天贵卷瓣兰内生真菌分离鉴定及其促生作用研究

Isolation and identification of endophytic fungi of Bulbophyllum tianguii

关键词:  天贵卷瓣兰，内生真菌，分离，鉴定，促生特性

Key words:  Bulbophyllum tianguii  endophytic fungi, isolation, identification, growth-promoting properties

摘要:

为了获得天贵卷瓣兰各组织间内生真菌，探究其促生特性及对幼苗的促生作用。该研究以广西雅长兰科植物国家级自然保护区内分布的野生天贵卷瓣兰植株为试验材料，采用传统的组织分离法对其内生真菌进行分离纯化，通过形态学和分子生物学方法进行鉴定，对分离得到的内生真菌开展溶磷及产IAA能力测定，并通过盆栽试验验证其对天贵卷瓣兰幼苗的促生作用。结果表明：（1）从天贵卷瓣兰不同组织中共获得真菌74株，根部、横走茎、假鳞茎和叶片中分离的菌株分别为5株、14株、30株和25株，分离频率分别为12.5%、35%、75%、62.5%。（2）根据菌落形态以及显微结构特征，把同一海拔、同一器官部位分离的相同菌株归为同一菌株后，共获得16株；经分子生物学鉴定，其隶属于2门4纲7目8科8属。（3）在所分离到的内生真菌中，4株具有溶有机磷能力，4株具有溶无机磷能力，3株具有产IAA能力。（4）将部分菌株发酵液喷施于天贵卷瓣兰幼苗表面，发现菌株YJ2的发酵液整体促生效果最好。该研究分离获得了天贵卷瓣兰不同组织内生真菌，并筛选获得具有促生特性的内生真菌，为天贵卷瓣兰种苗栽培提供了宝贵的微生物资源，为后续探究病原菌的拮抗作用奠定了基础。

Abstract:

In order to isolate endophytic fungi from different tissues of Bulbophyllum tianguii and characterize their plant growth-promoting properties, as well as evaluate their effects on seedling growth. In this study, different tissues and organs of B. tianguii distributed in the Guangxi Yachang Orchid National Nature Reserve were used as experimental materials. Endophytic fungi were isolated and purified from B. tianguii using the traditional tissue isolation method, and were further identified through morphological and molecular analyses. Finally, the abilities of phosphate-solubilizing and indole-3-acetic acid (IAA)-producing of these isolated endophytic fungi were screened. And the growth-promoting effects on B. tianguii seedlings were evaluated through pot experiments, too. The results indicated that a total of 74 strains were obtained from different tissue of B. tianguii. The strain number collected from roots, rhizomes, pseudobulbs and leaves were 5, 14, 30 and 25 strains, respectively. And the isolation frequencies were 12.5%, 35%, 75% and 62.5%, respectively. After removing duplicate strains obtained from the same altitude or the same tissue, 16 distinct strains remained. These strains cover 2 phyla, 4 classes, 7 orders, 8 families, and 8 genera identified by molecular biology methods. Among the 16 strains, 4 strains demonstrated the ability to solubilize organic ophosphorus, 4 strains could solubilize inorganic phosphorus, and 3 strains were capable of producing indole-3-acetic acid (IAA). The fermentation broth of selected strains was sprayed on the surface of B. tianguii seedlings, and strain YJ2 demonstrated the most significant growth-promoting effects among all tested strains in this study. This study isolated endophytic fungi from various tissues of B. tianguii successfully and identified strains with plant growth-promoting properties, providing valuable microbial resources for seedling cultivation of B. tianguii and laying a foundation for further investigation into their antagonistic effects against pathogens.