Abstract: The wild fruit forests in the Tianshan Mountains, Xinjiang are one of the areas where deciduous fruit trees are originally cultivated in the world, they have the large area and are the most primitive, densest and relatively rare in Eurasia. In recent years, the wild fruit forest ecosystems have been seriously damaged due to the large-scale human development, and the species diversity was decreased. Current research on wild fruit ecosystem focuses mainly on the aboveground biomass and its related aspects, but the microbial change in groundwater is paid little attention to. The objective of this study was to evaluate the diversity of cultivable fungi isolated from topsoil under health fruit trees (H soil) and diseased fruit trees (D soil) in a degenerated wild fruit forest. Dilution plate technique and 18s rDNA sequence analysis were applied to obtain the sequences of 25 difference strains isolated from the degenerated wild fruit forest, which were subsequently submitted to GenBank and compared with the known sequences to build up a phylogenetic tree. Results revealed that: ① These strains were clustered into 3 subdivisions, 6 classes, 8 orders, 11 families and 11genera; ② The dominant genera of the H soil was Penicillium, while Penicillium and Fusarium were the majority of the D soil, the endemic genera of H soil were Clonostachys and Purpureocillium, but Phoma and Leptosphaeria existed only in the D soil; ③ The Shannon-Wiener diversity index of the H soil was 2.10, it was higher than that of the D soil (1.98), the evenness index of the H soil was 0.91, and it was higher than that of the D soil (0.79). The biological characteristics of these cultivable fungi isolated from the wild fruit forest need to be further studied so as to be better applied in the soil pest control under the wild fruit forests.

Key words: degenerated wild fruit forest, topsoil, cultivable fungi, diversity, Ili