新疆药用植物牛至内生细菌多样性与抗菌活性

Diversity and antagonistic effect of endophytic bacteria isolated from Origanum vulgare L. in Xinjiang

摘要:

【背景】植物内生菌作为微生物群落中一类非常重要的组成部分，在多个领域都有广泛的应用价值，如促进植物生长、抵抗病虫害、生物固氮、降解有毒有害化合物等。【目的】进一步丰富新疆野果林苹果腐烂病害的生防资源以及分析牛至内生细菌多样性特征。【方法】通过纯培养方法，对健康植物牛至组织进行内生细菌的分离纯化，并进行16S rRNA基因序列分析；再利用平板对峙法筛选具有抑制苹果腐烂病病原菌生长的内生细菌。【结果】共分离到168株内生细菌，最终确定为4门5纲8目12科17属，其中优势属为芽胞杆菌属(Bacillus)。由分离实验结果可知，M1号TSA培养基，M5号组氨酸-棉子糖培养基和M6号NA培养基是分离牛至内生细菌较为理想的培养基；采自新源县野果林的牛至内生细菌多样性较为丰富，在牛至根部内生细菌种类更多；通过拮抗实验共筛选出59株牛至内生细菌具有较好的抑菌效果。【结论】新疆药用植物牛至内生细菌的物种多样性较为丰富，而且富含一批有效抑制野苹果腐烂病病原菌生长的内生细菌菌株。因此，本研究在新疆野果林苹果腐烂病的生物防治和药用植物内生细菌种质资源的填补等方面具有重要意义。

Abstract:

[Background] Endophytes associated with plant have a wide range of applications in various fields, such as promoting plant growth, antagonistic activity, biological nitrogen fixation and degradation of toxic compounds. [Objective] The purpose of this study is to isolate and identify endophytic bacteria associated with Origanum vulgare L. and to evaluate their biological control ability against the apple canker disease in Xinjiang Wild Fruit Forest. [Methods] Culture-dependent method and 16S rRNA gene sequencing were used to identify the isolated strains. Endophytic bacteria were screened by plate confrontation method for their ability against the pathogen of apple canker. [Results] In this study, a collection of 168 endophytic bacteria were isolated from Origanum vulgare L. and identi?ed based on their 16S rRNA gene sequences as 4 phyla, 5 classes, 8 orders, 12 families and 17 genera. The dominant genus was Bacillus. Additionally, the results of isolation of endophytic bacteria from Origanum vulgare L. showed that TSA medium (M1) produced the highest diversity of bacteria, followed by NA medium (M6) and then Histidine-Raffinose medium (M5). The diversity of culturable endophytic bacteria from Origanum vulgare L. was rich in Xinyuan Wild Fruit Forest. The distribution of endophytic bacteria in root was more plentiful compared to that in stem and leaf. Fifty-nine strains of isolated endophytic bacteria were screened by plate confrontation method for their antagonistic against apple canker. The results demonstrate that a number of endophytic bacteria which can effectively inhibit the growth of pathogenic fungi of apple canker. [Conclusion] The diversity of endophytic bacteria associated with Origanum vulgare L. in Xinjiang was rich. In this study, a number of endophytic bacteria which can effectively inhibit the growth of pathogenic fungi of apple canker were screened out. Therefore, the results of this study provide a more abundant and effective source of endophytic bacteria from Origanum vulgare L. for biological control of apple canker disease in Xinjiang Wild Fruit Forest.