Cytospora xylocarpi Norphanphoun, T.C. Wen & K.D. Hyde

Norphanphoun, Chada, Raspe, Olivier, Jeewon, Rajesh, Wen, Ting-Chi & Hyde, Kevin D., 2018, Morphological and phylogenetic characterisation of novel Cytospora species associated with mangroves, MycoKeys 38, pp. 93-120 : 93

Cytospora xylocarpi Norphanphoun, T.C. Wen & K.D. Hyde sp. nov. Figure 5

Etymology.

refers to the host genus that fungus was collected.

Holotype.

MFLU 17-0708

Associated with Xylocarpus granatum branches. Sexual morph: Stromata immersed in bark. Ascostromata 230-600 × 90-250 µm diameter, semi-immersed in host tissue, scattered, erumpent, multi-loculate, with ostiolar neck. Ostiole 160-200 µm diameter, numerous, dark brown to black, at the same level as the disc, occasionally area surrounded with white hyphae. Peridium comprising several layers of cells of textura angularis, with innermost layer thick, pale brown, outer layer dark brown to black. Hamathecium comprising long cylindrical, cellular, anastomosed paraphyses. Asci (22 –)24– 28.8 × 3.6 –4.8(– 5.1) μm (x‒ = 26 × 4 μm, n = 15), 6-8-spored, unitunicate, clavate to elongate obovoid, with a refractive, J-, apical ring. Ascospores (5.5 –)6– 6.5 × 1.7 –1.8(– 2) μm (x‒ = 5.7 × 1.8 μm, n = 20), biseriate, elongate-allantoid, unicellular hyaline, smooth-walled. Asexual morph: Conidiomata 700-1200 × 400-480 µm diameter, semi-immersed in host tissue, solitary, erumpent, scattered, multi-loculate, with ostiole. Ostioles 200-250 µm long, with 1-2 ostiolar necks. Peridium comprising several layers of cells of textura angularis, with innermost layer brown, outer layer dark brown to black. Conidiophores unbranched or occasionally branched at the bases, formed from the innermost layer of pycnidial wall, with conidiogenous cells. Conidiogenous cells (6.3 –)7.9– 10 × 0.9 –1.4(– 1.6) μm (x‒ = 8.5 × 1.4 μm, n = 15), blastic, enteroblastic, flask-shaped, phialidic, hyaline and smooth-walled. Conidia (2.4 –)3– 3.1 × 0.8 –1(– 1.2) µm (x‒ = 3 × 1 µm, n = 30), unicellular, subcylindrical, hyaline, smooth-walled.

Material examined.

THAILAND, Ranong Province, Ngao Mangrove Forest, on branches of Xylocarpus granatum , 6 December 2016, Norphanphoun Chada NG09b (MFLU 17-0708, holotype; PDD); ex-type-living cultures, MFLUCC 17-0251, ICMP.

Notes.

The asexual morph of C. xylocarpi , studied here, is most similar to C. rhizophorae from dead roots of Rhizophora mangle L. in Guatemala, in having multi-loculate conidiomata and allantoid, slightly curved, hyaline and 3-6 × 1.1-1.5 μm conidia ( Kohlmeyer and Kohlmeyer 1971). However, the phylogenies, generated herein, show that C. xylocarpi is distinct from C. rhizophorae (ATCC 38475), a strain from Rhizophora mangle that was identified by Kohlmeyer, the author of the species (Fig. 2). The two species also differ by 25 substitutions in ITS1+ITS2 and were collected from different hosts. Therefore, the collection in the present study is designated as a new species.

Our phylogeny also indicates a close relationship to unpublished sequences from GenBank (Figs 1, 2). Given that no morphological descriptions are available for these, the similarity in the ITS1 and ITS2 sequence between our strain and the sequences from GenBank (HAB16R13, M225, A761, MUCC302) are presented in Table 3. Those strains were collected from different hosts (Table 3) and, together with our strain, show substantial variation in ITS1 and ITS2 (Table 4). More collections are needed to further study morphological and genetic variation in this group.