An AP2/ERF transcription factor VvERF63 positively regulates cold tolerance in Arabidopsis and grape leaves

Cold stress adversely impacts grape growth, development, and yield. Thus, enhancing the cold tolerance of grape is a priority for grape breeding. Several APETALA2/ETHYLENE RESPONSIVE FACTOR (AP2/ERF) transcription factors (TFs) play critical roles in plant responses to various abiotic stresses. However, only a few ERF TFs in grape have been identified under various stress. Here, we cloned a novel ERF gene, VvERF63 from 'Cabernet Sauvignon' (Vitis vinifera L.), which is strongly induced by cold treatment and exogenous abscisic acid (ABA) treatment, and has transcriptional activation activity in yeast. Overexpression of VvERF63 in Arabidopsis improved cold resistance at the seedling and mature stages. Moreover, VvERF63-overexpressing and silencing grape leaves displayed improved and decreased cold tolerance, respectively. These results indicated that VvERF63 plays a positive role in cold tolerance by enhancing the photosynthetic capacity, and ameliorating cellular damage, which was evidenced by improved maximum photosynthetic efficiency of photosystem II (Fv/Fm), chlorophyll content, lower electrolyte leakage and malondialdehyde, as well as by increased antioxidant enzymes activities in the transgenic Arabidopsis. Additionally, the expression levels of stress- and antioxidant- related genes were upregulated in VvERF63-overexpressing plants. Our results suggested that VvERF63 positively participated in the cold resistance response and has excellent potential as a candidate gene for improving the cold tolerance of plant.