Antioxidant response and <i>Lea</i> genes expression under salt stress and combined salt plus water stress in two wheat cultivars contrasting in drought tolerance

Abstract

Two wheat cultivars, C306 and PBW343 contrasting in drought tolerance were compared for their antioxidant response and <i>Lea</i> genes’ expression under salt stress (SS) and combined stress (CS) of salt stress plus water stress during seedlings growth. The drought susceptible cultivar (PBW343) behaved different towards SS/CS than towards WS. It accumulated more dry masses in shoots, more ascorbate, had higher ascorbate to dehydroascorbate ratio, lesser dehydroascorbate, lesser malondialdehyde (MDA), more proline and higher antioxidant enzymes under SS than under WS. CS increased dry masses, ascorbate, ascorbate to dehydroascorbate ratio, antioxidant enzymes and decreased dehydroascorbate and MDA contents from levels under WS. The drought tolerant cultivar (C306) though showed higher levels of ascorbate, ascorbate to dehydroascorbate ratio, lower levels of dehydroascorbate, showed lesser dry biomasses in shoots, higher MDA and lesser ascorbate peroxidase and catalase activities under SS than under WS and these features were improved on combining WS with SS. All <i>lea</i> genes were induced under all stresses in both cultivars except <i>Wrab17</i> in C306 only, was not induced under any stress. Eight <i>Lea</i> genes out of ten were induced higher under WS than SS in C306 but induced same in PBW343. <i>Wdhn13 </i>gene was higher salt-responsive than other <i>lea</i> genes in both cultivars.