Effect and Mechanism of Maize and Pepper Recruit Bacteria to Reduce Disease in Monoculture or Intercropping System

PurposeThe aim of this study was to identify the correlation between bacterial community and disease occurrence in pepper and maize monoculture or intercropping system and explore the role of soil microbiome involved in disease control.

MethodWe assessed the effect of microbiome from the bulk soil of maize and pepper in monoculture and intercropping system on the disease incidence of corn southern leaf blight and pepper phytophthora blight, then analyzed the soil bacterial community structure and diversity by Illumina MiSeq high-throughput sequences.

ResultThe microbiome from the bulk soil of monocultured maize could significantly suppress pepper phytophthora blight (P<0.05), and microbiome from the bulk soil of the monocultured pepper or the intercropped maize could enhance the resistance of maize to B. maydis. Bacterial community analysis indicated that the relative abundances of Aeromonas, Sorangium, and Azospirillum were significantly enriched in bulk soil from monocultured maize compared with that in intercropped maize and monocultured pepper (P<0.05). The relative abundance of some bacteria was significantly enriched in bulk soils from the monocultured pepper and intercropped maize (P<0.05), including Bacteroidetes at the phylum level, Bacteroides, Niastella, Sphingobacterium, and Muribaculum at the genus level.

ConclusionThese results demonstrated that microbiome in the bulk soil of the maize and pepper monoculture and intercropping system can help each other to alleviate disease. The changes in bacterial community is the key factor to suppress disease in monoculture and intercropping system.