Mucor aseptatophorus V.G. Hurdeal, E. Gentekaki, K.D. Hyde & H.B. Lee, 2021

Hurdeal, Vedprakash G., Gentekaki, Eleni, Hyde, Kevin D., Nguyen, Thuong T. T. & Lee, Hyang Burm, 2021, Novel Mucor species (Mucoromycetes, Mucoraceae) from northern Thailand, MycoKeys 84, pp. 57-78 : 57

Mucor aseptatophorus V.G. Hurdeal, E. Gentekaki, K.D. Hyde & H.B. Lee sp. nov.

Figs 1 , 2

Etymology.

Named after the aseptate sporangiophores produced by this species.

Holotype.

MFLU 21-0145

Gene sequences.

(ITS) MZ433252; (LSU) MZ433249

Diagnosis.

Mucor aseptatophorus is phylogenetically distinct from M. irregularis . In the phylogenetic analysis, M. aseptatophorus groups as sister to two Mucor sp. and all of them cluster as sister to the clade formed by M. irregularis strains with high bootstrap support. In contrast to M. irregularis , the ellipsoidal, cylindrical, or pyriform columella are not observed in M. aseptatophorus . Columella formed in the latter are globose. Mucor aseptatophorus has smaller sporangiospores (3.5-5 × 2-2.5 µm), slightly bigger sporangia, forms sympodial, and monopodial branching of sporangiospores and has a lower growth rate than M. irregularis . The species differs from M. merdicola and M. nidicola , by having smaller columella, sporangia and sporangiospore. Compared to M. souzae , sporangiophores in M. aseptatophorus are aseptate (below sporangia). Septation, when observed, is usually present at the branching point. Septae below the sporangia rarely observed.

Material examined.

Thailand. Chiang Mai Province, Omkoi District , Sop Khong , 17°45'25"N; 98°20'21"E, from soil, 24th October 2019, collected by Oundhyalah Devi Padaruth, and isolated by Vedprakash Godadhar Hurdeal, ex-type living culture, MFLUCC 21-0040.

Description.

Asexual morph (based on cultures grown in MEA at 25 °C): Sporangiophores hyaline to pale brown, variable in length, erect, arising directly from the substrate, up to 17 µm in width (x - = 8.5 µm, n = 30), sympodial, and monopodial, with occasional circinate branches (mostly sympodial branches), and no septae observed. Sporangia 18-56.5 × 19-54 µm (x - = 41.5 × 41.5 µm, n = 40), globose to subglobose, smooth-walled, thick-walled and persistent, yellow to pale brown. Columellae 13-35 × 14-37.5 µm (x - = 19 × 20 µm, n = 40), globose, with very short collar, hyaline to pale brown, non-collapsing, smooth-walled. Sporangiospores 3.5-6 × 2-4 µm (x - = 4 × 3 µm, n = 70), mostly ellipsoidal, occasionally oval to globose, some irregular, hyaline. Chlamydospores and rhizoids present. Sexual morph not observed.

Culture characteristics.

Colonies on MEA reaching 62 mm diameter after 2 days of incubation at 25 °C. Colony white at first, becoming pale yellow with age; reverse pale yellow. Colony fully covers the Petri plate (90 mm) by the third day at 25 and 30 °C but does not reach the lid of the plate. At 20 °C, colony reaches a diameter of 70.5 mm after 3 days. Vertical growth is lower at 25 and 30 °C than at 20 °C. The colony does not reach the lid after 3 days. At 30 °C, sporulation is excellent, with branching of sporangiophore more frequent than in others. Monopodial branching more prominent but sympodial and dichotomous branches also observed. On PDA, cultures are white and pale brown in the middle with grey to pale brown sporangia. Colony reaching 64 mm diameter after 3 days of incubation at 25 °C. Optimal growth and excellent sporulation were observed on both MEA and PDA media at 30 °C. At 37 and 8 °C in MEA, growth is observed but with no sporulation. The colony reaches a diameter of 31 mm at 37 °C after 3 days. At 8 °C, the colony reaches a diameter of 14 mm after 9 days. Growth is observed at temperatures ranging from 8 to 37 °C.

Distribution.

Thailand.

Figures

Figure 1. Maximum likelihood phylogram inferred from 102 taxa and 2017 characters based on ITS, and LSU matrix using GTR + G + I model and partition analysis. Maximum likelihood bootstrap support (≥ 70 %) and Bayesian posterior probability (≥ 0.70) are indicated above the branches or near the nodes in this order. The tree is artificially rooted using Backusella dispersa (CBS 195.28), and B. grandis (CBS 186.87). The new species are in bold and the type species in the dataset are indicated using T. (-) represent bootstrap support lower than 70 % or posterior probability lower than 0.70.

Figure 2. Mucor aseptatophorus (MFLU 21 - 0145) a-c columella with collar d branching of sporangiophores e, f developing sporangium g short sporangiophore with sporangium h rhizoids i granular content in mycelium j sporangiospores k front and reverse of the colony in MEA. Scale bars: 10 µm (a-c, e-h, j); 20 µm (d, i).