The present study investigated the antagonistic and plant growth promoting (PGP) potential of actinobacteria TT3 isolated from tea rhizosphere soil of Tocklai tea germplasm preservation plot, Jorhat, Assam, India. It is a Gram-positive, filamentous with flexible spore chains actinobacteria. The 16S rRNA gene sequencing and phylogenetic analysis indicated that TT3 is closely related to genus Streptomyces for which it was referred to as Streptomyces sp. TT3. It showed very promising PGP traits such as phosphate solubilization, production of indole acetic acid (IAA), siderophore, and ammonia. Evaluation of ethyl acetate extract of TT3 exhibited broad spectrum antagonistic activity against various fungal pathogens. This antagonistic Streptomyces sp. TT3 showed positive for polyketide synthase type II (PKS-II) gene, which was predicted to be involved in the production of actinorhodin as a secondary metabolite pathway product using DoBISCUIT database. Further, the crude ethyl acetate extract of TT3 was analyzed by using GC–MS and revealed the presence of significant chemical constituents responsible for antimicrobial activity. Thus, the present study suggests that actinobacteria isolated from the rhizosphere soil may be explored for the production of bioactive compounds and use as a potential candidate for tea and other agricultural application.

中文翻译：

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链霉菌的拮抗和促进植物生长潜力的评价。从茶（Camellia sinensis）根际土壤中分离的TT3

本研究调查了从印度阿萨姆邦 Jorhat 的 Tocklai 茶种质保存区的茶根际土壤中分离出的放线菌 TT3 的拮抗和植物生长促进 (PGP) 潜力。它是一种革兰氏阳性、丝状的具有柔性孢子链的放线菌。16S rRNA基因测序和系统发育分析表明，TT3与链霉菌属密切相关，因此被称为链霉菌属。TT3。它显示出非常有前途的 PGP 特性，如磷酸盐溶解、吲哚乙酸 (IAA)、铁载体和氨的产生。TT3 的乙酸乙酯提取物的评价显示出对各种真菌病原体的广谱拮抗活性。这种拮抗链霉菌属。TT3 显示聚酮合酶 II 型（PKS-II）基因阳性，使用 DoBISCUIT 数据库预测其参与作为次级代谢产物途径产物的放线菌素的生产。此外，使用 GC-MS 分析了 TT3 的粗乙酸乙酯提取物，并揭示了导致抗菌活性的重要化学成分的存在。因此，本研究表明，从根际土壤中分离出的放线菌可用于生产生物活性化合物，并用作茶叶和其他农业应用的潜在候选物。