Conidiobolus longiconidiophorus B. Huang & Y. Nie, 2023

Nie, Yong, Cai, Yue, Zhao, Heng, Zhou, ZhengYu, Zhao, ChangWei, Liu, XiaoYong & Huang, Bo, 2023, Morphological and phylogenetic analyses reveal two new species in Conidiobolus s. s. (Conidiobolaceae, Entomophthorales) from China, MycoKeys 98, pp. 221-232 : 221

Conidiobolus longiconidiophorus B. Huang & Y. Nie sp. nov.

Fig. 2

Etymology.

Longiconidiophorus (Lat.), referring to the long size of its conidiophores.

Known distribution.

Anhui Province, China.

Typification.

China, Anhui Province, Huangshan City, Qimen County, Guniujiang National Nature Reserve, 30°2′84′′N, 117°53′31′′E, from plant debris, 12 Dec. 2019, Y. Nie and W. Wang, holotype BWPU 191212. Ex-type culture RCEF 6563. GenBank: nucLSU = OQ540746; EFL = OQ550509; mtSSU = OQ540744.

Additional specimens examined.

China, Anhui Province, Chizhou City, Shitai County, Guniujiang National Nature Reserve , 30°10'66"N, 117°50'4"E, from plant debris, 15 Dec. 2019, Y. Nie and W. Wang, culture RCEF 6568. GenBank: nucLSU = OR100884 ; EFL = OR113355 ; mtSSU = OR100881 .

Description.

Colonies on PDA at 21 °C after 3 d white, reaching ca 15 mm in diameter. Aerial hyphae flourishing after 6 d. Mycelia white, 5-10 μm wide, often unbranched at the edge of colony. Primary conidiophores often evolving from aerial hyphae, long, 150-340 × 6-9 μm, unbranched and producing a single primary conidium, without widening upward near the tip. Primary conidia forcibly discharged, globose, obovoid to ellipsoidal, 31-49 × 24-42 μm, papilla tapering and pointed, 7-13 μm wide, 3-7 μm long. Secondary conidiophores short or long, arising from primary conidia, bearing a single similar replicative conidium to primary conidia. Microspores not observed on the 2% water agar, but the structure similar to sterigmatas bearing microspores observed. Resting spores absent after 1 month.

Notes.

Conidiobolus longiconidiophorus forms a distinct phylogenetic clade from other Conidiobolus s.s. species. Morphologically, its primary condia are similar in size to those in C. coronatus (Cost.) Batko (14.5-38.5 × 17-48.5 μm), C. dabieshanensis Y. Nie & B. Huang (29-38 × 32.5-45), C. macrosporus Srin. & Thirum. (38-45 × 48-54 μm), C. megalotocus Srin. & Thirum. (30-50 μm), and C. utriculosus Brefeld (25-35 × 37.5-51 μm). However, it can be distinguished from C. coronatus and C. macrosporus by its longer primary conidiophores and the absence of resting spores ( Batko 1964; Srinivasan and Thirumalachar 1967). Additionally, it is differentiated from C. dabieshanensis and C. utriculosus by its obovoid and ellipsoidal primary condia, as well as the absence of resting spores ( Brefeld 1884; Nie et al. 2017). While it is closely related to C. megalotocus , it can be differentiated by the shape of its primary condia ( Srinivasan and Thirumalachar 1962). Furthermore, in the phylogenetic tree (Fig. 1 ), C. longiconidiophorus is found to be distantly related to C. megalotocus .

Figures

Figure 1. The phylogenetic tree of Conidiobolus s. s. constructed based on combined nucLSU, EFL and mtSSU sequences. Azygosporus and Microconidiobolus species were used as outgroups. New species are shown in red. Maximum Likelihood bootstrap values (≥ 70 %) / Bayesian posterior probabilities (≥ 0.95) of clades are provided alongside the branches. The scale bar at the bottom left indicates substitutions per site.

Figure 2. Conidiobolus longiconidiophorus RCEF 6563 a colony on PDA after 3 d at 21 ° C b colony on PDA after 6 d at 21 ° C c mycelia unbranched at the edge of the colony d-g primary conidiophores bearing primary conidia h, i globose primary conidia j, k obovoid to ellipsoidal primary conidia l, m primary conidia bearing a single secondary conidium n, o structure similar to sterigmatas arsing from conidia. Scale bars: 100 μm (c); 20 μm (d-o).