Leucaenicola coffeae L. Lu & Tibpromma, 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-

Leucaenicola coffeae L. Lu & Tibpromma sp. nov.

Fig. 2

Etymology.

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

Diagnosis.

Differs from L. phraeana Jayasiri, E. B. G. Jones & K. D. Hyde , by the brown and large conidia (5–6 × 2.5–3.5 μm vs. 3–4 × 1.5–2 μm) and distinct guttules.

Holotype.

HKAS 137605 .

Description.

Saprobic on decaying branch of C. arabica . Teleomorph: Ascomata 200–350 high × 200–300 µm diam. (x- = 239 × 273 µm), solitary or scattered, immersed, raised as brown to black spots on the substrate, globose to subglobose, coriaceous, uniloculate with ostioles. Peridium 25–35 μm wide (x- = 30 μm, n = 20), thin-walled, composed of dark brown and 2–4 layers of textura angularis cells, with the basal part composed of thinner, hyaline, smaller cells. Hamathecium 1.5–3.5 µm wide (x- = 2.7 µm, n = 20), dense, comprising numerous pseudoparaphyses, filamentous, hyaline, cellular, branched, with distinct septa. Asci 40–80 × 8–15 µm (x- = 57 × 9.6 µm, n = 20), 4–8 - spored, bitunicate, fissitunicate, cylindrical, long-stalked with club-shape, apically rounded, with a shallow ocular chamber. Ascospores 15–25 × 4–8 µm (x- = 21 × 6 µm, n = 30), overlapping, uniseriate to biseriate, fusiform to ellipsoidal, straight, hyaline, mainly 1 - septate, sometimes 2–3 septate, constricted at the centre septa, conical at both ends, upper cell wider than the lower cell, guttulate, mucilaginous sheath. Anamorph on PDA: Mycelium 1.5–2.5 μm broad (x- = 2.2 μm, n = 20), hyaline, septate, branched. Conidia 5–6 × 2.5–3.5 μm (x- = 5.6 × 3.1 μm, n = 30), ellipsoidal to cylindrical, hyaline when young, brown when mature, thin and smooth-walled, aseptate, with 1–2 - guttules.

Culture characteristics.

Ascospores germinating on PDA within 24 h. Colonies reached 3.5 cm in diameter after one month at 25 ° C. Colonies circular, slightly fluffy with an entire margin, white; the reverse is white to yellowish. After four months, conidia mass formed as globose to subglobose, dark brown to black spots in culture.

Materials examined.

China • Yunnan Province, Pu’er , on a decaying branch of Coffea arabica ( Rubiaceae ) (23°43'01"N, 101°73'90"E, 1085 m alt.), 18 November 2020, LiLu, MJ-C 8 ( HKAS 137605 , holotype), isotype MHZU 23-0058 , ex-type living culture KUNCC 24-18335 = KUNCC 24-18336 , ex-isotype living culture ZHKUCC 23-0626 = ZHKUCC 23-0627 .

Notes.

Based on the multi-gene sequence analysis, Leucaenicola coffeae forms an independent lineage allied to L. phraeana (Fig. 3 ). In the NCBI BLASTn searches, the ITS, LSU, SSU and TEF 1 - α sequences are similar to L. camelliae Ariyaw., I. Tsai & Thambugala , ( MT 112301 , 98 %), ( MT 071278 , 90 %), ( MT 071229 , 99.9 %) and ( MT 374091 , 97 %), respectively, while RPB 2 is 97 % similar to L. osmanthi Ariyaw., I. Tsai & Thambugala , ( MN 915020 ). Leucaenicola coffeae is the first species with a teleomorph known in Leucaenicola . The teleomorph characteristics of L. coffeae conform to the basic concept of Bambusicolaceae . The anamorph can be distinguished from L. phraeana by the brown and large conidia (5–6 × 2.5–3.5 μm vs. 3–4 × 1.5–2 μm) and distinct guttules (Fig. 2 ; Jayasiri et al. (2019)). Based on nucleotide comparisons, L. coffeae ( ZHKUCC 23-0626 ) differs from L. phraeana ( MFLUCC 18-0472 ) by 102 / 418 bp (24 %, 3 gaps) in ITS, 80 / 844 bp (9 %, without gaps) in LSU, 2 / 1017 bp (0.2 %, without gaps) in SSU, 16 / 920 bp (1.7 %, without gaps) in TEF 1 - α and 30 / 1036 bp (2.9 %, without gaps) in RPB 2; and differs from L. osmanthi ( NTUCC 18-101-3 ) by 10 / 620 bp (1.6 %, without gaps) in ITS, 78 / 756 bp (10 %, without gaps) in LSU, 2 / 780 bp (0.2 %, without gaps) in SSU, 21 / 816 bp (2.5 %, without gaps) in TEF 1 - α and 26 / 818 bp (3 %, without gaps) in RPB 2. In addition, the PHI test results (Fig. 22 a ) revealed no significant recombination relationships between L. coffeae and its phylogenetically related taxa within the dataset. Therefore, we introduce L. coffeae as a new species in Leucaenicola with the first record of a teleomorph associated with the decaying branch of C. arabica .

Figures

Figure 2. Leucaenicola coffeae (HKAS 137605, holotype). A, B appearance of ascomata on a decaying branch of C. arabica; C, D longitudinal section of ascomata; E peridium wall; F pseudoparaphyses; G – J asci; K germinated ascospores; L – O ascospores; P ascospores stained with Indian ink; Q conidia mass in culture after four months; R conidia; S culture on PDA from obverse and reverse. Scale bars: 150 μm (C, D); 50 μm (E); 100 μm (F); 20 μm (G – K); 10 μm (L – P, R).

Figure 3. Phylogram generated from the best scoring RAxML tree, based on a combined ITS LSU, SSU, RPB 2 and TEF 1 - α sequence dataset. Sulcatispora acerina Kaz. Tanaka & K. Hiray., (KT 2982) and S. berchemiae Kaz. Tanaka & K. Hiray., (KT 1607) 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 indicated at the nodes as ML / PP. 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.