Development of expressed sequenced tags (EST) to identify some pathogen resistance genes expressed in Gossypium arboreum

Abstract Cotton the most important fiber crop is facing a major threat due to a viral disease caused by cotton leaf curl virus (CLCuV). The cotton specie, Gossypium arboreum is resistant to this disease. Cotton scientists are working to find the key genes in G . arboreum that confer resistance against cotton leaf curl disease (CLCuD). Current research work is an effort to find some potential biotic stress related resistance genes from G . arboreum and the their evaluation against CLCuV infection utilizing functional genomics approaches. Leaf cDNA library was constructed from field grown G . arboreum which was further utilized to identify and isolate clones involved in resistance against CLCuD. The clone sequences were exploited to establish expressed sequence tags (EST). The EST represented some important biotic stress resistance genes like lipoxygenase, cytochrome P450, CPMMV like coat protein, serine threonine kinase, a RGA, lipid transfer protein and ubiquitin conjugating enzyme E2. As cotton is a fiber crop so some trichome development genes like aquaporin, arabinogalactans and cellulose synthase were also found. Lipoxygenases are known to be involved in apoptosis and biotic and abiotic stress responses in plants. Here the members of LOX are identified in biotic stress resistant G . arboreum . G . arboreum genome encode 13 LOX proteins. The G . arboreum LOXs are validated based on protein alignment studies. This is the first report wherein number of LOXs are identified in cotton which may help to better understand the apoptosis and responses to biotic and abiotic stresses in naturally resistant G . arboreum .