Acremonium guizhouense S.Q. Tong & Y.J. Wu, 2023

Tong, Shuo-Qiu, Peng, Lei & Wu, Yong-Jun, 2023, Acremonium capsici and A. guizhouense, two new members of Acremonium (Hypocreales, Sordariomycetes) isolated from the rhizosphere soil of Capsicum annuum, MycoKeys 95, pp. 1-13 : 1

Acremonium guizhouense S.Q. Tong & Y.J. Wu sp. nov.

Fig. 3

Etymology.

Referring to the country where this fungus was first isolated.

Type.

Guiyang City , Guizhou Province, China 26°45'75"N, 106°64'87"E, isolated from the rhizosphere soil of Capsicum annuum , August 2022, Shuo-Qiu Tong (dried holotype culture SQT H04, ex-holotype culture SQT04). GenBank: ITS = OP703289 ; LSU = OP740981 ; SSU = OP750193 ; TEF 1 -α = OP757290 ; RPB2 = OP730525 .

Description.

Culture characteristics (14 days at 25 °C) - Colonies on PDA 16-19 mm in diameter, yellowish white to grayish yellow, flat, zonate, with regular edge; reverse brownish orange. Colonies on MEA 9-13 mm in diameter, yellowish white to white, compact, convex with papillate surface, margin dentate, aerial mycelia extremely sparse; reverse yellowish white to umber. Colonies on OA 14-16 mm in diameter, pale, felty, with regular edge; reverse pale white. Colonies on CMA 16-14 mm in diameter, pale white, felty, with regular edge; reverse pale white. Hyphae hyaline, smooth, septate, branched, 1.0-3.0 µm wide. Phialides straight to flexuous, hyaline, smooth, arising from hyphae, 15.5-33.5 μm (n = 50) long, 1.5-2.5 μm (n = 50) wide at the base. Conidia gathered in slimy heads, one-celled, ovoid to ellipsoidal, 2.5-3.0 × 3.5-5.0 µm (n = 50), hyaline, smooth or rough. Chlamydospores and teleomorph not observed.

Additional specimens examined.

Guiyang City , Guizhou Province, China 26°45'75"N, 106°64'87"E, isolated from the rhizosphere soil of Capsicum annuum , August 2022, Shuo-Qiu Tong, SQT05 = SQT06, ibid., SQT07. GenBank: ITS = OP703290 - OP703292 ; LSU = OP740982 - OP740984 ; SSU = OP750194 - OP750196 ; TEF 1 -α = OP757291 - OP757293 ; RPB2 = OP730526 - OP730528 .

Known distribution.

Guiyang City, Guizhou Province, China.

Notes.

Phylogenetic and morphological data (Figs 1 , 3 ) support our isolates SQT04-SQT07 as new species of Acremonium . A. guizhouense is phylogenetically closely related to A. verruculosum and A. persicinum . However, they can be distinguished by their sequence similarity (97% similarity, 10 base pairs (bp) differences and two gaps in 497 bp of LSU in A. verruculosum CBS 989.69; 98% similarity, 12 base pairs (bp) differences, and four gaps in 809 bp of LSU in A. persicinum CBS310.59). Since A. verruculosum and A. persicinum lack ITS sequences, it was not possible to compare A. guizhouense with them. Morphologically, the conidia of A. verruculosum are long ellipsoidal to cylindrical, rather than ovoid to ellipsoidal in A. guizhouense ( Gams 1971). A. verruculosum , on the other hand, has larger conidia than A. guizhouense (5.6-6.0 × 2.3-2.5 µm vs. 2.5-3.0 × 3.5-5.0 µm) ( Gams 1971). Furthermore, conidia of A. verruculosum are catenulate, fusiform, pyriform to ellipsoidal rather than arranged as slimy heads, ovoid to ellipsoidal in A. guizhouense ( Gams 1971). The conidia of A. guizhouense , on the other hand, are smaller than that of A. persicinum (2.5-3.0 × 3.5-5.0 µm vs. 3.2-4.8 × 1.2-3.0 µm) ( Gams 1971).

Figures

Figure 1. Phylogram generated from maximum likelihood analysis based on LSU + ITS sequence data. Bootstrap support values of maximum likelihood higher than 75 % and Bayesian posterior probabilities greater than 0.75 are given above each branch. The new collection is highlighted in blue bold. Clades are identified using clade nomenclature formally defined by Summerbell et al. (2011), and Yang et al. (2019). Ex-type strains are indicated by " T ".

Figure 3. Morphology of Acremonium guizhouense sp. nov. a-d colony on PDA, MEA, OA, and CMA after 14 days at 25 ° C (upper surface and lower surface) e, f phialides and conidia g, h conidia are held together in slimy heads. Scale bars: 10 μm (e-h).