Copper excess transcriptional responses in roots of grapevine (Vitis sp.) rootstocks

Copper (Cu) is an essential element for plants, participating in photosynthesis as acofactor for plastocyanin, in oxidative metabolism and in cell wall synthesis. However,excessive Cu may become toxic, as Cu can participate in Fenton chemistry and causeoxidative stress. Grapevine (Vitis sp.) is an important perennial crop, with grapes beingused for in natura consumption as well as the basis for wine and juice, and a source ofmolecules used in industry. Vineyards are susceptible to fungal diseases, which arecommonly controlled by using Cu-based fungicides, which can lead to Cu accumulationin the soil. Since grape production is based on grafting scions of consumed-friendlyvarieties onto rootstocks that can withstand soil-borne diseases and stresses, it isimportant to identify genotypes that can be used as rootstocks and are tolerant to Cuexcess. Is this work, we compared physiological and molecular responses of four Vitissp. genotypes to Cu excess. We identified core Cu excess-responsive genes in grapevineroots, as well as candidate genes associated with different Cu partitioning in shoots. Ourdata also suggest that Cu crosstalk with iron (Fe) homeostasis plays a role in Cu excessstress. We also identified promising candidate genes for engineering Cu tolerance ingrapevine. Our work provides a valuable dataset for understanding variation in Cutolerance and how roots respond transcriptionally to Cu stress in grapevine.