Laying the foundation for a taxonomic review of Puccinia coronata s.l. in a phylogenetic context

Abstract

Intra-specific classification of Puccinia coronata has been controversial, with previous approaches falling into three major categories: 1. A two-species system, namely P. coronifera and P. coronata; 2. The same two-species system subdivided into many formae speciales, in which the host range of each is restricted to species within one genus of Poaceae; 3. A one-species system, P. coronata, subdivided into a few varieties with host ranges that may overlap. To re-assess these concepts in the context of multigene analyses and comparative morphological assessments, data were generated for a comprehensive set of herbarium and recently collected specimens, representing a broad range of hosts and geographic origins. Phylogenetic analyses of a combined data set of DNA sequences for four loci (BT, COI, ITS, and RPB2) revealed a high degree of genetic variation. Morphological differences among phylogenetic lineages were overlapping but nine lineages were differentiated using calculated means for teliospore and urediniospore length/width as well as measurements for the teliospore hilum and digitation. The taxon infecting Avena also comprises collections from a wide range of other grass hosts while other lineages, such as those on Bromus and Agrostis, were restricted in host association. Type specimen DNA sequences included in the analyses resolved the placement of five previously described varieties. Based on evidence of host specificity, morphology and multigene analyses, we recognized seven species, one of which was further divided into two varieties. Expanded descriptions, illustrations and a synoptic key are provided. A new series, Puccinia Series Coronata, was erected to accommodate all the lineages comprising P. coronata sensu lato.

Multiple genotypes within aecial clusters in Puccinia graminis and Puccinia coronata: improved understanding of the biology of cereal rust fungi

“…Our results on host specific allele sizes of SSR loci confirm the usefulness of SSR markers to distinguish between formae speciales of P. coronata , as they agree with the previously described DNA sequence based genetic differentiation of the two formae speciales [ 35 ] and their ability to only infect specific alternate hosts [ 4 ].…”

Puccinia coronata f. sp. avenae: a threat to global oat production

“…Nonetheless, some of these designations remain in use to indicate the major grass hosts, as in the case of Pca . Most recently, the implementation of molecular analysis has shown that P. coronata encompasses multiple species (Szabo, ) and suggests the division of the complex into seven species (Liu and Hambleton, ). For the purpose of this review, we refer to Pca as a pathogen affecting primarily cultivated and wild oat, as well as some grasses, such as Lolium , and which, in previous publications, has been denominated as P. coronata var.…”

A dynamic, web-based resource to identify rust fungi (Pucciniales) in southern Africa

“…Further diversity may be expected from cryptic species, which have been found in multiple genera of rust fungi on hosts in the Annonaceae (Beenken 2014), Fabaceae (Doungsa-ard et al 2015;McTaggart et al 2015a) and Poaceae (Demers et al 2017;Liu and Hambleton 2013). Doidge (1950) recorded one species of rust, Uromyces aloës, on 18 different host species, and this may represent a taxon with cryptic diversity.…”