Gac two-component system in Pseudomonas syringae pv. tabaci is required for virulence but not for hypersensitive reaction.
Pseudomonas syringae pv. tabaci 6605 causes wildfire disease on host tobacco plants. To investigate the regulatory mechanism of the expression of virulence, Gac two-component system-defective mutants, DeltagacA and DeltagacS, and a double mutant, DeltagacADeltagacS, were generated. These mutants produced smaller amounts of N-acyl homoserine lactones required for quorum sensing, had lost swarming motility, and had reduced expression of virulence-related hrp genes and the algT gene required for exopolysaccharide production. The ability of the mutants to cause disease symptoms in their host tobacco plant was remarkably reduced, while they retained the ability to induce hypersensitive reaction (HR) in the nonhost plants. These results indicated that the Gac two-component system of P. syringae pv. tabaci 6605 is indispensable for virulence on the host plant, but not for HR induction in the nonhost plants.
Marutani
Mizuri
M
Laboratory of Plant Pathology and Genetic Engineering, Graduate School of Natural Science and Technology, Okayama University, Tsushima-naka 1-1-1, Okayama, 700-8530, Japan.
Taguchi
Fumiko
F
Ogawa
Yujiro
Y
Hossain
Md Mijan
MM
Inagaki
Yoshishige
Y
Toyoda
Kazuhiro
K
Shiraishi
Tomonori
T
Ichinose
Yuki
Y
D054742:Acyl-Butyrolactones / Q000378:metabolism; D001422:Bacterial Adhesion / Q000235:genetics / Q000502:physiology; D001426:Bacterial Proteins / Q000235:genetics / Q000502:physiology; D001483:Base Sequence; D017931:DNA Primers / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D015870:Gene Expression; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D009154:Mutation; D010935:Plant Diseases / Q000382:microbiology; D044224:Pseudomonas syringae / Q000235:genetics* / Q000472:pathogenicity* / Q000502:physiology; D053038:Quorum Sensing / Q000235:genetics / Q000502:physiology; D012808:Sigma Factor / Q000235:genetics / Q000502:physiology; D014026:Nicotiana / Q000382:microbiology; D014157:Transcription Factors / Q000235:genetics / Q000502:physiology; D014774:Virulence / Q000235:genetics
D054742:Acyl-Butyrolactones; C079619:AlgU protein, Pseudomonas aeruginosa; D001426:Bacterial Proteins; D017931:DNA Primers; D004269:DNA, Bacterial; C091100:GacA protein, Bacteria; D012808:Sigma Factor; D014157:Transcription Factors; C074165:lemA protein, bacterial