Abstract
Endogonales is a lineage of early diverging fungi within Mucoromycota. Many species in this order produce small sporophores (“sporocarps”) containing a large number of zygospores, and many species form symbioses with plants. However, due to limited collections, subtle morphological differentiation, difficulties in growing these organisms in vitro, and idiosyncrasies in their rDNA that make PCR amplification difficult, the systematics and character evolution of these fungi have been challenging to resolve. To overcome these challenges we generated a multigene phylogeny of Endogonales using sporophores collected over the past three decades from four continents. Our results show that Endogonales harbour significant undescribed diversity and form two deeply divergent and well-supported phylogenetic clades, which we delimit as the families Endogonaceae and Densosporaceae fam. nov. The family Densosporaceae consists of the genus Densospora, Sphaerocreas pubescens, and many diverse lineages known only from environmental DNA sequences of plant-endosymbiotic fungi. Within Endogonaceae there are two clades. One corresponds to Endogone and includes the type species, E. pisiformis. Species of Endogone are characterized by above- and below-ground sporophores, a hollow and infolded sporophore form, a loose zygosporangial hyphal mantle, homogeneous gametangia, and an enigmatic trophic mode with no evidence of ectomycorrhizal association for most species. For the other clade we introduce a new generic name, Jimgerdemannia gen. nov. Members of that genus (J. flammicorona and J. lactiflua species complexes, and an undescribed species) are characterized by hypogeous sporophores with a solid gleba, a well-developed zygosporangial hyphal mantle, heterogeneous gametangia, and an ectomycorrhizal trophic mode. Future studies on Densosporaceae and Endogonaceae will be important for understanding fungal innovations including evolution of macroscopic sporophores and symbioses with plants.
Highlights
Endogonales is an order of early diverging fungi that belong to the subphylum Mucoromycotina and is represented by the single family Endogonaceae
Recent studies indicate that ectomycorrhizal symbioses and endosymbioses with several lineages of land plants have emerged independently more than once (Tedersoo & Smith 2013, Field et al 2015a, Orchard et al 2017a, Yamamoto et al 2017a)
Tedersoo & Smith (2017) considered four ectomycorrhizal lineages in Mucoromycotina: the “/ densospora lineage” (Endogone group C sensu Yamamoto et al 2017a) comprising members of the genus Densospora (McGee 1996) and uncultured ectomycorrhizal fungi associated with Eucalyptus and Nothofagus (Tedersoo et al 2008); the “/endogone1 lineage”
Summary
While Endogonales contains four extant genera (see above), there is poor resolution of the phylogenetic relationships of the taxa within the order, and still uncertainty whether Sphaerocreas pubescens (Saccardo 1882), members of Densospora (McGee 1996), and numerous Endogone-related Mucoromycotina associated with plants belong to Endogonales Even though they are distributed across temperate and tropical habitats in the Northern and Southern Hemispheres, sporophores of most of these fungi are rarely collected and molecular data are limited or not available. Jimgerdemannia was sister of a clade of hornwort- and liverwort-associated fungi (“group G” sensu Desirò et al 2013), whereas a second clade encompassing DNA sequences retrieved from the liverwort Neohodgsonia mirabilis ZDV WKH ¿UVW GLYHUJLQJ FODGH of Endogonaceae (Fig. 2). Diagnosis: The family Densosporaceae is erected here WR DSSO\ WR DOO GHVFHQGDQWV RI WKH QRGH 3' ́ GH¿QHG LQ WKH phylogeny (Fig. 2) as the terminal Densosporaceae clade. :H GH¿QH Densosporaceae as the least inclusive clade containing the genus Densospora and Sphaerocreas pubescens (sensu Hirose et al 2014), and environmental DNA sequences generated from fungal symbionts of non-vascular and vascular plants (JF414222, JF414224, KC708392, KC708404, KC708409, KC708417, KC708436, KJ952212, KJ952213, UDB002714)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
