Analysis of the fungal diversity and community structure in the root system of yellowing Torreya grandis ‘Merrillii’ in Guizhou

The differences between mycorrhizal fungi species and dominant flora of Torreya grandis in Guizhou were explored, and the fungal community composition in the root and rhizosphere soil of Torreya grandis in four regions was compared, in order to explore the diversity and community structure of the fungi of Torreya grandis roots.

The Torreya grandis communities with yellowing phenomenon in Guiyang, Xiuwen County, Zheng'an County and Wuchuan Gelao and Miao Autonomous County were selected as the research objects. The root system and rhizosphere soil of Torreya grandis were collected for high-throughput sequencing. The fungal diversity and the difference in the community structure of root systems were analyzed, and the differences in fungal structures between root and rhizosphere soils were compared in the four regions.

The results showed that there were 558253 effective sequences in the root system and 568821 effective sequences in the rhizosphere soil of Torreya grandis. The root-rhizosphere fungi of yellow Torreya grandis belonged to 5 phyla, 15 classes, 23 orders, 33 families, 46 genera and 61 species. The dominant fungal phyla were Ascomycota, Mortierellomycota and Basidiomycota, which accounted for more than 90% of the total abundance of the whole fungal community. From the perspective of fungal population structure, Ascomycota was the most dominant phylum among the endophytic fungi in the four regions, Mortierellomycota was the most dominant phylum among the rhizosphere soil fungi, and there were some differences between endophytic roots and the rhizosphere. Among all regions, Mortierellomycota and Mortierellomycotes in Wuchuan County and Zheng'an County were relatively abundant, while Mortierellomycota and Mortierellomycotes in Xiuwen County and Guizhou Botanical Garden were relatively low. Wuchuan County and Zheng'an County shared highly similar fungal structures, and Xiuwen County and Guizhou Botanical Garden had highly similar fungal structures, which were different from the fungal structures of Wuchuan County and Zheng'an County. There were 2 485 fungal OTUs in the Torreya grandis samples from the four regions, including 1 198 fungal OTUs in rhizosphere soil and 1 287 fungal OTUs in root endophytic fungi.

It is concluded that the rhizosphere microbial community structure is influenced not only by plant health, but also by different regions, and there are obvious differences in the composition and structure of fungal populations in the root system of yellow Torreya grandis in the four regions.