Changes in the Proteins of Bean Leaves Infected With Tobacco Necrosis or Alfalfa Mosaic Viruses

Acidic extracts from TNV and AMV infected “Saxa” bean leaves were electrophoretically examined for protein content. In native conditions of resolution (PAGE) at least three protein bands (PS_1–3) not present in the control were found. In denaturing conditions (SDS–PAGE) at least one (PS_a), but often two or three such proteins (PS_{b, c}) were found in the same extracts. Chromatographic resolution of proteins on Sephadex G-100 column resulted in partial purification of the PS-proteins. Additional, not known before, slow-migrating protein (PS₀) induced by hypersensitive viral infection was discovered in some of the eluted fractions. Both PS_0–3 and PS_a–c proteins were present in the same fractions. This fact suggests their similarity in molecular weights and/or shapes.