Actinomyctes, Vol 5, Part 2, 31-39, 1994
Rapid detection of Clavibacter toxicus and of its bacteriophage responsible for annual ryegrass toxicity in Australia and the effect of selected herbicides on toxin production
Code Number: AC94007
Graphics: Photos (Jpg) 133K / Halftone 68K
ABSTRACT. Annual ryegrass toxicity bacterium, Clavibacter
toxicus, was isolated from toxic ryegrass seeds and livestock
feed by exposing the material to bacteriophages affecting
plant pathogenic coryneform and saprophytic bacteria.
Susceptibility to phages provided a selective means of
reducing the cell numbers on isolation plates and hence
facilitated the detection and isolation of C.toxicus.
Bacteriophages specific to C.toxicus were also isolated from
toxic ryegrass seeds and livestock feed. Plaque morphology,
host range, and particle morphology of the phage isolated are
described. Various concentrations (20-400 ug/ml) of
herbicides, commonly used in Western Australia, Simazine
(registered trademark), Glean (registered trademark), Hoegrass
(registered trademark), Trifluralin (registered trademark),
and Sertin (registered trademark), were tested to determine
their effect on the conversion rate of nontoxigenic C.toxicus
strains into toxigenic derivatives by two different
bacteriophages isolated from the toxlc ryegrass seeds and
livestock feed. The number of toxigenic strains increased when
herbicide concentrations of 200 and 400 ug/ml were applied.
Copyright 1994 C. E. T. A.