MODIFICATION OF POLYPEPTIDE PATTERNS DURING NODULE DEVELOPMENT IN THEFRANKIA-ALNUS SYMBIOSIS

The soluble proteins from nodules (actinorhizae), roots of Alnus gluti nosa (L.) Gaertn., and free-living Frankia alni subsp. pommerii isolat e ACN1 AG cultures were analysed in order to investigate if any actino rhiza-specific proteins were induced by the inoculation of clonal plan tlets (AG2) by Frankia. Comparisons of protein patterns from actinorhi zae and non-infected roots, obtained by sodium dodecyl sulphate polyac rylamide gel electrophoresis (SDS-PAGE), showed that three polypeptide s of molecular weights 36, 50 and 61 kD could be detected in actinorhi zae but not in roots. Immunoblotting techniques using heterologous ant isera ''directed'' against members of the nitrogenase enzyme complex i dentified the 36 and 61 kD polypeptides as the Fe protein and MoFe pro tein of the Frankia nitrogenase. Analysis of the protein extracts by t wo-dimensional polyacrylamide gel electrophoresis (2D-PAGE) revealed f ive additional nodule-specific polypeptides in developing actinorhizae .