Diversity of rhizosphere and root endophytic fungi in Kadsura coccinea under different habitats

Kadsura coccinea is a perennial vine medicinal plant, and its growth, development, and authentic medicinal qualities are affected by growing habitat, rhizosphere soil, and endophytic fungi. In order to explore the composition and diversity of fungal community in K. coccinea under different habitats, as well as their correlations with soil environmental factors, the rhizosphere and root endophytic fungi of K. coccinea from three different habitats in Guizhou were studied based on Illumina high-throughput sequencing method. The results were as follows: (1) Under three habitats, the number of OTU detected in rhizosphere soil (3 867) was much more than that in root endophyte (801). The common OTU of rhizosphere soil was 72, which were annotated to 5 phyla and 49 genera, most of which were ascomycetes. At the genus level, the proportions of Mortierella, Exophiala, and Cylindrocarpon were relatively high. The common OTU of root endophytic fungi was 14, which were annotated to 2 phylums and 11 genera. Ascomycetes (13, accounting for 92.9%) were overwhelmingly dominant. At the genus level, Mortierella, Exophiala, Cylindrocarpon and Nectria were dominant genra. There were only 6 OTU in total, annotated to 2 phylums and 5 genera, and the ascomycetes phylum (5, accounting for 83.3%) were the dominant phylum. At the genus level, Exophiala (2, 33.3%) accounted for the highest proportion and the rest were Mortierella, Cylindrocarpon and Nectria, respectively. Alpha diversity analysis showed that the diversity and richness of fungal communities in rhizosphere soil were significantly higher than those in root endophytic fungi, while the diversity of fungi under wild habits was higher than that under cultivated habits. (2) At the phylum level, the main endophytic fungal groups under three habitats were Ascomycota and Basidiomycota, accounting for 88.28% of the total flora. At the genus level, the community structures of endophytic fungi in rhizosphere and root were significantly different under different habitats. The endophytic fungi flora in the root had a certain preference under the cultivation habitat, while the evenness under the wild habitat was higher than that under cultivation habitat. The prediction functions of fungal community based on FUNGuild showed that pathotroph-saprotroph type in the root endophytic fungi was relatively high under the cultural habit, while the proportion of saprophytic type and symbiotroph type was relatively high under the wild habit. (3) Soil environmental factors had different effects on root endophytic fungi and rhizosphere fungi in K. coccinea. Total potassium (TK) and total phosphorus (TP) in soil were positively correlated with Shannon index and Simpson index of endophytic fungi in K. coccinea root; whereas, soil organic matter (SOM), total nitrogen (TN) and available nitrogen (AN) were positively correlated with Ace index and Chao1 index of rhizosphere soil fungi. In conclusion, SOM, TN and AN are the main soil environmental factors affecting the rhizosphere soil fungal community of the K. coccinea.