Spegazzinia radermacherae
Spegazzinia radermacherae Jayasiri, E.B.G. Jones & K.D. Hyde, Mycosphere 10(1): 73 (2019)
Index Fungorum number: IF555547; Facesoffungi number: FoF05249
Saprobic on Radermachera sinica. Sexual morph: Undetermined. Asexual morph: Hyphomycetous. Sporodochia dark, dense, dry, powdery, velvety. Conidiophores micronematous. Conidiogenous cells 4–5 μm × 3.5–4.5 μm (
= 4.5 × 3.7 μm; n = 10), basauxic, ampulate, verrucose, producing an erect, verruculose unbranched filament up to 43–52 × 1.5–2.5 μm 
= 48 × 1.8 μm; n = 20), pale, or golden brown. Conidia of two kinds: α conidia 4-celled, brown to black brown, 18–22 × 17.5–20 μm ( = 19 × 18 μm; n = 30), with conspicuous spines 2–3 μm, scattered; β conida 15–17 × 8–10 μm ( = 16.5 × 9.2 μm; n = 30), 4-celled, pale brown to dark brown, subglobose, flattened in one plane, cuciately septate, smooth to verrucose
Culture characters: Conidia germinated on MEA within 24 hr and germ tubes produced from several cells. Colonies growing on MEA, reaching 15–20 mm diam. after 2 weeks at 18°C, flat, surface smooth, with entire edge, white to pale greenish-olivaceous, moderately dense, circular; reverse white to greenish olivaceous.
Material examined: THAILAND, Chiang Rai Province, Mae Fah Luang University, on fallen pod of Radermachera sinica (Bignoniaceae), 7 July 2017, S.C. Jayasiri, C 264 (MFLU 18– 2122, holotype); ex-type living culture MFLUCC 17–2285, KUMCC 18–0297.
GenBank numbers: SSU: MK347848, ITS: MK347740, LSU: MK347957, tef1: MK360088, rpb2: MK434893
Notes: Spegazzinia radermacherae and S. tessarthra are related with high statistical support in the multigene phylogenetic analysis of SSU, ITS, LSU and tef1 gene sequences. Spegazzinia radermacherae is characteristic of Spegazzinia in having two types of conidia. However, the type species of Spegazzinia tessarthra has longer spines (up to 10 μm) while in S. radermacherae, they are only 2–3 μm long. To further support the establishment a new taxon, as proposed by Jeewon & Hyde (2016), we examined the nucleotide differences of ITS and tef1 gene regions. There were 10 (3.1%) and 18 (2.0%) nucleotide differences between S. radermacherae and S. tessarthra for ITS and tef1 gene regions.
Figure 1. Phylogram generated from maximum likelihood analysis based on combined SSU, ITS, LSU and tef1 sequenced data of Didymosphaeriaceae. Related sequences were obtained from Wanasinghe et al. (2018b). Ninety-six strains were included in the combined sequence analyses, which comprised 3300 characters including alignment gaps. Pleospora herbarum (CBS 191.86 and IT 956) and P. tarda (CBS 714.68) are used as the outgroup taxa. Tree topology of the ML tree was similar to the BY tree. The best scoring RAxML tree with a final likelihood value of - 18303.530692 is presented. The matrix had 1159 distinct alignment patterns, with 33.72% of undetermined characters or gaps. Estimated base frequencies were as follows; A = 0.240711, C = 0.244769, G = 0.273737, T = 0.240783; substitution rates AC = 1.476563, AG = 2.183231, AT = 1.233338, CG = 0.923088, CT = 6.926094, GT = 1.000000. ML bootstrap support (first set) equal or greater than 70 % and Bayesian posterior probabilities equal or greater than 0.95 are given near to each branch. The new isolates are in blue. Strains isolated from the holotype, isotype and reference specimens are indicated in red superscript H, I and R respectively.
Figure 2. Spegazzinia radermacherae (MFLU 18–2122, holotype). a Host seed pods. b, c Sporodochia on the host surface. d–g Conidiogenous cells and conidia (note conidiogenous mother cell in g). h, i α conidia. j β conidia. k Germinated conidium. Scale bars: a = 2 cm, b = 500 μm, d–g, k = 20 μm, h–j = 20 μm.
- Jayasiri SC, Hyde KD, Jones EBG, McKenzie EHC et al. (2019) Diversity, morphology and molecular phylogeny of Dothideomycetes on decaying wild seed pods and fruits. Mycosphere, 10, 1-186, Doi /10.5943/mycosphere/10/1/1.
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