Advances research in Ralstonia solanacearum Pathogenicity Mechanism and Related Genes

This review was focused on the virulent and avirulent genes and the regulation of Ralstonia solanacearum pathogenicity. Ralstonia solanacearum had been described as a species-complex bacterium, therefore, many technology were applied to identify this bacterium. Meanwhile, the identification of R. solanacearum became more and more quick, convenient and sensitive. The genome of R.solanacearum strain had a size of 5.8 Mb with a high (G+C) content and a coding potential for approximately 5 120 proteins. It was organized in two replicons, a 3.7 Mb chromosome and a 2.1 Mb megaplasmid. The products of type III hrp section system, extrapolysaccharide, cell wall degrading enzymes such as pectinolytic and cellalolytic enzymes constituted were the major factors for the pathogenicity. All of these were mainly related to the hrp gene cluster, avr gene and virulence genes. The Type III secretion system (T3SS) and Type II secretion system (T2SS) that directly translocated effector proteins into the host cells were essential for the development of disease. Moreover, T2SS functionally interacts with T3SS. The virulence and pathogenicity genes of R. solanacearum were controlled by an elaborate sensory network. The system used PhcA concentration as a core to regulate the expression of pathogenic factors, and thus the growth status of bacteria.