Microdochium australiana Y. X. Shang, Z. Li & X. G. Zhang, 2025

Microdochium australiana Y. X. Shang, Z. Li & X. G. Zhang sp. nov.

Fig. 2 View Figure 2

Etymology.

Referring to the species name of the host plant, Phragmites australis .

Holotype.

HSAUP 6340-2-6 .

Description.

On leaves of Phragmites australis, Mycelia superficial and immersed, 2.2–2.9 µm wide, branched, membranous, hyaline. Conidiophores straight or slightly curved, aseptate, aggregated in the aerial mycelium, often reduced to conidiogenous cells borne directly from the hyphae. Conidiogenous cells terminal or intercalary, transparent, smooth, cylindric-clavate, 6.2–7.3 × 1.9–3.5 µm. Conidia solitary, cylindrical, ampulliform, 8.2–10.1 × 3.0–4.9 µm, multi-guttulate, 0–2 - septate, apex rounded, base usually flattened. Sporodochia and chlamydospores not observed.

Culture characteristics.

Cultures incubated on PDA at 25 ° C in darkness, reaching 48–50 mm diam, had a growth rate of 6.9–7.1 mm / day after 7 days. The center has obvious milky white aerial mycelium bulge, and the edge grayish, mycelium fluffy, back fawn.

Material examined.

China • Hainan Province, Jianfengling National Forest Park , on leaves of Phragmites australis , 26 June 2024, Y. X. Shang, ( HSAUP 6340-2-6 ), ex-holotype culture SAUCC 6340-2-6 = CGMCC 3.28622 View Materials ; Ibid., ( HSAUP 8723-2 , paratype), living culture SAUCC 8723-2 .

Notes.

Microdochium australiana is closely related to M. miscanthi ( SAUCC 211092 and SAUCC 211093 ) based on DNA sequence data in BLAST searches and phylogenetic analysis (Fig. 1 View Figure 1 ). However, M. australiana differs from M. miscanthi by 28 nucleotides (1 / 541 in ITS, 1 / 866 in LSU, 13 / 730 in tub 2, and 13 / 665 in rpb 2). In morphology, they are distinguished by different hosts ( Phragmites australis vs. Miscanthus sinensis ), and M. australiana colonies on PDA exhibit a prominent, milky white aerial mycelium bulge, with a central pale orange region and a grayish edge. In contrast, M. miscanthi colonies are overall white, featuring a central dark-green plaque covered by white mycelia. Mycelial width (2.2–2.9 µm) in M. australiana vs. (1.5–2.3 µm) in M. miscanthi . Conidia in M. australiana differ from those in M. miscanthi (cylindrical, ampulliform vs. transparent, spindle-to-rod-shaped) ( Liu et al. 2022). Therefore, we establish this fungus as M. australiana sp. nov.