Differential accumulation of phenolic compounds in potato in response to weakly and highly aggressive isolates of Verticillium dahliae

Verticillium wilt, caused by the soilborne pathogen Verticillium dahliae (Kleb.), is an important disease affecting more than 400 plant species, including many economic crops. This study explored differential accumulation of phenolic compounds in potato in response to weakly and highly aggressive isolates of this pathogen. After phenolic compounds were extracted from roots, stems and leaves of inoculated plants, those showing differential accumulation were identified using high performance liquid chromatography (HPLC) equipped with a photodiode array detector, a fluorescence detector, and co-elution with commercial standards. Profiling of phenolic compounds during the potatoV. dahliae interaction confirmed previous observations on rutin accumulation in response to infection and showed differential accumulation of hydroxycinnamic acids in different tissues in response to two isolates possessing different levels of aggressiveness. In particular, differential accumulation of caffeic and ferulic acids was recorded in the roots and stems after inoculation, especially with the highly aggressive isolate. In the stems, the accumulation of rutin in response to inoculation was inhibited by the highly aggressive isolate, as compared with the weakly aggressive one.