Cytospora hippophaopsis R. Ma & G. F. Cai, 2024

Cai, Guifang, Zhao, Ying, Zhai, Yawei, Yan, Meilin, Ma, Rong & Zhang, Daoyuan, 2024, Two new species of Cytospora (Diaporthales, Cytosporaceae) causing canker disease of Malus domestica and M. sieversii in Xinjiang, China, MycoKeys 109, pp. 305-318 : 305-318

Cytospora hippophaopsis R. Ma & G. F. Cai sp. nov.

Fig. 3

Etymology.

Referring to its morphological similarity to C. hippophaës .

Descriptions.

Ascostromata erumpent through the surface of bark. Disc black and circular with 6–16 ostioles per disc, ostiole black and circular, 54.5–103 µm (av. = 78.8 µm, n = 30) diam. Perithecium globular, 180.5–395 µm (av. = 285.1 µm, n = 30) diam. Asci clavate to elongate obovoid, 59.5–87 × 8–12.5 µm (av. = 73.6 × 9.9 µm, n = 30), eight-spored. Ascospores biseriate, elongate-allantoid, hyaline thin-walled and smooth-walled, 13–22.5 × 3.5–5.5 µm (av. = 18.4 × 4.4 µm, n = 50).

Cultural characteristics.

Colonies on PDA initially white, covering the petri dish in 7 d, becoming brown after 14 d. Ascomata formed after 16 d, white at the early stage, becoming black later.

Material examined.

China • Xinjiang Uygur Autonomous, Ili Autonomous Prefecture, Gongliu County, KurdinNing, Xiaomohe , 43°11'44.15"N, 82°43'41.66"E, 1288 m asl, on dead and dying branches of Malus sieversii, Rong Ma , 4 Aug 2016, holotype XJAU- 1378 , living cultures XJAU 1378 = CGMCC 3.18997 ( ITS: PP 965505, act: PP 957863, rpb 2: PP 957870, tef 1: PP 957877, tub 2: PP 957884) ; ibid. XJAU 1379 ( ITS: PP 965506, act: PP 957864, rpb 2: PP 957871, tef 1: PP 957878, tub 2: PP 957885) .

Notes.

Two isolates ( XJAU 1378 and XJAU 1379) from the present study formed a distinct clade in the genus Cytospora (Fig. 2 ), which represents a new species named C. hippophaopsis . Cytospora hippophaopsis is morphologically similar to C. hippophaës from Hippophaë rhamnoides but differs in larger asci (59.5–87 × 8–12.5 µm vs. 38.6–44 × 5.9–7.8 µm) and ascospores (13–22.5 × 3.5–5.5 µm vs. 11.8–15 × 3–4.1 µm) ( Fan et al. 2015).

Figures

Figure 2. Phylogenetic tree of Cytospora of ML analysis on basis of combined ITS, act, rpb 2, tef 1 and tub 2 loci. Numbers above the branches indicate ML bootstraps (left, ML BS ≥ 50 %). The tree is rooted with Diaporthe vaccinii (CBS 160.32). New species from the present study are marked in blue.

Figure 3. Morphology of Cytospora hippophaopsis (XJAU 1378) A, B habitat of ascostromata on the host bark C transverse section of the ascostromata D longitudinal section through the ascostromata E – G asci and ascospores. Scale bars: 300 µm (B – D); 10 µm (E – G).