广藿香内生真菌多样性及其对青枯菌的拮抗活性

【目的】对广藿香各部位内生真菌的类群结构及多样性进行系统分析,筛选出对青枯菌具拮抗活性的菌株。【方法】采用组织块分离法从广藿香健康植株的根、茎、叶中分离内生真菌,结合形态学和基于ITS-r DNA序列分析鉴定方法分析广藿香内生真菌的类群结构及多样性,并利用双层平板拮抗法筛选对青枯菌具有抑制活性的菌株。【结果】从广藿香中共分离获得313株内生真菌,隶属于30个属,其中链格孢属(占28.75%)、拟茎点霉属(占23.00%)和炭疽菌属(11.82%)为优势类群,此外还分离到炭皮菌属、弯孢聚壳属、Gibellulopsis、新萨托菌属、葡萄座腔菌属、篮状菌属等较为少见的类群。茎、叶内生真菌的定殖率和分离率明显高于根,而根部多样性指数为2.64,要高于茎(2.00)和叶(1.97);广藿香茎与叶、根与茎、根与叶之间的内生真菌相似性指数分别为0.35、0.20、0.19,均小于0.5,显示各部位之间的内生真菌组成不相似程度高。从313株广藿香内生真菌中通过拮抗实验筛选到16株对青枯菌有拮抗活性的菌株,其中GHXR07、GHXR27和GHXR29的拮抗活性尤为显著,分别被鉴定为Talaromyces sp.、Myrothecium roridum Tode和Talaromyces wortmannii(Kl?cker)Benjamin。【结论】广藿香内生真菌具有丰富的物种多样性且其类群分布具有一定的组织特异性,其中部分菌株对青枯菌具有明显的拮抗活性。

Diversity and the antagonistic activities of endophytic fungi from patchouli against Ralstonia solanacearum

Objective] The aim of this study was to analyze the taxonomic structure and biodiversity of the endophytic fungi from patchouli and screen the antagonistic endophytic fungi against Ralstonia solanacearum. Methods] The endophytic fungi were isolated from the roots, stems, and leaves of the healthy patchouli using the tissue isolation method. The taxonomic structure and biodiversity of the endophytic fungi from patchouli were explored based on the morphological traits, and fungal ITS region sequence analysis. And the antagonistic endophytic fungi against Ralstonia solanacearum were screened by double plate antagonistic method. Results] In the results, 313 strains belonging to 30 genera of endophytic fungi were isolated from patchouli. The dominant groups of the endophytic fungi were Alternaria (28.75%), Phompsis (23.00%) and Colletorichum (11.82%), respectively. In addition, there were some rare fungal endophytes taxa such as Biscogniauxia, Eutypella, Gibellulopsis, Neosartorya, Neofusicoccum, Talaromyces were also isolated. The colonization rates and the isolation rates of endophytic fungi in patchouli stems and leaves were higher than those in roots. However, the diversity index of fungal endophytes in roots (2.64) was higher than those in stems (2.00) and leaves (1.97). The similarity coefficients of fungal endophytes between stems and leave, roots and stems, roots and leaves was 0.35, 0.20, and 0.19, respectively, indicating that the species composition of fungal endophytes in patchouli roots, stems and leaves were not very similar each other. In addition, 16 strains of endophytic fungi showed the antagonistic activities to Ralstonia solanacearum. Among the 16 strains, GHXR07, GHXR27 and GHXR29 showed the best antagonistic activities, and they were identified as Talaromyces sp., Myrothecium roridum Tode and Talaromyces wortmannii (Kl?cker) Benjamin, respectively. Conclussion] The endophytic fungi in patchouli were very diverse and their distribution showed the tissue specificity, and the antagonistic strains against Ralstonia solanacearum were also demonstrated.