Clavibacter toxicus sp. nov., the Bacterium Responsible for Annual Ryegrass Toxicity in Australia

Abstract

The Clavibacter sp. associated with annual ryegrass toxicity (ARGT) in Australia has been reported to differ from other Clavibacter spp. in serological properties, allozyme electrophoretic mobility, bacteriophage sensitivity, and adhesion to nematodes (Anguina spp.). To clarify its taxonomic position, eight strains of the ARGT Clavibacter sp. were compared with strains of Arthrobacter ilicis, Clavibacter iranicum, Clavibacter michiganense, Clavibacter rathayi, Clavibacter tritici, Curtobacterium flaccumfaciens, and Rhodococcus fascians. The ARGT strains were distinguishable from the other bacteria on the basis of the results of a range of biochemical tests. DNA base composition, growth factor requirements, and growth rates were also determined. A new species, Clavibacter toxicus, is proposed, with type strain CS14 (= ICMP 9525 = NCPPB 3552).