Zhang Xin-Guo, Guo Si-Jia, Wang Wen-Na, Wei Guo-Xing, Ma Guo-Yan, Ma Xiao-Di
School of Life Sciences and Engineering, Lanzhou University of Technology, Lanzhou, China.
Key Laboratory of Screening and Processing in New Tibetan Medicine of Gansu Province, Gansu, China.
Front Microbiol. 2020 Aug 18;11:1489. doi: 10.3389/fmicb.2020.01489. eCollection 2020.
Plant seeds are not merely reproductive organs, they are also carriers of microorganism, particularly, inherent and non-invasive characteristic endophytes in host plant. Therefore, in this study, the endophytic diversity of seeds was studied and compared with endophytes isolated from healthy leaves, stems, roots, and seeds of . using 20 different media. The metabolites of endophytic strains were evaluated with six different methods for their antioxidant activity and the paper disc diffusion method for antimicrobial activities. As a result, 226 endophytes were isolated. Compared with the biodiversity and abundance of uncultured fungi from seed, the result showed that the most frequent endophytic fungi were sp. as seen in artificial media; moreover, compared with artificial media, the pathogenic fungi, including sp. and sp., were not found from the seed, the results suggested it may not be inherent endophytes in plants. In addition, bacteria from seven phyla were identified by high-throughput sequencing, while five phyla of endophytic bacteria were not isolated on artificial media including , , , , and . Furthermore, the sample JH-4 mycelium displayed the best antioxidant activity, and the active constituent may be a flavonoid as determined by total phenol and flavonoid content. Moreover, YH-12-1 mycelium had strong inhibitory activity against the five tested strains and the minimum inhibitory concentration (MIC) against and was found to be 25 μg/mL. Our results confirm that plant endophytes are rich in biodiversity and contain important resource of many uncultured microorganisms.
植物种子不仅是繁殖器官，也是微生物的载体，特别是宿主植物中固有的、非侵入性的内生菌。因此，在本研究中，对种子的内生菌多样性进行了研究，并与从[植物名称]的健康叶片、茎、根和种子中分离出的内生菌进行了比较，使用了20种不同的培养基。采用六种不同方法评估内生菌株的代谢产物的抗氧化活性，并用纸片扩散法评估其抗菌活性。结果，分离出226株内生菌。与[植物名称]种子中未培养真菌的生物多样性和丰度相比，结果表明，在人工培养基中最常见的内生真菌是[真菌名称]；此外，与人工培养基相比，在[植物名称]种子中未发现包括[致病真菌名称1]和[致病真菌名称2]在内的致病真菌，结果表明其可能不是植物固有的内生菌。此外，通过高通量测序鉴定出七个门的细菌，而在人工培养基上未分离出五个门的内生细菌，包括[细菌门名称1]、[细菌门名称2]、[细菌门名称3]、[细菌门名称4]和[细菌门名称5]。此外，样品JH-4菌丝体表现出最佳的抗氧化活性，通过总酚和黄酮含量测定，活性成分可能是黄酮类化合物。此外，YH-12-1菌丝体对五种测试菌株具有较强的抑制活性，对[测试菌株名称1]和[测试菌株名称2]的最低抑菌浓度（MIC）为25μg/mL。我们的结果证实，植物内生菌具有丰富的生物多样性，并且包含许多未培养微生物的重要资源。
