Isolation of pathogenesis-related proteins from TMV-infected tobacco and their influence on infectivity of TMV

Abstract

The composition of pathogenesis-related proteins (PR-proteins) in the intercellular fluid (ICF) and leaf tissue of the hypersensitive tobacco cultivar Xanthi-nc inoculated with Tobacco mosaic virus (TMV), and their inhibitory influence on TMV multiplication were studied. The ICF PR-proteins of infected plants were separated after solubilisation by decreasing gradient of ammonium sulphate, the cell PR-proteins were separated after acidic homogenisation of leaf tissues. The ICF and cell PR-proteins were further purified by ion exchange chromatography on DEAE cellulose. Using discontinuous non-denaturating polyacrylamide gel electrophoresis of DEAE cellulose fractions the PR-proteins were detected. Their molecular weights were estimated by SDS-PAGE. The ICF and cell proteins of infected leaves included PR-proteins of the molecular weights 15–16 kDa (Group 1), 27–28 kDa (Group 3: chitinases) and 36–40 kDa (Group 2a: &#1704-1,3-glucanases). Fractions with different PR-proteins were tested for their effect on infectivity of TMV. Particularly the PR3 and PR2a proteins seem to decrease the infectivity of TMV.