2.2 TRV-mediated VIGS (virus-induced gene silencing)
The specific fragments of MdWRKY33 were inserted into pTRV2 vector in the antisense orientation (TRV-MdWRKY33 ). The antisense expression plasmids pTRV1 or pTRV2 derivatives were transformed intoAgrobacterium GV3101 with a ratio of 1:1 (v/v). Rooted apple plants and plantlets of apple cultured in vitro were vacuum infiltrated. After five days, the injected apple materials were treated were exposed to 48°C.