Diaporthe aseana Dissanayake, Tangthirasunun & K.D. Hyde, sp. nov., Index Fungorum number: IF551402

Etymology: In reference to the ASEAN, the ‘Association of Southeast Asian nations’ where the fungus was collected
in Thailand, one of the member countries.

Saprobic on dead leaves. Sexual morph Undetermined. Asexual morph Conidiomata 140–200 µm diam. x 220–300 µm high (x = 185 x 260 µm, n = 10), associated with necrotic leaf tissue; pycnidial, globose, unilocular, black, erumpent, ostiolate, walls comprising 5–6 layers of dark brown cells of textura angularis. Conidiophores 8–15 x 2–3 µm, hyaline, smooth, densely aggregated, cylindrical, straight to sinuous. Conidiogenous cells 6–10 x 2–3 µm, phialidic, cylindrical, terminal and lateral, slightly tapering towards the apex. Paraphyses not observed. Alpha conidia 6–9 x 2–3 µm, aseptate, hyaline, smooth, guttulate, fusoid to ellipsoid, tapering towards both ends, straight, apex subobtuse. Beta conidia not observed.

Culture characteristics: Colonies covering 9 cm Petri dish after 2 weeks in the dark at 28 ºC. On PDA surface with fluffy white aerial mycelium with patches of saffron, in reverse patches of luteous to olivaceous-grey.

Material examined: THAILAND, Phayao, Jam Pa Thong Waterfall, on dead leaf, 12 March 2012, N. Tangthirasunun (MFLU 13-0256, holotype); ex-type living cultures MFLUCC 12-0299a, KUMCC 15-0112.

Notes: Diaporthe aseana did not produce a sexual morph in culture or on the host. Multi-gene phylogenies reveal a close relationship of D. aseana to D. hongkongensis, D. lithocarpus, D. eucalyptorum, but support our new taxa as not being conspecific. Our phylogenetic analyses position D. aseana basal to the above species. Based on a Blast search of NCBI’s GenBank nucleotide database, the closest matches for the ITS sequence of D. aseana are an undescribed endophytic Diaporthe sp. InaCC F-238 from Cinchona calisaya, Indonesia (AB899784; Identities = 544/549 (99 %), Gaps = 2/549 (0 %), and an endophytic Diaporthe sp. M23-2 from Abies beshanzuensis from Zhejiang Province, China (HM595506; Identities = 538/549 (98 %)).

Fig. Diaporthe aseana (MFLU 13-0256, holotype). a Specimen on dead leaf. b Conidiomata on the host surface. c Longitudinal section of a conidioma. d, e Longitudinal section of a conidioma wall. f, g Conidiogenous cells with developing conidia. h–k Conidia. l Germinating conidium. m, n Colonies on PDA, m from above n from below. Scale bars c = 100 µm, d = 50 µm, e–l = 10 µm.