Some Genetic, Biochemical and Morphological Analysis of Selected Powdery Mildew Strains at the Beginning of Sporulation on Barley

Abstract

The present work analyzes some characteristics of four powdery mildew pathotypes, RU-3, Sk-5/11, Sk-12/1 and A-4/0, selected from the wild strains of BGH from Central European regions. Our results showed that the studied BGH strains differ in the virulence and avirulence genes in their genomes, in prolongation of their asexual phase of the growth and also in morphological and biochemical characteristics. Protein analysis confirmed the genetic differences between the studied powdery mildew pathotypes. Abundant acid glucanases in all studied BHG pathotypes were found between molecular weights Mr ? 25-35 kDa and 11-22kDa. Races RU-3 and A-4/0 also contained low molecular weight glucanases with Mr ? 9-14kDa. Immunological analyses showed higher specificity of pathogen chitinases to plant antibody compared to barley cultivars carrying different dominant/semidominant resistance genes. Rabbit antibody prepared against the plant interacellular acid chitinase Chi 14.4 (PR-4) gave the positive signal for two powdery mildew races, Sk-5/11 and A-4/0. These pathotypes were more aggressive compared to races Sk-12/1 and RU-3. Their genomes contained more virulence genes and asexual phase of the growth was shorter. Ultrastructural analyses of BGH body in the sensitive barley cultivar cells, showed presence of virus like particles, which probably play role by the synthesis of some PR-proteins with hydrolytic function. Genetic and biochemical analyses indicate that some powdery mildew pathotypes contain genes in their genome which are orthological to those in their hosts, which makes them suitable subjects for the future as a source of new resistance genes for plant breeding.