Reproductive stage drought tolerance in blackgram is associated with role of antioxidants on membrane stability

Abstract

Drought is one of the major abiotic stresses that affect crop growth and yield through alteration in the physiological and molecular process in plants. Blackgram (Vigna mungo) being an important rainfed pulse crop in India, suffers a yield loss of 20–30%, because of drought at flowering stage. However, a comprehensive study on response of Vigna mungo to drought stress is not studied until now. In this work, pot experiment with randomized block design was conducted for seven varieties for assaying the physiological response to drought tolerance by V. mungo during flowering stage. Results showed two varieties namely VBN4 and K1 have higher tolerance due to increased synthesis of ABA (5-fold), proline (4.5-fold) and lipid peroxidase activity (5-fold) which collectively protects tissues from oxidative damage during drought stress. However, our SDA-PAGE and mRNA expression analysis during drought indicated differential expression at 23KDa molecular weight and with 1100 bp region respectively in the drought stressed Vigna mungo VBN4 samples homological to chloroplastic-Small HSPs’. Further, biplot analysis showed varieties VBN4 and K1 were associated with traits viz, gas exchange, ABA, proline, and lipid peroxidation contributing to 85% of the variation. Thus, our analysis identified trait of antioxidant accumulation protects membrane stability and contribute the major share of drought stress tolerance in Vigna mungo and these traits could be used as index for understanding the molecular response of blackgram during drought stress.