Zinc/Iron-Regulated Transporter-like Protein CsZIP4 Enhances Zinc and Nitrogen Uptake and Alleviates Zinc Stresses with Nitrogen Supply in .

Zinc (Zn) and nitrogen (N) are the two crucial nutrients for tea plant growth and development and contribute to the quality formation of tea fresh leaves. In this study, a zinc/iron-regulated transporter-like protein 4 gene (i.e., ) was functionally characterized. Expression profiling showed that could be induced by Zn stresses and a N deficiency. Heterologous expression of in yeast revealed that CsZIP4 possessed the capacity for Zn transport but not ammonium. Moreover, overexpression in promoted Zn and N uptake and transport and contributed to alleviate Zn stresses by collaborating with N supply, which might be interrelated to the expression of N or Zn metabolism-related genes, such as and . Additionally, CsZIP4 was localized in the plasma membrane and chloroplast, which was helpful in maintaining cellular homeostasis under a Zn excess. Furthermore, silencing of in tea plants by virus-induced gene silencing increased the chlorophyll content but decreased the Zn content. Finally, the yeast one-hybrid assay demonstrated that CsbZIP2 bound to the promoter. These results will shed light on the functions of in the N and Zn interaction in tea plants.