北京夏植黄瓜内生真菌区系研究

为了解黄瓜植株内生真菌的区系组成及其变化,从而为进一步研究黄瓜内生真菌的生态和功能奠定基础,对采自北京延庆的不同品种和不同生育期的40株黄瓜进行了内生真菌的分离培养。经形态学鉴定和18S rDNA序列分析,分离到的1,024株内生真菌属于18属,其中Exserohilum和Neocosmospora尚未见内生真菌的报道。Alternaria、Aspergillus、Chaetomium、Cladosporium和Fusarium在各生育期和各器官普遍存在。其中,Alternaria在叶中的定殖率达47.0%,远高于在其他器官中的定殖率;Fusarium在根中的定殖率达32.5%,远高于在其他器官中的定殖率。多数真菌类群表现出不同程度的器官偏好性,有些真菌类群则只出现在特定器官中。叶和根的内生真菌类群数量和总定殖率均高于茎和果实。随着黄瓜的生长,各器官内生真菌的类群数在增加,部分真菌的定殖率也呈上升趋势,但Neocosmospora和Chaetomium在各器官中的定殖率则随植株生长呈下降趋势。

The endophytic mycobiota in summer growing cucumber in Beijing

In order to understand the endophytic mycobiota and its variation in cucumber plants, endophytic fungi were isolated from 40 symptomless cucumber plants, including different cultivars at different stages, collected from Yanqing of Beijing. Based on morphological characteristics and 18S rDNA sequences, 18 genera were identified out of 1,024 endophytic fungi strains isolated from root, stem, leaf and fruit tissues. Among them, Exserohilum and Neocosmospora have not been known in previous reports about endophytic fungi. Alternaria, Aspergillus, Chaetomium, Cladosporium and Fusarium existed universally in different organs at all stages. The colonizing rate of Alternaria species reached 47.0% and was far higher in leaves than in other organs, and the colonizing rate of Fusarium species reached 32.5% and was far higher in roots than in other organs. Most of the endophytic fungi showed organ favoritism in different degrees. Some genera of fungi only existed in specified organs. The number of genus and total colonizing rate of endophytic fungi were higher in leaves and roots than in stems and fruits. Along with plant growth, the number of genera of endophytic fungi and the colonizing rates of some fungi increased, but the colonizing rates of Neocosmospora and Chaetomium species decreased from all organs. The results could provide some foundation for further researches on ecology and function of endophytic fungi in cucumber.