The Pto protein kinase from Solanum pimpinellifolium interacts with Pseudomonas syringae effectors AvrPto or AvrPtoB to activate effector-triggered immunity. The previously solved crystal structures of the AvrPto-Pto ...The Pto protein kinase from Solanum pimpinellifolium interacts with Pseudomonas syringae effectors AvrPto or AvrPtoB to activate effector-triggered immunity. The previously solved crystal structures of the AvrPto-Pto and AvrPtoB-Pto complexes revealed that Pro binds each effector through both a shared and a unique interface. Hera we use natural variation in wild species of tomato to further investigate Pto recognition of these two effectors. One species, Solanum chmielewskU, was found to have many accessions that recognize only AvrPtoB. The Pto ortholog from one of these accessions was responsible for recognition of AvrPtoB and it differed from Solanum pimpinellifolium Pto by only 14 amino acids, including two in the AvrPto-specific interface, glutamate-49/glycine-51. Converting these two residues to those in Pro （histidine-49/valine-51） did not restore recognition of AvrPto. Subsequent experiments revealed that a single substitution of a histidine-to-aspartate at position 193 in Pto, which is not near the AvrPto- specific interface, was sufficient for conferring recognRion of AvrPto in plant cells. The reciprocal substi- tution of aspartate-to-histidine-193 in Pto abolished AvrPto recognition, confirming the importance of this residue. Our results reveal new aspects about effector recognition by Pto and demonstrate the value of using natural variation to understand the interaction between resistance proteins and pathogen effectors.展开更多
基金This research was supported, in part, by National Science Foundation grant IOS-1025642 （G,B.M.）,
文摘The Pto protein kinase from Solanum pimpinellifolium interacts with Pseudomonas syringae effectors AvrPto or AvrPtoB to activate effector-triggered immunity. The previously solved crystal structures of the AvrPto-Pto and AvrPtoB-Pto complexes revealed that Pro binds each effector through both a shared and a unique interface. Hera we use natural variation in wild species of tomato to further investigate Pto recognition of these two effectors. One species, Solanum chmielewskU, was found to have many accessions that recognize only AvrPtoB. The Pto ortholog from one of these accessions was responsible for recognition of AvrPtoB and it differed from Solanum pimpinellifolium Pto by only 14 amino acids, including two in the AvrPto-specific interface, glutamate-49/glycine-51. Converting these two residues to those in Pro （histidine-49/valine-51） did not restore recognition of AvrPto. Subsequent experiments revealed that a single substitution of a histidine-to-aspartate at position 193 in Pto, which is not near the AvrPto- specific interface, was sufficient for conferring recognRion of AvrPto in plant cells. The reciprocal substi- tution of aspartate-to-histidine-193 in Pto abolished AvrPto recognition, confirming the importance of this residue. Our results reveal new aspects about effector recognition by Pto and demonstrate the value of using natural variation to understand the interaction between resistance proteins and pathogen effectors.
