PROTEIN-BIOSYNTHESIS CHANGES DURING MYCORRHIZA FORMATION IN ROOTS OF MICROPROPAGATED BIRCH

Birch (Betula pendula Roth) micropropagated plantlets were inoculated with 7 different isolates of the mycorrhizal fungus Paxillus involutus Batsch. Based on the level of fungal ergosterol measured in roots at the end of the ''mycorrhiza formation stage'', strain PO was chosen as the reference strain. Electrophoretic analysis of in vivo labeled pro teins extracted from mycorrhizal roots 96 h post-inoculation with this strain, noninoculated roots, and free-living mycelium, revealed that specific polypeptides were synthesized during ectomycorrhiza formation . To examine hypothetical similarity between some of these polypeptide s and defense proteins, parts of corresponding putative genes of birch were isolated. Partial sequencing of one clone have shown that it con tained a portion of the gene for phenylalanine ammonialyase.