Multifaceted and dual-edged native Trichoderma strains from subabul rhizospheric soil to combat Fusarium wilt disease – a sustainable approach

Abstract

ABSTRACT Fusarium wilt and gummosis disease is a major concern in Subabul plantations, resulting in quantitative and qualitative wood losses to the paper and pulp industry. Growers currently rely on agrochemicals, which are not environmentally safe. Therefore, developing a sustainable control strategy employing biocontrol agents is necessary. For this, the investigation was performed to identify native Trichoderma strains from Subabul rhizospheric soil having antagonistic, disease control efficiency, and PGPR attributes. Six antagonistic Trichoderma (TR1 to TR6) strains were isolated and their efficacy was tested against Fusarium in-vitro by dual plate technique and volatile metabolites. Among these, Trichoderma strains TR1 and TR2 were found efficient in counteracting the growth of F. equiseti (70–90% inhibition) compared to control. The effectiveness was primarily attributed to the increased production of volatile metabolites, siderophores, and the ability to solubilise the nutrients (P and K). Further, six potent Trichoderma strains were identified as T. asperellum (TR1, TR2, TR3, TR6), and T. hamatum (TR4, TR5) through rDNA ITS gene sequencing and phylogenetic analysis. These isolates were mass-multiplied, formulated using Talc powder followed by bio-priming in rooting media. The application of Trichoderma into rooting media reduced the wilt disease caused by artificial inoculation of F. equiseti. Further, TR1 and TR2 were found promising with conferred protection against wilt, enhanced survival rate (10–15%), and improved growth compared to untreated control. Application of adapted TR1 and TR2 antagonists in rooting media during clonal multiplication has the potential wilt control efficiency, enhanced survival rate, and plant growth promotion in Subabul.