Cloning and functional analysis of ZIP transporters in blueberry

Blueberry (Vaccinium spp., Vc) plants are highly susceptible to Fe deficiency stress. An understanding of the mechanisms involved in Fe as well as other mineral ions uptake and transportation is critical for the improvement of mineral ions use efficiency in the field practices. The functional roles of the VcZIPs in mineral ions uptake and transportation were not well understood. To elucidate the functions of ZIP transporter family that is involved in the uptake and transport of metal elements in blueberry, VcZIPs such as VcZIP1, VcZIP2, VcZIP6, VcZIP7, VcZIP8 and VcZIP11 were cloned and identified from blueberry genome. The results of functional complementarity and heterologous expression of yeast mutant verified that most of VcZIPs had the ability to transport Fe and Zn, and VcZIP1 and VcZIP7 could mediate the transport of Cd in yeast. Furthermore, higher chlorophyll contents and bigger crown diameter sizes were observed in VcZIP6, VcZIP7 and VcZIP8 over-expressed Arabidopsis thaliana at Fe deficient treatments. In this study, VcZIP1, VcZIP2, VcZIP6–VcZIP8 and VcZIP11 were Fe-deficient responsive genes in blueberry. VcZIP6–VcZIP8 participated in the uptake of Fe and likely contributed to Fe uptake and transportation in plants. VcZIP1, VcZIP7, VcZIP8 and VcZIP11 were involved transportation Zn in blueberry. Comparatively, higher Zn-transport abilities were observed in VcZIP1 and VcZIP7.