Verruconis soli Yasanthika, Tennakoon & Wanas., 2023

Erandi Yasanthika, W. A., Tennakoon, Danushka S., Gomes De Farias, Antonio R., Thilini Chethana, K. W., Bhat, D. Jayarama & Wanasinghe, Dhanushka N., 2023, Isolation and characterization of novel Dothideomycetes species from forest soils in Chiang Rai and Krabi (Thailand): additions to the diversity of Curvularia and Verruconis, Phytotaxa 609 (1), pp. 17-44 : 33

Verruconis soli Yasanthika, Tennakoon & Wanas. , sp. nov.

Index Fungorum number: IF 558479, Faces of Fungi number: FoF 12888, FIGURE 5 .

Etymology—The specific epithet “soli”, from Latin, refers to the soil, the substrate of which the holotype was collected.

Holotype — MFLU22-0257

Asexual morph: Conidiophores 20–62 × 1–3.5 µm (x = 39 × 2 μm, n = 20), micronematous, mononematous, solitary, unbranched, cylindrical to sub-cylindrical, straight to slightly flexuous, hyaline to brown, smooth. Conidiogenesis cells holoblastic, determinate, and rarely intercalary. Conidia 5–11 × 3–4.5 µm (x = 8 × 3.5 μm, n = 20), hyaline, obovoid, smooth becoming sub-cylindrical or ellipsoidal, slightly verruculose thick and sometimes pale brown, 1-septate and constricted at the septum at maturity. Sexual morph: Undetermined.

Culture characteristics:— Colonies on PDA at 25 °C after 7 days become 3.5 cm diam., irregular margined, velvety, dark brown, raised, grayish brown at center, reverse dark brown. Mycelium hyaline, become pale brown to brown at maturity, 1–3 µm (x = 1.5 µm), smooth to verruculose, septate.

Material examined:— Thailand, Chiang Rai, 20°4’35”N, 100°5’43”E, 450 m, from forest soil, 7 January 2020, W.A.E. Yasanthika ( MFLU 22-0257 , holotype) ; ex-type living culture MFLUCC 22-0082 ; ( MFLU 22-0253 , paratype) , ex-paratype living culture MFLUCC 22-0090 .

Notes— Verruconis is aggregated with thermophilic species, and several have been reported from the soil, viz., V. gallopava from thermal soils, V. verruculosa from grassland soils, and V. thailandica from soils near the waterfall ( Zhang et al. 2018, Hernández-Restrepo et al. 2020, Shen et al. 2020). Herein, we introduce V. soli from soil in Thailand with morpho-molecular justifications. Verruconis soli is phylogenetically adjacent to V. hainanensis ( YMF 1.04165), V. pseudotricladiata ( YMF 1.04915), and V. mangrovei ( NFCCI 4390, NFCCI-4389) ( FIGURE 2 ). Though V. soli has low bootstrap support in the phylogenetic tree, and pairwise comparisons of LSU and ITS sequences of closely related species ( TABLE 5 ) showed significant differences that are higher than 1% in each scenario, which is common to many species in this genus. Further, they differ ecologically from V. soli as V. hainanensis and V. pseudotricladiata have been reported from freshwater habitats ( Qiao et al. 2019) while V. mangrovei reported from marine habitats ( Hyde et al. 2020). Verruconis hainanensis , V. pseudotricladiata , and V. soli ( MFLUCC 22-0082) are mainly distinguishable by their conidiophores and conidial morphology. Verruconis hainanensis and V. pseudotricladiata have macronematous conidiophores, whereas V. soli ( MFLUCC 22-0082) has micronematous conidiophores ( Qiao et al. 2019). In addition, V. soli ( MFLUCC 22-0082) has sub-cylindrical or ellipsoidal, 1-septate mature conidia and obovoid immature conidia, while V. hainanensis has fusiform, 3-septate conidia that are rostrate at the apical cell ( Qiao et al. 2019). Verruconis pseudotricladiata has staurosporic, branched or unbranched conidia (cylindrical-clavate and 2–4-septate while branched conidia are Y-, or T-shaped) ( Qiao et al. 2019). Furthermore, the conidia of V. hainanensis and unbranched conidia in V. pseudotricladiata have a slight constriction at the median septum, but V. soli ( MFLUCC 22-0082) have a prominent constriction at the septum and septation is absent at immature stages in conidia. Verruconis mangrovei has been recorded as a sexual morph ( Hyde et al. 2020); therefore, we could not compare the morphological characteristics with our collection. The base pair differences of ITS sequences between V. mangrovei and V. soli were 31% (with gaps). Therefore, we accommodate V. soli ( MFLUCC 22-0082) isolated from forest soils in Thailand as a new species with morpho-molecular support.

Figures

FIGURE 2. Maximum likelihood phylogenetic tree based on combined SSU-ITS-LSU sequence data for Sympoventuriaceae. Bootstrap support values of maximum likelihood greater than 60% and Bayesian posterior probabilities (BYPP) greater than 0.95 are indicated above the nodes. Newly added strains are in blue and ex-type strains are in bold. The tree is rooted to Venturia inaequalis (CBS 594.70 and CBS 815.69). Isolated substrates are indicated in triangles. Black: Human/ animal, green: plants, brown: soil, purple: rock/ sediments, blue: aquatic habitat. unknown: empty

FIGURE 5. Verruconis soli (MFLU22-0257, holotype) a. Colony from above (on PDA). b. Colony from below (on PDA). c. Sporulated colony. d. Melanized hyphae. e. Hyaline hyphae f–l. Conidiogenesis. m–r. Conidia. Scale bars: e = 15 μm, d, f–k = 10 μm, l–r = 5 μm.