Biocontrol efficacy and induced defense mechanisms of indigenous Trichoderma strains against Fusarium wilt [F. udum (Butler)] in pigeonpea

Abstract

This study aimed to identify efficient Trichoderma isolate(s) for the management of Fusarium wilt in pigeonpea. In vitro and in vivo (greenhouse) experiments were conducted to evaluate 17 Trichoderma isolate(s) for their anti-pathogenic activity, induction of plant biochemical functions, disease suppression, and plant growth traits comparing with standard Trichoderma strains. Among the indigenous isolates, IIPRTh-31 (T. asperellum) and IIPRTh-33 (T. afroharzianum) had a higher mycelia growth inhibition in vitro [membrane assay (>74%), binary assay (>65%)]. Seed treatment with IIPRTh-31 and IIPRTh-33 isolates led to an increase in peroxidase (173–244%), polyphenol oxidase (48–80%), phenylalanine ammonia–lyase (147–178%) activities in pigeonpea plants over control and reduced disease incidence by 78–85%. Hence, IIPRTh-31, and IIPRTh-33 strains demonstrate excellent bio-control of Fusarium wilt in pigeonpea via induction of defense-related enzymes. These isolates have been registered (Registration No. NAIMCC-R-5, NAIMCC-R-6) and used for talc-based bio-formulations for field application.