The tomato gene Pti1 encodes a serine/threonine kinase that is phosphorylated by Pto and is involved in the hypersensitive response.
The Pto gene encodes a serine/threonine kinase that confers resistance to bacterial speck disease in tomato. Using the yeast two-hybrid system, we identified a second serine/threonine kinase, Pto-interacting 1 (Pti1), that physically interacts with Pto. Cross-phosphorylation assays revealed that Pto specifically phosphorylates Pti1 and that Pti1 does not phosphorylate Pto. Fen, another serine/threonine kinase from tomato that is closely related to Pto, was unable to phosphorylate Pti1 and was not phosphorylated by Pti1. Expression of a Pti1 transgene in tobacco plants enhanced the hypersensitive response to a P. syringae pv. tabaci strain carrying the avirulence gene avrPto. These findings indicate that Pti1 is involved in a Pto-mediated signaling pathway, probably by acting as a component downstream of Pto in a phosphorylation cascade.
Department of Agronomy, Purdue University, West Lafayette, Indiana 47907-1150, USA.
J
J
Zhou
Y T
YT
Loh
R A
RA
Bressan
G B
GB
Martin
D000595:Amino Acid Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D017343:Genes, Plant / Q000235:genetics*; D018551:Solanum lycopersicum / Q000196:embryology / Q000235:genetics*; D008969:Molecular Sequence Data; D009154:Mutation; D010766:Phosphorylation; D010935:Plant Diseases / Q000382:microbiology; D010940:Plant Proteins; D010947:Plants, Toxic; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011549:Pseudomonas / Q000472:pathogenicity; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction / Q000502:physiology*; D013379:Substrate Specificity; D014026:Nicotiana / Q000235:genetics; D019076:Transgenes
D018076:DNA, Complementary; D010940:Plant Proteins; C091599:Fen protein, Lycopersicon esculentum; C084354:Pto protein, Lycopersicon; D017346:Protein Serine-Threonine Kinases