Simplicillium formicae D.P. Wei & K.D. Hyde

Wei, De-Ping, Wanasinghe, Dhanushka N., Hyde, Kevin D., Mortimer, Peter E., Xu, Jianchu, Xiao, Yuan-Pin, Bhunjun, Chitrabhanu S. & To-anun, Chaiwat, 2019, The genus Simplicillium, MycoKeys 60, pp. 69-92 : 69

Simplicillium formicae D.P. Wei & K.D. Hyde sp. nov. Figure 3 , 4

Etymology.

the epithet refers to its host–ant.

Holotype.

HKAS 102459; living culture: MFLUCC 18-1379.

Description.

Parasitic on ant ( Formicidae ). Asexual morph: Hyphomycetous. Mycelium rarely septate, hyaline, smooth-walled, covering the whole body of the ant host. Synnemata 250-350 × 65-100 (xˉ = 300 × 86, n = 10) µm, forming at the head region of ant host in circular arrangement, flask-shaped, hyaline to yellowish, composed of dense hyphae, somehow curved. Phialides 25-100 × 0.5-1.5 (xˉ = 49 × 1.1, n = 20) µm, arising from procumbent hyphae or synnemata, blastic, enteroblastic, phialidic, monophialidic, discrete, terminal, unbranched, solitary, aseptate, hyaline, smooth-walled, slender, occasionally a swollen node present. Conidia 2-3.5 × 1.5-2.5 (xˉ = 2.6 × 2, n = 30) µm, globose to ellipsoidal, hyaline, one-celled, smooth-walled, round at both ends, adhering in slimy head on the tip of phialides. Sexual morph: Undetermined.

Culture characteristics.

The colonies were rapid-growing on PDA medium, reaching a diameter of 2.5-3 (xˉ = 2.6, n = 9) cm, in 13 days at 22 °C, entire margin, circular, velvety and white from above, with radial crack and primrose-yellow on reverse. In vitro, Synnemata absent. Phialides 25-75 × 0.4-0.6 (xˉ = 50 × 0.55, n = 10) µm, arising from procumbent hyphae, blastic, enteroblastic, phialidic, discrete, terminal, unbranched, solitary, aseptate, hyaline, smooth-walled, relatively slender and long. Conidia 1.5-3 × 1.5-2.5 (xˉ = 2.3 × 1.7, n = 100) µm, hyaline, globose to ellipsoidal, aseptate, smooth-walled, slightly guttulate, adhering in slimy head on the tip of phialides.

Material examined.

THAILAND, Chiang Mai Province, Mushroom Research Centre, on an adult ant, 1 April 2018, Deping Wei, MRC18040102 (holotype: HKAS 102459; ex-type living culture: MFLUCC 18-1379). Sequences generated from this strain have been deposited in GenBank with accession numbers: SSU = MK765046, LSU = MK766512, ITS = MK766511, TEF = MK926451, RPB1 = MK882623.

Note.

Isolate MFLUCC 18-1379 has a close phylogenetic relationship with Simplicillium obclavatum , based on ITS sequence analysis. The new isolate is similar to Simplicillium obclavatum in terms of shape and dimensions of the conidia with slender phialides tapering towards the apex. However, they have a different conidial arrangement, by Simplicillium obclavatum having short-imbricate chains, whereas the new fungus has subglobose to globose head. There are numerous synnemata in a circular arrangement which can be observed in our isolate and those are absent in Simplicillium obclavatum . The comparisons of ITS sequences between our isolate MFLUCC 18-1379 and ex-type strain of Simplicillium obclavatum (CBS 311.74) show 23 bp differences within 550 bp (4.2%). Thereby, we identify our isolates as a new species according to Jeewon and Hyde (2016).

Figures

Figure 3. Simplicillium formicae (from HKAS 102459, holotype) a superficial hyphae associated with the ant host b-e flask-shaped synnemata f-k phialides bearing conidia l-p conidia. Scale bars: 1000 µm (a); 500 µm (b); 100 µm (d); 30 µm (e, f); 15 µm (j, k); 10 µm (l-p) (e stained with cotton blue solution).

Figure 4. Simplicillium formicae (MFLUCC 18 - 1379, ex-type living culture) a upper and reverse view of cultures on PDA after 30 days e-g phialides indicated with black arrow c, d, h-j conidial mass on the tip of phialides k-m conidia. Scale bars: 10 µm (c, d, f, g); 20 µm (e); 3 µm (h-j); 1 µm (k-m) (e-j stained with cotton blue solution).