Sphaeropsis eucalypticola (Doilom, J.K. Liu, & K.D. Hyde) A.J.L. Phillips

Rathnayaka, Achala R., Chethana, K. W. Thilini, Phillips, Alan J. L. & Jones, E. B. Gareth, 2022, Two new species of Botryosphaeriaceae (Botryosphaeriales) and new host / geographical records, Phytotaxa 564 (1), pp. 8-38 : 25

Sphaeropsis eucalypticola (Doilom, J.K. Liu, & K.D. Hyde) A.J.L. Phillips , in Phillips et al., Stud. Mycol. 76: 158 (2013)

Synonym: Sphaeropsis chromolaenicola Mapook & K.D. Hyde , in Mapook et al., Fungal Diversity 101: 113 (2020)

Index Fungorum number: IF 805464; Facesoffungi number: FoF 00169; Figs 10 , 11

Saprobic on dead branches of Ficus ampelas and Tamarindus indica . Sexual morph: Ascostromata 145–270 μm diam., 155–290 μm high, solitary or gregarious, semi-immersed, erumpent at maturity, uniloculate, globose to subglobose, ostiolate. Peridium 10–90 μm wide, composed of brown to dark brown cells of textura angularis. Hamathecium composed of 2–5 μm wide, oblong to cylindrical, septate, hyaline pseudoparaphyses. Asci 65–190 × 20–30 μm (x̄ = 110 × 25 μm, n = 15), bitunicate, fissitunicate, 8-spored, clavate to cylindro-clavate, short pedicellate, straight to slightly curved, apically rounded with well-developed ocular chamber. Ascospores 20–35 × 10–17 μm (x̄ = 28 × 14 μm, n = 30), 1−2-seriate, overlapping in the ascus, hyaline to yellowish brown when immature, becoming brown to dark brown at maturity, ellipsoid to ovoid, aseptate, with granular appearance, widest at the center and tapering toward narrow ends, straight, small apiculus at either end, smooth-walled. Asexual morph: Undetermined.

Culture characteristics:—Ascospores germinating on PDA within 6 hours and germ tube produced from one side of the ascospore. Colonies on PDA reaching 5–7 cm diam. after 3 days at 25 °C, circular, flattened, fluffy, dense, grey in both upper and lower sides.

Material examined: — THAILAND. Chiang Mai: Mae Tang Watershed Research Station, on dead branches of Tamarindus indica (Fabaceae) , 7 July 2021, Achala Rathnayaka (MFLU 22-0095, new host record). TAIWAN. National Chiayi University (NCYU), on dead branch of Ficus ampelas (Moraceae) , 21 August 2019, Dhanushka Tennakoon (MFLU 22-0099, new host and geographical record); living culture NCYUCC 19-0423.

Known hosts and distribution:— Chromolaena odorata , Eucalyptus sp. , Tectona grandis , Tamarindus indica in Thailand (Mapook et al. 2021, Liu et al. 2012, Phillips et al. 2013, this study), Ficus ampelas in Taiwan (this study).

Notes:—Our collections (MFLU 22-0095 and NCYUCC 19-0423) clustered with Sphaeropsis eucalypticola isolates (MFLUCC 11-0579, MFLUCC 11-0654, MFLUCC 13-0701 and MFLUCC 17-1499) with relatively high 99% ML bootstrap and 1.00 PP support ( Fig. 2 ). Morphologically, our collections show similar characters to the holotype, such as erumpent, globose to subglobose, solitary or gregarious ascostromata. Asci are cylindro-clavate, short pedicellate, and apically rounded with a well-developed ocular chamber. Ascospores are hyaline, becoming yellowish-brown to dark brown at maturity, ellipsoid to ovoid, widest at the center, aseptate, and smooth-walled with small apiculus at either end ( Liu et al. 2012). However, the size of asci and ascospores (x̄ = 110 × 25 μm and x̄ = 28 × 14 μm) are slightly different to the holotype (x̄ = 106 × 29 μm and x̄ = 30 × 12 μm) ( Liu et al. 2012). Based on morpho-molecular evidence, we conclude that our collections represent new host records on Tamarindus indica and Ficus ampelas in Thailand and Taiwan, respectively. Also, NCYUCC 19-0423 represents a new geographical record of S. eucalypticola from Taiwan. Mapook et al. (2021) introduced MFLUCC 17-1499 isolate as Sphaeropsis chromolaenicola , a new species of Sphaeropsis . When comparing the ITS region (ITS1-5.8S-ITS2), no base pair (0%) differences were found between S. chromolaenicola (MFLUCC 17-1499) and other strains of S. eucalypticola (MFLUCC 11-0579, MFLUCC 11-0654, MFLUCC 13-0701, MFLU 22-0095 and NCYUCC 19-0423). According to our phylogenetic analyses, the S. chromolaenicola isolate clusters with other S. eucalypticola isolates ( Fig. 2 ). Therefore, we synonymize S. chromolaenicola under S. eucalypticola .

Figures

FIGURE 2. Phylogram generated from ML analysis based on combined dataset of ITS, tef1-α and β-tub. The tree is rooted to Barriopsis stevensiana (CBS 174.26) and B. tectonae (MFLUCC 12-0381). Tree topology is similar to previous study conducted by Dissanayake et al. (2021). Bootstrap support values for ML ≥ 70% and Bayesian posterior probabilities (PP) ≥ 0.90 are noted at the nodes. Strain numbers are noted after the species names. Strains isolated in this study are presented in red and type strains are in bold.

FIGURE 10. Sphaeropsis eucalypticola on dead branch of Tamarindus indica (MFLU 22-0095). a, b.Appearance of ascostromata on host surface. c, d. Sections through ascomata. e. Section through peridium. f. Pseudoparaphyses. g–j. Asci. k–p. Ascospores. Scale bars: a = 2 mm, b, c = 200 μm, d = 100 μm, e, f = 20 μm, g–j = 50 μm, k–p = 10 μm.

FIGURE 11. Sphaeropsis eucalypticola on dead branch of Ficus ampelas (NCYUCC 19-0423). a, b. Appearance of ascostromata on host surface. c, d. Sections through ascomata. e. Section through peridium. f–h. Asci. i Ascospore. j. Germinating ascospore. k, l. Colony on PDA (k upper, l lower). Scale bars: a = 200 μm, b, c = 50 μm, d = 50 μm, e = 10 μm, f –h = 20 μm, i, j = 5 μm.