Root- Nodulating Ensifer Adhaerens Ks23 of Pisum Sativum L. In Optimisation of Cadmium Biosorption Using Rsm Based Approach

Abstract

The Cadmium tolerance by root nodulating bacteria Ensifer adhaerens KS23 inhabiting in Pisum sativum L. var. Arkel revealed linear relationship with inorganic salt cadmium sulphate (CdSO4) upto 200 μg/ml, corresponding to growth and survival in solid as well as liquid Yeast Extract Mannitol (YEM) medium with LC50 value of 107.2 μg/ml and LC95 of 184.5 μg/ml. The results of phylogenetic and morpho-physiological analysis exhibited the genus E. adhaerens. KS23 was found to be the most promising among all the 20 isolates. The increase in Glutathione S-transferase (GST) activity by KS23 was 9.7 fold under Cd stress. Wherein, P and F values were <0.05 and 26.54 respectively and predicted r2 value of 0.8192 and adjusted r2 value 0.8908 were reasonable (i.e. <0.2) of the Box Behnken design. The data showed that 81.24% cadmium bio-removal achieved at pH 6.0, 30°C and 168 h of incubation while supplementing the YEM medium with 25 μg/ml cadmium. Further, its effect on plant growth and development exhibited due to production of IAA, secretion of siderophores, phosphate solubilisation and 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase activity by E. adhaerens KS23. In addition to inherent PGP attributes, Cd tolerant E. adhaerens KS23 played dual role of biosorption of cadmium and upsurge in growth promotion of P. sativum which may provide a new root-nodulating bacterium inhabiting in P. sativum cultivated at high altitudes of Himalayan region.