In planta Transfer of the Gene (s) for Virulence between Isolates of Pseudomonas syringae pv. atropurpurea

Abstract

A phytotoxin (coronatine)-producing ability of Pseudomonas syringae pv. atropurpurea NIAES 1309 is associated with 58 Mdal plasmid designated as pCOR1. A conjugative plasmid pBPW1:: Tn7 from P. syringae pv. tabaci BR2 was introduced into the strain NIAES 1309. When the strain was mated with avirulent strains derived from NIAES 1309 in Italian ryegrass, pBPW1:: Tn7 was transferred to the avirulent strain at a high frequency. Twenty strains out of 894 transconjugants contained the pCOR1 plasmid co-transferred with pBPW1:: Tn7. All of these strains produced coronatine and induced typical symptoms on Italian ryegrass. That is, in planta transfer of virulence genes between isolates of phytopathogenic pseudomonad was confirmed.