Diaporthe betulicola C.M. Tian & Z. Du, 2016

Du, Zhuo, Fan, Xin-Lei, Hyde, Kevin D., Yang, Qin, Liang, Ying-Mei & Tian, Cheng-Ming, 2016, Phylogeny and morphology reveal two new species of Diaporthe from Betula spp. in China, Phytotaxa 269 (2), pp. 90-102 : 96-98

Diaporthe betulicola C.M. Tian & Z. Du , sp. nov. FIGURE 3

Fungal Names FN 570262; Facesoffungi FoF02173

Holotype:— BJFC-S1333 .

Etymology:— betulicola , referring to Betula albosinensis , the known host for this species.

Host/Distribution:—Pathogen on twigs and branches of Betula albosinensis in China.

Original description:—Sexual morph: undetermined.Asexual morph: Conidiomatal pycnidial, conical, immersed, scattered, with a single locule. Ectostromatic disc brown to black, one ostiole per disc. Ostiole medium black, up to the level of disc, (110–)130–220(–240) μm (av. = 180 μm, n = 20) diam. Locule undivided, (680–)700–1300(–1350) μm (av. = 960 μm, n = 20) diam. Conidiophores reduced to conidiogenous cells. Conidiogenous cells hyaline, cylindrical, filiform, straight to curved. Alpha conidia hyaline, oblong, and acute at two sides, aseptate, smooth, not biguttulate, 10–14.5(–15) × 1.5–2.5 μm (av. = 12 × 2 μm, n = 50). Beta conidia hyaline, filiform, straight or curved, eguttulate, aseptate, apex acutely rounded, tapering from lower fourth towards base, 17–24 × 0.5–1(–1.5) μm (av. = 20 × 1 μm, n = 50).

Cultures:—Colony originally compact and flat with white felty aerial mycelium, then developing white to light brown aerial mycelium, zonate with 3–5 well defined zones 0.5–1 cm wide with a regular smooth edge; conidiomata distributed in circularity over agar surface.

Material examined:— CHINA, Shaanxi Province: Ankang City, Ningshan County, Huoditang, 33°26’24.15”N, 108°26’46.30”E, 1625 m asl, on twigs and branches of Betula albosinensis , coll. Qin Yang, 3 April 2015 ( BJFC-S 1333, holotype), ex-type culture, CFCC 51128. Shaanxi Province: Baoji City, Feng County, Tangzang Town, Tongtian River Forest Park, 34°16’26.21”N, 106°31’39.58”E, 2127 m asl, on twigs and branches of Betula albosinensis , coll. Qin Yang, 31 July 2015 ( BJFC-S 1334, paratype) living culture, CFCC 51129.

Notes:—This new species is distinguished from other Diaporthe species by its distinctive hyaline, oblong alpha conidia which are acute at both ends and lack guttules. It also has larger (10–14.5 × 1.5–2.5 μm) conidia, as compared to many other Diaporthe species. The most closely related species in the phylogram are D. woolworthii (Peck) Sacc. from Ulmus americana and Diaporthe rostrata C.M. Tian, X.L. Fan & K.D. Hyde from Juglans mandshurica . Diaporthe woolworthii was introduced from Quercus from America ( Saccardo 1882), but there are no illustrations, detailed descriptions or loanable specimens, and thus the species needs to be epitypified or provided with a reference specimen from the same country and host (sensu Ariyawansa et al. 2014). Gomes et al. (2013) provided DNA data for this species using a putatively named strain, CBS 148.27, from Ulmus (a different host) in America. Two strains of D. betulina clustered in distinct clade in combined sequence analysis with high support ( MP / ML / BI = 100/100/1, Fig. 1 ), and differs from the strain of D. woolworthii ( Gomes et al. 2013) . The new taxon also can be distinguished from D. rostrata , which has central perithecial necks, with a black conceptacle and shorter ellipsoidal alpha conidia (8.5–11.5 × 4–5 μm) ( Fan et al. 2015).

Figures

FIGURE 1. Phylogram of Diaporthe based on combined ITS, CAL, HIS, TEF1-α and TUB2. MP and ML bootstrap support values above 75 % are shown at the first and second position. Thickened branches represent posterior probabilities above 0.95 from BI. Scale bar = 200 nucleotide substitutions. Ex-type strains are in bold. Strains in current study are in blue.

FIGURE 3. Morphology of Diaporthe betulicola from Betula albosinensis (BJFC-S1333). A, B: Habit of conidiomata on twig. C: Transverse sections through conidiomata. D: Longitudinal sections through conidiomata. E: Conidiophores and conidia. F: Alpha conidia. G: Beta conidia. H: Colonies on PDA at 3 days (left) and 30 days (right). Scale bars: B–D = 500 μm; E–G = 10 μm.