[Effect of Land-use on Soil Fungal Community Structure and Associated Functional Group in Huixian Karst Wetland]

Studying the impact of land-use on fungal communities and their functional groups in wetland soil can provide a theoretical basis for the protection of wetlands. The top soil (0-20 cm) samples were collected from the wetlands with Phragmites communis (PCW), wetlands with Cladium chinense (CCW), abandoned paddy fields (APF), paddy fields (PF), and corn fields (CF) in the Huixian Karst Wetland. The fungal community structure and its functional groups were analyzed using high-throughput sequencing methods and the FUNGuild database, respectively. The results showed that the Simpson and Shannon index in PF and CF were significantly higher than those in PCW and CCW. Ascomyceta was the most dominant phylum in five land-use types with the abundance of 70.60%-87.02%, followed by Rozellomycota in PCW with the abundance of 7.14% and Basidiomycota in CCW, APF, PF, and CF with the abundance of 9.70%, 5.19%, 8.13%, and 7.50%, respectively. Pleosporales was the most dominant order in PCW with the abundance of 16.47%, while Hypocreales was the dominant one in CCW, APF, PF, and CF with the abundance of 22.52%, 23.50%, 17.60, and 23.80%, respectively. Ascobolus and Archaeorhizomyces were the most dominant genera in PCW and CCW with the abundance of 6.65% and 13.44%, respectively, and Fusarium was the most dominant genus in APF, PF, and CF with the abundance of 10.22%, 10.51%, and 11.12%, respectively. Saprotroph was the main trophic mode in the Huixian wetland with the abundance of 48.67%-80.13%. The abundance of pathotroph in CF (5.39%) was higher than that in PCW (2.34%) and CCW (1.53%). Dung saprotroph-wood saprotroph and soil saprotroph were the most dominant functional groups in PCW and CCW, respectively, while animal pathogen-endophyte-lichen parasite-plant pathogen-soil saprotroph-wood saprotroph was the most dominant functional group in APF, PF, and CF. Redundancy analysis showed that both soil water content and the ratio of carbon-to-nitrogen were the main factors affecting fungal communities, and available nitrogen was the main factor affecting the functional groups. Overall, the results indicated that land-use has changed the soil fungal diversity and community structure, complicated the functional groups, and increased the risk of corn disease in the Huixian Karst wetland.