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He Yawen’s Team Made Breakthroughs in New Metabolite Pesticide

September 18, 2020      Author:

Recently, the reearch team led by He Yawen from School of Life Sciences and Biotechnology, SJTU had their research published on the website of ACS Synthetic Biology, a high-impact journal in the field of biosynthesis. The paper is titled “Identification of a strong quorum sensing- and thermo-regulated promoter for the biosynthesis of a new metabolite pesticide phenazine-1-carboxamide in Pseudomonas strain PA1201”. Doctoral student Jin Zijing from School of Life Sciences and Biotechnology is the first author, and Professor He Yawen is the corresponding author.

Following RNA Seq and promoter-lacZ fusion analyses, they identified a strong quorum sensing (QS)- and thermo-regulated promoter PrhlI. After three rounds of promoter editing and swapping by PrhlI, they generated a new Phenazine-1-carboxamide-overproducing strain UP46, which is more effective and active. The high-yield strains have been sent to enterprises for further development and application.

Their research has been sponsored by National Key Research and Development Project and National Natural Science Foundation of China, etc. 

 

Abstract

Phenazine-1-carboxamide (PCN) produced by multifarious Pseudomonas strains represents a promising candidate as a new metabolite pesticide due to its broad-spectrum antifungal activity and capacity to induce systemic resistance in plants. The rice rhizosphere Pseudomonas strain PA1201 contains two reiterated gene clusters, phz1 and phz2, for phenazine-1-carboxylic acid (PCA) biosynthesis; PCA is further converted into PCN by this strain using a functional phzH-encoding glutamine aminotransferase. However, PCN levels in PA1201 constitute approximately one-fifth of PCA levels and the optimal temperature for PCN synthesis is 28 °C. In this study, the phzH open reading frame (ORF) and promoter region were investigated and reannotated. phzH promoter PphzH was found to be a weak promoter, and PhzH levels were not sufficient to convert all of the native PCA into PCN. Following RNA Seq and promoter-lacZ fusion analyses, a strong quorum sensing (QS)- and thermo-regulated promoter PrhlI was identified and characterized. The activity of PphzH is approximately 1% of PrhlI in PA1201. After three rounds of promoter editing and swapping by PrhlI, a new PCN-overproducing strain UP46 was generated. The optimal fermentation temperature for PCN biosynthesis in UP46 was increased from 28 to 37 °C and the PCN fermentation titer increased 179.5-fold, reaching 14.1 g/L, the highest ever reported.

 

Translated by Zhang Wenying