Pseudodictyosporium yunnanensis M.Y. Han & Tibpromma, 2025

Han, Meiyan, Karunarathna, Samantha C., Lu, Li, Zheng, Dege, Dai, Dongqin, Suwannarach, Nakarin, Kumla, Jaturong, Elgorban, Abdallah M., Zhang, Lijuan, Chukeatirote, Ekachai & Tibpromma, Saowaluck, 2025, Pseudodictyosporium yunnanensis sp. nov. (Dictyosporiaceae, Pleosporales) from dead twigs of Coffea arabica in China, Phytotaxa 711 (1), pp. 28-42 : 33-35

Pseudodictyosporium yunnanensis M.Y. Han & Tibpromma , sp. nov. Fig. 2

Index Fungorum number: IF903903, Facesoffungi number: FoF 17940

Etymology:— The name reflects the type location, “ Yunnan ” Province, China. Holotype: GMB-W1496

Saprobic on dead twigs of Coffea arabica . Sexual morph: Undetermined. Asexual morph: Hyphomycetous. Conidiomata on natural substratum sporodochia, superficial, compact, punctiform to effuse, scattered or in small groups, with base attached on surface of host plant, dark brown to black. Mycelium immersed, composed of septate, branched, subhyaline to pale brown, smooth-walled hyphae. Conidiophores 21–55 × 4.7–9.4 μm (x̄ = 34.4 × 6.8 μm, n = 30), micronematous, septate, often constricted at septa, simple, hyaline to pale brown, cylindrical or swollen to 4–10.4 μm wide, somewhat moniliform, verrucose or smooth. Conidiogenous cells 6.8–10.4 × 6.9–7.2 μm (x̄ = 8.5 × 6.5 μm, n = 30), integrated, holoblastic, polyblastic, doliiform, cylindrical or inflated, terminal or intercalary, determinate. Conidia 20.2–27.3 × 13.1–19.8 μm (x̄ = 23.5 × 15.2 μm, n = 30), dictyosporous, acrogenous and pleurogenic, solitary, dry, most cheiroid, some oblong with obtuse ends or oval, pale brown or brown, smooth-walled, multi-septate, consisting of a truncate basal cell on which three rows of cells arise parallelly and compactly with (2-) 3 rows in different planes, appendages absent.

Culture characteristics:— Conidia germinated on PDA medium within 24 h. Germ tubes produced from ends. Colonies on PDA reaching 15 mm diam. after one week at 25 °C in natural light. Mycelium superficial, with regular margins, white from above, orange-yellow in the center, and brown in the middle zone from below, paler toward the margins.

Material examined:— China, Yunnan Province, Pu'er City, Simao District (101°2'44'' E, 22°31'18'' N, 856.89 m), a dead twig of Coffea arabica , 1 August 2024, Meiyan Han, BG90 (GMB-W1496, holotype), ex-type GMBCC 2237, other living culture GMBCC 2238.

GenBank numbers:— ITS: PV618259, LSU: PV618339, SSU: PV620840, tef 1-α: PV631995 (GMBCC 2237, ex-type); ITS: PV618260, LSU: PV618340, SSU: PV620841, tef 1-α: PV631996 (GMBCC 2238).

Notes:— In the phylogenetic analyses, Pseudodictyosporium yunnanensis formed a distinct lineage within Pseudodictyosporium with statistical support (100 ML/1.00 BYPP, Fig. 1 ). In the NCBI blast results of sequences, ITS was 96.24% similar to P. elegans (NR_137148), LSU was 99.52% similar to P. wauense ( MH875472 ), and tef 1- α was similar to P. thailandica ( KX259526 , 97.16%), while SSU had a high overlap of 96.37% with Dictyosporium tetrasporum ( AB797229 ). Morphologically, our strain P. yunnanensis exhibits the typical characteristics of the genus, including conidia that consist of a truncate basal cell from which three rows of cells arise parallelly and compactly, with all three rows in different planes and the majority of the conidia are cheiroid in shape ( Boonmee et al. 2016, Li et al. 2017). However, it can be distinguished from other species by differences in conidial size and color, as well as the size and morphology of conidiophores and conidiogenous cells ( Kirschner et al. 2013, Boonmee et al. 2016, Hyde et al. 2016, Li et al. 2017). Furthermore, our new species exhibits distinctly swollen conidiophores and conidiogenous cells, with some nodes being transparent and others having wart-like protrusions or containing oil droplets within the enlarged portions ( Fig. 2 ). And our new species shows multiple sites on the enlarged portions of the conidiogenous cells serve as points of conidial production, resulting in the formation of conidial chains or clusters ( Fig. 2 , Table 2). Therefore, based on morphological characteristics and multi-gene phylogenetic analysis, Pseudodictyosporium yunnanensis is introduced as a new species.

Figures

FIGURE 1. RAxML tree based on a combined dataset of ITS, LSU, SSU, and tef1-α gene sequences. Bootstrap support values for ML equal to or greater than 60% and BYPP equal to or greater than 0.90 are given above the nodes. Newly generated sequences are in red, and type strains are in bold.

FIGURE 2. Pseudodictyosporium yunnanensis (GMB-W1496, holotype). a, b Sporodochia on natural substrate. c Section of sporodochium. d–f Conidiophores with conidiogenous cells and conidia. g–k Conidia. l Germinating conidium. m, n Colonies on PDA from above and reverse. Scale bars: c = 50 µm, d–g, l = 20 µm, h–k = 10 µm.