DIFFERENTIAL EXPRESSION OF PATHOGEN-RESPONSIVE GENES ENCODING 2 TYPESOF GLYCINE-RICH PROTEINS IN BARLEY

Gene-specific probes (3' ends of cDNAs) were obtained from barley cDNA s encoding two types of glycine-rich proteins: HvGRP2, characterized b y a cytokeratin-like and a cysteine-rich domain, and HVGRP3, whose mai n feature was an RNA-binding domain. Expression of genes Hvgrp2 and Hv grp3, which are present at one (or two) copies per haploid genome, was ubiquitous and gene Hvgrp3 was under light/darkness modulation. Cold treatment increased Hvgrp2 and Hvgrp3 mRNA levels. Methyl jasmonate (1 0 mu M) switched off the two genes. Expression of Hvgrp2, but not that of Hvgrp3, was induced by ethylene treatment (100 ppm). Fungal pathog ens Erysiphe graminis and Rhynchosporium secalis increased the mRNAs l evels of the two genes, both in compatible and in incompatible interac tions, while bacterial pathogens did not.