Exploring The Trehalose Synthesis Pathway Of Pseudomonas Syringae

The foliar pathogen Pseudomonas syringae is a useful model for understanding the role of stress adaptation in leaf colonization.Trehalose is a disaccharide which is accumulated by many plant bacteria in stress,it can help cells to defense osmotic stress during periods of physiological stress.We explore the trehalose synthesis pathway in two strains B728 a and DC3000 of Pseudomonas syringae and we found that their trehalose synthesis pathway exist differences.We indicated that genes related to trehalose synthesis in Pseudomonas syringae B728 a are distribute to two gene clusters tre1 and tre2.and via growth curve and trehalose quantification we find these two gene clusters are required for the trehalose synthesis.In tre1 gene cluster,glgE and glgB are important to trehalose synthesis ? treS has little effect on trehalose synthesis.In tre2 gene cluster,glgA,treX,treY,treZ are required for the trehalose synthesis.These results indicated that the main trehalose synthesis pathway is TreYZ in B728 a.We also find it is similar with B728 a that the gene clusters related to trehalose synthesis are alsomost on tre1 and tre2 two gene clusters.And these gene clusters are required for the trehalose synthesis too.But in DC3000 tre1 gene cluster,treS plays an important role in trehalose synthesis,glgE is also important to defense osmotic stress,glgB is still unknow.In tre2 gene cluster,glgA and treX are required for defensing osmotic stress,but unlike B728 a,treY and treZ are not necessary to resist osmotic stress in DC3000.These results indicated that the main trehalose synthesis pathway is TreS in DC3000.We found that in two strains B728 a and DC3000 exist differences in their trehalose synthesis pathways,which provides a new theoretical basis for understanding the difference in osmotolerance between these two strains.By exploring the role and mechanism of trehalose synthesis in Pseudomonas syringae defensing osmotic stress,it provides a new theoretical basis for discussion on the adaptability and stress resistance of the plant bacteria survive in hyperosmotic stress environment.