桃儿七内生真菌分离及其抑菌活性初步研究

目的 探明桃儿七内生真菌资源多样性及其抑菌活性特征。方法 通过组织块法对内生真菌进行分离，并选择5种植物病原真菌和4种细菌作为指示菌，采用对峙法和改进的菌块法测定抑菌活性。结果 从桃儿七根、茎、叶中分离出49株内生真菌，根部最多，22株，其次为茎部，18株，叶部最少，9株；经形态学分类鉴定归于2个目，3个科，9个属，梭孢霉属为优势菌属；有22株菌对1种或多种供试植物病原真菌有不同程度的抑制作用，占分离菌株数的44.8%，有8株菌对2种或多种供试植物病原真菌有明显的抑制作用，其占所分离菌株总数的16.3%，有3株菌对4种或多种供试植物病原真菌有明显抑制作用，2株内生真菌分别对2种供试指示细菌具有明显的抑制作用。结论 桃儿七内生真菌具有多样性和明显的抗外源真菌活性，抑菌活性菌株主要分布在曲霉属、单孢枝霉属、梭孢霉属，其内生真菌的研究和开发具有重要的生态和经济意义。

Study on isolation of endophytic fungi from Sinopodophyllum hexandrum and their antimicrobial activities

Objective To explore the resource diversity of endophytic fungi from the endangered Sinopodophyllum hexandrum and its antimicrobial activity. Methods The endophytic fungi were isolated by tissue block method. Five pathogenic fungi and four bacteria were used as indicators to test the antimicrobial activity by agar plate antagonistic action and improved agar gel diffusion methods. Results The results indicated that 49 endophytic fungi strains were isolated from the roots, stems, and leaves of S. hexandrum, the most was from the roots (22), then from the stems (18), but the least was from the leaves (19); The isolated strains attributed to nine genera, three families, and two orders, and Fusidium sp. was the dominant genera based on morphological characters; For the isolated strains, 22 of them expressed the inhibition to one or more pathogenic fungi, amounting to 44.8% of the total isolates, and eight strains were found to have significant inhibition against two or more pathogenic fungi, making up 16.3% of the total isolated strains, and three isolated endophytic fungal strains showed the evident inhibition against four or more indicating pathogenic fungi, and the two isolated strains showed the obvious antibacterial activity against the two indicating bacteria. Conclusion The endophytic fungi isolated from S. hexandrum have the diversity and evident inhibition against exterior fungi, active strains belong to the fungi of Aspergillus sp., Hormodendrum sp., and Fusidium sp., respectively, and its research and development are of ecological and economic significances.