Bioaugmentation of Phanerochaete concrescens KS7 for enhanced growth and zinc nutrition in rice (Oryza sativa L.)

Bioaugmentation of microbial strains could act as sustainable intervention in soil for enhancing the availability of nutrients. Zinc deficiency is widely reported across the world and application of zinc based fertilizers mostly resulted in formation of unavailable zinc in soil. A fungus with zinc solubilisation was isolated from rice and identified as Phanerochaete concrescens KS7. Inoculation of fungus in culture medium resulted in decrease of pH to 4.4 and analysis of medium revealed higher content of citric and gluconic acid in comparison with uninoculated broth. Indole acetic acid production by the strain was found to be enhanced in presence of tryptophan under broth conditions. Zinc solubilisation potential of strain was quantified in medium amended with insoluble zinc source. There was enhanced root growth and significantly higher zinc concentration in rice seedling on inoculation with KS7. There was increase in plant height, leaf area, number of grains per panicle and grain yield per plant on inoculation with P. concrescens in two selected varieties of rice grown in zinc deficient soil. Partition analysis was done for zinc in root, stem and grains and there was significant increase of zinc content in rice grain on inoculation with KS7. Total and available zinc was quantified from soil after harvest of rice and found that zinc contents were higher in soil of KS7 inoculated plants. Phanerochaete concrescens KS7 could act as potential solubilizer of zinc in soil and improve the zinc content of crop produce especially in zinc deficient soils.