Indole-3-Acetic Acid in Burkholderia pyrrocinia JK-SH007: Enzymatic Identification of the Indole-3-Acetamide Synthesis Pathway

Abstract

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.

Highly Efficient Biosynthesis of Indole-3-acetic acid by Enterobacter xiangfangensis BHW6

“…As reported, the highest IAA yield for B. pyrrocina JK-SH007 was achieved at pH 7.0 and the fastest growth of this strain was observed at pH 4.0 (Liu et al 2019). In our study, the highest yield of IAA was found at pH 5.0 and the optimal growth of the strain was found at pH 5.0-7.0 ( Fig.…”

Metagenomic insight into the plant growth-promoting potential of a diesel-degrading bacterial consortium for enhanced rhizoremediation application

“…Previous studies on siderophore and pyrroloquinoline quinone biosynthesis have focused on Pseudomonas 42 . Similarly, studies on indoleacetic acid production by PGPR have generally been limited to a few microorganisms such as Azospirillum, Pseudomonas, Rhizobium and Burkholderia 7, [43][44][45][46] . Hence, the identification of Acidocella and Acidobacterium as being potentially involved in these processes, coupled with their hydrocarbon-degrading potentials 18 , significantly expands the range of PGPR applicable for microbially-enhanced phytoremediation of organic pollutants.…”

Solubilización de fosfatos por bacterias del género Burkholderia aisladas de oxisoles de la altillanura colombiana

“…Las cepas M15 (B. ubonensis) y M18 (B. cepacia) seleccionadas como BSF produjeron cantidades bajas de compuestos indólicos comparadas con otras cepas de Burkholderia, que han sido reportadas como productoras de este tipo de compuestos empleando la misma metodología para esta determinación. Tal es el caso de Burkholderia heleia PAK1-2 con rendimientos cercanos a 100 µM y capacidad para inhibir patógenos como Burkholderia plantarii (Wang et al, 2016), y Burkholderia pyrrocinia con un máximo de producción de compuestos indólicos de 6,9 mg/L después de 36 horas de cultivo in vitro (Liu et al, 2019). En otros estudios con bacterias aisladas a partir de la rizosfera de mango Mangifera indica L. (Anacardiaceae) reportaron la producción de 2 ± 0,2 mg/L de compuestos indólicos para Burkholderia caribensis (De los Santos-Villalobos et al, 2015).…”