Sydowia
Sydowia Bres., Hedwigia 34(Beibl.): (66) (1895).
Index Fungorum number: IF 5311; Facesoffungi number: FoF 00093, 11 morphological species (Species Fungorum 2022), 4 species with molecular data.
Parasitic or saprobic on conifer plants or branches and wood. Sexual morph: Ascostromata black, immersed to erumpent, solitary or gregarious, globose to subglobose, coriaceous, uniloculate, ostiolate. Peridium several layers thick, composed of dark brown cells of textura angularis or occasionally prismatica, more darkened on the outside, hyaline to lightly pigmented towards the interior. Hamathecium lacking pseudoparaphyses. Asci 8-to poly-spored, bitunicate, fissitunicate, clavate to oblong with a short pedicel, apically rounded. Ascospores crowded to overlapping, hyaline, transversely multiseptate, constricted at the primary septum, sometimes with a vertical septum in the mid cells or rarely in the end cells, straight to inequilateral, guttulate, upper part usually wider and shorter than the lower part, elliptic, obovate, smooth. Asexual morph: Hormonema and sclerophoma-like (Wijayawardene et al. 2012; Hyde et al. 2013). Pycnidia stromatic, immersed at first, later erumpent, globose to irregular, solitary or aggregated, uni or multi locular or convoluted. The wall is thick and dehisces by breaking down the overlying wall tissue. Conidiogenous cells phialidic, enteroblastic, determinate, discrete, hyaline to pale brown, doliiform to ampulliform, with a wide channel and minute collarette, formed from the inner cells of the wall lining the locule. Conidia hyaline, aseptate, ellipsoid, and rarely tapered at the base smooth-walled, sometimes guttulate (adapted from Sivanesan 1984; Thambugala et al. 2014).
Type species: Sydowia gregaria Bres.
Notes: Sydowia is characterised by black, immersed to erumpent ascostromata, 8- to poly-spored, bitunicate asci and hyaline, transversely multiseptated ascospores. The asexual morph is hormonema and sclerophoma-like characterised by stromatic pycnidia, phialidic, enteroblastic conidiogenous cells and hyaline, aseptate, ellipsoid conidia. Barr (1972) accepted five polysporous species in Sydowia, while Sivanesan (1984) included only two. Luttrell (1973) transferred Sydowia to Dothioraceae based on its phragmosprous ascospores. Arx and Müller (1975) referred Sydowia to Dothideaceae based on the broad unilocular stromata and ascospores with only transverse septa. Barr (2001) included phragmosporous species in both 8-spored and poly-spored asci and added three new species, S. slippii, S. taxicola and S. wolfii which were previously placed in Dothiora. Schoch et al. (2006) demonstrated that Sydowia belongs to Dothioraceae based on multigene analysis of SSU, LSU, TEF-1 and RPB2 gene regions. The type species, Hormonema dematioides is considered to be the asexual state of Sydowia polyspora (Butin 1964; Cheewangkoon et al. 2009; Thambugala et al. 2014). In the phylogenetic analysis of Bills et al. (2004) based on ITS sequence data, S. polyspora and Hormonema dematioides clustered in the same clade but sequences of ex-type strain of H. dematioides is lacking and no authentic specimen is available. Thambugala et al. (2014) re-examined the holotype specimen of S. gregaria (S-F6473) and provided an updated account of the genus. Thambugala et al. (2014) did not include H. dematioides in their phylogenetic analysis and did not synonymize Hormonema under Sydowia. Sydowia differs from other genera of Dothideaceae in having uniloculate ascostromata. Sydowia is a distinct genus in Dothideaceae but fresh collections are required to confirm this taxonomic position. Molecular markers available for Sydowia are ITS, LSU, SSU, RPB2 and TEF-1.
Recent News
Recent paper to be publishedRecent Genus
NothocladosporiumPhillipsiella
Curreya
Recent Species
Nothocladosporium syzygiiPhillipsiella atra
Curreya conorum
