Can Catalase and Exopolysaccharides Producing Rhizobia Ameliorate Drought Stress in Wheat?

Catalase and exopolysaccharides producing ability of rhizobia increases its survival in arid and semiarid climates. Rhizobial exopolysaccharides activity increases root colonization and nutrient or water holding capacity of the rhizosphere. For the reason, a series of experiments were conducted to sort out efficient rhizobial isolates (belonging to Lens culinaris L., Vigna radiata L. and Cicer arietinum L. cultivated in Chakwal (arid) and Faisalabad (semiarid) areas which can ameliorate the impact of water deficit stress on wheat seedlings. Among 35 isolates, Rhizobium leguminosarum (LR-30), Mesorhizobium ciceri (CR-30 and CR-39), and Rhizobium phaseoli (MR-2) improved the growth, biomass and drought tolerance index of the wheat seedlings under PEG-6000 simulated drought. Selected isolates were producers of indole acetic acid, which enhanced the root length of the seedlings to dilute the drought impact. However, isolates LR-26, MR-17 and CR-34 remained deleterious for seedling growth whether drought was applied or not. In conclusion, rhizobial capability to survive under drought and improving seedling growth under drought is a good criterion to select beneficial bacteria for rescuing wheat seedlings growth under water deficit conditions. copyright 2014 Friends Science Publishers