Iσozymic identification of individual ectornycorrhizas synthesized between Scots pine (Pinus sylvestris L.) and isolates of two species of Suillus

Abstract

SUMMARYMorphologically similar ectornycorrhizas between Scots pine (Pinus sylvestris L.) seedlings and different geographic isolates of Suillus variegatus (Fr.) O. Kuntze and Suillus bovinus (Fr.) O. Kuntze were synthesized under semi‐aseptic conditions in a sand and peat growth mixture containing ureaformaldehyde as the organic nitrogen source. Fourteen weeks after inoculation significant increases in shoot height were recorded in most of the infected seedlings and in two inoculated treatments where no mycorrhizal infection was detected. Based on the assumption that 50% of the dry mass of these ectomycorrhizas was of fungal origin, the soluble protein content of the synthesized ectomycorrhizas was found to be between 10‐ and 15‐fold greater than in equivalent amounts of the non‐symbiotic tissues (short roofs and axenically grown mycelium of S. variegatus and S. bovinus). Extracts from individual ectornycorrhizas exhibited considerable esterase (EST) and peptidase (PEP) isozyme activities following PAGE and it was confirmed that diagnostic species‐specific fungal isozymes, reproducibly detected in these extracts, were present in extracts of excised sheath tissue. Acid phosphatase (ACP) isozyme activities were also detected in the ectomycorrhizas but were restricted to a single isozyme known to be common to both fungal species. In addition to the identification of taxonomically useful diagnostic fungal isozymes, the lack of detectable host PEP or ACP isozymes in these individual ectomycorrhizas, which also exhibited induced isolate‐specific EST isozymes, provides further information on the biochemical relationships in the ectomycorrhizas.