Abstract
Cotton is major fiber crop among agricultural commodities grown worldwide. Prolonged osmotic stress and seasonal water shortage effect plant growth and yields. To explore the drought responsive molecular mechanism in cotton roots, we constructed cDNA library for the identification, functional annotation and expression analysis of potential drought responsive transcripts. mRNA extracted from cotton roots under drought stress was used to construct cDNA library. A total of 711 expressed sequence tags were generated from cDNA library. NCBI BLAST analysis of reported expressed sequence tags showed homology of 27% sequences with Gossypium species while 24% sequences showed no sequence similarity in non-redundant nucleotide database. Remaining 49% sequences revealed sequence similarity results with other plant species. Functional annotation was performed for sequenced EST's using Arabidopsis Gene ontology database (TAIR). We examined the expression pattern of 08 differentially expressed ESTs using RT- qPCR and validated that all these were up-regulated in roots under osmotic stress, but to different folds. The candidate EST sequences identified in this study will be valuable resource to elucidate stress responsive molecular mechanism and genetic breeding of cotton in future.