Re-Evaluation of the Podosphaera tridactyla Species Complex in Australia

Abstract

The Podosphaera tridactyla species complex is highly variable morphologically and causes powdery mildew on a wide range of Prunus species, including stone fruit. A taxonomic revision of the Po. tridactyla species complex in 2020 identified 12 species, seven of which were newly characterised. In order to clarify which species of this complex are present in Australia, next generation sequencing was used to isolate the fungal ITS+28S and host matK chloroplast gene regions from 56 powdery mildew specimens of stone fruit and ornamental Prunus species accessioned as Po. tridactyla or Oidium sp. in Australian reference collections. The specimens were collected in Australia, Switzerland, Italy and Korea and were collected from 1953 to 2018. Host species were confirmed using matK phylogenetic analysis, which identified that four had been misidentified as Prunus but were actually Malusprunifolia. Podosphaera species were identified using ITS+28S phylogenetic analysis, recognising three Podosphaera species on stone fruit and related ornamental Prunus hosts in Australia. These were Po.pannosa, the rose powdery mildew, and two species in the Po. tridactyla species complex: Po. ampla, which was the predominant species, and a previously unidentified species from peach, which we describe here as Po. cunningtonii.

An Annotated Checklist of Powdery Mildew Fungi (Erysiphaceae) in the Ile-Alatau Mountains (within Kazakhstan)

“…The taxonomic list of powdery mildew species, which included the collections of the authors and literature data, was compiled using the fundamental taxonomic manual of Erysiphaceae (Braun, 2012) with additions for the several taxonomic revisions of the species complexes: Blumeria graminis (Liu et al, 2021;Heluta, 2022), Erysiphe adunca (Darsaraei et al, 2021), E. lonicerae (Bradshaw et al, 2021), Golovinomyces biocellatus (Scholler et al, 2016), G. cynoglossi (Braun et al, 2018), G. orontii (Braun et al, 2019), Podosphaera tridactyla (Meeboon et al, 2020;Smith et al, 2021), P. cerasi and P. prunicola (Moparthi et al, 2019); Leveillula taurica (Khodaparast et al, 2001;2012). All names of host plant species are given by the open database "Catalogue of life" (Catalogue of Life Database, 2022).…”

“…Over the past 10 years, the list of powdery mildew fungi has increased by another 20 species, which can be considered as new for the Ile-Alatau due to taxonomic revisions of the species complexes: Blumeria graminis (Liu et al, 2021;Heluta, 2022), Erysiphe adunca (Darsaraei et al, 2021), E. lonicerae (Bradshaw et al, 2021), Golovinomyces biocellatus (Scholler et al, 2016), G. cynoglossi (Braun et al, 2018), G. orontii (Braun et al, 2019), Podosphaera tridactyla (Meeboon et al, 2020;Smith et al, 2021), P. cerasi and P. prunicola (Moparthi et al, 2019); Leveillula taurica (Khodaparast et al, 2001;2012).…”