The tomato gene Pti1 encodes a serine/threonine kinase that is phosphorylated by Pto and is involved in the hypersensitive response

• Published in: Cell Vol. 83; no. 6; pp. 925 - 935
• Main Authors: Zhou, Jianmin, Loh, Ying-Tsu, Bressan, Ray A., Martin, Gregory B.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 15-12-1995
• Subjects: Amino Acid Sequence; Cloning, Molecular; DNA, Complementary - genetics; Genes, Plant - genetics; lycopersicon esculentum; Molecular Sequence Data; Mutation; Nicotiana - genetics; Phosphorylation; Plant Diseases - microbiology; Plant Proteins; Plants, Toxic; Protein Serine-Threonine Kinases - chemistry; Protein Serine-Threonine Kinases - genetics; Protein Serine-Threonine Kinases - metabolism; Pseudomonas - pathogenicity; Pseudomonas syringae; Sequence Analysis, DNA; Sequence Homology, Amino Acid; Signal Transduction - physiology; Solanum lycopersicum - embryology; Solanum lycopersicum - genetics; Substrate Specificity; Transgenes
• ISSN: 0092-8674; 1097-4172
• DOI: 10.1016/0092-8674(95)90208-2

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. Crossphosphorylation assays revealed that Pto specifically phosphorylates Ptil and that Ptil does not phosphorylate Pto. Fen, another serine/threonine kinase from tomato that is closely related to Pto, was unable to phosphorylate Ptil 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 Ptomediated signaling pathway, probably by acting as a component downstream of Pto in a phosphorylation cascade.