Wheat-stem rust system

The second step of the proposed chain of events, resistance as a direct consequence of cell death, is still controversial (82-86). In the wheat-stem rust system, evidence favouring the idea of hypersensitive cell death as the cause of resistance (30,31,87-90) contrasts to results suggesting cell collapse as being a mere consequence of a yet unknown preceding resistance mechanism (90-97). 

The biochemical similarities of leaf and stem rust elicitors, the missing gene specificity of both elicitors, the fact that an equally active elicitor was isolated from germ tube cell walls of oat crown rust (60), together with the described reactions of different non-hosts to the stem rust elicitor led us to speculate that the isolated elicitors may play a role in the induction of general mechanisms of non-host resistance (130). Although they may be involved in the elicitation of race-cultivar specific resistance as well, race-cultivar specificity in the wheat-stem rust system clearly cannot be explained on the basis of the specificity of the isolated elicitors. One possible explanation would be the occurrence of race-cultivar specific suppressors of the resistance reaction (124,131,132). 

United States Department of Agriculture. Office of Pest Management National Plant Disease Recovery System. "Recovery Plan for Leaf Rust, Stem Rust, and Stripe Rust of Wheat Caused by Puccinia triticina, Puccinia graminis, and Puccinia striiformis, Respectively." August 28,2006. 

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