Molecular identification of the magnesium transport gene family in Brassica napus.

Magnesium (Mg2+) is an essential element for plant growth. Its transport and homeostasis in plants is mainly maintained by the MRS2/MGT of Mg2+ transporters. Little is known about the MRS2/MGT gene family in Brassica napus L. (B. napus), one of the most important oil grains. In our present study, we identified 36 putative MRS2/MGT genes (BnMGTs) from B. napus and investigated their phylogeny, expression pattern and function. These BnMGT genes were sorted into five distinguished groups by the phylogenetic analysis, and they were clearly homologous with the MRS2/MGT genes in Arabidopsis and rice. Complementation assays using the Salmonella typhimurium mutant MM281 demonstrated that the BnMGT genes were capable of mediating Mg2+ uptake and transport, with varied affinities to Mg2+. The expression pattern analysis showed that the expression of BnMGTs were tissue-specific and varied in different tissues. This work provides the molecular basis to discover the function of BnMGT gene family in plant growth and development.