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 P_phzH 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 P_rhlI was identified and characterized. The activity of P_phzH is approximately 1% of P_rhlI in PA1201. After three rounds of promoter editing and swapping by P_rhlI, 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.

中文翻译：

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用于假单胞菌菌株PA1201的新型代谢农药Phenazine-1-caramide的生物合成的强群体感应和温度调控启动子的鉴定。

由多种假单胞菌菌株生产的吩嗪-1-羧酰胺（PCN）由于其广谱抗真菌活性和诱导植物体内抗性的能力，成为一种有望成为新型代谢农药的候选药物。水稻根际假单胞菌菌株PA1201包含两个重复的基因簇phz1和phz2，用于吩嗪-1-羧酸（PCA）的生物合成。使用功能性的phzH编码谷氨酰胺转氨酶，该菌株将PCA进一步转化为PCN 。但是，PA1201中的PCN含量约为PCA含量的五分之一，PCN合成的最佳温度为28°C。在这项研究中，phzH开放阅读框（ORF）和启动子区域进行了调查和重新注释。发现phzH启动子P _phzH是弱启动子，而且PhzH水平不足以将所有天然PCA转化为PCN。在RNA Seq和启动子-lacZ融合分析之后，鉴定并鉴定了强群体感应（QS）和温度调控的启动子P _rhlI。P _phzH的活性约为_PA1201中P _rhlI的1％。经过三轮启动子编辑和P _rhlI交换，产生了新的过量生产PCN的菌株UP46。UP46中PCN生物合成的最佳发酵温度从28°C升高到37°C，PCN发酵效价提高了179.5倍，达到14.1 g / L，这是有史以来的最高记录。