Morphological, cultural, molecular, and pathogenic characterization of Cladosporium proteacearum causing leaf and fruit blight on sweet pepper in the central Ecuadorian highlands

Pallo E.; Garcés-Fiallos F.R. · Physiological and Molecular Plant Pathology (2026) · DOI: 10.1016/j.pmpp.2026.103130

Resumen

In this work, we aimed to identify and characterize the causal agent of leaf and fruit blight on sweet pepper ( Capsicum annuum L.) in the central Ecuadorian highlands (Chimborazo and Tungurahua provinces) through morpho-cultural and molecular analysis, as well as pathogenicity tests. We obtained six strains (UTAC2023M1 … UTAC2023M6) in six different locations in the provinces of Chimborazo and Tungurahua. All these exhibited an olive-green coloration and morphological characteristics consistent with the diagnostic traits typically associated with members of the Cladosporium genus. Similar morphometry such as septate mycelium (width = P ≤ 0.2762 and 4.61 ± 0.38 μm), micronematous conidiophores (length = P ≤ 0.7715 and 30.83 ± 2.25 μm), microconidia (width = P ≤ 0.6472 and 2.61 ± 0.48; length = P ≤ 0.0994 and 5.00 ± 0.58), was observed in all strains. Additionally, ramoconidia was also observed but not quantified. Mycelial growth and slope were higher in strains UTAC2023M2, UTAC2023M3, and UTAC2023M1 than in other strains. Phylogenetic analysis of strains UTAC2023M1 and UTAC2023M6, based on the concatenation of the genes encoding actin, elongation factor 1 alpha, and internal transcribed spacer, confirmed the identification of the fungal species as Cladosporium proteacearum . Pathogenicity tests showed that all strains can cause leaf and fruit blight, with UTAC2023M1 being the most aggressive. To our knowledge, this is the first report of C. proteacearum causing leaf and fruit blight in sweet pepper crops worldwide. Copyright

Instituciones: Universidad Nacional de Trujillo