Diaporthe sennae C.M. Tian & Q. Yang, 2017

Yang, Qin, Fan, Xin-Lei, Du, Zhuo & Tian, Cheng-Ming, 2017, Diaporthe species occurring on Senna bicapsularis in southern China, with descriptions of two new species, Phytotaxa 302 (2), pp. 145-155 : 149-150

Diaporthe sennae C.M. Tian & Q. Yang , sp. nov. FIGURE 2 .

MycoBank no: MB 820452

Holotype:— BJFC-S1370 .

Etymology:— sennae , named after the genus of the host, Senna .

Host/Distribution:—from Senna bicapsularis in southern China.

Original description:—Sexual morph: undetermined. Asexual morph: Conidiomata pycnidial, circular to ovoid, immersed, scattered, erumpent through the bark surface, with a single locule. Ectostromatic disc brown to dark, one ostiole per disc. Locule undivided, (400–)500–600(−680) μm (av. = 570 μm, n = 20) in diam. Conidiophores reduced to conidiogenous cells. Conidiogenous cells hyaline, phialides, straight or slightly curved. Alpha conidia hyaline, aseptate, smooth, ellipsoidal to oval, usually one guttulate at each end, rarely 3 small guttulate, (5.0–)5.5–6.3(−6.5) × 1.5–1.7(−1.8) μm (av. = 6.0 × 1.6 μm, n = 50). Beta conidia present on the host, aseptate, hyaline, smooth, straight to hamate, (17.3–)18.4–20.0(−23.3) × 0.9 μm (av. = 19.1 × 0.9 μm, n = 50).

Culture characters:—Cultuers incubated on PDA at 25° C in darkness, colony originally flat with white felty aerial mycelium, becoming pale brown mycelium due to pigment formation, conidiomata absent.

Material examined:— CHINA, Guangxi Province: Nanning city, 21°47’32.36”N, 118°23’19.37”E, 216 m asl, on twigs and branches of Senna bicapsularis, Q. Yang , 7 November 2015 ( BJFC-S 1370, holotype; ex-type culture, CFCC 51636). Guangxi Province: Nanning city, 21°47’32.36”N, 118°23’19.37”E, 216 m asl, on twigs and branches of Senna bicapsularis, Q. Yang , 7 November 2015 ( BJFC-S 1371, paratype; living culture, CFCC 51637).

Notes:—Two isolates of D. sennae cluster in a well-supported clade ( MP / ML / BI =100/100/1) and appeared closely related to D. pascoei R.G. Shivas, J. Edwards & Y.P. Tan from Persea americana ( Fig. 1 ). However, the new taxon can be distinguished from D. pascoei in longer alpha conidia and shorter beta conidia (alpha conidia: 5.5–6.3 μm in D. sennae vs. 4–5 μm in D. pascoei ; beta conidia: 18.4–20.0 μm in D. sennae vs. 19–31 μm in D. pascoei ) ( Tan et al. 2013). This is the first time to discover from infected branches or twigs on Senna bicapsularis and demonstrate it as a new species based on phylogeny and morphology.

Figures

FIGURE 1. Phylogram of Diaporthe based on combined ITS, CAL, HIS, TEF1-α and TUB. MP and ML bootstrap support values above 50 % are shown at the first and second position. Thickened branches represent posterior probabilities above 0.90 from BI. Scale bar = 90 nucleotide substitutions. Ex-type strains are in bold. Strains in current study are in blue.

FIGURE 2. Morphology of Diaporthe sennae from Senna bicapsularis (BJFC-S1370).A, B: Habit of conidiomata on twig. C: Transverse sections through conidiomata. D: Longitudinal sections through conidiomata. E: Alpha and beta Conidia. F: Beta conidia. G: Colonies on PDA at 3 days (left) and 30 days (right). Scale bars: C–D = 200 μm; E–G = 5 μm.