Evidence for binding between host proteins and pathogen wall components in the wheat stem rust system from affinity protein blotting technique

Abstract

Polypeptides extracted from the urediosporeling walls of Puccinia graminis tritici were separated by two-dimensional isoelectric focusing – polyacrylamide gel electrophoresis and stained with Coomassie brilliant blue or silver or electrophoretically transferred onto nitrocellulose membrane and probed for glycosylation using concanavalin A – horseradish peroxidase, soybean agglutinin-biotin – avidin peroxidase labeled, and Lotus lectin-biotin – avidin peroxidase labeled. More than 40 proteins were distributed in the gel by silver staining. Forty concanavalin A binding glycopeptides were identified in the blot, but none of them had affinity to soybean agglutinin or Lotus lectin. When fungal polypeptides were electrophoretically transferred through a nitrocellulose membrane that was pretreated with wheat leaf proteins, several fungal glycoproteins bound to the plant protein, suggesting that these pathogen wall components bound selectively to host proteins.