title: Identification, and Functional and Expression Analyses of the CorA/MRS2/MGT-Type Magnesium Transporter Family in Maize.
abstract: Magnesium (Mg(2+)) is an essential macronutrient for plant growth and development, and the CorA/MRS2/MGT-type Mg(2+) transporters play important roles in maintaining Mg(2+) homeostasis in plants. Although the MRS2/MGT genes have been identified in two model plant species, Arabidopsis and rice, a comprehensive analysis of the MRS2/MGT gene family in other plants is lacking. In this work, 12 putative MRS2/MGT genes (ZmMGT1- ZmMGT12) were identified in maize and all of them were classified into five distinct subfamilies by phylogenetic analysis. A complementation assay in the Salmonella typhimurium MM281 strain showed that five representatives of the 12 members possess Mg(2+) transport abilities. Inhibition of ZmMGT protein activity using the hexaamminecobalt (III) (Co-Hex) inhibitor indicated that the ZmMGT protein mediated both low-affinity and high-affinity Mg(2+) transport in maize. A semi-quantitative reverse transcription-PCR (RT-PCR) analysis revealed that eight genes were constitutively expressed in all of the detected tissues, with one being specifically expressed in roots and three having no detectable expression signals. A quantitative RT-PCR analysis showed that some ZmMGT members displayed differential responses to Mg(2+) deficiency and aluminum (Al) stress. Furthermore, root growth inhibition and Mg(2+) accumulation analyses in two maize inbred lines, which conferred different levels of Al tolerance, revealed that ZmMGT proteins contributed to the Al resistance of the Al tolerance genotype. We hypothesize that ZmMGT family members function as Mg(2+) transporters and may play a role in linking Mg(2+) deficiency and Al stress responses. Our results will be valuable in a further analysis of the important biological functions of ZmMGT members in maize.
authors.affiliation: Key Laboratory of Biology and Genetic Improvement of Maize in Southwest China of Agricultural Department, Ministry of Agriculture, Maize Research Institute, Sichuan Agricultural University, Chengdu 611130, China.
authors.forename: Hongyou
authors.initials: H
authors.lastname: Li
authors.affiliation: Key Laboratory of Biology and Genetic Improvement of Maize in Southwest China of Agricultural Department, Ministry of Agriculture, Maize Research Institute, Sichuan Agricultural University, Chengdu 611130, China.
authors.forename: Hanmei
authors.initials: H
authors.lastname: Du
authors.affiliation: Key Laboratory of Biology and Genetic Improvement of Maize in Southwest China of Agricultural Department, Ministry of Agriculture, Maize Research Institute, Sichuan Agricultural University, Chengdu 611130, China.
authors.forename: Kaifeng
authors.initials: K
authors.lastname: Huang
authors.affiliation: Key Laboratory of Biology and Genetic Improvement of Maize in Southwest China of Agricultural Department, Ministry of Agriculture, Maize Research Institute, Sichuan Agricultural University, Chengdu 611130, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Chen
authors.affiliation: Key Laboratory of Biology and Genetic Improvement of Maize in Southwest China of Agricultural Department, Ministry of Agriculture, Maize Research Institute, Sichuan Agricultural University, Chengdu 611130, China.
authors.forename: Tianyu
authors.initials: T
authors.lastname: Liu
authors.affiliation: Key Laboratory of Biology and Genetic Improvement of Maize in Southwest China of Agricultural Department, Ministry of Agriculture, Maize Research Institute, Sichuan Agricultural University, Chengdu 611130, China.
authors.forename: Shibin
authors.initials: S
authors.lastname: Gao
authors.affiliation: Key Laboratory of Biology and Genetic Improvement of Maize in Southwest China of Agricultural Department, Ministry of Agriculture, Maize Research Institute, Sichuan Agricultural University, Chengdu 611130, China.
authors.forename: Hailan
authors.initials: H
authors.lastname: Liu
authors.affiliation: Key Laboratory of Biology and Genetic Improvement of Maize in Southwest China of Agricultural Department, Ministry of Agriculture, Maize Research Institute, Sichuan Agricultural University, Chengdu 611130, China.
authors.forename: Qilin
authors.initials: Q
authors.lastname: Tang
authors.affiliation: Key Laboratory of Biology and Genetic Improvement of Maize in Southwest China of Agricultural Department, Ministry of Agriculture, Maize Research Institute, Sichuan Agricultural University, Chengdu 611130, China.
authors.forename: Tingzhao
authors.initials: T
authors.lastname: Rong
authors.affiliation: Key Laboratory of Biology and Genetic Improvement of Maize in Southwest China of Agricultural Department, Ministry of Agriculture, Maize Research Institute, Sichuan Agricultural University, Chengdu 611130, China suzhi1026@163.com.
authors.forename: Suzhi
authors.initials: S
authors.lastname: Zhang
mesh_terms: D000222:Adaptation, Physiological / Q000187:drug effects / Q000235:genetics; D000535:Aluminum / Q000633:toxicity; D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics; D032461:Chromosomes, Plant / Q000235:genetics; D020440:Gene Duplication; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D017343:Genes, Plant; D005816:Genetic Complementation Test; D005838:Genotype; D007178:Inbreeding; D008274:Magnesium / Q000378:metabolism*; D026901:Membrane Transport Proteins / Q000235:genetics* / Q000378:metabolism; D005810:Multigene Family; D009154:Mutation / Q000235:genetics; D012275:Oryza / Q000235:genetics; D010802:Phylogeny; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D016415:Sequence Alignment; D013312:Stress, Physiological / Q000187:drug effects / Q000235:genetics; D003313:Zea mays / Q000187:drug effects / Q000235:genetics* / Q000502:physiology
chemical_list: D026901:Membrane Transport Proteins; D010940:Plant Proteins; D000535:Aluminum; D008274:Magnesium
keywords: Al tolerance; CorA; Expression analysis; MRS2/MGT; Magnesium transporter; Maize