Lasiodiplodia theobromae (Pat.) Griffon & Maubl., Bull. Soc. mycol. Fr. 25: 57 (1909)

MycoBank number: MB 188476; Index Fungorum number: IF 188476; Facesoffungi number: FoF 00167; Fig. 1

Holotype – Not designated. (CBS H-21411 designated as the neotype with CBS 164.96 as ex-neotype culture in Phillips et al. 2013)

Endophytic on Morinda officinalis How. Sexual morph: Undetermined. Asexual morph: Conidiomata 200–400×100–400 μm diam. (x=348×368 μm, n=10), pycnidial, semi-immersed, unilocular, solitary, scattered, globose or subglobose, dark brown. Conidiomata wall 20–50 μm wide, outer layers dark brown to black, thick-walled, inner layers thin-walled, pale brown to hyaline, comprising 2–3 layers of dark brown cells of textura angularis. Paraphyses up to 35 μm long, 2–3 μm wide, hyaline, septate, cylindrical, occasionally branched. Conidiogenous cells holoblastic, hyaline, thin-walled, smooth, cylindrical. Conidia 20–30×10–15 μm (x=24×13 μm, n=50), initially hyaline, aseptate, becoming median, 1-septate, dark brown when mature, thick-walled, ellipsoid to obovoid, base truncate or rounded, with longitudinal striations from apex to base.

Culture characteristics – Colonies growing on PDA reaching 80 mm diam. after 2 days at 25 °C in the dark, initially white, circular, raised, fluffy, dense, filamentous, becoming grey and then dark grey from the center after 4 days. Reverse initially white and turning to dark gray when old.

Material examined – China, Guangdong Province, Zhaoqing City, healthy stem of Morinda officinalis (Rubiaceae), June 2020, W. Guo, (MHZU 22-0051), living cultures (ZHKUCC 22-0085, ZHKUCC 22-0086).

Hosts and distribution – wide range of hosts and substrate in worldwide (Farr and Rossman 2023).

GenBank numbers – ITS: ON603982, ON603983, β-tubulin: OP893937, OP893935, tef1-α: OP893934, OP893936

Notes – The blast results of ITS, β-tubulin and tef1-α loci of our isolates (ZHKUCC 22-0085, ZHKUCC 22-0086) revealed Lasiodiplodia theobromae strains as the closest matches. The phylogenetic analyses of combined loci of ITS, β-tubulin and tef1-α sequences (Fig. 2) showed that our isolates clustered with the ex-type strain of L. theobromae (CBS 164.96) with ML=78% and BI=0.90 bootstrap support. Further, our collection is morphologically similar to L. theobromae (Alves et al. 2008). Based on the morphology and phylogeny, we identified our isolates as L. theobromae. Lasiodiplodia theobromae also reported as a pathogen in several hosts (Kamil et al. 2018; Huda-Shakirah et al. 2022). However, this is the first report of L. theobromae on Morinda officinalis.

Figure 1 – Lasiodiplodia theobromae (ZHKUCC 22-0085). a Surface view of colony on PDA. b Reverse view of colony on PDA. c Pycnidia on PDA. d Longitudinal section of pycnidium, e Conidiogenous cells with developing conidia. f, g Immature conidia. h Mature conidium. Scale bars: d–h=10 µm

Figure 2 – The best scoring RAxML tree for combined dataset of ITS, β-tubulin and tef1-α sequence data of Lasiodiplodia. The topology and clade stability of the combined gene analyses was compared to the single gene analyses and there was no significant difference between them. The tree is rooted to Diplodia mutila (CMW 7060). The matrix had 306 distinct alignment patterns with 13.19% undetermined characters and gaps. Estimated base frequencies were as follows; A=0.209302, C=0.309977, G=0.254177, T=0.226543; substitution rates AC=0.878409, AG=3.555855, AT=0.948385, CG=0.796113, CT=5.584748, GT=1.0; gamma distribution shape parameter α=0.132147 with a final likelihood value of − 3623.854076. Ex-type strains are in bold and newly generated sequences are in blue bold. Bootstrap support for ML equal to or greater than 50% and BI equal to or greater than 0.90 are given at the nodes

Figure 2 – (continued)