Expression of LEA gene in common bean (Phaseolus vulgaris L) cultivars under drought stress at vegetative and reproductive stages

Common beans (Phaseolus vulgaris L.) are susceptible to drought stress especially in reproductive stage. A series of genes are identified recently in which their transcription either increase or decrease in response to drought stress. Out of these genes, identified in common bean, could be referred to LEA gene. The present study was conducted at Shahrekord University aimed to analyze LEA gene expression in response to drought stress at vegetative and reproductive stages in 11 beans genotypes. Water deficit stress was induced at vegetative stage with the appearance of the third trifoliate and at reproductive stage when flower buds were passing through meiosis. The leaves and flower buds were sampled from control and water-stressed plants at vegetative and reproductive stages, respectively. Results indicated that drought stress at either of vegetative and reproductive stages increased the expression of the gene LEA, but the level of expression was not similar in all genotypes. The increment in the expression of LEA gene was 75 and 95 fold in leaf tissues of Goynok98 under stress at vegetative stage in comparison with the gene expression of its control and control of the susceptible line G-14088, respectively. However in flower buds of line KS-21191, the increment in the expression of LEA gene due to stress was 366 and 250 fold of that in its control and control of the susceptible line, respectively. The expression trend of LEA gene was similar in cultivars Kara and Daneshkadeh. The lines KS-21189 and KS- 21191also showed similar expression trend. Considering the trend and the level of expression for LEA gene, it could probably be concluded that the line KS-21191 is more tolerant to stress than other studied genotypes.