Speaker
Description
Morphological and Molecular Characterization of Biscogniauxia mediterranea Isolates Associated with Almond Canker in Portugal
Ana Faustino¹˒², Liliana Marum¹˒², Orges Cara³, Marilita Gallo³, Toufic Elbeaino³
¹ CEBAL/IPBeja, 7801-908 Beja, Portugal
² MED & CHANGE, CEBAL, 7801-908 Beja, Portugal
³ CIHEAM Bari, Via Ceglie 9, 70010 Valenzano, Bari, Italy
Abstract
Biscogniauxia mediterranea, an opportunistic fungal pathogen mainly associated with charcoal canker of cork oak and other woody hosts, was recently detected in symptomatic almond trees in Beja, Portugal. Its pathogenicity on almond was subsequently confirmed, representing the first reported association of this pathogen with cultivated almond in Portugal and worldwide. This study characterized three isolates obtained from symptomatic almond trees using cultural, morphological, and molecular approaches and assessed their variability and pathogenic potential.
Colony growth, pigmentation, mycelial morphology, and sporulation were evaluated on PDA-based media under controlled conditions. Genomic DNA was extracted, and the ITS, LSU, TEF1-α, and β-tubulin regions were amplified by PCR and sequenced using the Sanger method. Sequence data were compared to evaluate genetic variability. Pathogenicity tests were also conducted on different almond cultivars to assess isolate virulence and host response.
All isolates showed rapid mycelial growth but differed markedly in colony density, radial growth pattern, surface and reverse pigmentation, concentric colour zoning, and sporulation. Acidified PDA generally enhanced pigmentation. Two isolates produced conidia under near-UV light, whereas the third remained non-sporulating. Differences in conidial size and morphology further demonstrated substantial phenotypic variability. Molecular analysis of the four loci revealed genetic variation among all isolates, consistent with their distinct cultural traits and suggesting biologically differentiated genotypes or strains. Pathogenicity assays are ongoing to clarify isolate virulence, host susceptibility, disease aetiology, and host–pathogen interactions.
Keywords: Biscogniauxia mediterranea; almond canker; genetic variability; pathogenicity
Reference
Faustino, A., Marinho, C., Oliveira, M.M., Félix, M.R. & Marum, L. (2025). Phytopathologia Mediterranea*, 64(2), 191–197.
| Are you participating to the "AnaEE Environmental Rising Star Award "? | Yes |
|---|