Identification of a novel drought tolerance gene in Gossypium hirsutum L. cv KC3

Development of drought resistant cotton cultivars has long been a major breeding objective, since water stress limits fiber production and productivity. Recent advances in functional genomics can increase the efficiency of conventional breeding for genetic improvement of crop plants for improved abiotic stress resistance. To this end, a novel drought resistance gene was identified by comparing the gene expression profile of Gossypium hirsutum cv KC3 and MCU12 by employing a cDNA-RAPD approach. Physiological and biochemical studies showed that KC3 has relatively better drought tolerance than MCU12. Among 25 random primers, OPA15 has identified differentially expressed cDNA in KC3. Results of BLASTP algorithm have shown that this cDNA has significant homology with P-Glycoprotein, ACC oxidase2 and ABC transporter which are involved either directly, or indirectly, in stress tolerance in animals and plants. Hence, the cDNA sequence identified in this study may be a novel gene that confers drought resistance in cotton as KC3 is well adapted and is widely cultivated in rain-fed tracts of Tamil Nadu, India. Further characterization of this gene may show it has potential application for development of cotton with improved drought resistance, through genetic engineering and/or marker aided selection (MAS)