Biochemical and molecular changes in three genotypes of beans (Phaseolus vulgaris L.) under drought stress

Drought stress is one of the major causes of reduction in crop production. Study physiological and biochemical processes related to drought stress can give better insight about mechanism of drought tolerance. To study the physiological and biochemical processes, three genotypes including K-S-31167, GE-288 and Naz were subjected to 3 level of drought stress based on 25, 50 and 100 percent of field capacity using CRD design with three replication using Factorial arrengment, Droght stress was applied five weeks after planting and lasted for 10 days. Second terifoliate were used for sampling. The results indicated significant changes in the electrolyte leakage (EL), prolin content (PC) and carbohydrates content (CC). Tolerant genotype (K-S-31167) had greater PC but lesser EL compare to relatively tolerant genotype (GE-288) and sensitive genotype (Naz). This indicates that tolerant genotype had higher membrane stability during stress. Results from measurement of soluble carbohydrate and expression of sucrose synthase and vacuolar invertase genes showed increase and decrease in the expression of these genes resulted in increase and decrease in the activity of the invertase and sucrose synthase enzyme which in turn influences the concentration of soluble materials which acts as metabolic signal in response to stress.