Fusarium fujianense Lin Huang, Jiao He & D.W. Li, 2024

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 fujianense Lin Huang, Jiao He & D.W. Li sp. nov.

Fig. 6

Etymology.

Epithet is after Fujian province where the type specimen was collected.

Holotype.

China, Fujian Province, Nanping City, Shunchang County, Yangkou Forest Farm, 26°48′36″N, 117°52′48″E, isolated from leaf spots of Cunninghamia lanceolata , May 2017, Wen-Li Cui, (holotype: CFCC 57576). Holotype specimen is a living specimen being maintained via lyophilization at the China Forestry Culture Collection Center (CFCC). Ex-type (LC14) is maintained at the Forest Pathology Laboratory, Nanjing Forestry University.

Host/distribution.

From C. lanceolata in Yangkou Forest Farm, Shunchang County, Nanping City, Fujian Province, China.

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 unbranched, bearing terminal or intercalary monophialides, often reduced to single phialides. Phialides subulate to subcylindrical, smooth, thin-walled, (9.2-)10.3-16.3(-18.0) μm × (2.5-)2.6-3.4(-3.6) μm, (mean ± SD = 13.3 ± 3.0 μm × 3.0 ± 0.4 μm, n = 11), without periclinal thickening; microconidia subcylindrical to clavate, hyaline, smooth- and thin-walled, 0-septate, (5.6-)6.0-8.2(-8.3) μm × (1.9-)2.1-2.5(-2.7) μm, (mean ± SD = 7.1 ± 1.1 μm × 2.3 ± 0.2 μm, n=11), forming small false heads on the tips of monophialides. Sporodochia pale orange colored, formed abundantly on PDA after 40 days. Conidiophores in sporodochia (9.7-)18.8-31.5(-37.9) μm, (mean ± SD = 25.1 ± 6.4 μm, n = 37), irregularly branched and densely packed, bearing apical whorls of monophialides or 2-3 ployphialides; sporodochial phialides subulate to subcylindrical, (5.6-)10.0-16.1(-18.8) × (1.4-)2.5-3.9(-4.8) μm, (mean ± SD = 12.7 ± 3.4 × 3.2 ± 0.7 μm, n = 39), smooth, thin-walled. Sporodochial mesoconidia falcate, curved dorsiventrally with almost parallel sides tapering slightly towards both ends, with a blunt to papillate, curved apical cell and a foot-like basal cell, 1-septate, (21.8-)22.0-23.6(-23.8) × (4.7-)4.9-5.3(-5.3) μm, (mean ± SD = 22.8 ± 0.8 × 5.1 ± 0.2 μm, n = 6), macroconidia 4-6-septate, (40.2-)45.9-59.1(-63.4) × (4.5-)4.8-5.8(-6.9) μm, (mean ± SD = 52.5 ± 6.6 × 5.3 ± 0.5 μm, n = 18), hyaline, smooth, thin-walled. Chlamydospores absent.

Culture characteristics.

Colonies on PDA growing in the dark with an average growth rate of 6.2 mm/d at 25 °C. Colony surface white to red, flat or slightly raised at the center; colony margins regular, round. Reverse red with white periphery. Odor absent. Colonies on SNA incubated at 25 °C in the dark were regular, round, growing at 5.4 mm/d. Colony surface pure white, aerial mycelium abundant. Reverse pure white, without diffusible pigments. Colonies on OMA incubated at 25 °C in the dark were regular, round, aerial mycelium abundant, loose to densely floccose, growing at 6.0 mm/d. Reverse red with white periphery. Colonies on CMA incubated at 25 °C in the dark were regular, round, colony surface and reverse red with white periphery, aerial mycelium absent or scant, growing at 7.1 mm/d.

Additional materials examined.

China, Fujian Province, Nanping City, Shunchang County, Yangkou Forest Farm , 26°48′36″N, 117°52′48″E, isolated from leaf spots of Cunninghamia lanceolata , May 2017, Wen-Li Cui, isolates: LC14-1, LC14-2, LC14-3 .

Notes.

The isolates of F. fujianense were phylogenetically closely related to F. citri-sinensis (ex-type, YZU 191316), F. cassiae (ex-holotype, MFLUCC 18-0573), and F. stilboides (ex-type, CBS 746.79) (Fig. 2 ). Between F. fujianense isolates and ex-type of F. citri-sinensis YZU 191316, there were 13/672 differences in TEF-1α, and 8/776 in RPB2. Between F. fujianense isolates and ex-holotype of F. cassiae MFLUCC 18-0573, there were 25/672 differences in TEF-1α, and 7/776 in RPB2. Between F. fujianense isolates and ex-type of F. stilboides CBS 746.79, there were 16/672 differences in TEF-1α, and 2/776 in RPB2. The RPB1 sequences of F. stilboides CBS 746.79, F. cassiae MFLUCC 18-0573, and F. citri-sinensis YZU 191316 were missing. The PHI analysis showed that there was no significant recombination between F. fujianense isolates and its related species (Φw = 0.2461) (Fig. 3A ). Morphologically, F. fujianense differed from F. citri-sinensis in colony characteristics on PDA. The former developed dense mycelia and abundant red pigmentation, while the latter was characterized by sparse and loose aerial mycelia and pale pink pigment ( Zhao et al. 2022). F. fujianense can be differentiated from F. cassiae in having abundant red pigmentation produced in PDA vs. without diffusible pigments in F. cassiae ( Perera et al. 2020). F. fujianense can be distinguished from F. stilboides by having different 0-septate conidia (5.6-8.3 × 1.9-2.7 μm vs. 7-14 × 2-2.5 µm) ( Booth and Waterston 1964). Thus, F. fujianense is recognized as a novel species in F. lateritium species complex.

Figures

Figure 2. Phylogenetic relationships of 16 isolates of the Fusarium lateritium species complex with related taxa with concatenated sequences of the TEF- 1 α, RPB 2, and RPB 1 loci using Bayesian inference (BI) and maximum likelihood (ML) methods. Bootstrap support values from ML ≥ 70 % and BI posterior values ≥ 0.9 are shown at nodes (ML / BI). Fusarium sublunatum CBS 189.34 T was the outgroup. * indicates strains of this study. T indicates the ex-type strains. LT: Ex-lectotype, NT: Ex-neotype, HT: Ex-holotype.

Figure 3. Splitgraphs showing the results of the pairwise homoplasy index (PHI) test of three newly described taxa and closely related species using both LogDet transformation and splits decomposition A the PHI of Fusarium fujianense sp. nov. with their phylogenetically related isolates or species B the PHI of F. hunanense sp. nov. with their phylogenetically related isolates or species C the PHI of F. guizhouense sp. nov. with their phylogenetically related isolates or species. PHI test value (Φw) <0.05 indicate significant recombination within a dataset. * indicates isolates of this study. T indicates ex-types. HT indicates ex-holotypes.

Figure 6. Fusarium fujianense (LC 14) A-D colonies on PDA, SNA, OMA, and CMA, respectively, after 5 days at 24 ° C in the dark E, F sporodochia formed on PDA G, H aerial conidiophores, phialides, and microconidia I-L sporodochial conidiophores, phialides, and macroconidia M mesoconidium (1 - septate) and macroconidia (4 - 6 - septate). Scale bars: 200 μm (E, F); 10 μm (G-M).