The Sporangial Phase of the Downy Mildew on Eleusine coracana with a Discussion of the Identity of Sclerospora macrospora Sacc.

Reclassification of an enigmatic downy mildew species on lovegrass (Eragrostis) to the new genus Eraphthora, with a key to the genera of the Peronosporaceae

“…As consequence, Sclerophthora has been described by Thirumalachar et al (1953). Basidiophora differs from all other genera to which the causal agent of lovegrass is morphologically similar in having simple, mostly unbranched, club-shaped sporangiophores.…”

“…The clade that contained the majority of Sclerophthora sequences contained specimens from four different tribes of the Poaceae, including one specimen from Eragrostis, highlighting the broad host range of this lineage. The monophyly of this group received high support a b (1869); Sclerophthora macrospora sporangial stage (c) based on Thirumalachar et al (1953) and oogonial stage (g) based on Thirumalachar and Narasimhan (1949); Sclerospora graminicola sporangial stage (d) based on Weston and Uppal (1932) and oogonial stage (h) based on Fischer (1892) in the analyses of the longer cox2 fragment and moderate to high support in the analyses of the shorter one. Lovegrass downy mildew attributed to either Basidiophora or Sclerospora showed little variation between the Australian specimens and the sample recently collected from Europe.…”

“…The monophyly of these genera seems likely . The genus Sclerophthora was established by Thirumalachar et al (1953). This genus has characteristics intermediate between Phytophthora (hardly differentiated, hyphal sporangiophores) and Sclerospora (thick-walled oospores) (Thirumalachar et al 1953;Erwin and Ribeiro 1996;Thines 2009), which is reflected by the chimeric name Sclerophthora chosen by Thirumalachar et al (1953).…”

“…The genus Sclerophthora was established by Thirumalachar et al (1953). This genus has characteristics intermediate between Phytophthora (hardly differentiated, hyphal sporangiophores) and Sclerospora (thick-walled oospores) (Thirumalachar et al 1953;Erwin and Ribeiro 1996;Thines 2009), which is reflected by the chimeric name Sclerophthora chosen by Thirumalachar et al (1953). While Peronosclerospora and Sclerospora are seemingly restricted to a rather narrow host range of C4 grasses within the tribes Antropogoneae and Paniceae, Sclerophthora has a much broader host range, encompassing several tribes within the Ehrhartoideae, Pooideae, and Chloroideae of the Poaceae.…”

“…In their monographic study, Barreto and Dick (1991) rejected Basidiophora butleri from Basidiophora and returned the species to the genus Sclerospora. Later, the species was listed as Sclerophthora butleri by Dick (2001), but it can be assumed that this was a typing error, as Weston (1931) was given as authority for this name and the respective publication antedates the description of Sclerophthora (Thirumalachar et al 1953). It should also be noted that the combination Sclerophthora butleri was not introduced by Thirumalachar et al (1953), contrary to entries found in several taxonomic databases.…”