IMMUNOGOLD LOCALIZATION OF GLUTAMINE-SYNTHETASE AND NBDP-GLUTAMATE DEHYDROGENASE OF LACCARIA-LACCATA IN DOUGLAS-FIR ECTOMYCORRHIZAS

Using antibodies raised against glutamine synthetase (GS) and NADP-glu tamate dehydrogenase (NADP-GDH) from Laccaria laccata, we examined tis sular localization of GS and NADP-GDH in symbiotic tissues of Douglas fir/L. laccata ectomycorrhizas by immunogold labeling. Thin sections o f mycorrhizal roots were first treated either with an anti-GS- or anti -NADP-GDH-specific antibody and then with a colloidal gold marker. Bot h enzymes appeared to be cytoplasmic. Our results also indicated the p resence of GS in some fungal cells in dense cytoplasmic patches. It al so appeared that GS is more abundant than NADP-GDH. The distribution o f these nitrogen-assimilating enzymes in the fungal Hartig net and the sheath did not differ significantly. No labelling was observed in hos t cells.