Xu Xindong, Han Li, Zhao Lixing, Chen Xiao, Miao Cuiping, Hu Linfang, Huang Xueshi, Chen Youwei, Li Yiqing
Key Laboratory of Microbial Diversity in Southwest China, Ministry of Education, College of Life Sciences, Yunnan University, Kunming, 650091, China.
Institute of Microbial Pharmaceuticals, College of Life and Health Sciences, Northeastern University, Shenyang, 110819, China.
Folia Microbiol (Praha). 2019 Mar;64(2):171-175. doi: 10.1007/s12223-018-0642-z. Epub 2018 Aug 16.
Actinomycete strain YIM PH20520, isolated from the rhizosphere soil sample of Panax notoginseng collected in Wenshang, Yunnan Province, China, exhibited antifungal activity against root-rot pathogens of the Panax notoginseng. The structures of bioactive molecules, isolated from the ethyl acetate extract of the fermentation broth of the strain, were identified as echinosporin (1) and 7-deoxyechinosporin (2) based on extensive spectroscopic analyses. 1 exhibited antifungal activity against four tested root-rot pathogens of Panax notoginseng include Fusarium oxysporum, Fusarium solani, Alternaria panax, and Phoma herbarum with the MIC value at 64, 64, 32, and 64 μg/mL, respectively. 2 exhibited antifungal activities against F. oxysporum, F. solani, A. panax, and P. herbarum with the MIC value at 128, 128, 64, and 128 μg/mL, respectively. Based on the phylogenetic analyses, the closest phylogenetic relative of strain YIM PH20520 is Amycolatopsis speibonae JS72 (97.69%), so strain YIM PH20520 was identified as Amycolatopsis strain. To the best of our knowledge, this is the first report of echinosporin antibiotics isolated from Amycolatopsis strain besides Streptomyces strain and their antifungal activity against four tested root-rot pathogens of the Panax notoginseng. The results provide a reliable evidence for the following related biosynthetic investigations on Amycolatopsis strain YIM PH20520 due to echinosporins antibiotics' unique tricyclic acetal-lactone structures.
从中国云南省文山州采集的三七根际土壤样本中分离得到的放线菌菌株YIM PH20520，对三七根腐病原菌具有抗真菌活性。基于广泛的光谱分析，从该菌株发酵液的乙酸乙酯提取物中分离得到的生物活性分子的结构被鉴定为刺孢霉素（1）和7-脱氧刺孢霉素（2）。1对四种测试的三七根腐病原菌，即尖孢镰刀菌、茄形镰刀菌、人参链格孢和草本茎点霉表现出抗真菌活性，其最低抑菌浓度（MIC）值分别为64、64、32和64μg/mL。2对尖孢镰刀菌、茄形镰刀菌人参链格孢和草本茎点霉也表现出抗真菌活性，其MIC值分别为128、128、64和128μg/mL。基于系统发育分析，菌株YIM PH20520最接近的系统发育亲缘种是斯氏拟无枝酸菌JS72（97.69%），因此菌株YIM PH20520被鉴定为拟无枝酸菌属菌株。据我们所知，这是除链霉菌属菌株外，首次从拟无枝酸菌属菌株中分离得到刺孢霉素类抗生素及其对四种测试的三七根腐病原菌的抗真菌活性的报道。由于刺孢霉素类抗生素独特的三环缩醛-内酯结构，这些结果为后续对拟无枝酸菌属菌株YIM PH20520的相关生物合成研究提供了可靠的证据。
