The genus Ravenelia (Pucciniales) in South Africa

Abstract

The genus Ravenelia represents the third largest genus of rust fungi and parasitizes a great number of leguminous shrubs and trees, mainly in the subtropics and tropics. Molecular phylogenetic analyses of this genus using nc 28S rDNA and CO3 sequences are presented with a special focus on South African representatives of Ravenelia. Many of the specimens had been collected by us in recent years, mainly from acacia species of the genera Vachellia and Senegalia. Morphological characters were extensively studied using light microscopy and scanning electron microscopy. The analyses resolved several well-supported phylogenetic groups. By linking these groups to their morphology and life cycle characteristics, it was possible to interpret the outcomes in terms of their evolutionary ecology and biogeography. Several characters previously used to define subgeneric groups within Ravenelia were found to be misleading because of assumed convergent evolution. However, host associations, the ability to induce aecial galls as well as the development of two-layered probasidial cells emerged as useful criteria for inferring monophyletic groups. Six novel Ravenelia species were discovered and described. Furthermore, five species represent new reports for South Africa, species descriptions were emended for two taxa, and a new host report emerged for R. inornata. Keywords Pucciniales. Raveneliaceae. Ravenelia moloto sp. nov.. Ravenelia molopa sp. nov.. Ravenelia modjadji sp. nov. Ravenelia doidgeae sp. nov.. Ravenelia spinifera sp. nov.. Ravenelia dumeti sp. nov.. Phylogeny. Diversity study This article is part of the topical collection on Basidiomycote Mycology in honor of Franz Oberwinkler who passed away in March 2018

Species diversity of Basidiomycota

“…New species of rust will certainly be found in isolated, under-explored, biodiverse areas, as well as through discovery of cryptic diversity in species complexes. For example, species diversity of rust fungi has increased through resolution of taxa in Chrysomyxa (Feau et al 2011), Coleosporium (McTaggart and Aime 2018), Dasyspora (Beenken et al 2012), Endoraecium (McTaggart et al 2015, Gymnosporangium (Zhao et al 2016a, b), Melampsora (Toome and Aime 2015;Zhao et al 2017a), Milesina (Bubner et al 2019), Neophysopella (Chatasiri and Ono 2008), Phakopsora (Beenken 2014;Maier et al 2016), Phragmidium (Liu et al 2018), Puccinia (Demers et al 2017;Hambleton 2010, 2013), Pucciniastrum (Liang et al 2006), Ravenelia Ebinghaus et al , 2020 and Uromycladium (Doungsa-ard et al 2018) (Fig. 12).…”