The role of BADH gene in oxidative, salt, and drought stress tolerances of white clover

Abstract

The aim of this study was to confirm the presence of BADH gene and control whether it plays an important role to protect white clover (Trifolium repens L.) against oxidative, salt, and drought stresses. Three genotypes possessing BADH and 1 genotype lacking BADH were selected, considering the expression levels of BADH in response to methyl viologen mediated oxidative stress. The genotypes possessing BADH displayed significantly less ion leakage under oxidative stress treatment, compared to that lacking BADH. In order to test salinity tolerance, the plants were treated with 300 mM NaCl for 2 weeks, and to mimic drought conditions, plants were, grown without irrigating for 5 days. Under the salt stress, the plants possessing BADH contained lower malondialdehyde levels and higher chlorophyll contents than that of plants lacking BADH. Similarly, under the drought conditions, the plants possessing BADH were found to have increased levels of glycinebetaine, proline, and high relative water contents than the plant lacking BADH. These findings indicate that the plants having BADH exhibited enhanced tolerance to salt and drought stresses. These enhanced tolerances of plants possessing BADH gene is attributed to its ability to induce glycinebetaine synthesis. Moreover, the plants possessing BADH were found to exhibit higher relative feed value under both stress and normal conditions. These plants could be used as forage crops on marginal areas having salinity or drought problems.