Peh production, flagellum synthesis, and virulence reduced in Erwinia carotovora subsp. carotovora by mutation in a homologue of cytR.
Erwinia carotovora subsp. carotovora is a causal agent of soft-rot diseases in a wide variety of plants. Here, we have isolated a new regulatory factor involved in the virulence of E. carotovora subsp. carotovora by in vivo insertional mutagenesis using a transposon Tn5. The gene was homologous to cytR encoding a transcriptional repressor of nucleoside uptake and catabolism genes in Escherichia coli, Salmonella typhimurium, and Vibrio cholerae. Phenotypic characterization of a nonpolar deletion mutant of the cytR homologue (delta cytR) revealed that the delta cytR mutant produced a reduced level of polygalacturonase (Peh) and lost its motility compared to that in the parental strain. With electron microscopy, the delta cytR mutant was shown to be aflagellate. Furthermore, the expression of fliA and fliC (encoding sigma28 and flagellin, respectively) was also reduced in delta cytR mutant. The virulence of delta cytR mutant was reduced in Chinese cabbage and potato compared to that of the parental strain. These results suggest that the CytR homologue of E. carotovora subsp. carotovora positively controls Peh production and flagellum synthesis and plays an important role in its pathogenicity.
Faculty of Agriculture, Shizuoka University, 836 Ohya, Shizuoka 422-8529, Japan.
Hiroyuki
H
Matsumoto
Hironobu
H
Muroi
Masahiro
M
Umehara
Yoshimasa
Y
Yoshitake
Shinji
S
Tsuyumu
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D003001:Cloning, Molecular; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D029968:Escherichia coli Proteins; D005407:Flagella / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D008969:Molecular Sequence Data; D009154:Mutation; D016973:Pectobacterium carotovorum / Q000235:genetics* / Q000472:pathogenicity; D011096:Polygalacturonase / Q000096:biosynthesis*; D012097:Repressor Proteins / Q000235:genetics* / Q000378:metabolism; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D014774:Virulence
D001426:Bacterial Proteins; C048425:CytR protein, E coli; D004269:DNA, Bacterial; D029968:Escherichia coli Proteins; D012097:Repressor Proteins; D011096:Polygalacturonase