Antimicrobial Traits of Beauveria bassiana Against Rhizoctonia solani, the Causal Agent of Sheath Blight of Rice Under Field Conditions

Abstract

Beauveria bassiana, an entomopathogenic fungus, has recently drawn attention worldwide not only as a potential biocontrol agent against insect pests but also for its other beneficial roles as plant disease antagonist, endophyte, plant growth promoter, and beneficial rhizosphere colonizer. In the present study, 53 native isolates of B. bassiana were screened for antifungal ability against Rhizoctonia solani, the causal agent of sheath blight of rice. Also, the mechanisms underlying such interaction and the responsible antimicrobial traits involved were studied. Following this, potential B. bassiana isolates were assayed against the reduction of sheath blight of rice under field conditions. The results showed that B. bassiana exhibited antagonistic behavior against R. solani with a percent mycelial inhibition recorded maximum of up to 71.15%. Mechanisms behind antagonism were the production of cell-wall-degrading enzymes, mycoparasitism, and the release of secondary metabolites. The study also deciphered several antimicrobial traits and the presence of virulent genes in B. bassiana as a determinant of potential plant disease antagonists. Under field conditions, combined application of the B. bassiana microbial consortium as a seed treatment, seedling root dip, and foliar sprays showed reduced sheath blight disease incidence and severity up to 69.26 and 60.50%, respectively, along with enhanced plant-growth-promoting attributes. This is one of the few studies investigating the antagonistic abilities of the entomopathogenic fungus B. bassiana against phytopathogen R. solani and the underlying mechanisms involved.

First record of Aspergillus nomiae as a broad-spectrum entomopathogenic fungus that provides resistance against phytopathogens and insect pests by colonization of plants

“…To the best of our knowledge, there have been few reports on the biocontrol effects against soil-borne diseases and their causal agents induced by endophytic colonization of EPF; only Metarhizium spp. and B. bassiana have been mentioned for the control of Fusarium culmorum , Rhizoctonia spp., and S. sclerotiorum in the literature ( Jaber, 2018 ; Raad et al, 2019 ; Tomilova et al, 2020 ; Deb et al, 2023 ). Here, we found that A. nomiae strain AnS1Gzl-1 has great potential for sclerotinia disease control, although its mechanism of resistance requires further investigation.…”

The potential of the entomopathogenic fungus Beauveria bassiana to manage insect pests and diseases

“…and cotton [11] ; bacterial blight caused by Xanthomonas axonopodis pv. malvacearum in cotton [11] , the Zucchini yellow mosaic virus in squash [23] , downy mildew caused by Plasmopara viticola in grapevines [12] , and sheath blight caused by Rhizoctonia solani in rice [64] .…”