Flabellascoma coffeae L. Lu & Karun., 2025

Lu, Li, Karunarathna, Samantha C., Rajeshkumar, Kunhiraman C., Elgorban, Abdallah M., Jayawardena, Ruvishika S., Hongsanan, Sinang, Suwannarach, Nakarin, Kumla, Jaturong, Xiong, Yin-Ru, Hyde, Kevin D., Han, Mei-Yan, Zheng, De-Ge, Li, Qiang, Dai, Dong-Qin & Tibpromma, Saowaluck, 2025, Unveiling fungal diversity associated with coffee trees in China using a polyphasic approach and a global review of coffee saprobic fungi, IMA Fungus 16, pp. e 144874-e 144874 : e144874-

Flabellascoma coffeae L. Lu & Karun. sp. nov.

Fig. 8

Etymology.

The species epithet “ coffeae ” refers to the host plant genus “ Coffea ” from which the fungus was isolated.

Diagnosis.

Differs from F. fusiforme D. F. Bao, Z. L. Luo, K. D. Hyde & H. Y. Su , by an internal chamber at both ends of ascospores.

Holotype.

HKAS 137607 .

Description.

Saprobic on decaying branch of C. arabica . Teleomorph: Ascomata 280–450 µm high × 200–280 µm diam. (x- = 356 × 230 µm, n = 20) (including neck), solitary, rarely clustered, immersed, visible as black, crest-like ostiolar neck on the substrate, globose to subglobose, uniloculate. Ostioles central, with a pore-like opening, periphysate. Peridium 15–30 µm wide (x- = 24 µm, n = 30), composed of several layers of brown, thick-walled cells of textura angularis. Hamathecium 1.5–3 µm wide (x- = 2.2 µm, n = 30), hyphae-like, septate, branched, pseudoparaphyses. Asci 60–100 × 10–15 µm (x- = 75 × 12 µm, n = 30), 8 - spored, bitunicate, fissitunicate, cylindrical to clavate, straight, with a short furcate sessile, apically rounded with a broad ocular chamber. Ascospores 20–25 × 5–7 µm (x- = 22 × 6 µm, n = 30), overlapping biseriate, fusiform, hyaline, 1 - septate, constricted at the septum, the upper cell slightly wider than the lower cell, guttulate, smooth-walled, with a narrow bipolar sheath. Sheath drawn-out at both ends, 4–7 µm long × 2–3 µm wide (x- = 5.6 × 2.5 µm, n = 30), with an internal chamber at both ends of ascospores. Anamorph: Not observed.

Culture characteristics.

Ascospores germinating on PDA within 24 h, colonies reached 1.5–2 cm in diameter after twenty days at 25 ° C, circular, flat to umbonate, fluffy, smooth, with entire margin, from above, grey, from below, dark grey at the centre, white at the edge.

Materials examined.

China, Yunnan Province, Baoshan , on a decaying branch of Coffea arabica ( Rubiaceae ) (24°9'N, 98°8'E, 1050 m alt.), 30 July 2022, LiLu, BS 1 - C 3 ( HKAS 137607 , holotype), isotype MHZU 23-0063 , ex-type living culture KUNCC 24-18341 = KUNCC 24-18342 , ex-isotype living culture ZHKUCC 23-0636 = ZHKUCC 23-0637 ; China, Yunnan Province, Dali , on a decaying branch of C. arabica , (26°09'N, 101°91'E, 1416.46 m alt.), 25 July 2022, LiLu, DL-C 41 ( HKAS 137612 , paratype), isoparatype MHZU 23-0062 , ex-paratype living culture KUNCC 24-18343 = KUNCC 24-18344 , ex-isoparatype living culture ZHKUCC 23-0634 = ZHKUCC 23-0635 .

Notes.

The phylogenetic result, based on SSU, ITS, LSU, RPB 2 and TEF 1 - α sequence data, showed our new collection Flabellascoma coffeae is close to F. fusiforme (Fig. 9 ). Flabellascoma coffeae can be distinguished from F. fusiforme in having an internal chamber at both ends of ascospores (Fig. 8 ; Bao et al. (2019 )). Flabellascoma coffeae also fits well with the morphological characteristics of Flabellascoma , such as immersed ascomata with crest-like ostiolar neck, cylindrical-clavate asci and fusiform, hyaline, 1 - septate ascospores with a narrow bipolar sheath (Fig. 8 ; Hashimoto et al. (2018)). Based on nucleotide comparisons, F. coffeae ( ZHKUCC 23-0636 ) is different from F. fusiforme ( MFLUCC 18-1584 ) by 19 / 500 bp (3.8 %, without gaps) of the ITS, 7 / 835 bp (0.8 %, without gaps) of the LSU and 22 / 839 bp (2.7 %, without gaps) of the TEF 1 - α. In addition, the PHI test results (Fig. 22 d ) revealed no significant recombination relationships between F. coffeae and its phylogenetically related taxa. Therefore, we introduce F. coffeae as a new species from coffee in China, based on morphology and multigene phylogeny.

Figures

Figure 8. Flabellascoma coffeae (HKAS 137607, holotype). A, B ascomata on a decaying branch of C. arabica; C a longitudinal section of an ascoma; D ostioles; E peridium wall; F pseudoparaphyses; G germinated ascospore; H, I culture on PDA from the obverse and reverse; J – M asci; N – S ascospores (S: arrowheads indicate an internal chamber in ascospore). Scale bars: 100 μm (C); 20 μm (D – G, J – M); 10 μm (N – S).

Figure 9. Phylogram generated from the best scoring RAxML tree, based on a combined ITS LSU, SSU, RPB 2 and TEF 1 - α sequence dataset. Bambusicola guttulata X. D. Yu, S. N. Zhang & Jian K. Liu, (CGMCC 3.20935 and UESTCC 22.0002) are selected as the outgroup taxa. Bootstrap support values for ML equal to or greater than 70 % and PP equal to or greater than 0.90 are given above the nodes. All type strains are in bold and newly-generated sequences are in red.

Figure 22. Split graphs showing the results of the pairwise homoplasy index (PHI) test of the new taxa and closely-related taxa using LogDet transformation and splits decomposition. a Leucaenicola coffeae; b Montagnula coffeae; c Xenodidymella coffeae; d Flabellascoma coffeae; e Longiostiolum coffeae; f Helminthosporium puerensis; g Neomassaria coffeae; h Neooccultibambusa coffeae; i Pararoussoella coffeae; j Cycasicola coffeae. PHI test result P-value (Φw) ≤ 0.05 indicates that there is significant recombination between the isolates included in the alignment. The new taxa are in red, “ T ” indicate the type species and each PHI test value and scale bars are given in the bottom right corner.