OAT ENDOSPERM PROTEINS ASSOCIATED WITH RESISTANCE TO STEM RUST OF OATS

The presence of oat (Avena sativa L.) endosperm proteins, extracted with dimethylformamide mercaptoethanol - sodium dodecylsulfate and separated by dodecylsulfate polyacrylamide gel electrophoresis, was compared among cv. Rodney (carrying Pg4) and Rodney 0 derived backcross lines carrying single known genes Pg1, Pg2, Pg3, Pg8, Pg9, Pg13, Pg15, and Pg16, for stem rust resistance, and among other lines or cultivars with or without these genes. Most single-gene lines had polypeptide patterns similar to that of Rodney 0, a near-isogenic line with no known stem rust resistance. However, lines Rodney Pg3 and Rodney Pg9 were missing a 25.3-kDa avenin present in Rodney 0 and present in lines or cultivars that did not carry Pg9. The Rodney Pg13 line and several lines or cultivars that carried Pg13 were missing a 56.6-kDa polypeptide present in Rodney 0 and in several lines and cultivars that did not carry this gene. These results suggest that the Pg3/Pg9 and Pg13 loci were associated with the loci controlling the synthesis of the 25.3- and 56.6-kDa polypeptides, respectively. Results from genetic studies showed that gene Pg13 was linked in repulsion (linkage value 4.2 +/- 1.9 cM) to the 56.6-kDa polypeptide locus.