Diaporthaceae Höhn. ex Wehm., Am. J. Bot. 13: 638 (1926)
Index Fungorum number: IF 80691; 497 species.
Endophytic, pathogenic or saprobic on terrestrial and rarely submerged plants. Sexual morph: Pseudostromata well or poorly developed, erumpent, pulvinate, slightly convex or flat, circular, orbicular or irregular, coriaceous, sclerotioid, whitish or brownish to black, with or lacking black zone or a crust containing of fungus tissue, solitary or having up to 10 ascomata in a stroma. Ectostromatic disk subhyaline to hyaline or brown. Ascomata immersed to erumpent, perithecial, globose or compressed, solitary or aggregated in a valsoid shape, black, coriaceous, ostiolate, papillate. Papilla short or long, black, convergent, erumpent, conical or cylindrical, internal wall concealed by hyaline periphyses, composed of vertically organized parenchymatous tissues. Peridium covering exterior layer of thick-walled, flattened, dark-brown cells of textura angularis and inner, thin-walled, hyaline cells of textura angularis. Paraphyses unbranched, septate, cylindrical. Asci 8-spored, clavate, oblong-clavate to broadly fusoid, unitunicate, sessile, with a distinct apical ring. Ascospores biseriate to partially biseriate, hyaline, dark brown, ellipsoid, oblong to fusoid, unicellular or one septate, constricted at septum, with or without appendages at both ends, occasionally narrowly rounded at ends, multi-guttulate, smooth-walled. Asexual morph: Coelomycetous. Conidiomata globose, acervular or pycnidial, initially immersed, erumpent when mature, black, solitary, coriaceous, scattered, elongated ostiolar necks, sometime becoming multiloculate with one to numerous noticeably demarcated black necks extending over the stroma, frequently with yellowish conidial mass extruding from ostiole. Peridium comprising 3–4 layers of light brown cells of textura intricata to textura angularis. Conidiophores dimorphic. Alpha conidiophores subcylindrical, firmly aggregated, branched in middle area, comprising 2–3 associate cells, ampulliform, giving rise to septate, cylindrical to irregular conidiogenous cells or paraphyses, straight to sinuous, smooth, 1–5-septate, hyaline to pale brown, cylindrical, branched merely at the base, formed from the inner most layer cells of the conidiomata wall, sometime terminal and lateral, apex with minute periclinal thickening and collarette. Beta conidiophores hyaline, scattered between alpha conidiophores, subcylindrical, branched, 1–3-septate. Alpha Conidiogenous cells phialidic, enteroblastic, cylindrical or subcylindrical, terminal and lateral, slightly tapering towards the apex or sometimes apex with minute periclinal thickening and collarette. Beta conidiogenous cells integrated, phialidic, terminal and lateral. Alpha conidia hyaline, fusiform to ovate, subcylindrical to narrowly ellipsoid, straight or curved, occasionally irregular, smooth-walled, abundant, 0–2-septate, apex obtuse, base truncate to sub-truncate, straight to curved, occasionally slightly sigmoid, pale to medium brown, with many guttules, sometimes short, bear appendages at both ends. Beta conidia hyaline, aseptate, smooth, subcylindrical, straight to slightly curved, fusiform to hooked, base sub-truncate, occasionally widest in middle, tapering to acutely rounded apex, truncate at base.
Type genus – Diaporthe Nitschke
Notes – Diaporthaceae was introduced and placed in Diaporthales by Höhnel (1917d) and it encompasses numerous endophytic and phytopathogenic fungal species. Wehmeyer (1975) confined two genera, Diaporthe and Mazzantia to this family. However, Barr (1978) synonymized Diaporthaceae in Valsaceae. Castlebury et al. (2002) presented the distinct placement of Diaporthaceae in Diaporthales, forming an analyzed LSU sequence data of diaporthoid taxa in a well-supported clade. Previously, only Diaporthe (Phomopsis) and Mazzantia were accommodated in Diaporthaceae based on phylogenetic analysis (Castlebury et al. 2002). Nevertheless, Apioporthella and Leucodiaporthe were included in this family by Lumbsch & Huhndorf (2010). Lamprecht et al. (2011) showed the phylogenetic placement of Stenocarpella and Phaeocytostroma in Diaporthaceae using LSU sequences analysis. Based on combined gene analysis of LSU, SSU and tef1 sequence data, Dai et al. (2014b) introduced Pustulomyces. Phylogenetic placement of Phaeodiaporthe in Diaporthaceae was confirmed by Voglmayr & Jaklitsch (2014). Maharachchikumbura et al. (2015) listed Allantoporthe, Apioporthella, Clypeoporthella, Diaporthe, Diaporthella, Diaporthopsis, Leucodiaporthe, Mazzantia, Mazzantiella, Ophiodiaporthe and Pustulomyces as genera of Diaporthaceae based on an analysis of LSU sequence data. Based on greater usage of the name Mazzantia, Rossman et al. (2015) synonymized Mazzantiella under Mazzantia. Clypeoporthella was established on C. brencklei Petr., and a newly collected C. brencklei (BPI 843482) specimen was developed in culture and sequenced. It has a Phomopsis asexual morph and DNA sequence data disclosed that C. brencklei clustered together with Diaporthe. Thus, Clypeoporthella is regarded as a synonym of Diaporthe (Sogonov et al. 2008). Diaporthopsis was introduced to accommodate species that are similar to Diaporthe, with unicellular ascospores and was typified by D. angelicae. Molecular analysis of LSU sequence data showed that D. angelicae clustered within the Diaporthe. In addition, Diaporthopsis angelicae has similar characters of Diaporthe such as stromata, perithecia, and centrum to species. Diaporthopsis was synonymized under Diaporthe based on morphology and molecular data (Castlebury et al. 2002, Gomes et al. 2013). Diaporthella is comprised of aggregated perithecia within well-developed stromata and median, 1-septate ascospores. Diaporthella corylina is parasitic and causes dieback of Corylus stems. Diaporthella corylina shows similar characters to Anisogramma anomala morphologically. Anisogramma belongs in the Gnomoniaceae based on A. virgultorum (Castlebury et al. 2002, Vasilyeva et al. 2007). Based on combined LSU, ITS, rpb2 and tef1 gene analysis, Senanayake et al. (2017a) confirmed the phylogenetic placement of Diaporthella outside of Diaporthaceae, and it does not show affinities with any families in Diaporthales. A recent study by Senanayake et al. (2017a) accepted a few genera within this family in addition to Maharachchikumbura et al. (2016b) by introducing three new genera: Chiangraiomyces, Hyaliappendispora and Paradiaporthe based on morphology and phylogeny. Massariothea was added to the family by Thambugala & Hyde (2018). Therefore 15 genera: Apioporthella, Apiosphaeria, Chaetoconis, Chiangraiomyces, Diaporthe, Hyaliappendispora, Leucodiaporthe, Massariothea, Mazzantia, Ophiodiaporthe, Paradiaporthe, Phaeocytostroma, Phaeodiaporthe, Pustulomyces and Stenocarpella are accepted in Diaporthaceae (Senanayake et al. 2018).
Clypeoporthe, Cryptonectriella, Kensinjia, Lollipopaia and Skottsbergiella were listed in Diaporthaceae by Wijawawardene et al. (2017). Clypeoporthe was introduced and is typified by C. monocarpa. There are five species listed under this genus (Species fungorum 2020). However, some species in this genus have eutypelloid configuration of ascomata in parenchymatous stromatic tissues. Clypeoporthe was reduced to synonymy under Gnomonia by Monod (1983), while Kirk et al. (2008) mentioned Clypeoporthe is the sexual morph of Phaeocytostroma. However, the latter is not proven by culture or molecular data and it is necessary to obtain DNA sequence data to resolve this genus. Therefore, Senanayake et al. (2017a, 2018) and Wijayawardhene et al. (2018) accepted this genus in Gnomoniaceae. Cryptonectriella (Höhn.) Weese (≡ Cryptonectriopsis (Höhn.) Weese) was introduced and is typified by C. biparasitica and a second species C. geoglossi (Species Fungorum 2020). Weese (1919) accommodated this genus in Hypocreales. Kensinjia was introduced and is typified by K. umbrina by Reid & Booth (1989). However, this species was synonymized under Cryptosporella as C. umbrina (Jenkins) Jenkins & Wehm., which is a genus in Gnomoniaceae. The monotypic genus Lollipopaia was introduced and typified by L. minuta and accommodated in Diaporthales genera incertae sedis (Inderbitzin and Berbee 2001). There are only two nrSSU sequences and blast searches in GenBank show L. minuta is closely related to economically important plant pathogens in Diaporthaceae. However our phylogenetic analysis (unpublished) shows that L. minuta clusters away from Diaporthaceae; but within Diaporthales. Lollipopaia minuta is somewhat different from taxa of Diaporthaceae in having solitary to aggregated, carbonaceous ascomata with long, slender necks and long, filiform, multiseptate ascospores. Senanayake et al. (2017a, 2018) accepted Lollipopaia within Diaporthales genera incertae sedis based on morphology and here we follow this. Skottsbergiella was introduced and typified by Skottsbergiella diaporthoides which has large perithecia immersed in massive, externally crustose, pseudoparenchymatous stromata. Petrak (1971) assigned this genus to eutypoid fungi based on its stromata. This genus is morphologically similar to Diaporthella, which is placed in Diaporthales genera incertae sedis (Barr 1978). However, Skottsbergiella diaporthoides was synonymized under Diaporthe diaporthoides (Barr 1978) and accommodated in Diaporthaceae. This was followed by Senanayake et al. (2017a, 2018).
Ecological and economic significance of Diaporthaceae
Species of Diaporthaceae includes a number of plant pathogens of major importance causing diseases of a wide variety of plants (Dissanayake et al. 2017, Senanayake et al. 2018). Fruit production is especially affected (Dissanayake et al. 2017, Senanayake et al. 2018).