Flagellin glycosylation island in Pseudomonas syringae pv. glycinea and its role in host specificity.
The deduced amino acid sequences of the flagellins of Pseudomonas syringae pv. tabaci and P. syringae pv. glycinea are identical; however, their abilities to induce a hypersensitive reaction are clearly different. The reason for the difference seems to depend on the posttranslational modification of the flagellins. To investigate the role of this posttranslational modification in the interactions between plants and bacterial pathogens, we isolated genes that are potentially involved in the posttranslational modification of flagellin in P. syringae pv. glycinea (glycosylation island); then defective mutants with mutations in these genes were generated. There are three open reading frames in the glycosylation island, designated orf1, orf2, and orf3. orf1 and orf2 encode putative glycosyltransferases, and mutants with defects in these open reading frames, deltaorf1 and deltaorf2, secreted nonglycosylated and slightly glycosylated flagellins, respectively. Inoculation tests performed with these mutants and original nonhost tobacco leaves revealed that deltaorf1 and deltaorf2 could grow on tobacco leaves and caused symptom-like changes. In contrast, these mutants failed to cause symptoms on original host soybean leaves. These data indicate that putative glycosyltransferases encoded in the flagellin glycosylation island are strongly involved in recognition by plants and could be the specific determinants of compatibility between phytopathogenic bacteria and plant species.
Laboratory of Plant Pathology & Genetic Engineering, Faculty of Agriculture, Okayama University, Tsushima-naka 1-1-1, Okayama 700-8530, Japan.
Kasumi
K
Takeuchi
Fumiko
F
Taguchi
Yoshishige
Y
Inagaki
Kazuhiro
K
Toyoda
Tomonori
T
Shiraishi
Yuki
Y
Ichinose
D005408:Flagellin / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D006031:Glycosylation; D016695:Glycosyltransferases / Q000235:genetics; D008969:Molecular Sequence Data; D009154:Mutation; D009580:Nitroblue Tetrazolium / Q000378:metabolism; D010935:Plant Diseases / Q000382:microbiology*; D018515:Plant Leaves / Q000382:microbiology; D011499:Protein Processing, Post-Translational; D044224:Pseudomonas syringae / Q000254:growth & development / Q000378:metabolism / Q000472:pathogenicity*; D017422:Sequence Analysis, DNA; D013025:Glycine max / Q000382:microbiology*; D014026:Nicotiana / Q000382:microbiology*
D005408:Flagellin; D009580:Nitroblue Tetrazolium; D016695:Glycosyltransferases