为探讨铁皮石斛种质、附生立木对其内生真菌物种多样性及分布状况的影响.该研究分别从不同附生立木和不同种质铁皮石斛的根、茎、叶中分离到内生真菌3 835株,根据菌株的培养特征及5. 8S和ITS区片段序列相似性比较和系统发育分析,将其鉴定为152个分类单位,归属到2个门5个纲21个目35个科60个属.结果表明,立体栽培铁皮石斛内生真菌具有极为丰富的物种多样性,内生真菌的优势类群在临安和义乌两地的分布存在较大差异,存在具有地理特异性的优势类群, Arthrinium,Coniochaeta,Fusarium,Neofusicoccum,Zopfiella仅为临安潘山的优势属,Alternaria,Bjerkandera,Cercophora,Nigrospora, Trichoderma仅为义乌上溪的优势属;种质、附生立木对铁皮石斛内生真菌丰富度及多样性无显著影响,而组织类型对其有显著影响(P＜0. 05);种质、附生立木对菌种组成和分布的影响小于组织类型,大部分菌种具有组织特异性;不同种质、附生立木铁皮石斛内生真菌优势类群相对频率均存在一定的差异,具有种质、附生立木特有的菌种,这可能与种质遗传背景、附生立木上微环境差异导致铁皮石斛生长性状、化学成分等差异有关.研究结果为立体栽培模式下铁皮石斛与内生真菌的相互关系研究提供基础.
In order to investigate the effects of germplasm and host tree trunk on endophytic fungal communities in epiphytic Den-drobium catenatum,a total of 3 835 isolates were recovered from roots,stems and leaves of four D. catenatum germplasms attached to one kind of host tree trunk and one germplasm attached to four kinds of epiphyte-host tree trunks. A total of 152 taxa were identified and classified based on the fungal cultural characteristics and phylogenetic analyses of ITS sequences. The taxa were assigned to 60 genera,35 families,21 orders and 5 classes of 2 phyla. The results indicated that D. catenatum cultivated in stereo cultivation harbor variety of fungi. The dominant fungal groups were different between Lin'an and Yiwu. Moreover,several groups showed geographical specificity,such as Arthrinium,Coniochaeta,Fusarium,Neofusicoccum and Zopfiella only dominating in Panshan of Lin'an,while Al-ternaria,Bjerkandera,Cercophora,Nigrospora and Trichoderma only dominating in Shangxi of Yiwu. There was no significant differ-ence in diversity or species richness of endophytic fungi neither among germplasm nor host tree trunk. However,the richness and diver-sity indices exhibited a strong dependence on tissue type (P＜0. 05). The germplasm and host tree trunk impact the distribution pat-terns of endophytic fungi less than tissue type. Nevertheless,the relative frequencies of the dominant fungal groups were different among germplasms or host tree trunk types. Furthermore,there were some fungal species specific to certain germplasm or host tree trunk. This might be due to the distinctions in growth traits and chemical compositions of D. catenatum owning to the differences in D. catenatum genetic background and microenvironment of host tree. Most of fungal taxa exhibit tissue specificity or preference. These results provide the basis for the study on the relationship between endophytic fungi and D. catenatum in stereo cultivation mode.