Ambisporaceae - C. Walker, Vestberg & Schüßler
Biochemical Properties
Studies of biochemical properties, such as monoclonal antibody specificities (Wright et al., 1986) and fatty acid profiles (Graham et al., 1995) indicated that members of this family (and Paraglomeraceae) were phylogenetically distant from species in Acaulospora and Glomus. Morphology of spores and mycorrhizas also were atypical, at least for the Acaulospora-like spores (Morton and Benny, 1990). SSU sequences provided the evolutionary polarity that this family was ancestral to members of Acaulosporaceae and typical glomoid species found in Glomeraceae and Claroideoglomeraceae (Redecker et al., 2000; Sawaki et al., 1997).
Species in this family were first classified together with Ar. trappei in the family Archaeosporaceae (Morton et al., 2001) because of unique morphologies, antibody specificities (Wright et al., 1986) fatty acid profiles (Graham et al., 1995), and SSU sequences (Redecker et al., 2000; Sawaki et al., 1997). Spain et al. (2006) placed the dimorphic species into Appendicispora, which Walker et al (2007a) placed in the family Appendicisporaceae. Walker et al. (2007b) found a nomenclatural problem with this naming scheme (homonym) and reclassified the group in Ambisporaceae.
Definition
Arbuscular mycorrhizal fungi producing dimorphic propagules of both glomoid and acaulosporoid spores, although both spore types may not be produced concurrently in culture. Glomoid spores hyaline with bilayered spore wall and subtending hyphae lacking discrete species level characters; formed singly or in clusters. Acaulosporoid spores formed from a pedicel on the neck of a sporiferous saccule. All acaulosporoid spores possess a multilayered spore wall with a semi-pliable inner wall. Spore wall outer layer forms crazed surface, cerebriform folds or both that is highly unstable and degrades. The middle and inner layers of the spore wall together provide diagnostic features for each species. Distinguished from other families in the Archaeosporales by dimorphism, unique spore morphology, and rDNA sequence divergence. Mycorrhizas are mostly arbuscular; vesicles produced rarely; staining is typically very faint.
GENUS: Ambispora
References
- Schüßler, A and C. Walker C. 2010. The _Glomeromycota: a species list with new families._ Electronic copy available online at Glomeromycota PHYLOGENY.
- VanKuren, N. W., H. C. den Bakker, J. B. Morton, and T. Pawlowska. 2012. Ribosomal RNA gene diversity, effective population size, and evolutionary longevity in asexual Glomeromycota. Evolution doi:10.1111/j.1558-5646.2012.01747.x.