Differential gene expression in leaves of a scab susceptible and a resistant apple cultivar upon Venturia inaequalis inoculation

Apple scab, one of the most damaging diseases in apple worldwide is caused by the fungal pathogen Venturia inaequalis. Pathogen-induced gene expression was analyzed in leaves of greenhouse- and field-grown trees of the scab susceptible cultivar Golden Delicious and the resistant cultivar Rewena using the macroarray technique. The results show that the defence of the Vf-resistant cultivar Rewena is based on different mechanisms than the basal defence response of the susceptible Golden Delicious: whereas lignification seems to play an essential role in scab defence of Rewena, a thaumatin-like as well as a flavonoid gene are assumed to be involved in the mostly insufficient defensive response of Golden Delicious. Furthermore, a method was developed for quantification of the V. inaequalis in infected leaves using real-time quantitative reverse transcription-PCR.