Poisoning of livestock in Oregon in the 1940s to 1960s attributed to corynetoxins produced by Rathayibacter in nematode galls in chewings fescue (Festuca nigrescens)

Abstract

Tunicaminyluracil antibiotics, similar to the corynetoxins produced by Rathayibacter toxicus in Australia and South Africa, were found in old nematode seed-galls from Festuca nigrescens from New Jersey (USA) and New Zealand (NZ). The toxin profiles from the NZ and USA galls were similar to each other, but differed from those produced by R toxicus from Australia and South Africa, suggesting that a geographical variant of R toxicus or closely related species may be involved. The NZ galls gave a positive response to a R toxicus-specific monoclonal antibody assay, albeit a considerably weaker response than that seen with Australian R toxicus galls, but the older USA galls were negative, possibly due to deterioration of the antigen. From these findings, it is postulated that livestock deaths associated with the feeding of nematode and bacterial infected screenings of F nigrescens in Oregon, USA, in the 1940s to 1960s were caused by corynetoxin-like toxins produced by the bacterium.