Zinc deficiency responses: bridging the gap between Arabidopsis and dicot crops.

Zinc (Zn) deficiency is a widespread phenomenon in agricultural soils worldwide and has a major impact on crop yield and quality, and hence on human nutrition and health. Although dicotyledonous crops represent more than 30% of the human plant-based nutrition, relatively few efforts have been dedicated to the investigation of Zn deficiency response mechanisms in dicots in contrast to monocotyledonous crops, such as rice or barley. Here, we describe the Zn requirement and impact of Zn deficiency in several economically important dicot crops, Phaseolus vulgaris, Glycine max, Brassica oleracea and Solanum lycopersicum. We briefly review our current knowledge of the Zn deficiency response in Arabidopsis and outline how this knowledge is translated in dicot crops. We highlight commonalities and differences between dicot species (and with monocots) regarding the function and regulation of Zn transporters and chelators, as well as the Zn sensing mechanisms and the role of hormones in the Zn deficiency response. We moreover show how the Zn homeostatic network intimately interacts with other nutrients, such as iron or phosphate. Finally, we outline how variation in Zn deficiency tolerance and Zn use efficiency among cultivars of dicot species can be leveraged for the design of Zn biofortification strategies.