Pathogenic Diversity of Xanthomonas campestris pv. poae within the Genus Poa

Abstract

The diversity of pathogenicity of Xanthomonas campestris pv. poae, the causal agent of bacterial wilt in the genus Poa, was studied. Strains of X. c. pv. poae were distinguishable into three groups, according to differences in their pathogenicity against Poa species. Group 1, represented by strain JT-P192, caused mild wilt and a pale yellow appearance in leaves of annual bluegrass and supina bluegrass. Group 2, represented by strain JT-P482, was pathogenic to annual bluegrass, rough bluegrass and supina bluegrass, but caused only wilt symptoms. Group 3 included the type strain of X. c. pv. poae, which caused only a wilt in annual bluegrass, rough bluegrass, supina bluegrass and big bluegrass. Compatible and incompatible relationships were evaluated from the symptoms on infected plants and from bacterial multiplication in the lowest part of the culm after leaf clipping-inoculation.