论文部分内容阅读
Magnesium is an abundant divalent cation in plant cells and plays a critical role in many physiological processes.We have previously described the jdentification of a 10-member Arabidopsis gene family encoding putative magnesium transport(MGT)proteins.Here,we report that a member of the MGT family,AtMGT5, functions as a dual-functional Mg-transporter that operates in a concentration-dependent manner, namely it serves as a Mg-importer at micromolar levels and facilitates the efflux in the millimolar range.The AtMGT5 protein is localized in the mitochondria,suggesting that AtMGT5 mediates Mg-trafficking between the cytosol and mitochondria.The AtMGT5 gene was exclusively expressed in anthers at early stages of flower development.Examination of two independent T-DNA insertional mutants of AtMGT5 gene demonstrated that AtMG7-5 played an essential role for pollen development and male fertility.This study suggests a critical role for Mg2+ transport between cytosol and mitochondria in male gametogenesis in plants.