Fluorescent pseudomonads, an antidote and drought stress mitigating PGPR from groundnut (Arachis hypogaea L.) rhizosphere

Abstract

Fluorescent pseudomonads drawn broad attention as production of secondary metabolites, phytohormones, siderophores, enzymes, antibiotics, hydrogen cyanide and volatile compounds. The present study was to exhilarate traits of plant growth promotion by fluorescent pseudomonads under drought stress. Fifty one efficient bacterial isolates were taken to evaluate their growth in different concentrations of polyethylene glycol 6000 (PEG) at 0 % (-0.05 MPa), 10 % (-0.65 MPa), 20 % (-1.57 MPa), 30 % (-2.17 MPa) and 40 % (-2.70 MPa). On the basis of growth at higher PEG (40 %) concentration, four efficient bacteria were preferred. Plant growth promoting traits such as IAA, exopolysachharides (EPS) production, ACC deaminase activity, phosphate solubilization and potassium releasing characters were tested for the selected drought tolerant fluorescent pseudomonads. Among four efficient strains, two strains i.e., PCKR-2 showed P-solubilization Index was (3.80 mm), followed by AGVS (4.33 mm), PCKS (4.12 mm) and PVAS (2.28 mm). Data on potassium solubilization activity show that out of two isolates, PCKR-2 showed the highest solubilization zone (3.50 mm), followed by PCKS (3.17 mm), AGVS (2.83 mm) and PVAS (2.50 mm). The findings suggests that the use of fluorescent pseudomonads will aid better plant growth promotion under drought stress.