TIME-COURSE STUDY AND PARTIAL CHARACTERIZATION OF A PROTEIN ON HYPHAEOF ARBUSCULAR MYCORRHIZAL FUNGI DURING ACTIVE COLONIZATION OF ROOTS

Material on the surface of hyphal walls of arbuscular mycorrhizal fung i (AMF) during active colonization of plant roots was detected by a mo noclonal antibody. Pot-cultured isolates of Glomus, Acaulospora, Gigas pora, Scutellospora, and Entrophospora had immunofluorescent material (IM) on younger, thinner, intact hyphae, but IM was scant to absent on thicker, melanized or lysing hyphae. Colonization of corn (Zea mays L .), Sudangrass (Sorghum sudanense (Piper) Staph.) or red clover (Trifo lium pratense L.) was examined during 5 months of plant growth by remo ving cores and performing an indirect immunoassay on roots with attach ed hyphae. Fresh spores of some Glomus spp. had IM on the outer layer of the spore wall. Abundant IM was seen on root hairs of plants coloni zed by some isolates, and some IM was detected on root surfaces of all plants examined even during early colonization. After cultures were d ried, hyphae, roots and spores had little to no IM. Uninoculated contr ol roots had very rare, small patches of IM. An immunoreactive protein was extracted from hyphae of Gigaspora and Glomus isolates by using 2 0 mM citrate (pH 7.0) at 121 degrees C for 90 min. Gel electrophoresis profiles indicated that all isolates tested had the same banding patt erns. Lectin-binding of extracted protein is suggestive of a glycoprot ein. The immunofluorescence assay can be used to examine root sections for active colonization by AMF, and the potential use of the protein to quantify AMF activity in soil is discussed.