Pattersoniomyces tillandsiae gen. et comb. nov.: linking sexual and asexual morphs of the only known smut fungus associated with Bromeliaceae

Abstract

The enigmatic species Ustilago tillandsiae is the only known smut fungus associated with Bromeliaceae. Its generic position is evaluated by morphological, physiological, and molecular phylogenetic analyses using large subunit rDNA sequences. Phylogenetic analyses resolved U. tillandsiae as a member of the Ustilaginales in a sister relationship to the lineage containing Tranzscheliella species. However, U. tillandsiae differs from Tranzscheliella species by the development of sori in flowers, a different structure of sori and a different type of spore ornamentation. Consequently, a new genus Pattersoniomyces is described to accommodate U. tillandsiae. The new combination Pattersoniomyces tillandsiae is substantiated. In the sexual stage (teleomorph), this species infects bromeliads: Tillandsia flabellata, Tillandsia leiboldiana, and Tillandsia sp. in Central America between southern Mexico and Costa Rica. The yeast stage (anamorph) of P. tillandsiae was found associated with the phylloplane of Canistrum improcerum and in water tanks (phytotelmata) of Vriesea minarum, two bromeliads occurring in northeast and southeast Brazil, respectively. The link between the teleomorph and anamorphic strains is supported by identical sequences of the D1/D2 domains of the large subunit rDNA. Pattersoniomyces represents the tenth endemic smut genus to the Americas, but the only one that occurs in both North and South America, being a truly neotropical genus. The host plant families of Ustilaginales are extended to the Bromeliaceae. As far as we know, Pattersoniomyces represents the single event of a host jump from Cyperaceae or Poaceae to Bromeliaceae, apparently without further species radiation on multiple bromeliad species and genera growing in South America.

The first smut fungus, Thecaphora anthemidis sp. nov. (Glomosporiaceae), described from Anthemis (Asteraceae)

“…Host jumps have been reported before in the Ustilaginomycotina (e.g. Begerow et al 2002, Piątek et al 2017) and are thought to be a driver of plant pathogen diversification (Choi and Thines 2015). …”

New light on names and naming of dark taxa

“…In the context of “ Eumycota ” and “ Deuteromycota ”, molecular data are often used to link the teleomorph and anamorph stages of species, thus resolving the issue (e.g. Piątek et al 2017 ). This is also the reason why sequence data from type specimens are very valuable to sort out nomenclature and DNA barcoding issues and to bring dark taxa under the realm of taxonomy by providing them with a name ( Robbertse et al 2017 ; Torres-Cruz et al 2017 ).…”

Graphiola fimbriata: the first species of Graphiolaceae (Exobasidiales, Basidiomycota) described only based on its yeast stage

“…Assuming that its host specificity developed to the same degree shown for other plant pathogens (Piątek et al 2013, Savchenko et al 2014, Vasighzadeh et al 2014, Choi & Thines 2015, Scholler et al 2016, the number of 12 Graphiola species on 38 palm species from 21 plant genera (Farr & Rossman n.d., Piepenbring et al 2012) is lower than in other known plant-parasite systems. Intensive sampling and molecular analyses were used successfully in other groups to link anamorph and teleomorph stages (Sampaio 2004, Boekhout et al 2006, Inácio et al 2008, Kruse et al 2017, Piątek et al 2017. However, both sexual and asexual species are yet strongly under sampled in many lineages (Liu et al 2015a.…”