Changes in the rhizosphere bacterial community of maize after Bipolaris maydis leaf infection
Southern corn leaf blight (SCLB), caused by Bipolaris maydis, is a serious maize disease that is currently managed through the use of resistant varieties and fungicides. However, the rapid loss of resistance in maize variety and fungicide hinders effective prevention and control of SCLB. Regulating root secretions to recruit beneficial microbes for enhancing plant disease resistance is an ecological strategy that synergizes disease-resistant varieties and chemical control to reduce diseases. However, the regulation of root secretions for recruiting beneficial microbes remains a complex challenge.To test the effect of foliar pathogen infection on the root-soil bacteria community, we inoculated the maize leaves with Bipolaria maydis or PDA medium (as control) for 20 days, and monitored the change in soil microbiota using Miseq sequencing. Compared to the control, no significant difference was observed in the Shannon and Chao1 indexes of bacterial community in the rhizosphere soil of maize after infection with B. maydis, indicating that the \u03b1 diversity of the bacterial community of B. maydis-infected maize did not change significantly. However, principal co-ordinates analysis (PCoA) revealed that the bacterial community of B. maydis-infected maize rhizosphere soil were differed significantly from the control. These results confirmed that rhizosphere bacteria community significant changed when maize was infected by B. maydis. For bacteria at the phylum level, the relative abundance of Bacteroidetes in maize rhizosphere was significantly enriched by maize roots after foliar infection with B. maydis, while Firmicutes and Proteobacteria were suppressed. Genera with a relative abundance greater than or equal to 1% were selected for analysis, and several bacteria were found to be significantly altered in the maize rhizosphere caused by B. maydis infection. The relative abundance of Pseudomonas, Hydrogenophaga, Bacteroides, Microlunatus, Marvinbryantia, Tyzzerella, Anaerotruncus, Enterococcus, and Faecalitalea was significantly enriched in maize rhizosphere soil after infection, whereas Trichococcus was suppressed. Among these, Pseudomonas, a common beneficial bacterium involved in plant resistance and biocontrol, was particularly noteworthy that its substantial increase in abundance in the rhizospheres of B. maydis-infected maize compared to healthy maize.