Mechanisms Of Autophagy In Fusarium Verticillioides Regulating The Rhizosphere Microbial Community Of Maize

Fusarium verticillioides is a soil-borne pathogenic fungus that causes root,stem,and ear rots of maize,resulting in yield losses;it produces the secondary metabolite fumonisin,which causes poisoning in humans and animals.Eukaryotes maintain cellular homeostatic balance by transporting damaged organelles to lysosomes or vesicles for degradation through cellular autophagy,thereby recycling nutrients.Studies have shown that cellular autophagy plays a key role in regulating the cellular differentiation and virulence of many pathogenic fungi.The rhizosphere bacteria community is involved in plant disease regulation and is closely related to plant health.Currently,there are many studies on the assembly of rhizosphere microbiome of different host plants,but the impact of pathogenic fungi on the inter-root microbial community through cellular autophagy and the mechanisms regulating the microbial community are still unclear.Therefore,in this study,we used amplicon sequencing technology and large-scale bacterial isolation and identification technology to investigate and elucidate the specific mechanism of autophagy in Fusarium verticillioides to regulate the rhizosphere microbial community of maize,and lay the foundation for the establishment of a rhizosphere microecological control system of maize with beneficial bacterial population as the core.The main research results are as follows.1.FvAtg8 regulates the autophagy process of Fusarium verticillioides,and the deletion of FvAtg8 resulted in a significant reduction of Fusarium verticillioides pathogenicity in maize roots.Maize roots inoculated with Fusarium verticillioides wild-type spores did not form fibrous roots,while the mutant ΔFvAtg8 had no significant effect on the formation of fibrous roots.2.By 16 S r DNA amplicon sequencing,we found that autophagy in Fusarium verticillioides could significantly affect the construction of the B73 maize rhizosphere bacterial community.Treatment of maize with wild-type spores of Fusarium verticillioides increased the relative abundance of several genera such as Agrobacterium,Sphingomonas and Pseudomonas and decreased the relative abundance of genera such as Rhodobacter,Caenorhabditis and Nonomura.3.Autophagy in Fusarium verticillioides was found to inhibit Streptomyces and Bacillus enrichment in the maize rhizosphere.Under root extraction culture condition,we found that autophagy of Fusarium verticillioides directly inhibited the growth of Streptomyces,but not Bacillus.4.Autophagy-mutant-treated maize rhizosphere microbial communities were found to have higher similarity in species composition to healthy maize rhizosphere microbial communities compared to wild-type-treated maize rhizosphere microbial communities.Under maize root extraction culture condition,the species composition of Fusarium verticillioides autophagy-mutant-treated maize rhizosphere microbial communities was more similar to that of Fusarium verticillioides wild-type-treated communities.This suggests that autophagy in Fusarium verticillioides may regulate the species composition of the B73 maize rhizosphere microbial community by altering the host environment.In summary,FvAtg8 regulated the autophagy process of the Fusarium verticillioides,and the deletion of FvAtg8 led to a significant reduction in the pathogenicity of Fusarium verticillioides in maize roots.Autophagy in Fusarium verticillioides was able to significantly affect the construction of rhizosphere bacterial community of B73 maize and inhibit Streptomyces and Bacillus enrichment in maize rhizosphere.Under root extraction culture condition,autophagy in Fusarium verticillioides directly inhibited the growth of Streptomyces,but not Bacillus.Autophagy in Fusarium verticillioides may regulate the species composition of the B73 maize rhizosphere microbial community by altering the host environment.