Wei Wei, Zhou Yu, Chen Fanjie, Yan Xiaomei, Lai Yongmin, Wei Chaoling, Chen Xiaoyun, Xu Junfeng, Wang Xu
State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Institute of Quality and Standard for Agro-Products, Zhejiang Academy of Agricultural Sciences, Hangzhou, China.
State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, Hefei, China.
Front Microbiol. 2018 Jun 18;9:1304. doi: 10.3389/fmicb.2018.01304. eCollection 2018.
Endophytic actinobacteria exist widely in plant tissues and are considered as a potential bioresource library of natural products. Tea plants play important roles in human health and in the lifestyles of Asians, especially the Chinese. However, little is known about the endophytic actinobacteria of tea plants. In this study, 16 actinobacteria of 7 different genera and 28 actinobacteria of 8 genera were isolated and analyzed by 16S rRNA gene sequencing from tea cultivars of Zijuan and Yunkang-10 ( var. ), respectively. The diversity of actinobacteria species from Zijuan were higher in July than December (6 vs. 3 genera), but the diversity of species from Yunkang-10 were higher in December than July (7 vs. 3 genera). No actinobacteria isolates were obtained from any tea cultivar in September. Ten isolates from Yunkang-10 exhibited antimicrobial activity against at least one human pathogenic microorganism (, , and ), but none of the isolates from Zijuan exhibited antimicrobial activities. Fourteen strains were further exammined the genes of polyketide synthetase () and and non-ribosomal peptide synthetase (). sp. YXT131 from Yunkang-10 showed strong inhibitory activity against , , and , and and and genes were obtained from the strain. In assays, extracts from 14 actinobacteria that were tested for antibiotic biosynthetic genes showed no inhibition of concanavalin A (ConA)-induced murine splenocyte proliferation. In assays, the crude extract of YXT131 modulated the immune response by decreasing the proinflammatory cytokines interleukin (IL)-12/IL-23 p40 and tumor necrosis factor (TNF)-α in the serum of mice. These results confirm that endophytic actinobacteria from tea plants might be an undeveloped bioresource library for active compounds.
内生放线菌广泛存在于植物组织中，被认为是天然产物的潜在生物资源库。茶树对人类健康以及亚洲人尤其是中国人的生活方式都起着重要作用。然而，人们对茶树内生放线菌了解甚少。在本研究中，分别从紫娟和云抗10号茶树品种中，通过16S rRNA基因测序分离并分析了7个不同属的16株放线菌和8个属的28株放线菌。紫娟茶树中放线菌物种的多样性在7月高于12月（6个属对3个属），但云抗10号茶树中放线菌物种的多样性在12月高于7月（7个属对3个属）。9月从任何茶树品种中均未获得放线菌分离株。云抗10号的10株分离株对至少一种人类致病微生物（、和）表现出抗菌活性，但紫娟的分离株均未表现出抗菌活性。对14株菌株进一步检测了聚酮合酶（）和非核糖体肽合成酶（）的基因。云抗10号的sp. YXT131对、和表现出较强的抑制活性，并且从该菌株中获得了和基因。在检测中，对14株经抗生素生物合成基因检测的放线菌提取物未显示对伴刀豆球蛋白A（ConA）诱导的小鼠脾细胞增殖有抑制作用。在检测中，YXT131的粗提物通过降低小鼠血清中促炎细胞因子白细胞介素（IL）-12/IL-23 p40和肿瘤坏死因子（TNF）-α来调节免疫反应。这些结果证实，茶树内生放线菌可能是一个尚未开发的活性化合物生物资源库。
