Longisporomyces filisporum X. Yu. Zhang, Q. Y. Zhang & B. Fan, 2025

Longisporomyces filisporum X. Yu. Zhang, Q. Y. Zhang & B. Fan sp. nov.

Fig. 12 View Figure 12

Etymology.

referring to the distinctive filiform (thread-like) conidia produced by this species.

Type.

CHINA • Jiangsu Province, Nanjing, Nanjing Forestry University, Baima Campus , fungal endophytes from Pinus densiflora , May 2023, Ben Fan and Xiuyu Zhang, NF 595 ( holotype HMAS 352956 View Materials , culture ex-type CGMCC 3.29108 View Materials ) .

Description.

Mycelium composed of hyaline, smooth, multi-septate, branched, uniform hyphae in width, slender, 1.4–2.6 μm diam. Many aerial hyphae are clustered in bundles, thicker at the base and tapering upwards on MEA (Fig. 12 D, G View Figure 12 ). Asexual state: Conidiophores and conidiogenous cells absent or conidiophores reduced to conidiogenous cells. Conidiophores not obvious when present, and conidia developing directly from the ends or sides of hyphae. Conidia multiseptated, filiform or slightly flexuous, slender, hyaline, smooth, (9.9 –) 14.3–35.3 (– 52.2) × (1.5 –) 2.0–3.0 (– 3.5) μm (Fig. 12 E, H View Figure 12 ). Sexual state unknown.

Culture characteristics.

Colonies on MEA, with a fluffy surface, pale yellow to off-white in colour, and irregular edges. In contrast, colonies grown on OA and SNA medium are transparent to white, dense, with irregularly lobed edges and few aerial hyphae. The optimal temperature for growth was 20–25 ° C, reaching 8–12 mm diam in 10 days. No growth at 5 ° C and 35 ° C.

Additional specimen ( paratype) examined. CHINA • Jiangsu Province, Nanjing, Nanjing Forestry University, Baima Campus , fungal endophytes from Pinus densiflora , May 2023, Ben Fan and Xiuyu Zhang, paratype NF 692 .

Notes.

In the present study, the novel genus Longisporomyces was established to accommodate isolates producing filiform conidia, represented by Longisporomyces filisporum (NF 595 and NF 692). Phylogenetic analyses within Mycosphaerellaceae (Fig. 4 View Figure 4 ) revealed that Longisporomyces forms a well-supported clade (BS = 100 %, BPP = 1.00) and is sister to the clade containing Xenosonderhenioides indonesiana C. Nakash., Videira & Crous. It is clearly distinct from the genera Xenosonderhenia Crous and Xenomycosphaerella Quaedvl. & Crous.

Phylogenetically, Longisporomyces forms a well-supported, distinct lineage that is sister to a highly supported clade containing Xenomycosphaerella , Xenosonderhenia and Xenosonderhenioides . While we retain Longisporomyces as a distinct genus due to its genomic divergence and distinct morphological characteristics. L. filisporum NF 595 shows ITS sequence divergence of 3.98 % (19 / 477 bp) from Xenosonderhenioides indonesiana , 7.78 % (40 / 514 bp) from Xenomycosphaerella elongata , and 6.25 % (30 / 480 bp) from Xenosonderhenia eucalypti . Morphologically, the generic type, Longisporomyces filisporum , is characterized by filiform and flexuous conidia, which are slightly narrower than those of Xenosonderhenioides indonesiana (1.5–3.5 μm vs. 5–6 μm) ( Videira et al. 2017). In addition, conidia of L. filisporum are narrower than those of X. elongata (1.5–3.5 μm vs. 4–5 μm) and have more septa (0–3 vs. 1) ( Crous et al. 2007 c), and they are long-cylindrical, differing from the fusoid-ellipsoid conidia of Xenosonderhenia eucalypti ( Crous et al. 2014 b) .