The tomato kinase Pti1 contributes to production of reactive oxygen species in response to two flagellin-derived peptides and promotes resistance to Pseudomonas syringae infection

GREGORY B. MARTIN; SUMA CHAKRAVARTHY; ZHANGJUN FEI; MARINA A. POMBO; NOÉ FERNANDEZ-POZO; YI ZHENG; DIANE M. DUNHAM; CHRISTINE M. KRAUS; SIMON SCHWIZER

MOLECULAR PLANT-MICROBE INTERACTIONS

AMER PHYTOPATHOLOGICAL SOC

Año: 2017

0894-0282

The Pti1 kinase was identified from a reverse genetic screen as contributing to pattern-triggeredimmunity (PTI) against Pseudomonas syringae pv. tomato (Pst). The tomato genome has twoPti1 genes, referred to as Pti1a and Pti1b. A hairpin-Pti1 (hpPti1) construct was developed andused to generate two independent stable transgenic tomato lines, which had reduced transcriptabundance of both genes. In response to Pst inoculation, these hpPti1 plants developed moresevere disease symptoms, supported higher bacterial populations, and had reduced transcriptaccumulation of PTI-associated genes compared to wild-type plants. In response to two flagellinderivedpeptides the hpPti1 plants produced less reactive oxygen species (ROS), but showed nodifference in mitogen-activated protein kinase (MAPK). Synthetic Pti1a and Pti1b genesdesigned to avoid silencing were transiently expressed in the hpPti1 plants and restored theability of the plants to produce wild-type levels of ROS. Our results identify a new component ofPTI in tomato which, because it affects ROS production but not MAPK signaling, appears to actearly in the immune response.