Biological Control of Wheat Powdery Mildew Disease by the Termite‐associated Fungus Aspergillus chevalieri BYST01 and Potential Role of Secondary Metabolites

Background

Wheat powdery mildew, caused by the biotrophic pathogen Blumeria graminis f. sp. tritici (Bgt) is a serious fungal disease. Natural metabolites produced by the microorganisms are beneficial biological control agents to inhibit Bgt. In this study, we studied the control effect of Aspergillus chevalieri BYST01 on wheat powdery mildew.

Results

A strain isolated from the termite was identified as A. chevalieri BYST01 by morphological characteristics and phylogenetic analysis. The fermentation broth of BYST01 showed good biocontrol effect on the Bgt in vivo with the control efficiencies of 81.59% and 71.34% under the protective and therapeutic test, respectively. A total of four known metabolites, including the main compound physcion (30 mg/L), were isolated from the fermentation broth of BYST01 extracted with EtOAc. Importantly, under the concentration of 0.1 mM, physcion repressed conidial germination of Bgt with the inhibition rate of 77.04 % in vitro and showed important control efficiency of 80.36% and 74.64% in vivo under the protective and therapeutic test, respectively. Hence, the BYST01 showed an important potential as microbial cell factory for the high yield of the green natural fungicide physcion. Finally, the biosynthesis gene clusters responsible for physicon production in BYST01 was predicted by analyzing a chromosome‐scale genome constructed through a combination of Illumina, PacBio, and Hi‐C sequencing technologies.

Conclusion

A. chevalieri BYST01 and its main metabolite physcion had a significant control effect on wheat powdery mildew. The biosynthesis pathway of physcion in BYST01 was predicted.

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