白及内生真菌多样性研究

白及( Bletilla striata)是兰科地生型多年生植物，也是我国传统中药材之一。利用菌根技术进行白及的保护和人工栽培，需要获得白及可培养的内生真菌。该研究以广西野生的白及根和叶为材料，采用分离培养法分离内生真菌，并结合真菌形态特征，及其核糖体的转录间隔区( ITS)序列分析，确定内生真菌的分类地位。结果表明：从2株白及植物90块组织中分离获得37株内生真菌，鉴定为15个分类单元，由9个属组成，分属于2门4纲7目8科，包括锤舌菌纲( Leotiomycetes)、座囊菌纲( Dothideomycetes)和粪壳菌纲( Sordariomy-cetes)，伞菌纲( Agaricomycetes)。从根中分离获得内生真菌12种，蜡壳菌属为优势属；从叶中分离获得内生真菌3种，刺盘孢属为优势属；刺盘孢菌属( Colletotrichum)和蜡壳菌属( Sebacina)真菌的相对多度值均达到20％；4株担子菌均分布于根中，叶组织中未有分布。根组织中内生真菌的多样性指数(H＝1.863)高于叶组织(1.098)。该研究结果及其所分离培养的担子菌类真菌，为更好地利用菌根技术进行白及等兰科植物资源的保护与可持续利用奠定了基础。

Divetsity of endophytic fungi associated with Bletilla striata

Bletilla striata, as atraditional Chinese herbal medicine, is a terrestrial and perennial medicinal plant. It is necessary to obtain the culturable endophytic fungi in the application of mycorrhizal technology for the protection and artificial cultivation of B. striata. The independent fungal isolates were isolated from the roots and leaves of B. striata, and identified based on the fungal morphological characteristics and the analysis of the fungal internal transcribed spacer(ITS)of rDNA sequences. The results showed that thirty-seven independent fungal isolates were obtained from forty-five root tissues and forty-five leaf tissues of two wild plants of B. striata. The isolates were identified to 15 taxa, belonging to nine genera,eight families, seven orders, four classes, and two phyla. The four classes are corresponding to Leotiomycetes, Dothideomycetes, Sordariomycetes and Agaricomycetes. Twelve endophytic fungi were isolated from the roots, and Sebacina were dominant genus. Three endophytic fungi were isolated from the leaves, and Colletotrichum were dominant genus. The relative abundance of Sebacina or Colletotrichum was 20%. Four basidiomycetes all were not isolated from the leavf tissues but the roots. The diversity index of endophytic fungi in roots(H''=1.863)was higher than that in leaves(H''=1.098). The positive results in this report demonstrated that fungi isolated from B. striata could be used for the protection and artificial cultivation of the host. Moreover, these Basidiomycetous fungi simultaneously clould be used as a valuable candidate sources for the protection and sustainable utilization of orchid resources by mycorrhizal technology.