The phylogenetic position of Postia s.l. (Polyporales, Basidiomycota) from Patagonia, Argentina

Abstract

We investigated the phylogenetic relationships of Postia species from Patagonia with rDNA ITS and LSU sequences, together with morphological, cultural and biological features. All species in the genus were included in a ''Postia clade'' irrespective of whether their spores were thin-or thick-walled. This clade is characterized by tetrapolar mating, a normal nuclear behavior, metachromatic generative hyphae and absence of fiber hyphae in culture. One subclade merged the austral taxa P. pelliculosa and P. punctata, but otherwise no distinct relationships were found regarding spore shape, spore wall thickness and geographical distribution of taxa. The austral P. venata and the endemic P. carbophila, with thinwalled basidiospores, occupied variable positions in both analyses. Postia caesia from Patagonia grouped within the P. caesia species complex but on a separate branch. In contrast, P. rennyi and P. balsamea from Patagonia corresponded well with strains from other geographic areas. The two austral species in Ryvardenia, R. cretacea and R. campyla, characterized by nonmetachromatic hyphae, bipolar mating and an astatocoenocytic nuclear behavior, formed an independent subclade among the dimitic genera of the ''Antrodia clade'', far from other Postia taxa within which they had been placed previously, supporting their inclusion in a genus of their own. Postia carbophila grouped with other Postia species and not with Postia (Rhodonia) placenta as suggested previously on the basis of morphological comparisons. Instead, the latter species grouped with taxa in the dimitic genus Amyloporia with which it shares heterocytic nuclear behavior. A separation between specimens of Postia pelliculosa and Ryvardenia cretacea from either side of the Pacific (i.e. SE Australia/New Zealand and S Argentina/S Chile) suggests they could be considered different at the species level from a phylogenetic point of view.

Taxonomy and phylogeny of Postia.Multi-gene phylogeny and taxonomy of the brown-rot fungi: Postia (Polyporales, Basidiomycota) and related genera

“…Pildain & Rajchenberg (2013) sequenced the ITS and nLSU regions from eleven species of Postia and related species; their phylogenetic analysis indicated that most species in Postia and Oligoporus were monophyletic, but supported the transfer of P. placenta into its own genus as Rhodonia placenta , in agreement with previous studies (Boidin et al 1998, Kim et al 2001, Binder et al 2005, Niemelä et al 2005). Ortiz-Santana et al (2013) investigated the phylogenetic relationships among members of the antrodia clade with molecular data from ITS and nLSU regions; in their study, species of Postia s.lat.…”

“…In fact, Postia is the oldest name among the competing genera. Some mycologists combined the brown rot taxa of Tyromyces into Postia (Renvall 1992, Niemelä et al 2005, Wei & Dai 2006, Hattori et al 2011, Cui & Li 2012, Pildain & Rajchenberg 2013). With more species recognized in Postia , the definitions of the genus and related genera remain murky, and so are the genetic relationships among these fungi.…”

“…with sufficient sampling, and taxonomic delimitation of Postia s.lat. has been controversial and remained insufficiently resolved (Donk 1960, Larsen & Lombard 1986, Ryvarden 1991, Walker 1996, Pildain & Rajchenberg 2013). In this study, we carried out further taxonomic studies and phylogenetic analyses by sampling more species to clarify the relationships of Postia and related genera including Oligoporus , Osteina , Rhodonia and Spongiporus .…”

Postia caesia complex (Polyporales, Basidiomycota) in temperate Northern Hemisphere

“…We also utilized three ITS sequences provided by Viktor Papp as well as 63 ITS and 28S sequences from the INSDC (Suppl. 1), based on BLAST searches and Ortiz-Santana et al 2013, Pildain & Rajchenberg (2013), Shen et al (2014), and Justo et al (2017).…”

“…Yao et al (2005) showed that three ITS-sequence-based groups were present in England, but they could not connect those groups to existing names. Ortiz-Santana et al (2013) and Pildain & Rajchenberg (2013) presented genus-level phylogenies that included representatives of the Postia caesia complex. Both concluded that the Postia caesia complex belongs to the genus Postia, but did not touch upon species concepts.…”