A higher-rank classification for rust fungi, with notes on genera

Abstract

The rust fungi (Pucciniales) with 7000+ species comprise one of the largest orders of Fungi, and one for which taxonomy at all ranks remains problematic. Here we provide a taxonomic framework, based on 16 years of sampling that includes ca. 80 % of accepted genera including type species wherever possible, and three DNA loci used to resolve the deeper nodes of the rust fungus tree of life. Pucciniales are comprised of seven suborders - Araucariomycetineae subord. nov., Melampsorineae, Mikronegeriineae, Raveneliineae subord. nov., Rogerpetersoniineae subord. nov., Skierkineae subord. nov., and Uredinineae - and 18 families - Araucariomycetaceae fam. nov., Coleosporiaceae, Crossopsoraceae fam. nov., Gymnosporangiaceae, Melampsoraceae, Milesinaceae fam. nov., Ochropsoraceae fam. & stat. nov., Phakopsoraceae, Phragmidiaceae, Pileolariaceae, Pucciniaceae, Pucciniastraceae, Raveneliaceae, Rogerpetersoniaceae fam. nov., Skierkaceae fam. & stat. nov., Sphaerophragmiaceae, Tranzscheliaceae fam. & stat. nov., and Zaghouaniaceae. The new genera Araucariomyces (for Aecidium fragiforme and Ae. balansae), Neoolivea (for Olivea tectonae), Rogerpetersonia (for Caeoma torreyae), and Rossmanomyces (for Chrysomyxa monesis, Ch. pryrolae, and Ch. ramischiae) are proposed. Twenty-one new combinations and one new name are introduced for: Angiopsora apoda, Angiopsora chusqueae, Angiopsora paspalicola, Araucariomyces balansae, Araucariomyces fragiformis, Cephalotelium evansii, Cephalotelium neocaledoniense, Cephalotelium xanthophloeae, Ceropsora weirii, Gymnotelium speciosum, Lipocystis acaciae-pennatulae, Neoolivea tectonae, Neophysopella kraunhiae, Phakopsora pipturi, Rogerpetersonia torreyae, Rossmanomyces monesis, Rossmanomyces pryrolae, Rossmanomyces ramischiae, Thekopsora americana, Thekopsora potentillae, Thekopsora pseudoagrimoniae, and Zaghouania notelaeae. Higher ranks are newly defined with consideration of morphology, host range and life cycle. Finally, we discuss the evolutionary and diversification trends within Pucciniales. Citation: Aime MC, McTaggart AR (2020). A higher-rank classification for rust fungi, with notes on genera. Fungal Systematics and Evolution 7: 21-47. doi: 10.3114/fuse.2021.07.02.

Keywords: 37 new taxa; Uredinales; Urediniomycetes; host alternation; life cycles.

Fig. 1.

Pucciniales. Phylogram obtained from BEAST constrained to a ML topology from three concatenated loci (28S, 18S, and CO3). The tree is rooted with Eocronartium muscicola. Families are indicated by coloured blocks; dashed lines indicate uncertainty at the referenced nodes. Genera represented by types are indicated in bold; genera represented by type proxies (as explained in methods) are indicated by *. Support for nodes is provided from an approximate likelihood ratio test (≥ 0.90), ultrafast bootstraps (≥ 95 %) and genealogical concordance factors for the three loci at each node as aLRT/UFBoot/gCF.

Fig. 2.

Melampsorineae. ML topography generated from three concatenated loci (28S, 18S, and CO3) with expanded taxon sampling. The tree is rooted with Araucariomycetaceae and Zaghouaniaceae. Four families are indicated by coloured blocks; Pucciniastraceae is recovered as a grade in these analyses. Genera represented by types are indicated in bold; genera represented by type proxies (as explained in methods) are indicated by *. Support for nodes is provided from an approximate likelihood ratio test (≥ 0.90) and ultrafast bootstraps (≥ 95 %) as aLRT/UFBoot.

Fig. 3.

Raveneliineae. ML topography generated from 28S with expanded taxon sampling. The tree is mid-point rooted. Families are indicated by colour blocks; Raveneliaceae is not resolved. Only 26 of the estimated 45+ genera in this suborder are represented by types (indicated in bold) and type proxies (indicated by *), and poor resolution may be attributable to missing data (both locus and taxon sampling), combined with long branch lengths (Fig. S2) in this lineage. Support for nodes is provided from an approximate likelihood ratio test (≥ 0.90) and ultrafast bootstraps (≥ 95 %) as aLRT/UFBoot.

Fig. 4.

Uredinineae. ML topography generated from three concatenated loci (28S, 18S, and CO3) with expanded taxon sampling. The tree is rooted with Melampsorineae. Six families are resolved and indicated by coloured blocks; three genera are unresolved to family and indicated as incertae sedis. Genera represented by types are indicated in bold; genera represented by type proxies (as explained in methods) are indicated by *. Support for nodes is provided from an approximate likelihood ratio test (≥ 0.90), ultrafast bootstraps (≥ 95 %) and genealogical concordance factors for the three loci at each node as aLRT/UFBoot/gCF.