Physiological, biochemical, and molecular responses of thermotolerance in moth bean (Vigna aconitifolia (Jacq.) Marechal)

Among several abiotic stresses, heat stress has a large negative impact upon agricultural productivity worldwide. Moth bean (Vigna aconitifolia (Jacq.) Marechal) attracts a great deal of attention due to its better performance under drought and heat stress conditions. An experiment was designed to find out the effects of heat stress on relative water content (RWC), membrane stability index (MSI), and proline, protein, and chlorophyll (Chl) contents using 10 genotypes of moth bean. Physiological and biochemical parameters indicated that RMO 40 followed by Jadia, IC 36157, Jwala, and Marumoth were heat-tolerant (HT) genotypes, and IC 121051, IC 36392, IC 39702, IC 472257, and IC 140725 were heat-susceptible (HS) genotypes of moth bean. Under heat stress, the HT genotypes showed minimal reduction in RWC, MSI, and protein as compared to the susceptible ones, revealing that the HT genotypes performed well under heat stress. Many heat shock proteins and dehydration proteins are synthesized in plants under heat stress. Expression analysis of three such genes was performed in ten genotypes of moth bean. The analysis revealed that the HT genotypes showed better performance under stress conditions for survival. The above studied parameters would be very useful in the identification of HT varieties for future breeding programs in moth bean and related Vigna species.