Diaporthe forlicesenica Bundhun, Camporesi & K.D. Hyde, 2021

Bundhun, Digvijayini, Senanayake, Indunil C., Jayawardena, Ruvishika S., Camporesi, Erio, Huang, Yinghua, Dong, Zhangyong, Hyde, Kevin D., Anun, Chaiwat To- & Cheewangkoon, Ratchadawan, 2021, First reports of the sexual morphs of Diaporthe forlicesenica nom. nov. and Diaporthe goulteri (Diaporthaceae, Diaporthales) revealed by molecular phylogenetics, Phytotaxa 516 (1), pp. 1-27 : 5-7

Diaporthe forlicesenica Bundhun, Camporesi & K.D. Hyde , nom. nov. FIGURES 2 & 3

Basionym: Diaporthe dorycnii Dissan., Camporesi & K.D. Hyde , in Dissanayake, Camporesi, Hyde, Zhang, Yan & Li, Mycosphere 8(5): 867 (2017)

Index Fungorum number: IF558167, Facesoffungi number: FoF 03272

Etymology:— The specific epithet forlicesenica refers to Forlì-Cesena Province, where the fungus was collected.

Saprobic on dead aerial branches. Sexual morph: Ascomata 610–650 μm high, 215–370 μm diam. (x̅ = 630 × 310 μm, n = 15), perithecial, black, globose to subglobose, scattered, gregarious, embedded in bark epidermis, with short black cylindrical necks protruding through host surface, ostiolate. Neck 280–370 μm high, 70–170 μm diam. (x̅ = 305 × 133 μm, n = 15). Ostiole comprising hyaline periphyses. Peridium 2-layered; outer layer 10–20 μm wide, dense, composed of dark brown thick-walled cells of textura angularis, inner layer 5–10 μm wide, comprising thin-walled, light brown to hyaline cells of textura angularis. Paraphyses ca. 5 μm wide, hyaline, septate, constricted at the septa, guttulate, thin-walled. Asci 50–70 × 5–15 μm (x̅ = 57.5 × 9.7 μm, n = 30), unitunicate, 8-spored, sessile, cylindrical to elongate, apically truncate to rounded, with a non-amyloid refractive apical ring, straight or slightly curved. Ascospores 13–19 × 2–4 μm (x̅ = 15.7 × 3 μm, n = 30), uni- to bi-seriate, at times tri-seriate, hyaline, 1-septate, regularly tetra-guttulate, with the two larger guttules in the middle and smaller ones at the ends, oblong or cylindrical to broadly fusiform, slightly constricted at the septum, straight to slightly curved, with rounded to obtuse ends, smooth-walled, without appendage or sheath. Asexual morph: Coelomycetous. Conidiomata up to 900 μm high and 1.0 mm in diam. on PDA, superficial, pycnidial to multilocular, solitary or aggregated, scattered, globose to irregular, dark brown to black. Conidiophores 10–30 × 1–3 μm (x̅ = 19 × 1.8 μm, n = 20), cylindrical, aseptate, rarely 1-septate, straight or sinuous, terminal, slightly tapered towards the apex. Conidiogenous cells 3–15 × 1–2 μm (x̅ = 6 × 1.6 μm, n = 20) hyaline, subcylindrical, filiform, tapering towards the apex. Alpha conidia 5–9 × 1–3 μm (x̅ = 7.4 × 2.4 μm, n = 30) hyaline, often guttulate at maturity, fusiform or oval, both ends obtuse. Beta conidia not observed.

Culture characteristics:—Colonies on PDA, reaching 40 mm diam. after 1 week at 25 °C, initially white to light brown, becoming dark brown with age on surface, reverse dark brown, smooth surface, entire margin. Sporulation occurred on PDA after almost 45 days incubation period at 25 °C, in dark.

Material examined:— ITALY, Forlì-Cesena, Castagnolo, Civitella di Romagna, on dead aerial branches of Cytisus sp. (Fabaceae) , 17 December 2018, E. Camporesi, IT 4156 (MFLU 19-0348), living culture MFLUCC 21-0011.

Notes:— Diaporthe dorycnii was, upon its introduction, mistakenly given the name of an already existing epithet in Diaporthe ( Dissanayake et al. 2017b) . It was therefore, invalidly published. One of our isolate MFLUCC 21-0011 is clustered with “ D. dorycnii ” MFLUCC 17-1015 with high statistical support (100% ML, 1.00 BYPP) (FIGURE 1). Base pair (bp) comparison between ITS sequence data revealed 1 out of 472 (0.2%) difference in nucleotides while 11 out of 302 (3.6%) and 6 out of 376 (1.6%) bp differences in tef1 and tub2. Base pair differences in the latter two gene regions arose mainly from the dissimilar bases at the start of each sequence. We refrain from counting them as reliable differences since they are most probably the result of sequencing errors. According to the guidelines of Jeewon & Hyde (2016), the genetic variations mentioned above are therefore insignificant to delineate the two isolates as different species. Therefore, they are considered as one and we propose the new name D. forlicesenica to replace D. dorycnii Dissan., Camporesi & K.D. Hyde.

FIGURE. Sexual morph of Diaporthe forlicesenica (MFLU 9-0 8). a Specimen. b Ascomata on host substrate. c Close-up of ascomata on host substrate. d Vertical section through ascomata (in KOH) e Section through the neck (in KOH). f Vertical section of peridium. g Paraphyses. h–j Asci (j in Congo red). k Apical apparatus showing non-amyloid reaction in Melzer’s reagent. l–o Hyaline ascospores, slightly constricted at the septum. Scale bars: b,c = 100 μm, d = 200 μm, e = 50 μm, f, l–o = 10 μm, g, k = 5 μm, h–j = 20 μm.

FIGURE. Asexual morph of Diaporthe forlicesenica (MFLUCC -00). a Upper view of 45 days old colony on PDA. b Reverse view of 45 days old colony on PDA. c Conidiomata in culture. d,e Conidiophores with alpha conidia . f–i Alpha conidia . Scale bars: d = 10 μm, e,g,i = 5 μm, f,h = 3 μm.

The strain MFLUCC 17-1015 of D. forlicesenica was described in its asexual morph from host substrate ( Dissanayake et al. 2017b) while our strain MFLUCC 21-0011 has presently been retrieved in both its sexual (natural host) and asexual (culture on PDA) morphs. The conidiophores, conidiogenous cells and alpha conidia obtained from the culture of MFLUCC 21-0011, however, are different in size from those of D. forlicesenica MFLUCC 17-1015 (TABLE 2).

TABLE. Morphological comparison between Diaporthe forlicesenica MFLUCC 21-0011 and MFLUCC 17-1015.