Phosphate solubilization by Trichoderma koningiopsis (NBRI PR5) under abiotic stress conditions
Abstract Phosphate (P) solubilizing fungi contribute considerably in microbial phosphate mobilization. However, effects of different abiotic stresses on P solubilization mechanisms in Trichoderma are largely unexplored. In the present study we selected a P solubilizing Trichoderma to study the mechanism of P solubilization under alkaline and drought conditions. Among 33 Trichoderma isolates (NBRI PR1 NBRI PR33) NBRI PR5 was selected after screening for stress tolerance, antagonistic activity against phyto pathogens and P solubilization. The selected strain, Trichoderma koningiopsis (NBRI PR5) was characterized and identified using ITS and tef1 sequencing (Accession no. JN375992) Results show that NBRI PR5 uses different mechanisms of P solubilization under in vitro alkaline and drought conditions. NBRI PR5 produced organic acids for solubilizing insoluble tri calcium phosphate (TCP) at high pH stress. In drought conditions NBRI PR5 accumulated poly phosphate in its mycelia and produced alkaline phosphatase enzyme for P solubilization. The study concludes that T. koningiopsis employs different mechanisms of P solubilization in different stress conditions and therefore, it can be used in management of stressed soils.