Laboratory for Conservation and Utilization of Bio-Resources & Key Laboratory for Microbial Resources of the Ministry of Education, Yunnan University, Kunming, 650091, People's Republic of China.
Antonie Van Leeuwenhoek. 2013 Feb;103(2):299-312. doi: 10.1007/s10482-012-9810-3. Epub 2012 Sep 18.
Endophytes play an important role in protection of host plants from infection by phytopathogens. Endophytic bacteria were isolated from five different parts (root, stem, petiole, leaf and seed) of Panax notoginseng and evaluated for antagonistic activity against Fusarium oxysporum, Ralstonia sp. and Meloidogyne hapla, three major pathogens associated with root-rot disease complex of P. notoginseng. From 1000 endophytic bacterial strains evaluated in vitro, 104 strains exhibited antagonistic properties against at least one of these three pathogens. Phylogenetic analyses of their 16S rRNA gene sequences showed that these 104 antagonistic bacteria belong to four clusters: Firmicutes, Proteobacteria, Actinobacteria and Bacteroidetes/Chlorobi. Members of the Firmicutes, in particular the Bacillus spp., were predominant in all analyzed tissues. The root was the main reservoir for antagonistic bacteria. Of the 104 antagonists, 51 strains showed antagonistic activities to one pathogen only, while 43 and 10 displayed the activities towards two and all three pathogens, respectively. The most dominant species in all tissues were Bacillus amyloliquefaciens subsp. plantarum and Bacillus methylotrophicus, which were represented by eight strains with broad antagonistic spectrum to the all three test pathogens of root-rot disease complex of P. notoginseng.
内生菌在宿主植物免受植物病原菌感染方面发挥着重要作用。从三七的五个不同部位（根、茎、叶柄、叶和种子）中分离出内生细菌，并评估其对尖孢镰刀菌、罗尔斯顿氏菌和南方根结线虫三种与三七根腐病复合症相关的主要病原菌的拮抗活性。在体外评估的 1000 株内生细菌中，有 104 株对至少一种病原菌表现出拮抗特性。对其 16S rRNA 基因序列的系统发育分析表明，这 104 株拮抗菌属于四个类群：厚壁菌门、变形菌门、放线菌门和拟杆菌门/Chlorobi 门。厚壁菌门，特别是芽孢杆菌属，在所有分析的组织中都占优势。根是拮抗菌的主要宿主。在 104 株拮抗剂中，有 51 株仅对一种病原菌表现出拮抗活性，而 43 株和 10 株分别对两种和三种病原菌表现出活性。在所有组织中最占优势的物种是解淀粉芽孢杆菌亚种。和甲基营养芽孢杆菌，它们分别由 8 株对三七根腐病复合症的所有三种测试病原菌具有广谱拮抗作用的菌株代表。
