Li Song, Yue Sheng-Jie, Huang Peng, Feng Tong-Tong, Zhang Hong-Yan, Yao Rui-Lian, Wang Wei, Zhang Xue-Hong, Hu Hong-Bo
State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China.
Shanghai Nong Le Biological Products Company Limited (NLBP), Shanghai, China.
J Appl Microbiol. 2022 Nov;133(5):2790-2801. doi: 10.1111/jam.15727. Epub 2022 Aug 5.
Phenazines, such as phenazine-1-carboxylic acid (PCA), phenazine-1-carboxamide (PCN), 2-hydroxyphenazine-1-carboxylic acid (2-OH-PCA), 2-hydroxyphenazine (2-OH-PHZ), are a class of secondary metabolites secreted by plant-beneficial Pseudomonas. Ps. chlororaphis GP72 utilizes glycerol to synthesize PCA, 2-OH-PCA and 2-OH-PHZ, exhibiting broad-spectrum antifungal activity. Previous studies showed that the addition of dithiothreitol (DTT) could increase the phenazines production in Ps. chlororaphis GP72AN. However, the mechanism of high yield of phenazine by adding DTT is still unclear.
In this study, untargeted and targeted metabolomic analysis were adopted to determine the content of metabolites. The results showed that the addition of DTT to GP72AN affected the content of metabolites of central carbon metabolism, shikimate pathway and phenazine competitive pathway. Transcriptome analysis was conducted to investigate the changed cellular process, and the result indicated that the addition of DTT affected the expression of genes involved in phenazine biosynthetic cluster and genes involved in phenazine competitive pathway, driving more carbon flux into phenazine biosynthetic pathway. Furthermore, genes involved in antioxidative stress, phosphate transport system and mexGHI-opmD efflux pump were also affected by adding DTT.
This study demonstrated that the addition of DTT altered the expression of genes related to phenazine biosynthesis, resulting in the change of metabolites involved in central carbon metabolism, shikimate pathway and phenazine competitive pathway.
This work expands the understanding of high yield of phenazine by the addition of DTT and provides several targets for increasing phenazine production.
吩嗪类化合物，如吩嗪 - 1 - 羧酸（PCA）、吩嗪 - 1 - 甲酰胺（PCN）、2 - 羟基吩嗪 - 1 - 羧酸（2 - OH - PCA）、2 - 羟基吩嗪（2 - OH - PHZ），是一类由对植物有益的假单胞菌分泌的次生代谢产物。绿针假单胞菌GP72利用甘油合成PCA、2 - OH - PCA和2 - OH - PHZ，具有广谱抗真菌活性。先前的研究表明，添加二硫苏糖醇（DTT）可以增加绿针假单胞菌GP72AN中吩嗪类化合物的产量。然而，添加DTT提高吩嗪产量的机制仍不清楚。
在本研究中，采用非靶向和靶向代谢组学分析来确定代谢产物的含量。结果表明，向GP72AN中添加DTT会影响中心碳代谢、莽草酸途径和吩嗪竞争途径的代谢产物含量。进行转录组分析以研究细胞过程的变化，结果表明添加DTT会影响参与吩嗪生物合成簇的基因以及参与吩嗪竞争途径的基因的表达，促使更多的碳通量进入吩嗪生物合成途径。此外，参与抗氧化应激、磷酸盐转运系统和mexGHI - opmD外排泵的基因也受到添加DTT的影响。
本研究表明，添加DTT改变了与吩嗪生物合成相关的基因表达，导致中心碳代谢、莽草酸途径和吩嗪竞争途径中涉及的代谢产物发生变化。
这项工作扩展了对添加DTT提高吩嗪产量的理解，并为提高吩嗪产量提供了几个靶点。
