avrPto enhances growth and necrosis caused by Pseudomonas syringae pv. tomato in tomato lines lacking either Pto or Prf

AvrPto was introduced into three tomato genotypes with two biotic agents to study its role in compatible interactions. avrPto enhanced the capacity of the Pseudomonas syringae pv. tomato strain T1 to induce necrotic symptoms on tomato plants that lacked either Pto or Prf genes. The enhanced necrosis correlated with a small increase in bacterial growth. In planta expression of QvrPto in isolation did not elicit necrosis in the absence of a functional Prf gene.