Apple Valsa canker is one of the major fungal diseases adversely affecting the apple industry. Valine-glutamine motif-containing proteins (VQs) are a kind of plant transcription regulation cofactor, which are involved in regulating the growth and development of plants and their defence responses. Yet little is known about the role of VQs in the biotic stress response of woody plants, especially in apple trees. Recently, we identified MdVQ37 as a negative regulator of apple resistance to Glomerella leaf spot by inhibiting MdWRKY100-mediated salicylic acid (SA) accumulation via protein interaction. Here we found that MdVQ37 expression was induced significantly by Valsa mali infection. Overexpressing MdVQ37 in apple increased its susceptibility to V. mali, accompanied by a reduction in H