Isolation and evaluation of the biocontrol potential of Talaromyces spp. against rice sheath blight guided by soil microbiome

Rice sheath blight caused by Rhizoctonia solani is the major disease of rice that seriously threatens food security worldwide. Efficient and eco-friendly biological approaches are urgently needed since no resistant cultivars are available. In this study, fallow and paddy soils were initially subjected to microbiome analyses, and the results showed that Talaromyces spp. were significantly more abundant in the paddy soil, while Trichoderma spp. were more abundant in the fallow soil, suggesting that Talaromyces spp. could live and survive better in the paddy soil. Five Talaromyces isolates, namely, TF-04, TF-03, TF-02, TF-01 and TA-02, were isolated from the paddy soil using sclerotia of R. solani as baits and were further evaluated for their activity against rice sheath blight. These isolates efficiently parasitized the hyphae and rotted the sclerotia even at higher water contents in the sterilized sand and the soil. Isolate TF-04 significantly promoted rice growth, reduced the severity of rice sheath blight and increased the rice yield under outdoor conditions. Defence-related genes were upregulated and enzyme activities were enhanced in rice treated with isolate TF-04. Our research supplies a microbiome-guided approach to screen biological control agents and provides Talaromyces isolates to biologically control rice sheath blight.

Automated summary

This study identified Talaromyces isolates, particularly TF-04, from paddy soil that demonstrated significant potential in controlling rice sheath blight by promoting rice growth, reducing disease severity and increasing yield. Defense-related genes were upregulated and enzyme activities were enhanced in rice treated with TF-04, indicating its effectiveness as a biological control agent. The microbiome-guided approach used in this research provides valuable insights for screening biological control agents against rice sheath blight.