Acaulospora colossica sp. nov. from an Old Field in North Carolina and Morphological Comparisons with Similar Species, A. laevis and A. koskei

Abstract

Abstract:A new arbuscular mycorrhizal fungal species, Acaulospora colossica, ( Glomales, Acaulosporaceae) is described, and its distribution and seasonality discussed. Spores of A. colossica develop from saccules that empty their contents in the developing spores. Spore wall structure consists of 3 layers, all originating from the subtending hyphae. The two inner layers are laminated. The outermost spore wall layer is typically sloughed off before the spores mature. Two inner walls arise sequentially. Both inner walls are comprised of two layers. The outer layer of the innermost wall is beaded. Acaulospora colossica is described from a population in Durham, North Carolina. Its name refers to the relatively large size of the spores. Finally, the morphology of the new species A. colossica is compared and contrasted to two closely related species A. laevis and A. koskei.

Arbuscular Mycorrhizal Fungi: More Diverse than Meets the Eye, and the Ecological Tale of Why

“…We have also found evidence that AM fungi differ in their seasonality, with some fungi sporulating in late spring and others sporulating at the end of summer ( Figure 5; Schultz et al 1999). As the spores represent the dormant state of the fungus, the physiologically active state is most likely the mirror image of the seasonal spore counts.…”

“…These differences in sporulation patterns within this field, therefore, quite likely reflect distinct differences in seasonal activity of these fungal species. In fact, further work on these fungi confirms the distinct seasonal behavior of these species (Schultz et al 1999), with Ac. colossica being physiologically active during the cool season and dormant during the summer months, while Gi.…”

“…For example, Glomus fasciculatum, a small-spored species whose thick wall exhibits a distinctive staining reaction in response to Melzer's reagent, was observed only when mature Plantago plants were dug from the field, had their roots washed free of soil, and were then planted in sterile soil and grown in a cool greenhouse (Bever et al 1996). Other species, such as Acaulospora colossica (the large red spore in Figure 2) sporulated in traps only after being grown under conditions typical of the cool winter and spring months in North Carolina (Schultz et al 1999). The distinct conditions favorable to successful growth and sporulation reflect differences in AM fungal ecologies.…”

Divergent phenologies may facilitate the coexistence of arbuscular mycorrhizal fungi in a North Carolina grassland

“…Hostspecificity in fungal population growth rates may contribute to the maintenance of fungal diversity (Bever et al, 1996); in addition, the high diversity of AM fungi might result from a temporal partitioning of the habitat. In fact, prior sampling suggests that fungi differ in their seasonalities: Schultz, Bever, and Morton (1999) observed that Acaulospora colossica sporulates in spring, but other species, particularly Gigaspora gigantea, are observed to sporulate in winter (Schultz, 1996). In this study, we aimed to rigorously test for the distinct seasonalities of Ac.…”

Notas sobre Acaulospora bireticulata Rothwell & Trappe e primeiro registro de Acaulospora koskei Blask. para o Brasil

“…Esporos de A. koskei podem ser confundidos com os de A. colossica Schultz, Bever & Morton principalmente pela coloração que se superpõe (Schultz et al 1999 Distribuição e habitat: conhecido para dunas na Polônia (Blaszkowski 1995), áreas alagadiças dos EUA (Miller & Bever 1999) Rothwell & Trappe, Mycotaxon 8: 472. 1979.…”