Physiological, biochemical and molecular manifestations in response to seed priming with elicitors under drought in cotton

Water stress has a detrimental effect on growth and development, which alters physio-biochemical activities. Seed priming with elicitors such as methyl jasmonate and paclobutrazol can mitigate the impact of drought stress. Therefore, pot-culture studies were conducted with drought-tolerant (DTS-155) and drought-suscep­tible (IC-357055) cotton genotypes to assess the seed priming effects of elicitors (methyl jasmonate and paclobutrazol) on the physio-biochemical changes and gene expression. The dose (50, 100, 150 and 200 mM) and time interval (1.5 and 2.5 h) experiments of both the elicitors were performed separately. On the basis of germination, seedling growth and vigour, a 150 mM elicitor for 1.5 h time interval was found to be the best. Biochemical and physiological parameters confirmed an increase in relative water content, total antioxidant activities, chlorophyll, superoxide dismutase, catalase and proline under drought stress in both the genotypes, but a decrease in lipid peroxidation. Among the elicitors, methyl jasmonate improved drought tolerance as compared to paclobutrazol. Gene expression studies with Rub-S, Rub-L and Osmotin confirmed the results. Transcript abundance of Osmotin and Rub-L was upregulated under drought stress in both the genotypes and was highest in methyl jasmonate primed samples. These findings suggest that priming with methyl jasmonate enhances drought tolerance in cotton