Expression of miRNAs regulates Growth and Development of French bean (Phaseolus vulgaris) under Salt and Drought Stress conditions

Abstract

Identification of stress-regulated miRNAs is crucial for understanding how plants respond to environmental stimuli. We are interested in the identification of miRNAs in French bean (Phaseolus vulgaris) to uncover different plant strategies to cope with adverse conditions and because of its relevance as a crop in developing countries. In this study, we investigated the effect of salt and drought stress in expression of small regulatory RNAs. Both salt and drought stresses altered the expression pattern of miRNA in a dose-dependent manner. However, each miRNA responded to drought stress in a different pattern. Salt and drought stress changed the expression level of miRNAs mainly from 0.9-fold up-regulation to 0.7-fold down-regulation. Micro RNAs were less sensitive to drought than salinity, as evidenced by the narrow fold change in expression levels. Although the range of change in expression level of miRNAs was similar under salt and drought stress, no miRNAs displayed significant change in expression level under all tested salt conditions. Micro RNAs, miR156 and miR162, showed significant change in expression level under high drought stress. This suggests that miR156 and miR162 may attribute to the adaption to drought stress and are good candidates for improving the vegetable crop by transgenic technology.