Aspergillus dhakephalkarii Rajeshk., Harik. & Visagie, 2025

Harikrishnan, Kuniyil, Rajeshkumar, Kunhiraman C., Patil, Ravindra M., Jeewon, Rajesh & Visagie, Cobus M., 2025, Aspergillus dhakephalkarii and A. patriciawiltshireae spp. nov., two new species in Aspergillus sect. Nigri ser. Japonici (Eurotiales, Aspergillaceae) from India, Phytotaxa 695 (1), pp. 57-79 : 64

Aspergillus dhakephalkarii Rajeshk., Harik. & Visagie , sp. nov. ( Figures 3 , 4 )

MycoBank No. MB854231

Etymology: Named after Dr. Prashant K. Dhakephalkar (Director, MACS Agharkar Research Institute, Pune) for his invaluable contributions to Indian industrial microbiology and bioenergy research.

Holotype: INDIA, Kerala, Kannur, Aniyaram , 11.72416°N, 75.584167°E, from soil associated with Anthurium andraeanum (rhizosphere), 29 January 2023, Harikrishnan K & Rajeshkumar KC (holotype AMH 10690 [dried culture], ex-holotype NFCCI 5750 [living culture]).

Diagnosis: Phylogenies resolve Aspergillus dhakephalkarii as a distinct lineage in series Japonici . Aspergillus dhakephalkarii produces uniseriate conidiophores with ellipsoidal, smooth-walled conidia. Aspergillus saccharolyticus ( Sørensen et al. 2011) is its closest relative ( Figure 1 ), but this species and other uniseriate species of series Japonici typically produce globose, subglobose or ellipsoidal conidia with echinulate or roughened walls. Furthermore, A. dhakephalkarii produces yellowish white (4A2) to yellowish orange (4A6–B7) sclerotia on OA and lacks acid production on CREA , while its closest relative typically lacks sclerotia and produces acid on CREA . See Table 2.

Classification: Aspergillus subg. Circumdati sect. Nigri ser. Japonici .

Description: Colony diam (25 ˚C, 7 d, in mm): CREA 29–30; CYA>70; CYA 30 ˚C>70; CYA 37 ˚C 10–12; CY20S>70; CZ 39–40; DG18 38–40; MEA 55–60; MEA 30 ºC 59–62; MEA 37 ˚C 14–16; MEAbl 53–57; M20S;>70; OA 55–58; YES>70.

Colony characters (25 ˚C, 7 d): CYA: Colony surface velutinous, radially sulcate, margins irregular; mycelia white (1A1); sporulation dense, brown (7E4); exudates and soluble pigments absent; reverse white (1A1). CYA20S: Colony surface velutinous, margins irregular; mycelia white (1A1); sporulation dense, greyish brown (8E3); exudates and soluble pigments absent; reverse greyish yellow (4B4) at the centre, white (1A1) at the margin. CZ: Colony surface velutinous, plain, margins irregular; mycelia white (1A1); sporulation absent; exudates and soluble pigments absent; reverse hyaline. DG18: Colony surface velutinous, plain, margins irregular; mycelium white (1A1); sporulation sparse; exudates and soluble pigments absent; reverse hyaline. MEA : Colony surface velutinous, margins irregular; mycelia white (1A1); sporulation dense, greyish brown (8E3); exudates and soluble pigments absent; reverse yellowish white (4A2). MEAbl: Colony surface velutinous, margins irregular; mycelia white (1A1); sporulation dense, greyish brown (8E3); exudates and soluble pigments absent; reverse yellowish white (4A2). M20S: Colony velutinous, margins irregular; mycelia white (1A1); sporulation dense, greyish brown (8E3); exudates and soluble pigments absent; reverse yellowish white (4A2). OA: Colony surface velutinous, margins irregular; mycelia white (1A1); sporulation moderate, dark brown (8F4); reverse white (1A1); sclerotia present, yellowish white (4A2) to yellowish orange (4A6–B7). YES: Colony surface velutinous, irregularly sulcate, margins irregular; mycelia white (1A1); sporulation dense, greyish brown (5E5); reverse pale orange (5A3) at centre, orange-white (5A2) at margin. CREA : Colonies weak growth, acid not produced.

Conidiophores uniseriate, radiate, splitting into 2–3 columns. Stipes 200–400 × 8–13 μm, hyaline, smooth. Vesicles 25–50 μm wide, globose to subglobose. Phialides 7–9 × 2.5–4 μm flask-shaped, covering the entire surface of the vesicle. Conidia 4.5–6.5 × 2.5–4 μm, brown, ellipsoidal, smooth. Ascomata not observed. Sclerotia 400–800 μm diam, yellowish white (4A2) when young, yellowish orange (4A6–B7) when mature.

Additional material examined: INDIA, Maharashtra, Pune, Mulshi, 18.460278°N 73.442222°E, from soil, 28 July 2023, Harikrishnan K & Rajeshkumar KC ( AMH 10691, NFCCI 5751).

Figures

FIGURE 1. Phylogenetic tree of Aspergillus section Nigri series Japonici based on a concatenated dataset of BenA, CaM, and RPB2 sequences. Strains of the new species are shown in bold orange text.

FIGURE 3. Aspergillus dhakephalkarii (NFCCI 5750T): A. Colonies on CYA after 3 days at 25± 2 °C, B. Colonies on MEA after 3 days at 25± 2 °C, C. CREA obverse, D. CZ obverse, E. DG18 obverse, F. CYA20S obverse, G. OA (natural) obverse, H. YES obverse, I–L. Conidial heads (MEA), M–P. Sclerotia (OA), Q–U. Splitting of Conidia head. Scale bars: I, M = 1 mm. J, L, Q–U = 200 µm.

FIGURE 4. Aspergillus dhakephalkarii (NFCCI 5750T): A. Developing conidiophore, B–I. Conidiophores, J, K. Conidia. Scale bars: A–F, H = 20 µm. G, I = 10 µm. J–K 10 µm.