中国中部太白山不同海拔杜鹃兰根部内生真菌多样性

本研究以太白山自然保护区蒿坪站杜鹃兰Cremastra appendiculata为材料,采用菌丝团和根组织分离法进行真菌分离,并用ITS序列分子鉴定;用变性梯度凝胶电泳（denaturing gradient gel electrophoresis,DGGE）分析根部内生真菌多样性,研究海拔和根际土理化性质对真菌多样性的影响。分离到79株19种真菌,均为子囊菌门Ascomycota,隶属于座囊菌纲Dothideomycetes 1目2科2种和粪壳菌纲Sordariomycetes 7目10科17种,其中12种兰科菌根真菌。DGGE检测到80种真菌,其中兰科菌根真菌交链链格孢、锈腐土赤壳和木霉属真菌可通过组织分离法得到,担子菌门Basidiomycota 3种真菌只在DGGE检测到。随着海拔升高,根际土硝态氮和速效磷下降,导致真菌丰富度和香侬维纳指数降低,辛普森指数升高。本研究为发掘此地区杜鹃兰菌根真菌资源进行杜鹃兰人工培育奠定基础。

Diversity of endophytic fungi in the roots of Cremastra appendiculata (Orchidaceae) at different altitudes in Taibaishan Nature Reserve,Central China

Cremastra appendiculata roots were collected from Haoping Station of Taibaishan Nature Reserve. The cultivable fungi were isolated from the pelotons and roots, and the fungal ITS sequences were used for molecular identification. The community diversity of endophytic fungi in the roots were analyzed by denaturing gradient gel electrophoresis (DGGE) to evaluate the influence of different altitudes (1 177m, 1 409m and 1 590m) and the physical and chemical properties of rhizosphere soil in the same habitat on the diversity of endophytic fungi in the roots of C. appendiculata. The result was that 79 fungal isolates were identified as 19 species. Ascomycetes were dominant including two species of Dothideomycetes and 17 species of Sordariomycetes. Among them, 12 taxa belonged to orchid mycorrhizal fungi. In total, 80 fungal bands were detected by DGGE. Alternaria alternata, Ilyonectria destructans and Trichoderma spp. were obtained by culture method. In addition, three species of basidiomycetes, which were not detected by culture method, were newly detected by DGGE. The diversity of fungal community was related to altitude and significantly affected by nitrate nitrogen and available phosphorus in the rhizosphere soil. With the increase of altitude, the fungal richness and the Shannon-winner index decreased, while the Simpson index increased. This study provided a foundation for the further exploration of orchid mycorrhizal fungi in this area and a reference for artificial breeding of C. appendiculata.