DETERMINATION OF THE ANTIGENIC PROTEIN SIZE ASSOCIATED WITH FABA BEAN PHYLLODY MLO BY USING (SDS-PAGE) ELECTROPHORESIS AND IMMUNOTRANSFER

The antigenic proteins of MLO associated with faba bean phyllody (FBP) occurring in the Sudan were studied by using SDS-PAGE electrophoresis followed either by silver nitrate staining or by transferring to nitrocellulose membrane probed with specific polyclonal antiserum. No remarkable differences between healthy and FBP infected plants were observed when the gel was colored with silver nitrate. In contrast, after probing the transferred membrane with the specific polyclonal FBP antisera, band formation was only detected with FBP infected plants. These results were treated through an image analyser using a BIOLAB logicial. The analysed proteins measure approximately 18,000 and 36,000 daltons with regard to the protein molecular weight markers used (Bio-Rad). Possibility of the existence of a dimer is discussed. The localization of the bands is the same whatever the origins of FBP: Vicia faba or Crotalaria saltiana. However, the partial purification of the MLO including differential centrifugations followed by precipitation with polyethylene glycol (PEG) and passage through a column of Sepharose 4B were found to be essential for having clear electrophoretic profiles.