Fusarium purpurea S.L. Han, M. Raza, W.J. Duan & L. Cai, sp. nov.
Index Fungorum number: IF 555883; MycoBank number: MB 555883; Facesoffungi number: FoF 10818; Fig. 1
Etymology – Refers to the pigment produced on PDA and OA, purpure.
Holotype – HMAS 351947.
Asexual morph: Hyphae 1.7–3.5 μm diam, hyaline, smooth-walled, septate, branched. Conidiophores arises on aerial mycelium, unbranched or irregularly branched, 11–29.5×2–4.5 μm (x̄ =19.9×3.0 μm, n=35). Phialides mono- and polyphialide, subulate to subcylindrical, smoothand thin-walled, 4.8–17.4×1.6–3.9 μm, periclinal thickening inconspicuous or absent. Microconidia hyaline, smoothand thin-walled, two types, clavate with truncate base conidia (aseptate): 4.5–9.5×1.5–3.5 μm (x̄ =6.3×2.5 μm, n=50); globose conidia (aseptate): 6.5–11 × 7–11.5 μm (x̄ =9.7×9.4 μm, n=50). Sporodochia and chlamydospores not observed. Sexual morph: Not observed.
Culture characteristics – Colonies on PDA slow growing, reaching 52–57 mm diam in 7 d after incubation at 25 °C in the dark, colony flat, medium, filamentous, felted to velvety, rhizoid; colony from above; raised, dull, wrinkled folded, surface orchid purple (14C8) in the center, white (–A1) at the margin; reverse beetroot purple (13D8) in the center, white (–A1) at the margin; odour absent, not producing pigment in PDA media. On OA reaching 41–49 mm in 7 d after incubation 25 °C in the dark; raised, felted to dusty, with abundant aerial mycelium, margin entire; surface amethyst (15C6) in the center, white (–A1) at the margin; reverse oak brown (5D6); odour absent.
Material examined – Kazakhstan, intercepted at Alashankou Port, isolated at Ningbo Customs, from seeds of Triticum aestivum imported to China, Jan. 2019, W.J. Duan & W.Z. Li (HMAS 351947, holotype), ex-type living culture, CGMCC 3.23515=LC15871. ibid., LC15872; ibid., LC15873; ibid., LC15874.
GenBank numbers – CGMCC 3.23515 – ON365812 (CaM), ON365816 (rpb1), ON365820 (rpb2), ON365828 (tef1), ON365824 (tub2), LC15872 – ON365813 (CaM), ON365817 (rpb1), ON365821 (rpb2), ON365829 (tef1), ON365825 (tub2), LC15873 – ON365814 (CaM), ON365818 (rpb1), ON365822 (rpb2), ON365830 (tef1), ON365826 (tub2), LC15874 – ON365815 (CaM), ON365819 (rpb1), ON365823 (rpb2), ON365831 (tef1), ON365827 (tub2)
Notes – Fusarium purpurea formed a well-supported sister clade to F. globosum with 100% ML and 1.00 Bayesian posterior probabilities (BYPP) support (Fig. 1). Fusarium purpurea differs by 3 bp in the CaM gene, 16 bp in the rpb2 gene, 6 bp in the tef1 gene, and 1 bp in the tub2 gene compared to F. globosum (Proctor et al. 2013; Yilmaz et al. 2021). Morphologically, F. purpurea differs in the types of microconida production and its number of septation. For example, F. purpurea produces two types of microconidia: clavate with a truncate base (aseptate) and globose (aseptate) without papilla, while three types of microconidia were found in F. globosum: clavate with a truncate base (0- to 3-septate), napiform/pyriform, and globose (0- to 1-septate) which often have a distinct papilla (Rheeder et al. 1996; Leslie and Summerell. 2006) (Fig. 2).
Figure 1 – Fusarium purpurea (CGMCC 3.23515, ex-type living culture). a Colony on PDA. b Colony on OA. c-d Aerial conidiophores and phialides. e–f Microconidia. Scale bars=10 μm
Figure 2 – RAxML phylogenetic tree generated from combined CaM, rpb1, rpb2, tef1 and tub2 sequence data of Fusarium fujikuroi species complex. Maximum likelihood bootstrap support values greater than 75% (in blue) and Bayesian posterior probabilities>0.95 (in green) are indicated on the branches. Ex-type and epi-type cultures are indicated in bold with ‘T’ and ‘ET’