StZIP2 promotes root growth by improving the transport efficiency of zinc in potato(Solanum tuberosum L.).

Zinc is an essential trace element for plant growth and development. Zinc transporters play an important role in regulating zinc homeostasis in plants. In this study, the potato cultivar 'Atlantic' was used as experimental material to analyze the expression characteristics of the StZIP2 gene in different potato tissues under zinc deficiency stress. Transgenic plants with overexpression and interference expression of the StZIP2 gene were obtained by genetic transformation and treated with zinc deficiency stress. Chlorophyll content, antioxidant enzyme activity, proline (Pro) and malonic dialdehyde (MDA) content, zinc content in aboveground parts and roots, and root indices were determined. The results showed that the expression level of the StZIP2 gene in roots, stems and leaves under zinc deficiency stress was significantly higher than that of the control, and the expression level of the StZIP2 gene in roots under zinc deficiency stress was the highest. After zinc deficiency treatment, the content of chlorophyll and Pro, the activity of catalase (CAT), peroxidase (POD), superoxide dismutase (SOD), root-to-shoot ratio, root length and root fresh weight of overexpressed plants were significantly increased, while the MDA content was significantly decreased. The ratio of zinc content between the above-ground part and the root of the overexpressed plants was significantly higher than that of the non-transgenic plants, and the transport efficiency from the root to the above-ground part was significantly increased in the overexpressed plants, whereas it was just the opposite in the interference expressing plants. The result provides basic data to further elucidate the StZIP2 gene function.