Fusarium concentricum Nirenberg & O'Donnell , Mycologia 90 (3): 442 (1998)

He, Jiao, Li, De-Wei, Cui, Wen-Li, Zhu, Li-Hua & Huang, Lin, 2024, Morphological and phylogenetic analyses reveal three new species of Fusarium (Hypocreales, Nectriaceae) associated with leaf blight on Cunninghamia lanceolata in China, MycoKeys 101, pp. 45-80 : 45

Fusarium concentricum Nirenberg & O'Donnell, Mycologia 90 (3): 442 (1998)

Description.

Sexual state not observed. Asexual state: sporulation abundant from sporodochia, rarely from conidiophores formed directly on the substrate mycelium. Conidiophores in the aerial mycelium branched, bearing terminal or intercalary monophialides, often reduced to single phialides. Phialides subulate to subcylindrical, smooth, thin-walled, (2.3-)4.9-15.5(-18.3) × (1.1-)1.4-2.8(-3.5) μm, (mean ± SD = 10.2 ± 5.3 × 2.1 ± 0.7 μm, n = 9), without periclinal thickening. Microconidia in the aerial mycelium hyaline, ellipsoidal to falcate, smooth, thin-walled, 0-1-septate, (3.8-)5.9-9.1(-11.3) × (1.9-)2.5-3.4(-4.3) μm (mean ± SD = 7.5 ± 1.6 × 3.0 ± 0.5 μm, n = 60), forming small false heads on the tips of monophialides. Sporodochia pale orange colored, formed abundantly on carnation leaves. Conidiophores in sporodochia (27.7-)40.6-49.8(-51.7) μm, (mean ± SD = 45.2 ± 4.6 μm, n = 35), verticillately branched and densely packed, bearing apical whorls of 2-3 monophialides or rarely single lateral monophialides; sporodochial phialides subulate to subcylindrical, (9.5-)11.4-16.5(-20.4) × (2.2-)2.7-4.0(-4.7) μm, (mean ± SD = 13.9 ± 2.5 × 3.4 ± 0.6 μm, n = 45), smooth, thin-walled. Sporodochial macroconidia falcate, curved dorsiventrally with almost parallel sides tapering slightly towards both ends, with a blunt to papillate, curved apical cell and a foot cell, 3-septate, (23.2-)30.2-40.5(-43.7) × (3.4-)3.9-4.9(-5.5) μm, (mean ± SD = 35.3 ± 5.2 × 4.4 ± 0.5 μm, n = 60), 4-septate, (35.5-)38.0-48.8(-49.4) × (3.4-)3.4-4.3(-4.4) μm, (mean ± SD = 43.4 ± 5.4 × 3.9 ± 0.4 μm, n = 10), 5-septate, (49.5-)49.7-57.2(-59.1) × (3.5-)3.6-4.2(-4.2) μm, (mean ± SD = 53.4 ± 3.6 × 3.9 ± 0.3 μm, n = 10), hyaline, thin- and smooth-walled. Chlamydospores absent.

Culture characteristics.

Colonies on PDA growing in the dark with an average growth rate of 9.3 mm/d at 25 °C. Colony surface white to pale purple, flat or slightly raised at the center; colony margins irregular, filiform. Reverse light yellow. Odor absent. Colonies on SNA incubated at 25 °C in the dark were regular, round, aerial mycelium absent or scant, growing at 13.1 mm/d. Colonies on OMA incubated at 25 °C in the dark were regular, round, aerial mycelium abundant, loose to densely floccose, growing at 13.2 mm/d. Reverse light purple. Colonies on CMA incubated at 25 °C in the dark were regular, round, colony surface and reverse pale gray at the center, aerial mycelium absent or scarce, growing at 11.9 mm/d.

Materials examined.

China, Guangxi Zhuang Autonomous Region, Liuzhou City , Sanjiang Dong Autonomous County, Guyi Town , 25°25′48″N, 109°28′47″E, isolated from leaf spots of Cunninghamia lanceolata , May 2017, Wen-Li Cui, isolates: SJ1-10, SJ1-10-1, SJ1-10-2, SJ1-10-3 .

Notes.

The isolate SJ1-10 in this study was in the same clade with F. concentricum CBS 450.97 (ex-type). Morphologically, 0-septate microconidia (3.8-11.3 × 1.9-4.3 μm) of the isolate SJ1-10 were similar with the 0-septate microconidia (7.0-12.2 × 2.3-3.9 μm) of the ex-type (CBS 450.97) of F. concentricum ( Nirenberg and O’Donnell 1998). Five-septate macroconidia (49.5-59.1 × 3.5-4.2 μm) of the isolate SJ1-10 were similar with the 5-septate macroconidia (49.0-64.8 × 3.6-4.0 μm) of the ex-type (CBS 450.97) of F. concentricum ( Nirenberg and O’Donnell 1998).