Novel synergism of Cedecea lapagei KU14 and Bacillus subtilis KU21for sustainable productivity of Rosmarinus officinalis in Northwest Himalayas

Aims: Rosmarinus officinalis (rosemary) is most extensively used culinary herbs rich in antioxidants and several other secondary metabolites. Soil quality affects the biosynthesis of secondary metabolites thereby reducing their quality. An approach to improve soil quality and boosting plant productivity in a sustainable manner is the use of plant growth promoting (PGP) endophytic bacteria. Previously three endophytic bacteria associated with roots of R. officinalis were characterized for in vitro PGP traits. The purpose of this study was to assess (1) the compatibility of isolated potential indigenous endophytic bacteria for PGP traits to develop potential consortium biofertilizer, and (ii) how the coordinated interaction among these strains mediates the response for productivity and nutrient acquisition of R. officinalis .Methods In vitro synergistic interactions among isolated strains ( Bacillus subtilis KU21, Pseudomonas aeruginosa SI12 and Cedecea lapagei KU14) were examined for multiple PGP traits. In vivo studies were carried out to assess synergistic effects of theses strains on productivity and soil quality of R. officinalis . ResultsThe consortia of strains exhibited higher production of IAA, siderophore and phosphorus solubilization. Further, assessment of consortia of these strains significantly improved rosemary growth parameters, nutrient acquisition and soil quality over single inoculation and uninoculated control. Conclusions 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, may be recommended for sustainable production of R. officinalis in Northwest Himalayan region.