Identification And Functional Analysis Of The Protein That C-di-GMP Signaling System In Xanthomonas Oryzae PV. Oryzae

Cyclic diguanylate (c-di-GMP) is found newly as a bacterial second messenger, and the same time, which is formed by diguanylate cyclases with GGDEF motifs that synthesize this second messenger; phosphodiesterases with EAL or HD-GYP motifs catabolize c-di-GMP. Many proteins with GGDEF, EAL or HD-GYP domains are existed in bacterial genomes,such as, there are 38 in Pseudomonas aeruginosa,98 in Serratia spp,53 in Vibrio cholerae, and 29 in E. coli. c-di-GMP has many key roles in regulation of a range of biochemical functions in virulence, biofilm formation, motility and environmental adaptation.Xanthomoans oryzae pv. oryzae (Xoo) is one of the most serious bacterial disease for rice. It mought contain that there was a signaling regulation network in Xoo which strictly control virulence gene expression through signal sensing, perception and transduction. However, at present, there was little new to be known about the virulence regulation network in Xoo. As reported,c-di-GMP regulated many kinds of complex physiological processes. There were 25-31 proteins with GGDEF, EAL or HD-GYP domains in Xoo, However,we still do not understood the functions of some proteins like as above. There are too many year research on c-di-GMP signaling.pathway and its functions in our laboratory. My research was focused on the identification and functional analysis of the new protein gene(PXO-02944,PXO-04753 and PXO-03877) that c-di-GMP signaling system in Xoo.PXO-02944,PXO-04753 and PXO-03877 were studied by gene cloning, sequence, deletion, complement and phenotype analysis; at the same time analyzing the expressions of the genes of EPS and T3SS inΔ02944xoo,Δ04753xoo andΔ03877xoo.My study aimed to identify the corresponding domain protein gene to revEAL its biological function from Xoo, so that providing the scientific basis for metabolic regulation mechanism of c-di-GMP.PXO-02944,PXO-04753 and PXO-03877 were investigated by gene deletion mutation using the marker exchange. Comparing to PXO99A, exopolysaccharide (EPS), biofilm production and virulence had a great ascent forΔ02944xoo; induction of hypersensitive responses (HR) in tobacco and biofilm formation reduced significantly forΔ04753xoo; theΔ03877xoo mutant demonstrated great deficiency in EPS, biofilm production and virulence. In general, That confirmed PXO-02944,PXO-04753 and PXO-03877 might act as important response regulators in c-di-GMP signaling system to be involved in regulation of many kinds of biological functions of Xoo.