Gongronella abortosporangia Yi Xin Wang, H. Zhao & X. Y. Liu, 2024

Wang, Yi-Xin, Zhao, Heng, Jiang, Yang, Liu, Xin-Ye, Tao, Meng-Fei & Liu, Xiao-Yong, 2024, Unveiling species diversity within early-diverging fungi from China III: Six new species and a new record of Gongronella (Cunninghamellaceae, Mucoromycota), MycoKeys 110, pp. 287-317 : 287-317

Gongronella abortosporangia Yi Xin Wang, H. Zhao & X. Y. Liu sp. nov.

Fig. 2

Etymology.

The epithet “ abortosporangia ” (Latin) refers to the abortive sporangia.

Type.

China • Hainan Province, Lingshui Li Autonomous County, Qixian Yaochi Yexi Hot Spring (18.70161 ° N, 109.69318 ° E), from soil sample, 10 April 2023, Yi-Xin Wang (holotype HMAS 352726 , ex-holotype strain CGMCC 3.27028 ) .

Description.

Colonies growing slowly on PDA in darkness at 25 ° C, reaching 49.2–52.4 mm in diameter in seven days, white, regular at edge and cottony in the centre, reversely milky white. Rhizoids hyaline, branched, irregularly shaped, with oil droplets. Stolons absent. Sporangiophores on aerial mycelia, erect or slightly curved, unbranched or branched (1–6 times), 4.0–96.8 × 1.0–4.2 μm, hyaline, smooth, mostly aseptate, sometimes one-septate and rarely two-septate, occasionally containing a line of oil droplets. Sterile (aborted) sporangia abundant, mainly on the top of short lateral branches of sporangiophores, mostly gourd-shaped, 11.6–16.7 × 5.5–17.7 μm, partially elliptical with a slight shrinkage, 12.5–18.0 × 6.7–10.6 μm, occasionally clavate, 20.1–22.7 × 9.5–10.4 μm. Fertile sporangia hyaline or light yellow, spherical, 7.0–23.2 μm in diameter, smooth and deliquescent-walled, leaving a collar after releasing sporangiospores. Columellae mostly hemispherical, 2.5–4.2 × 3.6–7.4 μm, sometimes sub-hemispherical, 1.3–3.9 × 3.6–5.5 μm, hyaline, smooth. Apophyses hyaline, smooth, variously shaped, mostly cup-shaped, 1.9–8.6 × 2.1–6.7 μm, partially hemispherical, 2.7–5.5 × 2.8–7.4 μm, occasionally pear-shaped, 8.2 × 7.2 μm. Sporangiospores not uniform, hyaline, smooth, ovoid, 2.6–3.5 × 1.7–2.1 μm, reniform, 2.9–3.5 × 1.7–2.3 μm. Chlamydospores gourd-shaped, 20.3–29.3 × 6.4–9.3 μm. Giant cells intercalary, globular, subglobular, 2.6–4.6 μm in diameter. Zygospores not found.

Additional specimen examined.

China • Hainan Province, Lingshui Li Autonomous County, Benhao Town (18.70161 ° N, 109.69318 ° E), from soil sample, 10 April 2023, Yi-Xin Wang (living culture SAUCC 4064-2 ) .

GenBank accession numbers.

CGMCC 327028 ( ITS, PP 195847; LSU, PP 195948; TEF, PP 850088; ACT, PP 933938; RPB 1, PP 842883), SAUCC 4064-2 ( ITS, PP 195848; LSU, PP 195949; TEF, PP 850089; ACT, PP 933939; RPB 1, PP 842882).

Notes.

Based on phylogenetic analyses of ITS + LSU + TEF + ACT + RPB 1 sequences, the two isolates of the new species Gongronella abortosporangia formed an independent clade with high supports ( MLBV = 100; Fig. 1 ), which is closely related to G. multiramosa ( BIPP = 0.95; Fig. 1 ). This new species differs morphologically from G. multiramosa in sporangium, septum, columella, collar and apophysis ( Wang et al. 2023 a). The G. abortosporangia is different from G. multiramosa in shape and size of sterile sporangia, the former being variously shaped, mostly gourd-shaped, 11.6–16.7 × 5.5–17.7 μm, partially elliptical with a slight shrinkage, 12.5–18.0 × 6.7–10.6 μm, occasionally clavate, 20.1–22.7 × 9.5–10.4 μm, while the latter being only ovoid, 9.6 × 6.2 µm in diameter. In fertile sporangia, G. abortosporangia has a smaller minimum diameter than G. multiramosa (7.0 μm vs. 15.5 μm). G. abortosporangia has more septa on sporangiophores compared to G. multiramosa (0–2 vs. 0–1). Although G. abortosporangia is similar in shape of columellae to G. multiramosa , it is shorter in length (hemispherical, 3.6–7.4 µm vs. 8.0–9.8 µm, sub-hemispherical, 3.6–5.5 μm vs. 7.6–10.0 µm). The G. abortosporangia has shorter collars than G. multiramosa , 0.6–3.9 μm vs. 1.3–7.2 µm. The G. abortosporangia is similar in shape of apophyses to G. multiramosa . However, they are different from each other in main pattern and size: The former mostly cup-shaped (1.9–8.6 × 2.1–6.7 μm vs. 4.6–7.0 × 8.5–10.0 µm) and partially hemispherical (2.7–5.5 × 2.8–7.4 μm vs. 4.4–5.6 × 8.5–9.0 µm) and the latter opposite. Combining morphological and molecular phylogenetic analyses, we classified the two isolates as a new species G. abortosporangia allied to G. multiramosa .

Figures

Figure 1. A Maximum Likelihood (ML) phylogenetic consensus tree inferred from DNA sequences of ITS, LSU, TEF, ACT and RPB 1, showing relationships amongst species of Gongronella with Cunninghamella echinulata CBS 156.28 as outgroup. The Maximum Likelihood bootstrap value (MLBV) and Bayesian Inference posterior probability (BIPP) are successively shown at the nodes and separated by a slash “ / ”. Strains marked with a star “ * ” are ex-types or ex-holotypes. The strains isolated and sequenced in this study are shown in red. Branches shortened to fit the page are represented by double slashes “ // ” and folds “ × ”. The scale in the bottom centre indicates 0.2 substitutions per site.

Figure 2. Gongronella abortosporangia ex-holotype CGMCC 3.27028 a, b colonies on PDA (a obverse b reverse) c an unbranched sporangiophore with a mature sporangium d an unbranched sporangiophore with an immature sporangium e an aborted sporangium with two septa f columellae, collars and apophyses g, h, j branched sporangiophores with sterile (aborted) sporangia i a branched sporangiophore with a mature sporangium, columellae, collars and apophyses k rhizoids l, m giant cells n sporangiospores. Scale bars: 10 μm (c – n).