盐角草内生真菌分离鉴定及抑制水产腐败细菌菌株的筛选

盐角草是一种耐盐植物,有重要的食用、药用价值。为研究盐角草的内生真菌及其活性次生代谢产物的多样性,该文对采集于广西北部湾沿海盐角草的内生真菌进行分离纯化,采用RAPD对内生真菌多样性进行分析,采用ITS基因序列对内生真菌进行鉴定,并对内生真菌提取物抑制几种水产腐败细菌的活性进行筛选。结果表明:(1)从北部湾盐角草植物中分离到14株形态不同的内生真菌,RAPD分析这些内生真菌有6种不同型别。ITS基因序列分析表明,这些菌株分别和Curvularia lunata、Aspergillus candidus、Guignardia mangiferae、Neocamarosporium chichastianum有较高的序列相似性; 其中有三株与Neocamarosporium chichastianum IBRC-M:30126的相似性为94%～95%,从系统发育树和菌落形态上看可能为Neocamarosporium salicornicola进化关系较近的一个新种。(2)抑菌实验表明,内生菌YJCJ3提取物具有比较好的抑制副溶血弧菌(Vibrio Parahaemolyticus)的活性,其菌丝体提取物的甲醇、石油醚和乙酸乙酯的溶解液都具有较强的抑制副溶血弧菌的活性; 而YJCJ5表现了较为广谱的抑制几种水产腐败细菌诺氏布丘氏菌(Buttiauxella noackiae)、气单胞菌(Aeromonas dhakensis)、乡间布丘氏菌(Buttiauxella gaviniae)的活性,其中YJCJ5的菌丝体石油醚和乙酸乙酯溶解液有抑制诺氏布丘氏菌和气单胞菌的活性,甲醇和石油醚溶解液具有一定抑制乡间布丘氏菌的活性。该研究结果表明盐角草存在较为丰富的内生真菌多样性,可以发现一些新的内生真菌种群,其具有多种活性提取物,可用于抑制水产品的腐败细菌的生长,具有较好的开发价值。

Endophytic fungi isolated from Salicornia europaea and their antibacteria activities to aquatic spoilage bacteria

Salicornia europaea is a kind of salt tolerant plant with important edible and medicinal value. Because this coastal plant grow in extreme salt tolerant environment, the diversity of its endophytic fungi and their active secondary metabolites may be distinctive from other plants. In our study, the endophytic fungi were isolated and purified, and the diversity of endophytic fungi was analyzed by RAPD, then the endophytic fungi were identified by ITS gene analysis. Finally, their activity inhibiting several aquatic spoilage bacteria was screened. The results were as follows:(1)A total of 14 endophytic fungi with different morphological characteristics were isolated from Salicornia europaea in Beibu Gulf. According to the RAPD analysis, these endophytic fungi had six different genetic types. The sequence analysis of ITS gene showed that these fungi had high sequence similarity with Curvularia lunata, Aspergillus candidus, Guarantaria mangiferae and Neocamarosporium chichastianum, and three of which showed relatively lower similarity with Neocamarosporium chichastianum IBRC-M:30126, which indicated 94%-95%. From the phylogenetic tree and colony morphology, three endophytic fungi, named YJCY2, YJCY3 and YJCG2, may be a new species closely related to Neocamarosporium salicornicola.(2)The antibacterial experiment showed that the extract content of strain YJCJ3 was a strong antibacterial activity to Vibrio parahaemolyticus, and the methanol, petroleum ether and ethyl acetate solution of the mycelium extract had a strong inhibiting activity against Vibrio parahaemolyticus. YJCJ5 showed a broad spectrum to inhibit several aquatic spoilage bacteria Buttiauxella noackiae, Aeromonas dhakensis and Buttiauxella gaviniae, in which the petroleum ether and ethyl acetate solution of mycelium inhibited the growth of Buttiauxella noackiae and Aeromonas dhakensis, while the extract content of methanol and petroleum ether solution inhibited the activities ofButtiauxella gaviniae. Our result is significant, for that the diversity of endophytic fungi in Salicornia europaea was extremely abundant, and that new endophytic fungi could be isolated and identified from this plant, a variety of whose active extracts can be screened and used to inhibit the growth of spoilage bacteria in aquatic products showing good potential for their utilization in this area.