Transcriptomic profiles of grapevine leaves in response to Plasmopara viticola. Vitis

V. vinifera cv. Pinot noir and V. piasezkii Liuba-8 were grown at the Grape Repository of Northwest A&F University, Yangling, Shaanxi, China. Leaves presenting oily-spot symptoms were harvested during summer and were placed abaxial surface uppermost, in the dark and at 100% RH overnight at room temperature. Next day, sporangia were collected from the abaxial surfaces using a soft brush and suspended in distilled water for inoculum.Leaves at third and fourth positions from the apex were selected and surface-sterilized with bleach (0.01%), followed by three washes in sterile water. Leaves were then inoculated with sporangial suspension (5×104 sporangia/ml). Inoculated leaves were placed in Petri dishes (adaxial surface downwards) on wet filter paper and incubated in a growth chamber at 20±2°C and 100% RH for 24 h in the dark, then under a 16 h light and 8 h dark photoperiod and 70% RH. The leaves inoculated with P. viticola were harvested at 12, 24, 48, and 96 hpi, respectively, leaves treated with water as control.