PMID:10707351

Citation	Vasse, J, Genin, S, Frey, P, Boucher, C and Brito, B (2000) The hrpB and hrpG regulatory genes of Ralstonia solanacearum are required for different stages of the tomato root infection process. Mol. Plant Microbe Interact. 13:259-67
Abstract	hrp genes, encoding type III secretion machinery, have been shown to be key determinants for pathogenicity in the vascular phytopathogenic bacterium Ralstonia solanacearum GMI1000. Here, we show phenotypes of R. solanacearum mutant strains disrupted in the prhJ, hrpG, or hrpB regulatory genes with respect to root infection and vascular colonization in tomato plants. Tests of bacterial colonization and enumeration in tomato plants, together with microscopic observations of tomato root sections, revealed that these strains display different phenotypes in planta. The phenotype of a prhJ mutant resembles that of the wild-type strain. An hrpB mutant shows reduced infection, colonization, and multiplication ability in planta, and induces a defense reaction similar to a vascular hypersensitive response at one protoxylem pole of invaded plants. In contrast, the hrpG mutant exhibited a wild-type level of infection at secondary root axils, but the ability of the infecting bacteria to penetrate into the vascular cylinder was significantly impaired. This indicates that bacterial multiplication at root infection sites and transit through the endodermis constitute critical stages in the infection process, in which hrpB and hrpG genes are involved. Moreover, our results suggest that the hrpG gene might control, in addition to hrp genes, other functions required for vascular colonization.
Links	PubMed Online version:10.1094/MPMI.2000.13.3.259
Keywords	Bacterial Proteins/genetics; Bacterial Proteins/metabolism; DNA-Binding Proteins; Lycopersicon esculentum/microbiology; Lycopersicon esculentum/ultrastructure; Microscopy, Electron; Plant Roots/anatomy & histology; Plant Roots/microbiology; Plant Roots/ultrastructure; Pseudomonas/genetics; Pseudomonas/growth & development; Pseudomonas/pathogenicity; Repressor Proteins/genetics; Repressor Proteins/metabolism; Transcription Factors
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
RALSO:HRPB		GO:0030260: entry into host cell	ECO:0000315:		P		Figure 4 shows that a mutant hrpB cell has reduced entry into a host cell than compared to wild type.	complete CACAO 4675
RALSO:HRPB	involved_in	GO:0030260: entry into host cell	ECO:0000315: mutant phenotype evidence used in manual assertion		P		Seeded From UniProt	complete

References

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