Beauveria bassiana (Balsamo-Crivelli) Vuillemin, 1912

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 : 45

Beauveria bassiana (Bals.-Criv.) Vuill., Bulletin de la Société Botanique de France 59: 40 (1912) ( Figure 5 )

Index Fungorum number: IF 199430

Saprobic or pathogenic on a dead Asian House Gecko, mycelium clusters on the forehead, recognized as a white, raised, fluffy region. Sexual morph: undetermined. Asexual morph: Aerial mycelium dense, raised, entire edge, white to yellowish, velutinous, powdery while sporulating, yellowish-brown from reverse. Vegetative hyphae 1–3 μm (x̅ = 1.7 μm, n = 30) wide, branched, hyaline, smooth, thick-walled, occasionally jagged wall, septate, constricted at the septum, terminal round, Conidiogenous cells 4–11 μm (x̅ = 7.5 μm, n = 20) long, 1–3 μm (x̅ = 2 μm, n = 20) wide, solitary or occurring in lateral clusters, cylindrical, subglobose to ampulliform. Conidia 2–3 × 1–2.5 μm (x̅ = 2.5 × 2 μm, n = 20), catenated, globose to ellipsoidal, hyaline, aseptate, smooth-walled.

Culture characteristics: Colonies growing on PDA reach 15 mm in diameter after one week at 27 °C, and randomly sporulating within one month in PDA, above low convex, entire edge, fluffy, white. Reverse: yellowish brown. Sporulated within one month, visible the effuse, white clusters of mycelia with conidia, without pigments produced in PDA.

Substratum: insect, Coleoptera ( Tzean et al. 1997) ; Fragaria ananassa ( Rigotti et al. 2003) ; Cosmopolites sordidus , Hypothenemus hampei , Leucoptera coffeella , Phyllophaga sp. , Plutella xylostella ( Delgado 2011) ; Vitis vinifera ( Elena et al. 2018) ; Cannabis sativa ( Punja et al. 2019) ; Coffea arabica ( Serrato-Diaz et al. 2020) .

Distribution: Taiwan, China ( Tzean et al. 1997); Switzerland ( Rigotti et al. 2003); Nicaragua ( Delgado 2011); Spain ( Elena et al. 2018); Canada ( Punja et al. 2019); Puerto Rico ( Serrato-Diaz et al. 2020), China mainland (this study).

Material examined: China, Yunnan Province, on dead Asian House Gecko, Peter E. Mortimer, F-5 (Herb. KUN-HKAS 122655), living culture, KUMCC 21-0468. Genbank numbers: ITS: OM 670163 , rpb1: OM 681324 , rpb2: OM 681325 , tef1-α: OM 681322 , Bloc: OM 681323 .

Notes: Our isolate KUMCC 21-0468 fits with the characteristics of Beauveria bassiana by having an asexual morph producing globose to subglobose, catenated conidia, aseptate, hyaline, with globose to flask-shaped phialides; conidiogenous cells normally cluster on the terminals of branched hypha ( Paul Vuillemin et al. 1912, Chen et al. 2013). The clade B. bassiana was analysed in detail by Khonsanit et al. (2020). The ITS BLASTn results of our isolate highly overlapped with Beauveria bassiana strains BCC 34332, ARSEF 751 and BBC12907, while rpb1, rpb2 and tef1-α show high matches to B. bassiana ARSEF 1040 (>99%). In addition, Bloc gene region showed 100% (1486/1492, 1 gap) similarity to B. bassiana ( ARSEF 4934), and our tree topology of the ML and BI analyses also shows KUMCC 21-0468 is closely related to B. bassiana ARSEF 1040 with high statistical supports ( Figure 4 ). Therefore, our isolate KUMCC 21-0468 is identified as Beauveria bassiana , which is a new host record based on morphological features and phylogenetic evidences.

Figures

FIGURE 4. Phylogram generated from maximum likelihood analysis based on a combined ITS, rpb1, rpb2, tef1-α and Bloc sequence datasets. Related sequences were taken from Chen et al. (2018) and Khonsanit et al. (2020). A total of 81 strains are included in the combined gene analyses; 5090 total characters including gaps (ITS: 1–566 bp, rpb1: 567–1307 bp, rpb2: 1308–2430 bp, tef1-α: 2431–3429 bp, Bloc: 3430-5090 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 -29154.321884 (ln). All free model parameters were estimated using the RAxML model, with 1867 distinct alignment patterns and 15.05% of undetermined characters or gaps. Estimated base frequencies were as follows: A = 0.242248, C = 0.283924, G = 0.257262, T = 0.216566, with substitution rates AC = 0.928484, AG = 3.845624, AT = 0.649405, CG = 0.874887, CT = 4.792288, GT = 1.000000. The gamma distribution shape parameter alpha = 0.712530 and the Tree-Length = 1.618181. The final average standard deviation of split frequencies at the end of total MCMC generations calculated as 0.009746 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 0.95 are given at the nodes. Hyphens (-) represent support values less than 70% in ML/0.95 in BI.

FIGURE 5. Beauveria bassiana (KUMCC 21-0468).aAppearance of fungal colonies on PDA.b Close-up of fungal colonies. c Mycelium with conidia. d Mycelium mass stained by cotton blue reagent. e Conidia connected with conidiogenous cells and stained by cotton blue reagent. f A conidophore. g A branched mycelium stained by congo red reagent. h Minus and plus mycelium stained by congo red reagent. i Conidia stained by congo red reagent. j Conidia stained by cotton blue reagent. Scale bars: d = 50 μm, c, e = 30 μm, g, h = 10 μm, f, i, j = 5 μm.