Endophytic fungi associated with cucumber (Cucumis sativus) leaves and stems

Abstract

Endophytic fungi were isolated from healthy leaves and stems of cucumber (Cucumis sativus) cultivars and lines from five major cucumber-growing regions of Iran. Out of 243 endophytic fungal isolates obtained 161 (66.25) isolates were isolated from leaves and 82 isolates (33.74) from stems. However, we only isolated and identified endophytic fungi that were culturable. Forty-one isolates representing individual morphospecies were used for phylogenetic analyses based on the internal transcribed spacer of the ribosomal DNA (ITS rDNA) as well as the ribosomal large subunit (LSU rDNA) regions. The results showed that the endophytic fungi belonged to the Phylum Ascomycota within which there are five classes of Sordariomycetes, Dothideomycetes, Eurotiomycetes, Pezizomycetes and Laboulbeniomycetes as well as to the Phylum Basidiomycota where only the class Agaricomycetes exists. Members of the Sordariomycetes and Dothideomycetes were the most frequently isolated fungi (20.58 and 55.14 respectively) and contained the richest genus composition (46.15 and 25.64 respectively). In contrast, Laboulbeniomycetes and Pezizomycetes were the least abundant (0.41 and 1.23 respectively) and had the lowest genus richness (2.56 for each). Eurotiomycetes had intermediate abundance (18.52) and genus richness (17.95) and Agaricomycetes isolation frequency (4.11) and genus richness (5.13) were also low. Stagonosporopsis sp. UT-St was the most abundant species (27.98) followed by Cladosporium sp. UT-Cl (9.46), Penicillium sp. UT-Pe2 and Podospora anserina UT-Po (7.82 for each) Aspergillus sp. UT-As2 (6.58) and Fusarium sp. UT-Fu2 (5.76). Greater endophyte genus richness was observed in leaves with 22 species compared to seven species observed in stems and 10 were shared by both leaves and stems. © Indian Phytopathological Society 2025.