SOLUBLE AND MEMBRANE SYMBIOSIS-RELATED POLYPEPTIDES ASSOCIATED WITH THE DEVELOPMENT OF ARBUSCULAR MYCORRHIZAS IN TOMATO (LYCOPERSICON-ESCULENTUM)

To analyse the effect of arbuscular mycorrhizal (AM) colonization on t omato gene expression, two-dimensional polyacrylamide gel electrophore sis (2D-PAGE) patterns of crude extracts, soluble and membrane protein s of tomato roots, either mycorrhizal and the AM fungus Glomus mosseae (Nicol. & Gerd.) Gerd. & Trappe or nonmycorrhizal, have been compared . In the three fractions analysed, AM colonization induced up-regulati on with down-regulation of the synthesis of polypeptides already prese nt in tomato roots and induction of some new polypeptides. Separation of root extracts into soluble and membrane fractions allowed us to ide ntify two soluble, and five membrane-bound, newly induced polypeptides in AM roots. Comparison of the protein patterns of AM roots with thos e of the external mycelium of G. mosseae showed that one of the newly induced polypeptides might correspond to a fungal polypeptide. By usin g this experimental approach, we have been able to detect 44 polypepti des that are differentially displayed in tomato roots as a consequence of the establishment of the AM symbiosis.