Phaseolotoxin production by P. syringae pv. phaseolicola strains.

(A) Structure of phaseolotoxin (top), which is cleaved by plant peptidases (arrow) to release octicidin, with indication of the inorganic moiety (N’-sulfodiaminophosphinyl). Octicidin is a transition state analog, structurally similar to carbamoylphosphate and ornithine (bottom), substrates of OCTase during biosynthesis of citrulline. (B) Evaluation of the production of phaseolotoxin by the wild type strain NPS3121 and mutant 3121phtD using the E. coli growth inhibition assay.