Analysis of the phyllosphere fungal community structure of naturally infected Solanum undatum in Xishuangbanna based on ITS high-throughput sequencing
As a representative member of the Solanum wild species complex within the Solanaceae family, Solanum undatum is a typical tropical wild Solanum species that forms stable natural populations in the tropical native habitat of Xishuangbanna, Yunnan Province, China. Under long-term natural selection in the wild environment with complex pathogenic stress, this species has accumulated a large number of excellent allelic variations for disease and stress resistance, and is a core research material for genetic improvement of disease resistance in Solanaceae crops, dissection of plant-pathogenic fungi interaction mechanisms, as well as conservation and utilization of wild germplasm resources. Wild plants and phyllosphere fungi have formed complex symbiotic, antagonistic and co-evolutionary relationships during long-term evolution. Natural fungal infection is the core driving force for the evolution of host disease resistance traits, and the composition and diversity characteristics of fungal communities in infected leaves are the core basis for revealing the host disease resistance response mechanism and identifying potential pathogens and beneficial functional fungi. At present, most studies on Solanum undatum focus on taxonomy and phylogeny. There is still an obvious gap in the omics research on the foliar fungal community structure, pathogen diversity and community assembly characteristics of naturally infected plants in the tropical native habitat of Xishuangbanna, China. In particular, there is a lack of systematic mycobiome analysis based on ITS high-throughput sequencing, which seriously restricts the mining and efficient utilization of disease resistance resources of this wild germplasm. In this study, infected leaf samples of 13 wild Solanum undatum plants with natural fungal infection growing in Xishuangbanna, Yunnan Province were collected. The taxonomic composition, diversity characteristics, distribution pattern of dominant groups of the fungal community in the infected leaves of this species were comprehensively clarified by high-throughput sequencing of fungal internal transcribed spacer (ITS) rRNA gene, and the potential pathogenic fungal groups in the community were screened.The results indicate: Fungal communities (13 samples) were dominated at phylum level by Basidiomycota (69.1%) and Ascomycota (28.2%); at class level by Ustilaginomycetes (34.5%) and Exobasidiomycetes (17.8%); at order level by Ustilaginales (34.4%); at family level by Ustilaginaceae (34.4%) and Exobasidiaceae (13.9%); and at genus level by Pseudozyma (28.7%)