Novel synergism of Cedecea lapagei KU14 and Bacillus subtilis KU21 for sustainable productivity of Rosmarinus officinalis in Northwest Himalayas

Abstract

The current study aimed to assess the scope of native potential endophytic bacteria Bacillus subtilis KU21, Pseudomonas aeruginosa SI12 and Cedecea lapagei KU14 for synergistic effect to develop as consortium biofertilizer of rosemary. All the three strains were assessed for multiple plant growth promoting (PGP) traits viz., P solubilization, siderophore and Indole-3-acetic acid production (IAA). Consortia of strains (KU21, SI12 and KU14) showed significantly high production of IAA, siderophore production and P-solubilization over the single inoculants. All the isolates i.e., KU21, SI12 and KU14 individually and their consortia were assessed for in vivo growth studies of rosemary under net house conditions. Combined application of these strains significantly increased growth parameters of rosemary over single inoculation and untreated control. Based on the results, two consortia i.e., B. subtilis KU21+ C. lapagei KU14 and B. subtilis KU21+ C. lapagei KU14+ P. aeruginosa SI12 were further evaluated under field conditions. The combined application of B. subtilis KU21+ C. lapagei KU14 significantly improved rosemary growth parameters (at vegetative and flowering stage), nutrient acquisition, and soil quality parameters over uninoculated control. This is the first field report that describes the efficacy of novel endophytic strains i.e., B. subtilis KU21+ C. lapagei KU14 for improving rosemary production and soil health simultaneously, hence may be recommended for sustainable production of R. officinalis in Northwest Himalayan region.