear. We used microarrays to study molecular mechanism of chilling stress causing Alternaria alternata infection and leading to cotton leaf senescence and find the key genes during this process. Plants were grown in growth chamber with a 14/10 hours photoperiod, 28â/22â. Three-to-four leaves stage cotton plants were pre-treated by chilling stress with the low temperatures of 16/12â day/night for a fixed time length of 3 days. While, the normal growth plants were sustained growing at optimal temperature of 28/20â day/night. And then, both chilling stress pre-treated and normal growth cotton plants were inoculated with Alternaria. alternata isolate A1. The mock inoculations were performed with sterilized water. Cotton leaf Samples were respectively collected at 3, 6 days after inoculation (DAI) for RNA extraction and hybridization on Affymetrix microarrays. To that end, we collected 8 samples, i.e. chilling stress pre-treated cotton leaves: 3 DAI (C) and its mock control (D), 6 DAI (E) and its mock control (F); normal growth cotton leaves: 3 DAI (H) and its mock control (I), 6 DAI (J) and its mock control (K). All samples were arranged in completely randomized designed with three replications for each treatment.
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.
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:For environmental safety, the high concentration of heavy metals in the soil should be removed. Cadmium (Cd), one of the heavy metals polluting the soil while its concentration exceeds 3.4 mg/kg in soil. Potential use of cotton for remediating heavy Cd-polluted soils is available while its molecular mechanisms of Cd tolerance remains unclear in cotton. In this study, transcriptome analysis was used to identify the Cd tolerance genes and their potential mechanism in cotton. Finally 4,627 differentially expressed genes (DEGs) in the root, 3,022 DEGs in the stem and 3,854 DEGs in leaves were identified through RNA-Seq analysis, respectively. These genes contained heavy metal transporter genes (ABC, CDF, HMA, etc.), annexin genes, heat shock genes (HSP) amongst others. Gene ontology (GO) analysis showed that the DEGs were mainly involved in the oxidation-reduction process and metal ion binding. The DEGs mainly enriched in two pathways, the influenza A and the pyruvate pathway. GhHMAD5 protein, containing a heavy-metal domain, was identified in the pathway to transport or to detoxify the heavy ion. GhHMAD5-overexpressed plants of Arabidopsis thaliana showed the longer roots compared with the control. Meanwhile, GhHMAD5-silenced cotton plants showed more sensitive to Cd stress compared with the control. The results indicated that GhHMAD5 gene is remarkably involved in Cd tolerance, which gives us a preliminary understanding of Cd tolerance mechanisms in upland cotton. Overall, this study provides valuable information for the use of cotton to remediate the soil polluted with heavy metals.
Project description:Transcriptome analysis in cotton under drought stress. To study the molecular response of drought stress in cotton under field condition global gene expression analysis was carried out in leaf tissue. Gossypium hirsutum cv. Bikaneri Nerma was used for the gene expression analysis. Cotton plants were subjected to drought stress at peak flowering stage. Leaf samples were collected when the soil moisture content was 19.5% which is 50% of the normal control plots. Gene expression profiles in drought induced and their respective control samples were analyzed using Affymertix cotton Genechip Genome arrays to study the global changes in the expression of genome.