Burkholderia pyrrocinia JK-SH007 is a plant growth-promoting bacteria (PGPB), that can promote the growth of poplar and other trees, and, production of the plant hormone indole-3-acetic acid (IAA) is one of the reasons for this effect. Therefore, the aims of this study were to evaluate the effect of the external environment on the synthesis of IAA by B. pyrrocinia JK-SH007 and to perform a functional analysis of its IAA synthesis pathway. In this study, IAA and its synthetic intermediates indole-3-acetamide (IAM), indole-3-pyruvic acid (IPyA), tryptamine (TAM), and indole-3-acetonitrile (IAN) were detected in B. pyrrocinia JK-SH007 fermentation broth by high-performance liquid chromatography and tandem mass spectrometry (HPLC-MS/MS), and these indolic compounds were also found in the cell-free extraction of B. pyrrocinia JK-SH007, but the genomic analysis of B. pyrrocinia JK-SH007 indicated that IAA biosynthesis was mainly through the IAM and TAM pathways. The effects of L-tryptophan (L-Trp), temperature and pH on the synthesis of IAA were investigated, and the results showed that L-Trp exerted a significant effect on IAA synthesis and that 37°C and pH 7 were the optimal conditions IAA production by B. pyrrocinia JK-SH007. In addition, the protein expression of tryptophan 2-monooxygenase and indoleacetamide hydrolase, which are the key enzymes of the indole acetamide-mediated IAA synthesis pathway, was analyzed, and their activity was verified by substrate feeding experiments. The results revealed the existence of an IAA synthesis pathway mediated by IAM and indicated that this pathway plays a role in B. pyrrocinia JK-SH007. This study lays the foundation for further exploration of the specific pathway and mechanism of IAA synthesis in B. pyrrocinia JK-SH007.

中文翻译：

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吡咯伯克霍尔德菌 JK-SH007 中的吲哚-3-乙酸：吲哚-3-乙酰胺合成途径的酶法鉴定。

吡咯伯克霍尔德菌JK-SH007是一种植物促生长菌（PGPB），可以促进杨树等树木的生长，产生植物激素吲哚-3-乙酸（IAA）是其原因之一影响。因此，本研究的目的是评估外部环境对B.pyrocinia JK-SH007合成IAA的影响，并对其IAA合成途径进行功能分析。在本研究中，在 B.pyrocinia JK- 中检测到 IAA 及其合成中间体吲哚-3-乙酰胺 (IAM)、吲哚-3-丙酮酸 (IPyA)、色胺 (TAM) 和吲哚-3-乙腈 (IAN)。通过高效液相色谱-串联质谱（HPLC-MS/MS）对SH007发酵液进行分析，在B.pyrocinia JK-SH007的无细胞提取物中也发现了这些吲哚类化合物，但B.pyrocinia基因组分析中也发现了这些吲哚类化合物JK-SH007表明IAA生物合成主要通过IAM和TAM途径。考察了L-色氨酸（L-Trp）、温度和pH对IAA合成的影响，结果表明，L-Trp对IAA合成影响显着，且37℃和pH 7为最佳条件。 IAA 由 B.pyrocinia JK-SH007 生产。此外，还分析了吲哚乙酰胺介导的IAA合成途径的关键酶色氨酸2-单加氧酶和吲哚乙酰胺水解酶的蛋白表达，并通过底物补给实验验证了它们的活性。结果揭示了IAM介导的IAA合成途径的存在，并表明该途径在B.pyrocinia JK-SH007中发挥作用。本研究为进一步探索B.pyrocinia JK-SH007合成IAA的具体途径和机制奠定了基础。