Diaporthe litsease Y. R. Sun, Yong Wang bis & K. D. Hyde

Li, Xinyue, Xu, Xiulan, Xiang, Shasha, Liu, Feng, Wang, Feihu, Jiang, Xuejing, Liu, Yinggao & Yang, Chunlin, 2025, Morpho-phylogenetic evidence reveals two new species and two new host records of Diaporthe (Diaporthales, Diaporthaceae) from Phellodendron chinense in Sichuan, China, MycoKeys 123, pp. 205-233 : 205-233

Diaporthe litsease Y. R. Sun, Yong Wang bis & K. D. Hyde , Phytotaxa 665 (3): 248 (2024)

Fig. 5

Description.

Saprobic on decaying branch of Phellodendron chinense . Sexual morph: Not observed. Asexual morph: Coelomycetous. Conidiomata 298–341 × 207–257 μm (x ̄ = 316 × 228 μm, n = 10), solitary, scattered, dark brown to black, discoid to elliptical, unilocular. Conidiomatal wall 13–48 μm wide, parenchymatous consisting of multi-layers of brown, thick-walled cells of textura angularis or textura globulosa. Conidiophores hyaline, smooth, straight to flexural, basally branched or unbranched. Conidiogenous cells 12–23 × 1.7–2.8 μm (x ̄ = 16 × 2.3 μm, n = 20) for producing alpha-conidia, 11–15 × 1.2–2.5 μm (x ̄ = 12.6 × 1.7 μm, n = 20) for producing beta-conidia, terminal, enteroblastic, monophialidic, cylindrical, slightly tapering towards the apex. Alpha-conidia 6–10 × 2.3–3.3 μm (x ̄ = 8.4 × 2.7 μm, n = 50), hyaline, aseptate, ellipsoid to fusiform, smooth-walled, containing 1–5 guttules, base subtruncate. Beta-conidia 27–36 × 1.1–1.8 μm (x ̄ = 32 × 1.4 μm, n = 50), hyaline, aseptate, filiform, curved, tapering towards both ends. Gamma-conidia not observed.

Culture characteristics.

Alpha-conidia germinated in sterile water within 24 h at 25 ° C. Colonies on PDA reached 55–60 mm in diameter after 7 d at 25 ° C. Colony circular to slightly lobate, distinctly zonate, with a darker olivaceous-brown central disc surrounded by a thick pale buff to grey-green annulus of floccose tufts and an outer olivaceous ring. Surface uneven, numerous punctiform pycnidia, densest in the central disc. Aerial mycelium dense and cottony-floccose, forming small fasciculate tufts, margin entire to slightly lobate, with a thin band of submerged hyaline mycelium at the extreme edge. Reverse blackish to dark brown in the centre, becoming olivaceous-brown and then light brown towards the margin, with a conspicuous diffusing olivaceous-brown pigment in the PDA. Sporulation observed after approximately 20 d in culture, producing abundant alpha-conidia.

Material examined.

• China, Sichuan Province, Leshan City, Jinkouhe County, Jixing Village , 29°16'58.10"N, 103°13'7.42"E, 1599 m elev., from branches of Phellodendron chinense , 1 May 2024, X. Y. Li, LXY 202405031 A ( SICAU 25-0161 ), culture ( SICAUCC 25-0133 ) ; ibid., LXY 202405031 B ( SICAU 25-0162 ), culture ( SICAUCC 25-0134 ) .

Notes.

Diaporthe litseae was described as an endophyte on healthy leaves of Litsea kobuskiana from Guizhou Province, China ( Sun et al. 2024). In our phylogenetic analysis, two isolates obtained from branches of Phellodendron chinense grouped within the D. litseae clade with strong statistical support (100 % MLBS / 1.00 BYPP; Fig. 1 ). Morphologically, the new isolates exhibit characteristics consistent with D. litseae , particularly in having ellipsoid to fusiform, multiguttulate alpha conidia (6–10 × 2.3–3.3 μm vs. 5–9 × 2–3.5 μm). Pairwise sequence comparisons between our representative strain SICAUCC 25-0133 and the ex-type strain of D. litseae ( GUCC 23-0055 ) revealed high similarity, viz. 99.61 % in ITS (508 / 510 bp, 1 gap), 97.98 % in tef 1 - α (291 / 297 bp, 0 gap), 100 % in his 3 (422 / 422 bp, 0 gap) and 99.33 % in cal (446 / 449 bp, 0 gap). Therefore, we identify the new collections as D. litseae , marking the first record on P. chinense as saprobe in Sichuan, China.

Figures

Figure 1. Maximum Likelihood phylogenetic tree, based on concatenated sequences of the ITS, tef 1 - α, tub 2, cal and his 3 gene regions from Diaporthe species. Bootstrap support values ≥ 60 % (left) and Bayesian posterior probabilities ≥ 0.90 (right) are shown at the nodes. Isolates from the present study are indicated in bold. Ex-type or ex-epitype strains are marked with “ T ”.

Figure 5. Diaporthe litsease (SICAU 25-0161). a. Habitat of Phellodendron chinense; b, c. Conidiomata on host surface; d. Section through a conidioma; e. Conidiomatal wall; f – i. Conidiogenous cells bearing conidia; j. Alpha-conidia; k. Beta-conidia; l. Germinating alpha-conidium; m. Colony on PDA (left: above, right: reverse). Scale bars: 500 μm (c), 50 μm (d, e), 10 μm (f – l).