Fungal Diversity In Rhizosphere Soil Of Medicinal Plants In Northeastern China

Chinese herbs are widely cultivated in northeastern China. In recent years, the soil-borne diseases are becoming serious duo to the increasing cultivation area and continuous cropping index of various medical plants, and the diseases significantly affect the quantity and quality of medical plants. On the other hand, plentiful and specific groups of microorganisms grow in the rhizosphere soil of medical plants because of specific chemical compounds contained in and secreted by the rootlets of medical plants. This paper is designed to investigate the fungal diversity in rhizosphere soil of medical plants in northeastern China, in order to understand the main fungal species in the soil and their distribution characteristics. By the way some economically invaluable fungal resources will be acquired, they can be potentially used in bio-control of medical plant soil-borne diseases and bio-transformation in medicals.During May and October in 2007 and 2008,more than 800soil samples were collected from the rhizosphere of medicinal plants in herb growing areas of Northeastern China. The soil sampling sites include Dandong, Fengcheng, Qingyuan, Huanren of Liaoning province; Ji'an, Jingyu, Fusong, Huadian, Huangsongdian, Helong, Wangqing of Jilin province; Haerbin, Qinghe, Wuchang of Heilongjiang province. The method of soil diluting plate and soil particle plate were taken to isolate fungi. Based on morphological characteristics 89 fungal species belonging to38 genera were isolated and identified. Among them, 9 species in 4 genera belong to Zygomycetes, 4 species in 2 genera belong to Ascomycetes, while 74 species in 32 genera are anamorphic fungi, 2 species unidentified. Of which 5 species are newly recorded in China. Some of the fungi are important pathogens of medicinal plants, such as Cylindrocarpon destructans, Fusarium oxysporum, F. solani. Penicillium paxilli, P. expansum, while Trichoderma atroviride and T. viride are the predominant groups of fungi in the rhizosphere of medicinal plants in northeastern China.In this paper, each fungus was morphologically described and illustrated together with micrographs. The effect of different elevation, soil type and forest types on fungal diversity in Ji'an, Fusong of Jilin province, Huanren of Liaoning province was briefly analyzed and discussed. The fungal species abundances were investigated.The results show that the composition, quantity and distribution of fungal populations were closely associated with the climate and ginseng soil type. The results also indicate that the dominate fungal species in the three areas were Penicillium>Trichoderma>Fusarium. After fungal ecological analysis, the Shannon—Wienner index of Ji'an is 2.2794, and the Pielou index is 0.8045. They are all bigger than in Huanren and Fusong. The results suggest that the diverse environments had an evident effect on soil fungal distribution.