Pleosporaceae Nitschke, Verh. naturh. Ver. preuss. Rheinl. 26: 74 (1869).

The family Pleosporaceae was introduced by Nitschke (1869) based on the immersed ascomata and presence of pseudoparaphyses, and was classified in Sphaeriales. The family was transferred to Pseudosphaeriaceae and later raised to ordinal rank as the Pseudosphaeriales (Theissen and Sydow 1918). Pleosporaceae, Venturiaceae and Lophiostomataceae were assigned under Pleosporales by Luttrell (1955), while treating Pseudosphaeriales as a synonym of Pleosporales. Luttrell (1973) included eight families in Pleosporales including Pleosporaceae. Preliminary genera added to this family were based on ascospore characteristics, including shape, colour, septation, pigmentation and presence or absence of mucilaginous sheaths (Luttrell 1955, 1973; Wehmeyer 1961, 1975; Eriksson 1981; Sivanesan 1984; Barr 1987b; Abler 2003). Many of these characters were also found in other families, such as Leptosphaeriaceae, Melanommataceae, Phaeosphaeriaceae and Sporormiaceae. This led for confusion in the intergeneric and familial classification (Luttrell 1955, 1973; Wehmeyer 1961, 1975; von Arx and Müller 1975; Sivanesan 1984; Barr 1987a, b; Eriksson and Hawksworth 1986, 1991). Barr (1987b) redefined the Pleosporaceae to include Clathrospora (= Comoclathris), Kirschsteiniothelia, Lewia and Pleospora and grouped Cochliobolus, Pyrenophora and Setosphaeria into the family Pyrenophoraceae. Berbee (1996) disagreed, suggesting that all those genera belong to the Pleosporaceae. Kodsueb et al. (2006) showed the intergeneric relationships and phylogenetic perspectives of the family Pleosporaceae based on sequence analyses of partial 28S rDNA and accepted 14 genera in Pleosporaceae. Based on multi-gene phylogenetic analysis, Zhang et al. (2009) concluded that some species from Lewia, Cochliobolus, Pleospora, Pyrenophora and Setosphaeria resided in the Pleosporaceae. Lumbsch and Huhndorf (2010) accepted 13 genera in Pleosporaceae but Zhang et al. (2012) included only 10 genera by excluding Monascostroma, Kriegeriella, and Zeuctomorpha (see notes below). Hyde et al. (2013) included 23 genera in this family based on morphology coupled with molecular data. Multi-gene phylogenetic studies has shown that the familial placement of Pleosporaceae with respect to other families in order Pleosporales is valid (Lumbsch and Huhndorf 2010; Zhang et al. 2012; Hyde et al. 2013).

Asexual morphs of Pleosporaceae

The asexual morphs of Pleosporaceae can be coelomycetous or hyphomycetous (Zhang et al. 2012; Hyde et al. 2013) and some sexual genera in Pleosporaceae have been linked with asexual morphs (Zhang et al. 2012; Hyde et al. 2013). The type species of the family Pleospora is linked to Stemphylium, which causes leaf disease (Sivanesan 1984). Bipolaris was shown to be the asexual morph of “Cochliobolus”, and the cause of plant disease or infection in human beings (Khan et al. 2000; Manamgoda et al. 2014). The nomenclatural conflict in this complex was resolved by giving priority to the more commonly used established generic name Bipolaris (Manamgoda et al. 2012, 2014). At the same time, Manamgoda et al. (2012) showed that Curvularia grouped with “Pseudocochliobolus”. The type species of Pleoseptum (P. yuccaesedum A.W. Ramaley & M.E. Barr) has been linked with Camarosporium yuccaesedum Fairm (Ramaley and Barr 1995) and Pyrenophora has the asexual morph Drechslera (Farr et al. 1989). Ariyawansa et al. (2014c) proposed to conserve Pyrenophora over Drechslera by giving priority to the oldest name. Based on the combined gene analysis of GAPDH, RPB2 and TEF1, Woudenberg et al. (2013) synonymised Allewia, Brachycladium, Chalastospora, Chmelia, Crivellia, Embellisia, Lewia, Nimbya, Sinomyces, Teretispora, Ulocladium, Undifilum and Ybotromyces under Alternaria. In same study, Woudenberg et al. (2013) treated the 24 internal clades in the Alternaria complex as sections, which is a continuation of a recent proposal for the taxonomic treatment of lineages in Alternaria. Furthermore, Alternariaster, a genus formerly seen as part of Alternaria was transferred to Leptosphaeriaceae based on molecular data. Recently, new asexual genera were introduced by different researches based on both morphology and phylogeny. i.e. Porocercospora was introduced as a new genus in Pleosporaceae by Amaradasa et al. (2014) to accommodate the buffalo grass false-smut pathogen, while Johnalcornia was introduced to accommodate Bipolaris aberrans, which clusters sister to the newly described Porocercospora (Tan et al. 2014). Paradendryphiella was introduced by Woudenberg et al. (2013) to accommodate two marine Dendryphiella species (D. arenariae Nicot, D. salina (G.K. Sutherl.) Pugh & Nicot) that did not group with the type species D. vinosa (Berk. & M.A. Curtis) Reisinger (Jones et al. 2008; Woudenberg et al. 2013).

Taxa in Alternaria, Bipolaris, phoma like and Stemphylium are more common asexual morphs in Pleosporaceae and can be saprobic or parasitic on various hosts. Phoma betae A.B. Frank is a notorious pathogen of sugar beet, which causes zonate leaf spot. Alternaria porri (Ellis) Cif., Stemphylium solani G.F. Weber, S. botryosum Wallr and S. vesicarium (Wallr.) E.G. Simmons can cause leaf blight of garlic (Zheng et al. 2009). Phoma incompta Sacc & Martelli is a pathogen on olive, and S. botryosum, the asexual morph of Pleospora herbarum (Pers.) Rabenh, causes leaf disease of olive trees (Malathrakis 1979). Some Curvularia species have been reported as human pathogens, causing respiratory tract, cutaneous, and corneal infections (Carter and Boudreaux 2004).

We have been studying the families of Dothideomycetes based on morphology and molecular phylogeny, in order to provide a natural classification of this large class. Hyde et al. (2013) provide an account of all 105 families of Dothideomycetes, while Wijayawardene et al. (2014) provided an outline of Dothideomycetes and suggestions on the on the names to use where asexual and sexual genera were linked. The largest order in Dothideomycetes is Pleosporales and we also have provided a natural classification of this large order (Ariyawansa et al. 2013a, b; Ariyawansa et al. 2014a, b, c, d, e, f; Zhang et al. 2012). Zhang et al. (2012) provided an account for 105 genera in Pleosporales, however at that time there was little verified molecular data were available. The aim of the present study was to delineate the phylogenetic lineages within Pleosporaceae, and to build a robust taxonomy to act as a backbone tree for the family. Phylogenetic analysis were conducted on sequence data of parts of the 18S nrDNA (SSU), 28S nrDNA (LSU), the internal transcribed spacer regions 1 and 2 and intervening 5.8S nrDNA (ITS) and RNA polymerase second largest subunit (RPB2) gene regions of extype, reference and putative strains of all available allied genera in Pleosporaceae. We also focused on the phylogenetic lineages within Alternaria and allied genera, and to create a stable taxonomy. Phylogenetic inferences were conducted on sequence data of parts of the SSU, LSU, ITS, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), RPB2 and translation elongation factor 1-alpha (TEF1) gene regions of extype and reference strains of Alternaria species and all available allied genera.

Fig 1. RAxML tree based on a combined dataset of ITS, SSU, LSU and RPB2 of 98 strains representing the Pleosporineae. Bootstrap support values for maximum likelihood greater than 50% (black) and bayesian posterior probabilities greater than 0.90 (green) below and above the nodes. Halojulella avicenniae is the out group taxon. The original isolate numbers are noted after the species names. Ex-type culture numbers are in bold. Newly generated strains in this study are indicated in red. The type species of each genus is indicated in blue.

Taxonomy

Pathogenic or saprobic on wood and dead herbaceous stems or leaves or pathogen of humans. Sexual morph: Ascomata perithecial, initially immersed and becoming erumpent to nearly superficial, black, globose, subglobose or ovoid, sometimes hairy or setose, ostiolate. Ostiole papillate or apapillate, sometimes with a pore-like ostiole, ostiolar canal filled with or lacking periphyses. Peridium thin, usually thick at the sides, thinner at the base. Hamathecium of hyaline, septate, cellular pseudoparaphyses interspersed with asci. Asci 8-spored, bitunicate, fissitunicate, cylindrical, with an ocular chamber. Ascospores uniseriate or biseriate, partially overlapping, phragmosporous or muriform, brown or pale brown, with or without mucilaginous sheath. Asexual morph: coelomycetous or hyphomycetous, and the conidiogenous cells can be phialidic, annellidic or sympodial blastic.

Type: Pleospora Rabenh. ex Ces. & De Not., Comm. Soc. crittog. Ital. 1(4): 217 (1863)