Basidiobolus ranarum Eidam, Beiträge

Yang, Erfu, Tibpromma, Saowaluck, Dai, Dongqin, Promputtha, Itthayakorn, Mortimer, Peter E. & Karunarathna, Samantha C., 2022, Three interesting fungal species associated with the Asian House Gecko in Kunming, China, Phytotaxa 545 (1), pp. 37-56 : 42

Basidiobolus ranarum Eidam, Beiträge zur Biologie der Pflanzen 4: 194 (1886) ( Figure 3 )

Index Fungorum number: IF224388

Saprobic or pathogenic on dead house gecko. Mycelium 10–20 μm wide (x̅ = 16 μm, n = 20), hyaline, septate, branched, tubular, sightly constriction at the septum, soon forming zygospores, the zygospores are (sexual spores) characterized by globose to subglobose 25–40 × 25–35 μm (x̅ = 34 × 31 μm, n = 20), wrapped in mycelium, with smooth and thick wall, 1–3.5 μm (x̅= 2.5 μm, n = 20) thickness, and wall layer thinner with the maturity, attaching a prominent conjugation beaks 10–15 μm wide, 8–11 high ( Figure 3 : f, g), hyaline (the microscopic features observed with cotton blue), verruculose to granulate in cellular inner, some zygospores form meristospores by cleavage of the cytoplasm ( Figure 3 : i–k).

Culture characteristics: The pure culture was obtained from slimy tissue of gecko’s swollen forelimb, colonies circular, fast-growing on PDA at the room temperature, reaching around 40 mm diameter after two weeks, with an irritating odor, yellowish-brown to creamy grey, waxy, radially striated with barren crack at the centre, visible sparse mycelium tips at the margin, abundant global to subglobose zygospores (conidia) pave on folded surface; reverse sunken at the centre, yellowish to pale outwardly, without pigments produced from PDA.

Substratum: Fish ( Nickerson & Hutchison 1971); Amphibians (frogs, toads) ( Coremans-Pelseneer 1973); house gecko faeces (Hemiolactylus sp.) ( Claussen & Schmidt 2019); wall gecko (Hemiolactylus sp.) ( Gugnani & Okafor 1980); bat ( Chaturvedi et al. 1984); child/adult, human ( Khan et al. 2001, Yusuf et al. 2003); dead Asian House Gecko (Hemiolactylus sp.) (this study).

Distribution: Arkansas and Missouri, American ( Nickerson & Hutchison 1971); Kinshasa, Zaire (Coremans-Pelseneer 1973); Nsukka, Nigeria ( Gugnani & Okafor 1980); India ( Chaturvedi et al. 1984, Khan et al. 2001); Jizan, Saudi Arabia ( Yusuf et al. 2003); KwaZulu-Natal ( South Africa) ( Claussen & Schmidt 2019), Yunnan, China (this study)

Material examined: China, Yunnan Province, on dead Asian House Gecko, Peter E. Mortimer, F-4 (Herb. KUN-HKAS 122654), living culture, KUMCC 21-0467. Genebank numbers: ITS: OM 670164 , LSU: OM 670161 , mtSSU: OM 692370 .

Notes: Our isolate KUMCC 21-0467 shares similar characteristics with Basidiobolus magnus and B. ranarum in having globose to subglobose, smooth, thick-walled zygospore 20–60 μm in diameter, wrapped in mycelium, with a conjugation beak ( Eidam 1886, Davis et al. 1994). The BLASTn results show the ITS gene region highly overlaps with B. magnus (ARSEF 1139) at 99.3% (668/673 bp, 0 gap), at 99% (664/672 bp, 0 gap) similarity with B. ranarum ( ARSEF 260), and the LSU region indicates 99.8 % similarity (1010/1012bp, 0 gap) with B. ranarum ( ARSEF 8303) and B. magnus ( CBS 205.64). In addition, 667 bp of the mtSSU region was 100% similar to B. ranarum (AFTOL-ID 301); unfortunately, we were unable to amplify the rpb2 (7F/11aR) gene of our strain KUMCC 21-0467, The phylogenetic trees based on ITS, LSU, rpb2 and mtSSU show our isolate clusters with B. ranarum ( ARSEF 260 and ATCC 14449) ( Figure 2 ). Basidiobolus ranarum has also been found on frogs in Canada, and many infected cases in humans all over the world have been reported ( Gugnani 1999, Al-Hatmi et al. 2021). As morphological characteristics examined largely overlap with B. ranarum , also supported by the phylogenetic evidences, our isolate is identified as Basidiobolus ranarum with a new country record for China; however, B. ranarum has previously been reported on wall gecko and house gecko faeces ( Hemidactylus spp. ) ( Gugnani & Okafor 1980, Gugnani 1999, Claussen & Schmidt 2019).

Figures

FIGURE 2. Phylogram generated from maximum likelihood analysis based on a combined LSU, ITS, rpb2 and mtSSU sequence datasets. Related sequences were taken from Gryganskyi et al. (2013), Nie et al. (2020) and Al-Hatmi et al. (2021). The 14 strains are included in the combined gene analyses; 3258 total characters including gaps (LSU: 1–1021 bp, ITS: 1022–1745 bp, rpb2: 1746–2590 bp, mtSSU: 2591–3258 bp). Tree topology of the ML analysis was similar to the BI. The matrix had distinct alignment patterns, with the final ML optimization likelihood value of -10673.579273 (ln).All free model parameters were estimated using the RAxML model, with 586 distinct alignment patterns and 21.73% undetermined characters or gaps. Estimated base frequencies were as follows:A = 0.280858, C = 0.195362, G = 0.257773, T = 0.266007, with substitution rates AC = 1.709550, AG = 4.063199, AT = 2.099405, CG = 1.130856, CT = 8.827188, GT = 1.000000. The gamma distribution shape parameter alpha = 0.109274 and the Tree-Length = 4.770478. The final average standard deviation of split frequencies at the end of total MCMC generations were calculated as 0.009712 in BI analysis. The species determined in this study are indicated in red. Bootstrap values equal to or greater than 70% (ML, left) and Bayesian posterior probabilities (BI, right) equal to or greater than 0.90 are given at the nodes. Hyphens (-) represent support values less than 70% in ML/0.90 in BI.

FIGURE 3. Basidiobolus ranarnm (KUMCC 21-0467). a–c Appearance of colonies on PDA. d–e The branched hypha with zygospores stained by cotton blue reagent. f–g Zygospore with characteristic beak stained by cotton blue reagent. h Thick-walled zygospores stained by cotton blue reagent. i–k Producing meristospores stained by cotton blue reagent. Scale bars: d, e = 50 μm, f, g = 30 μm, h–k = 20 μm.