Paraphomopsis Udayanga & Castl., gen. nov. Fig. 2.
MycoBank number: MB 835529; Index Fungorum number: IF 835529; Facesoffungi number: FoF
Type species: Paraphomopsis obscurans (Ellis & Everh.) Udayanga & Castl.
Etymology: Morphologically similar to the well-known asexual morph Phomopsis (curr. name Diaporthe), but phylogenetically distinct.
Description: Asexual morph coelomycetous. Pycnidia globose, ostiolate, embedded in tissue, erumpent at maturity, with a slightly elongated, black neck, wider to- wards the apex at maturity; walls parenchymatous, consisting of 3–4 layers of medium brown textura angularis. Conidiophores hyaline, smooth, branched, ampulliform, long, slender, wider at the base, Conidiogenous cells phialidic, cylindrical, terminal, slightly tapering towards apex, alpha conidia aseptate, hyaline, smooth, ellipsoidal to fusiform, often biguttulate, rarely multiguttulate with minute particles aggregated towards the ends, base subtruncate. Sexual morph unknown.
Notes: – Paraphomopsis can be distinguished from its closely related genera (Greeneria, Melanconiella, Microascopsora) in Melanconiellaceae based on both molecular phylogeny and morphology. The genus Paraphomopsis is morphologically described herein, exclusively based on the characters of the asexual morph. The asexual morph of Melanconiella usually consists of both dark brown melanconium-like conidia as well as hyaline discosporina- like conidia (Voglmayr et al. 2012). Similarly, the genus Greeneria, which is typified by G. uvicola, forms pale brown conidia, smooth, variously shaped ranging from fusiform, oval, to ellipsoidal, each with a truncate base and obtuse to bluntly pointed apex (Farr et al. 2001). In Paraphomopsis, although the appearance of conidia is superficially similar to Diaporthe (syn. Phomopsis), micropscopic examination revealed that the shape and overall appearance are distinct from those in Diaporthe species. In general, conidia of Paraphomopsis are fusiform with minute guttules toward the end of the conidia, whereas most Diaporthe species form ovate to clavate conidia with no or prominent biguttulate or multiguttulate conidia. The morphology of sexual morph of the new genus described here remains unknown and is not available for comparison with other closely related genera. Although, the genus Paraphomopsis represents a sister clade to Microascopora in the phylogeny presented (Fig. 1), the asexual morph of the latter remains undetermined. The sexual morph of Microascospora distinct from other genera in the same family having immersed, solitary ascomata with narrow papilla with smaller hyaline, aseptate ascospores bearing long appendages (Senanayake et al. 2017a, 2017b). How- ever, the sexual morph of the saprobic genus Melanconiella is identified by its inconspicuous ectostroma projecting above the substrate and the hyaline, yellow or brown ascopsores, with or without short, blunt appendages and occasionally with a thin gelatinous sheath (Voglmayr et al. 2012; Senanayake et al. 2017a, 2017b).
Fig. 1 ML tree generated based on combined LSU, ITS, RPB2, and TEF1 alignment of representative taxa in the order Diaporthales. Isolates from Fragaria are indicated in red. Ex-type/epitype isolates are in bold and marked with asterisk (*). The ML bootstrap values/Bayesian PP greater than 90% /0.90 are indicated above or below the respective branches. The tree is rooted with Pyricularia grisea (M83) and Ceratosphaeria aquatica (MFLU 18–2323) (Magnaporthaceae, Magnaporthales)
Fig. 2 Morphology of Paraphomopsis obscurans (BPI 919201, culture CBS 143829/M1262, isolate DS020). a Infected leaf of Fragaria × ananassa. b– d Leaf blight symptoms under stereo microscope. e,f Pycnidia on alfalfa stems on WA. g Pycnidia on PDA. h Conidiophores. i,j Conidia. k 7-d-old culture on PDA. l 7-d-old culture on MEA. m 7-d-old culture on V8A. Scale bars: a = 4 cm, b = 1.5 cm, c,d = 1 cm, e-g = 300 μm, h-j = 10 μm
Species