Practice question

Arbuscular mycorrhizae most ancient mutualistic symbiosis colonizing 80% land plants formed exclusively by subphylum Glomeromycotina within phylum Glomeromycota. Members like Rhizophagus irregularis produce arbuscules highly branched and vesicles storage inside roots, coenocytic hyphae extending meters into soil exploring phosphate beyond root depletion zone. Unable to grow independent without plant, obligate biotrophs reliant on host lipids. Ascomycota form ectomycorrhizae and ericoid types, Basidiomycota predominantly ectomycorrhizae, Zygomycota obsolete grouping. DNA evidence separates Glomeromycota from former Zygomycota based on lack of zygospore, presence of atypical chitin synthesis and mutualism.