Synergistic effect of Mesorhizobium ciceri and 1-amino cyclopropane 1-carboxylate (ACC) deaminase producing rhizobacteria on chickpea growth and yield

Plant growth promoting rhizobacteria IIPR-ACC-3 and IIPR-ACC-79 with ACC deaminase activity of 862.41 and 417.32 nM of a-ketobutyrate/mg protein, respectively were isolated from chickpea rhizosphere. 16S rDNA sequence analysis indicated that IIPR-ACC-3 is Bacillus subtilis while IIPR-ACC-79 belongs to Pseudomonas stutzeri. Both the bacterial strains showed other plant growth promoting traits including the production of IAA, Siderophore and can reduce negative effects of stress ethylene with ACC deaminase under rainfed as well as irrigated field conditions. Gnotobiotic root elongation assay with bacterized chickpea recorded higher root length and bio mass up to 113% over stressed seedlings. Root biomass of rainfed chickpea was improved by seed bacterization with IIP R-ACC-79 andits combined inoculation with Mesorhizobium ciceri strain CR-13 up to 31.59 and 38.34% respectively over uninoculated control. Enhanced root nodulation at early vegetative stages of chickpea due to combined inoculation of bacterial strains helped the plant to develop 47.91% higher shoot biomass at 90 days post inoculation. ACC deaminase producing bacteria interact synergistically with M. ciceri strain CR-13 and enhanced plant growth and grain yield of chickpea under rainfed as well as irrigated field.