Gao Xiyang, Li Tao, Liu Wenliang, Zhang Yan, Shang Di, Gao Yuqian, Qi Yuancheng, Qiu Liyou
Ministry of Agriculture and Rural Affairs, Key Laboratory of Enzyme Engineering of Agricultural Microbiology, Henan Agricultural University, College of Life Sciences, Zhengzhou 450002, China.
Microorganisms. 2020 Jan 2;8(1):71. doi: 10.3390/microorganisms8010071.
1-aminocyclopropane-1-carboxylic acid (ACC) is a strong metabolism-dependent chemoattractant for the plant beneficial rhizobacterium sp. UW4. It is unknown whether enhancing the metabolic rate of ACC can intensify the chemotaxis activity towards ACC and rhizocompetence. In this study, we selected four promoters to transcribe the UW4 ACC deaminase (AcdS) gene in the UW4 Δ mutant. PA is the UW4 gene promoter, PB20, PB10 and PB1 are synthetic promoters. The order of the gene expression level and AcdS activity of the four strains harboring the promoters were PB20 > PA > PB10 > PB1. Interestingly, the AcdS activity of the four strains and their parent strain UW4 was significantly positively correlated with their chemotactic activity towards ACC, rhizosphere colonization, roots elongation and dry weight promotion. The results released that enhancing the AcdS activity of PGPRenable them to achieve strong chemotactic responses to ACC, rhizocompetence and plant growth promotion.
1-氨基环丙烷-1-羧酸（ACC）是植物有益根际细菌 UW4 的一种强烈的代谢依赖性趋化剂。目前尚不清楚提高 ACC 的代谢速率是否能增强对 ACC 的趋化活性和根际竞争能力。在本研究中，我们选择了四个启动子来转录 UW4 Δ 突变体中的 UW4 ACC 脱氨酶（AcdS）基因。PA 是 UW4 基因启动子，PB20、PB10 和 PB1 是合成启动子。含有这些启动子的四个菌株的基因表达水平和 AcdS 活性顺序为 PB20 > PA > PB10 > PB1。有趣的是，这四个菌株及其亲本菌株 UW4 的 AcdS 活性与它们对 ACC 的趋化活性、根际定殖、根伸长和干重促进显著正相关。结果表明，提高植物根际促生细菌（PGPR）的 AcdS 活性能够使其对 ACC 产生强烈的趋化反应、具备根际竞争能力并促进植物生长。
