Abstract:

The variation characteristics of microbial community in rhizosphere of papaya under papaya-leek intercropping pattern were studied by using volatile substances released in leek habitat to inhibit the pathogenic fungi in the rhizosphere of papaya. Soil microbial DNA was extracted at different intercropping periods, and soil microbial diversity in rhizosphere was analyzed by Illumina Miseq high-throughput sequencing technology. The results showed that: (1) the soil bacteria in the rhizosphere were classified into 27 phyla, 64 classes, 146 orders, 272 families and 437 genera, Acidobacteria, Actinobacteria, Chloroflexi and Proteobacteria were the dominant bacteria, and their proportions were 18.15%, 22.33%, 19.11%, and 25.53%, respectively, accounting for 85.12% of the total bacterial composition; with the increase of intercropping time, the advantages of Proteobacteria and Acidobacteria were obvious; (2) the soil fungi of rhizosphere were classified into 7 phyla, 24 classes, 64 orders, 126 families and 239 genera, Ascomycota, Zygomycota and Basidiomycota were the dominant, and their proportions were 93.71%, 3.94% and 1.18%, respectively, accounting for 98.83% of the total composition; and Ascomycota was the dominant; (3) at the genus level of bacteria, the relative abundance of Subgroup _6_ norank of Acidobacteria was the highest at 30, 60 and 120 d of intercropping; at 90 d, the relative abundance of Nitrospira was the highest; at the genus level of fungi, the relative abundance of the genus of Ascomycota was the highest whether papaya was intercropped with leek or not; (4) soil organic matter, soil total nitrogen and soil available phosphorus in the rhizosphere were the key factors affecting the soil microbial community structure and soil microbial diversity in papaya-leek intercropping pattern.

Key words: papaya, papaya-leek intercropping, soil nutrients, soil microorganism