Ralstonia solanacearum RSc0411 (lptC) is a determinant for full virulence and has a strain-specific novel function in the T3SS activity

Abstract

Previously, we have identified an avirulent Ralstonia solanacearum mutant carrying a transposon insertion in RSc0411, a gene homologous to the Escherichia coli LPS-transporting protein LptC. However, how the disruption of RSc0411 affects the bacterium-plant interactions and leads to decreased pathogenicity was not known. Here we show that the disruption of RSc0411 leads to pleiotropic defects, including reducing bacterial motility, biofilm formation, root attachment, roughform LPS production and virulence in tomato and increasing membrane permeability. Disruption of the orthologous RSc0411 present in other R. solanacearum strains proves that most of these functions are conserved in the species. In contrast, trans-complementation analyses show that only RSc0411 orthologues from closely related bacteria can rescue the defects of the disruption mutant. These results enable us to propose a function for RSc0411, and for the clustered genes, in LPS biogenesis, and for the first time, to our knowledge, also a role of a gene from the DUF1239 gene family in bacterial pathogenicity. In addition and notably, the RSc0411 mutant displays a strain-specific phenotype for hypersensitive response (HR), in which the RSc0411 disruption impairs the HR caused by strain Pss190 but not that by strain Pss1308. Consistent with this strain-specific defect, the mutation clearly affects expression of the type III secretion system (T3SS) in Pss190 but not in other strains, suggesting that the HR-deficient phenotype of the RSc0411 mutant in Pss190 is due to impairment of the T3SS and thus RSc0411 has a strainspecific role in the T3SS activity of R. solanacearum.

Lipopolysaccharides from Ralstonia solanacearum induce a broad metabolomic response in Solanum lycopersicum

“…, ii) determine the dominant LPS type extracted from the bacterial pathogen, and iii) assess whether the observed LPS R. sol. banding pattern corresponded to what has been previously described in the literature ( Yang et al, 2013 ). The LPS of B. cepacia (LPS B.cep. )…”

Functional Interaction between the Cytoplasmic ABC Protein LptB and the Inner Membrane LptC Protein, Components of the Lipopolysaccharide Transport Machinery in Escherichia coli

“…1) and Ralstonia solanacearum (38) and of an lptC frameshift mutation after codon 134 in Salmonella enterica conferring bile resistance (39).…”

A biomimetic platform for studying root-environment interaction

“…To cause disease, soilborne bacterial pathogens like Rs must first attach to the root surface. Root attachment is critical for disease, and Rs mutants that cannot attach to the root surface have decreased virulence (Kang et al 2002;Yang et al 2013;Dalsing and Allen 2014). After root attachment, Rs enters the root through minor wounds or cracks in the root surface that occur as the root grows through soil and Scheme 2 Schematic diagram for the preparation of positive replicas of M82 tomato root made from three different molding materials.…”