Analysis of acid invertase and comparison with acid phosphatase in the ericoid mycorrhizal fungus Hymenoscyphus ericae (Read) Korf and Kernan

Abstract

Fractions of acid invertase and acid phosphatase of the ericoid mycorrhizal fungus Hymenoscyphus ericae (Read) Korf & Kernan were compared by column chromatography and polyacrylamide gel electrophoresis. Acid invertase levels were measured during the exponential phase after 14 days growth in pure culture. Most acid invertase was wall associated (50%) with 41% forming an extracellular fraction and 9% a soluble, cytoplasmic fraction. The wall-bound fraction was partially solubilized by 1 M NaC1, bulked with the extraceUular fraction and separated by gel filtration into two acid invertase activity peaks. These peaks corresponded closely to two acid phosphatase activity peaks measured in the same eluates. Anion exchange chromatography under a continuous salt gradient separated the invertase and phosphatase isoforms from each other. Non-denaturing polyacrylamide gel electrophoresis demonstrated that the more active isoforms of each enzyme have different electrophoretic properties and are high mannose-type glycoproteins with a high affinity for the lectin, concanavalin A. The results are discussed in terms of the functional aspects of the two enzymes and their cytochemical localization.

Proton (H+) flux signature for the presymbiotic development of the arbuscular mycorrhizal fungi

“…Although some fungi possess cell wall‐bound invertase and transporters for Suc uptake (Aked & Hall, 1993; Lam et al ., 1994), this is not confirmed in AM fungi. In ericoid mycorrhizal fungus Hymenoscyphus ericae (Read) Korf & KernanMost, 50% of an acid invertase is wall‐associated, 41% forming an extracellular fraction and 9% a soluble, cytoplasmic fraction (Straker et al. , 1992).…”

“…Although some fungi possess cell wall-bound invertase and transporters for Suc uptake (Aked & Hall, 1993;Lam et al, 1994), this is not confirmed in AM fungi. In ericoid mycorrhizal fungus Hymenoscyphus ericae (Read) Korf & KernanMost, 50% of an acid invertase is wall-associated, 41% forming an extracellular fraction and 9% a soluble, cytoplasmic fraction (Straker et al, 1992). Studies on the detection of invertase activity, sugar uptake and isolation of the genes codifying sugar transporters in the AM germ tubes will eliminate the credence of sucrose uptake in AM fungal cells during the presymbiosis.…”

Sugar for my honey: Carbohydrate partitioning in ectomycorrhizal symbiosis

“…Pyrenopeziza brassicae, Walters et al, 1996, Sporisorium reilianum, Bhaskaran andSmith, 1993, Uromyces fabae, Voegele et al, 2001) but also ericoid mycorrhizal fungi (e.g. Hymenoscyphus ericae, Straker et al, 1992;Hughes and Mitchell, 1996). Since it makes the fungus dependent on the plant partner, lack of invertase might partially explain the low plant defense response faced by ectomycorrhizal fungi compared to pathogenic interactions (Smith and Read, 1997).…”

Mastering ectomycorrhizal symbiosis: the impact of carbohydrates

“…It is commonly accepted that sucrose, which is excreted by plant root cells into the common apoplast of the plantfungus interface, is hydrolysed by a plant-derived invertase in EM symbiosis (Lewis and Harley, 1965a;Salzer and Hager, 1991;Rieger et al, 1992;Schaeffer et al, 1995;Nehls, 2004). The lack of an invertase in (at least many) EM fungi (Palmer and Hacskaylo, 1970;Salzer and Hager, 1991;Hatakeyama and Ohmasa, 2004;Daza et al, 2006) is a profound difference from phytopathogenic (Walters et al, 1996;Voegele et al, 2001) and also ericoid mycorrhizal fungi (Straker et al, 1992;Hughes and Mitchell, 1996). In combination with their low cell wall-degrading activity (compared with wood-and litter-degrading but also ericoid mycorrhizal fungi), lack of invertase activity makes EM fungi dependent on the activity of the plant partner (Smith and Read, 1997), which might be essential for the function of this type of symbiosis.…”