High-affinity magnesium transporter that mediates the influx of magnesium in chloroplast. Expressed in the green part of the plant. Preferentially expressed in the spongy mesophyll cells and stomata of young leaves but also detected in cotyledons and at the base of the leaf petioles. By light. Has the ability to complement a mutant in yeast lacking magnesium transport capability. Belongs to the CorA metal ion transporter (MIT) (TC 1.A.35.5) family.