Evidence for a gene-specific RNA determining resistance in wheat to stem rust

Abstract

ALTHOUGH the inheritance of resistance¹ in wheat (Triticum aestivum L.) to stem rust (Puccinia graminis Pers. f. sp. tritici Eriks. & E. Henn.) is fairly well understood, most efforts to elucidate the biochemical mechanism involved have been unsuccessful. Biochemical studies of plant diseases involving rusts and other obligate parasites² have contributed to knowledge of biochemical symptomatology, but no chemical changes have been correlated with the action of specific genes for resistance. Future advances it seemed, would depend on a reliable test to facilitate such correlations, and so we have developed a bioassay with the necessary specificity, which detects the presence of metabolites involved in the expression of the resistance. We have thus been able to demonstrate a gene-specific RNA that seems to be directly responsible for initiating the resistant reaction in wheat against stem rust. A preliminary report of some of these findings has been presented³.