FungiOphiostomatalesOphiostomataceaeWangHuiMinLunYingYingLuQuanLiuHuiXiangDecockConyZhangXingYaoOphiostomatoid fungi associated with pines infected by Bursaphelenchusxylophilus and Monochamusalternatus in China, including three new speciesMycoKeys49201820183912710.3897/mycokeys.39.27014 Ophiostoma album MB825557 Wang & Lusp. nov.Figure 3Etymology.

The epithet reflects the white colour of the colonies.

Type.

CHINA, Zhejiang, Yuyao City, from Monochamusalternatus gallery of Pinusmassoniana infested by numerous PWN, November 2012, collected by Q Lu and YY Lun, culture ex-holotype MUCL 55189 = CFCC 52168 = CXY1622.

Description.

Sexual form: Unknown. Asexual form: Hyalorhinocladiella-like. Conidiogenous cells micronematous, (4.2–)9.5–16.5(–20.5) × (0.5–)1–2(–2.5) μm; conidia hyaline, single-celled, aseptate, clavate or fusiform obovoid with pointed bases and (occasionally) rounded apices, slightly curved at the base (4–)4.2–14.5(–18) × (0.5–)1–2(–2.3) μm.

Light micrographs of Ophiostomaalbum. a, b Growth on 2% MEA and 2% PDA, 2 weeks after inoculation c–eHyalorhinocladiella-like anamorph, conidiophores, and conidia (scale bar, 10 mm).

Culture characteristics.

Colonies on 2% MEA white, with the mycelium edge thinning radially; Hyphae are superficial on agar, sporulation weak. Colonies slowly growing, reaching 18.5 μm in diameter at 8 d at 25 °C, able to grow at 40 °C but not at 5 °C, with the optimal growth temperature of 35 °C. Growth characteristics on PDA culture medium are similar but the growth rate is slower than on MEA.

Habitat and distribution.

Galleries of Monochamusalternatus in Pinusmassoniana, infested by PWN, in Zhejiang Province, China.

Additional specimens examined.

CHINA, Zhejiang, Yuyao City, from Monochamusalternatus galleries of Pinusmassoniana infested by numerous PWN, November 2012, collected by Q Lu and YY Lun, MUCL 55190 = CFCC 52169 = CXY1642, CXY1643 = CFCC 52170.

Note.

Ophiostomaalbum only known in its asexual hyalorhinocladiella-like form. According to both ITS and tub2 based phylogenetic analysis, it is closely related to O.kryptum and O.olgensis in the O.minus complex (Figure 1). Ophiostomaalbum is easily distinguished from O.olgensis and O.kryptum based on their reproduction structure. Ophiostomaalbum only produces a hyalorhinocladiella-like asexual form in vitro, whereas the two other species produce both a sexual and asexual forms in vitro (Jacobs and Kirisits 2003, Wang et al. 2016). The conidial size and shape of the three species are obviously different. Ophiostomaalbum produces clavate or fusiform to obovoid and sometimes, slightly curved conidia; these are obovoid with pointed bases in both O.olgensis and O.kryptum. Furthermore, the conidia of O.album are much larger, 4.2–14.5 × 1.0–1.9 μm vs. 1.5–7 × 1.5–5 μm in the two other species.

Phylograms of fungal associates of pine infected by PWN and Monochamusalternatus in China. The phylograms were generated after MP analysis of the ITS1–5.8S–ITS2 rDNA and partial tub2 sequences. Novel sequences obtained in the current study are indicated in bold type. MP bootstrap values (10,000 replicates) and ML bootstrap support values (1000 replicates) (normal type) above 70% are indicated at the nodes. Values below 70% are indicated by asterisk (*). Posterior probabilities (above 90%) obtained from BI are indicated by bold lines at the relevant branching points. Scale bar, total nucleotide differences between taxa; ML, maximum likelihood; MP, maximum parsimony; BI, Bayesian inference.

JacobsKKirisitsT (2003) Ophiostomakryptum sp. nov. from Larixdecidua and Piceaabies in Europe, similar to O.minus.Mycological Research107(10): 1231–1242. https://doi.org/10.1017/S0953756203008402WangHMLuQMengXJLiuXWDecockCZhangXY (2016) Ophiostomaolgensis, a new species associated with Larix spp. and Ipssubelongatus in northern China.Phytotaxa282(4): 282–290. https://doi.org/10.11646/phytotaxa.282.4.5