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

Figs 1 , 3

Etymology.

The epithet refers to the province of Chiang Rai where the species was isolated.

Holotype.

MFLU 21-0079

Gene sequences.

(ITS) MZ433253; (LSU) MZ433250

Diagnosis.

In contrast to M. nederlandicus , this species produces smaller sporangia and has wider sporangiophores. The sporangia formed by M. nederlandicus are echinulate at maturity, while in M. chiangraiensis they are smooth-walled. This species mostly has subglobose or slightly elongated globose columellae while in M. nederlandicus they are mostly globose. Physiological data indicate that M. nederlandicus has a faster growth than M. chiangraiensis in MEA at 25 °C. Molecular phylogeny indicates that the newly isolated strain groups separately from M. nederlandicus and M. inaequisporus . Comparison with the protologue of M. inaequisporus indicates that M. chiangraiensis has smaller sporangia, columella and sporangiospores. The columellae in the latter are subglobose or slightly elongated globose columellae rather than commonly obovoid-pyriform or subspherical as in M. inaequisporus . Although the shape and size of sporangiospores are often variable in both species, the majority of spores of M. chiangraiensis are ellipsoidal. Sporangiospores are usually colorless and hyaline as compared to pale or greenish-yellow in M. inaequisporus .

Material examined.

Thailand. Chiang Rai Province, Doi Chang District , 19°49'9.984"N; 99°34'36.768"E, from soil, 7th December 2019, collected and isolated by Vedprakash Godadhar Hurdeal, ex-type living culture, MFLUCC 21-0042.

Description. Asexual morph (based on cultures grown in MEA at 25 °C): Sporangiophores hyaline, up to 12 µm (x - = 6, n = 30) in diameter, erect, unbranched or sympodial branches. Hyphae irregular septate, with occasional hyphal bulges. Sporangia 18-40.5 × 18.5-40.5 µm (x - = 28.5 × 27.5 µm, n = 30), globose, wall resistant, deliquescent, hyaline to pale brown. Columellae 12.5-23.5 × 11.5-23 µm (x - = 19 × 17 µm, n = 30), subglobose or slightly elongated globose columellae, obovoid, ellipsoid and sometimes round to subglobose without or with short collar, hyaline to pale brown, smooth-walled. Sporangiospores 4-6.5 × 2-3.5 µm (x - = 5 × 2.5 µm, n = 50) µm, mostly ellipsoidal, oval, smooth-walled, hyaline. Chlamydospores abundant, intercalary, terminal, variable in shape and size. Rhizoids absent. Sexual morph not observed.

Culture characteristics.

Day-old cultures are white, cottony, floccose, have erect sporangiophores with hyphae reaching the lid of the Petri plate in MEA. The white color of the colony persists even after 6 days. At maturity, the colony reverse is white or pale yellow. On MEA at 25 °C, the colony reaches a diameter of 51 mm after 3 days of incubation. At 20 and 30 °C, the colony reaches a diameter of 47 mm and 44.5 mm respectively after 3 days. Sporulation is excellent at 20 to 30 °C. At 30 °C, mostly unbranched sporangiophores are observed with few sympodial branches. On PDA at 25 °C, colony reaches a diameter of 48 mm after 3 days of incubation. The front and reverse of the colony are white in both MEA and PDA. Growth is observed at temperatures ranging from 8 to 30 °C. Optimal growth and excellent sporulation were observed at 25 °C on both MEA and PDA media. No growth was observed at 37 °C. At 8 °C in MEA, the colony reached a diameter of 34 mm after 9 days but with no sporulation.

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 3. Mucor chiangraiensis (MFLU 21 - 0079) a-e columella with and without collars f, g sporangia h-i chlamydospores j sporangiospores k front and reverse of the colony grown in MEA. Scale bars: 10 µm (a-j).