AcNRZ1, an endoplasmic reticulum-localized NAC transcription factor in kiwifruit, enhances zinc stress tolerance in Arabidopsis

The trace element zinc (Zn) is involved in various biological processes in plant, yet its excessive accumulation can result in plant toxicity. In this study, we unveiled a novel NAC transcription factor, AcNRZ1, in kiwifruit, and qRT-PCR analysis showed that the expression of AcNRZ1 can be up-regulated by Zn stress. Furthermore, Zn stress induces the translocation of AcNRZ1 from endoplasmic reticulum (ER) to nucleus. Overexpression of AcNRZ1 in Arabidopsis imparts tolerance and elevates the germination rates under Zn stress. Subsequent studies have demonstrated that the overexpression of AcNRZ1 facilitates the transport of Zn ions from the root to the leaf and enhances the Zn detoxification process in the vacuole by upregulating the expression of the Zn transport-related gene HMA4, as well as Zn detoxification-related genes including MTP1/3/5, GSH1, and PCS1. Additionally, overexpression of AcNRZ1 in Arabidopsis stimulates the expression of antioxidant enzyme related genes (SOD1 and CAT1), thereby leading to reduced accumulation of reactive oxygen species and ultimately enhancing tolerance to Zn stress. These findings suggest that AcNRZ1 influences plant response to Zn stress by modulating Zn ion transport, promoting detoxification processes, and regulating the accumulation of reactive oxygen species, thereby conferring plant tolerance to Zn stress.