Co-bombardment, integration and expression of rice chitinase and thaumatin-like protein genes in barley (Hordeum vulgare cv. Conlon)

Abstract

Pathogenesis-related (PR) proteins associated with degradation of structural components of pathogenic filamentous fungi were overexpressed in the two-rowed malting barley (Hordeum vulgare L.) cultivar Conlon. Transgenes were introduced by co-bombardment with two plasmids, one carrying a rice (Oryza sativa L.) chitinase gene (chi11) and another carrying a rice thaumatin-like protein gene (tlp). Each gene was under the control of the maize ubiquitin (Ubi1) promoter. Fifty-eight primary transformants from three independent transformation events were regenerated. T(1) plants with high rice chi11 and tlp protein expression levels were advanced to identify T(2) homozygotes by herbicide spray and subjected to further molecular analyses. T(3) progeny from one event (E2) had stable integration and expression of the rice chi11 and tlp while those from the other events (E1 and E3) showed stable integration only of tlp. The successful production of these lines overexpressing the antifungal chi and tlp proteins provides materials to test the effects of these genes on a variety of fungal diseases that attack barley and to serve as potential additional sources of disease resistance.