Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, National Engineering Research Center for Organic-based Fertilizers, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing Agricultural University, Nanjing, China.
Jiangsu Provincial Key Lab for Organic Solid Waste Utilization, National Engineering Research Center for Organic-based Fertilizers, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, Nanjing Agricultural University, Nanjing, China
Appl Environ Microbiol. 2019 Feb 20;85(5). doi: 10.1128/AEM.02116-18. Print 2019 Mar 1.
Rhizosphere colonization by plant growth-promoting rhizobacteria (PGPR) along plant roots facilitates the ability of PGPR to promote plant growth and health. Thus, an understanding of the molecular mechanisms of the root colonization process by plant-beneficial strains is essential for the use of these strains in agriculture. Here, we observed that an gene mutant of the plant growth-promoting rhizobacterium SQR9 was unable to form normal biofilm architecture, and differential protein expression was observed by proteomic analysis. A minor wall teichoic acid (WTA) biosynthetic protein, GgaA, was decreased over 4-fold in the Δ mutant, and impairment of the gene postponed biofilm formation and decreased cucumber root colonization capabilities. In addition, we provide evidence that the major WTA biosynthetic enzyme GtaB is involved in both biofilm formation and root colonization. The deficiency in biofilm formation of the Δ mutant may be due to an absence of UDP-glucose, which is necessary for the synthesis of biofilm matrix exopolysaccharides (EPS). These observations provide insights into the root colonization process by a plant-beneficial strain, which will help improve its application as a biofertilizer. is a Gram-positive plant-beneficial bacterium which is widely used in agriculture. Additionally, spp. are some of the model organisms used in the study of biofilms, and as such, the molecular networks and regulation systems of biofilm formation are well characterized. However, the molecular processes involved in root colonization by plant-beneficial strains remain largely unknown. Here, we showed that WTAs play important roles in the plant root colonization process. The loss of the gene affects the ability of SQR9 to sense plant polysaccharides, which are important environmental cues that trigger biofilm formation and colonization in the rhizosphere. This knowledge provides new insights into the root colonization process and can help improve our understanding of plant-rhizobacterium interactions.
植物促生根际细菌（PGPR）在植物根际定殖，有助于 PGPR 促进植物生长和健康。因此，了解植物有益菌株根定植过程的分子机制对于这些菌株在农业中的应用至关重要。在这里，我们观察到，植物促生根际细菌 SQR9 的一个基因突变体无法形成正常的生物膜结构，并且通过蛋白质组学分析观察到差异蛋白表达。微量壁磷壁酸（WTA）生物合成蛋白 GgaA 在Δ突变体中减少了 4 倍以上，并且基因的损伤推迟了生物膜形成并降低了黄瓜根定植能力。此外，我们提供了证据表明，主要 WTA 生物合成酶 GtaB 参与生物膜形成和根定植。Δ突变体生物膜形成不足可能是由于缺乏 UDP-葡萄糖，这是生物膜基质胞外多糖（EPS）合成所必需的。这些观察结果深入了解了植物有益菌株的根定植过程，这将有助于提高其作为生物肥料的应用。
是一种革兰氏阳性植物有益细菌，在农业中广泛使用。此外， spp. 是生物膜研究中使用的一些模式生物，因此，生物膜形成的分子网络和调控系统得到了很好的描述。然而，植物有益菌株根定植所涉及的分子过程在很大程度上仍然未知。在这里，我们表明 WTA 在植物根定植过程中发挥重要作用。的缺失基因影响 SQR9 感知植物多糖的能力，植物多糖是触发根际生物膜形成和定植的重要环境线索。这些知识为植物-根际细菌的根定植过程提供了新的见解，并有助于提高我们对植物-根际细菌相互作用的理解。
