基于rDNA ITS序列的油茶叶片内生真菌多样性研究(英文)

Detection of endophytic fungi within foliar tissues of Camellia oleifera based on rDNA ITS sequences

油茶是我国热带和亚热带地区广泛栽培的一类重要的经济树种,其种子可生产优质食用油(茶油)。为了比较全面地了解油茶的内生真菌多样性,采用基于rDNA ITS的免培养法从油茶叶片中提取了总DNA,再从总DNA样本中直接扩增了内生真菌核糖体RNA基因内转录间隔区序列(ITS),进而构建了ITS克隆文库。共计从50个克隆子中获得了22种不同的克隆序列,其中3个为嵌合体,7个归属为植物,其余克隆序列根据序列相似性和系统发育分析归为12个不同的分类操作单元(OTUs),全部为子囊菌,分属于4纲4目,其中Aspergillus属2种,Mycosphaerellaceae科1种,Sordariales目4种,Helotiales目5种,Aspergillus属真菌是优势菌。结果表明油茶叶片内生真菌的种类分布较广。

The diversity and phylogenetic relationships of endophytic fungi within the leaves of Camellia oleifera, a broadly cultivated economic tree species for its tea oil in China, were studied using a culture-independent method based on rDNA sequences. The internal transcribed spacer （ITS） regions of rDNA of the endophytic fungi were amplified directly from the total DNA extracted from the leaves of C. oleifera, and the ITS library was constructed successfully. A total of 22 different clone sequences were obtained from 50 clones examined. With the exception of three chimerical clonal sequences and seven clonal sequences being more closely related to the kingdom Plantae, the rest of clonal sequences were identified as 12 operational taxonomic units （OTUs） of fungi based on sequence comparison and phylogenetic analysis, all of which were members of Ascomycota. The 12 OTUs included 2 taxa of the genus Aspergillus, 4 taxa of the Sordariales, 1 taxon of the Mycosphaerellaceae, 5 taxa of the Helotiales, of which Aspergillus spp. were dominant. The endophytic fungi detected in the present study were distributed amongst 4 different orders, each representing a different class. Our study showed a broad fungal spectrum of endophytic fungi within the leaves of C. oleifera.