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

Fig. 3

Etymology.

Polysporus (Lat.), referring to several primary conidia arising from branched primary conidiophores.

Known distribution.

Anhui and Shandong Provinces, China.

Typification.

China, Anhui Province, Ma,anshan City, Huoli Mountain, 31°67′5′′N, 118°55′37′′E, from plant debris, 3 Nov. 2021, Z.Y. Zhou and C.W Zhao, holotype BWPU 211103. Ex-type culture RCEF 7058. GenBank: nucLSU = OQ540747; EFL = OQ550510; mtSSU = OQ540745.

Additional specimens examined.

China, Shandong Province, Qingzhou City, Yangtianshan National Forest Park, 36°46'31"N, 118°32'56"E, from plant debris, 18 Mar 2009, C.F. Wang, culture RCEF 4500. GenBank: nucLSU = MG272478 ; EFL = MG272476 ; mtSSU = OR100881 .

Description.

Colonies on PDA at 21 °C after 3 d white, reaching ca 20-23 mm in diameter. Mycelia colorless, rarely branched at the edge of colony, 8.8-13 μm wide, vegetative hyphae filamentous, frequently appearing pronouncedly vacuolated, 15-22 μm wide. Primary conidiophores often unbranched, producing a single primary conidium, without widening upward near the tip, but in some instances bifurcate thus bearing two primary conidia, or forming three conidiophores at the tip thus bearing three primary conidia, 68-270 × 11-19 μm. Primary conidia forcibly discharged, mostly globose, 42-55 × 33-45 μm, Papilla 7.5-14 μm wide, 4-12 μm long. Sometimes obovoid, up to 65 μm long. Secondary conidia arising from primary conidia, similar and smaller to the primary conidia. Microconidia rarely observed on the 2% water agar, globose to elongate ellipsoidal, 7.5-8.8 × 7.5-12.5 μm. Zygospores formed between adjacent segments after 15 days, smooth, mostly globose, less often ellipsoidal, 17.5-37 μm in diameter, with a 1-3 μm thick wall.

Notes.

Conidiobolus polysporus is characterized by several primary conidia (2-3) arising from conidiophores, which are similar to those in C. polytocus Drechsler and C. taihushanensis B. Huang & Y. Nie. However, C. polysporus has larger primary conidia (42-55 × 33-45 μm in C. polysporus vs. 14-29 × 12-25 μm in C. polytocus ), and forms zygospores while resting spores are absent in C. polytocus ( Drechsler 1955). In addition, C. polysporus differs from C. taihushanensis due to its larger primary conidia (42-55 × 33-45 μm in C. polysporus vs. 27-42 × 19-32 μm in C. taihushanensis ) and smaller zygospores (17.5-37 μm in C. polysporus vs. 34-48 × 23-40 μm in C. taihushanensis ) ( Nie et al. 2020b). Moreover, it is distantly related to C. polytocus and C. taihushanensis in the phylogenetic tree (Fig. 1 ). Although C. polysporus is grouped with C. incongruus , it can be distinguished by its larger primary conidia (42-55 × 33-45 μm in C. polysporus vs. 18-42 × 13-37 μm in C. incongruus ) and branched conidiophore ( Drechsler 1960).

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 3. Conidiobolus polysporus RCEF 7058 a colony on PDA after 3 d at 21 ° C b mycelia unbranched at the edge of the colony c, d hyphae appearing pronouncedly vacuolated e, f unbranched primary conidiophores g, h branched primary conidiophpores i-k globose primary conidia l obovoid primary conidia m, n primary conidia bearing a single secondary conidium o-q microconidia arising from a conidium r, s zygospores formed between adjacent segments of the same hypha t, u zygospores. Scale bars: 100 μm (b); 20 μm (c-u).