Submitted to: American Phytopathological Society Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 8/16/1995
Publication Date: N/A
Technical Abstract: Four cDNA clones encoding thaumatin-like (TL) proteins were isolated from oat infected with an incompatible isolate of Puccinia graminis f.sp. avenae (Pga). Northern blot analyses using gene-specific probes corresponding to each cDNA clone revealed that the expression of the four genes (rastl-1, -2, -3, -4) was activated in response to infection by either an incompatible isolate of Pga or an isolate of a nonhost pathogen, P. graminis f.sp. tritici, but not by a compatible isolate of Pga. The highest expression level was for rastl-1. The four cDNAs each encoded a polypeptide of 169 amino acids including a signal peptide of 21 amino acids, suggesting that these polypeptides were transported out of the cytoplasm. The polypeptides were similar in sequence to osmotin, PR-5, zeamatin, and TL proteins that are activated in response to stress or pathogen attack in several plant species. The abundance and the accumulation patterns of rastl-1 gene transcript in response to infection by stem rust fungi indicate that rastl-1 is a response gene associated with resistance in oat stem rust.