RNA silencing of PEX6 gene causes decrease in pigmentation, sporulation and pathogenicity of Fusarium oxysporum

Peroxisomes are single membrane‐bound organelles that play a pivotal role in various developmental processes in all eukaryotic cells. This study targeted the PEX 6 gene, which encodes for peroxisomal biogenesis factor 6, by RNA interference (RNA i) in Fusarium oxysporum f. sp. lycopersici . Fusarium oxysporum is a soilborne filamentous, hemibiotrophic fungus that invades tomato roots and colonizes the xylem vessels, thereby causing complete wilting of infected tomato plants. The expression of FoPEX 6 in F. oxysporum was found to be higher during early stages of growth and development. The FoPEX 6 gene was isolated and a hairpin RNA i construct was prepared and introduced into F. oxysporum 4471 through glass‐bead transformation. The fungal transformation status, i.e. integration, expression and presence of the intended small interfering RNA s (siRNA s), was confirmed by PCR , qPCR and stem‐loop PCR , respectively. The silenced fungal transformants exhibited reduced pigmentation and a significant reduction in sporulation as compared to the wild type. They also showed dramatic reduction in pathogenicity (virulence) on tomato, based on root infection and fruit invasion assays. These results suggest that PEX 6 has a central role in pigmentation, sporulation and pathogenicity in F. oxysporum .