Fusarium curvatum associated with lettuce wilt in Türkiye: Species-level identification and pathogenicity
Physiological and Molecular Plant Pathology, cilt.145, 2026 (SCI-Expanded, Scopus)
- Yayın Türü: Makale / Tam Makale
- Cilt numarası: 145
- Basım Tarihi: 2026
- Doi Numarası: 10.1016/j.pmpp.2026.103352
- Dergi Adı: Physiological and Molecular Plant Pathology
- Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, BIOSIS, Academic Search Ultimate (EBSCO)
- Anahtar Kelimeler: Cryptic species, Fusarium curvatum, Fusarium oxysporum species complex, Lettuce wilt, Multilocus phylogeny
- Ankara Üniversitesi Adresli: Evet
Özet
The genus Fusarium comprises highly diverse soil-borne fungi responsible for destructive diseases in numerous agricultural crops, with vascular wilt posing a major constraint in intensive vegetable production. Lettuce wilt has traditionally been attributed to Fusarium oxysporum f. sp. lactucae ; however, recent taxonomic revisions within the Fusarium oxysporum species complex (FOSC) have revealed cryptic species with distinct pathogenic potential. Field surveys conducted in Sakarya and Ankara provinces of Türkiye between September and October 2025 revealed wilt symptoms associated with vascular discoloration in commercial lettuce fields. Disease incidence across surveyed locations ranged from 8% to 20%, and Fusarium isolates were recovered from symptomatic plants. Six isolates obtained during these surveys were combined with five archived Turkish isolates (2019–2023) and one reference strain from the Netherlands, resulting in a total of 12 isolates subjected to phylogenetic and pathogenicity analyses. Multilocus phylogenetic analyses based on partial sequences of tef1 , cmdA , and rpb2 consistently placed all isolates within the Fusarium curvatum clade, clearly distinct from F. oxysporum sensu stricto. Pathogenicity assays confirmed that all isolates were pathogenic to lettuce, with mean disease severity values ranging from 45.0% to 92.5%. A preliminary host-reaction assay revealed significant differences among lettuce types under controlled conditions, with Romaine showing the lowest mean disease severity among the tested types. These findings provide species-level evidence that F. curvatum is associated with lettuce Fusarium wilt in Türkiye and confirm the pathogenicity of representative Turkish isolates under controlled conditions. Although broader surveys and additional pathogenicity studies will be needed to define its epidemiological importance, the present study establishes a multilocus baseline and provides locally obtained isolates that can support future diagnostic and resistance-screening efforts.