A cluster of mutations disrupt the avirulence but not the virulence function of AvrPto.
avrPto in Pseudomonas syringae pv. tomato encodes an avirulence protein that triggers race-specific resistance in tomato plants carrying Pto. The AvrPto protein is secreted from P. syringae pv. tomato to plant cells through the type III secretion pathway and activates race-specific resistance by a direct interaction with the Pto protein. Here we report that avrPto enhances the virulence of P. syringae pv. tomato in a strain-dependent manner in tomato plants lacking Pto. To determine whether the virulence function can be structurally separated from the avirulence function, we examined the virulence activity of a group of AvrPto mutants that carry single amino acid substitutions and lack the avirulence activity on tomato plants. Three mutants that were clustered in the center of AvrPto exhibited virulence activity in tomato plants with or without Pto. The rest of the mutations abolished the virulence. The identification of these mutants suggested that the avirulence function of AvrPto can be structurally separated from the virulence function.
Shan
L
L
Department of Plant Pathology, Kansas State University, Manhattan 66506-5502, USA.
He
P
P
Zhou
J M
JM
Tang
X
X
D020816:Amino Acid Motifs; D019943:Amino Acid Substitution; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D018551:Solanum lycopersicum / Q000235:genetics / Q000382:microbiology*; D010935:Plant Diseases / Q000235:genetics* / Q000382:microbiology; D010940:Plant Proteins; D017354:Point Mutation; D017346:Protein Serine-Threonine Kinases / Q000235:genetics; D011549:Pseudomonas / Q000235:genetics / Q000472:pathogenicity*; D014774:Virulence / Q000235:genetics
D001426:Bacterial Proteins; D010940:Plant Proteins; C081695:avrPto protein, Pseudomonas syringae; C084354:Pto protein, Lycopersicon; D017346:Protein Serine-Threonine Kinases