Abstract
Magnesium (Mg) is essential nutrient in organisms. Although several functions of Mg in plants are known, Mg homeostasis mechanisms are not clear. In this work, to identify the genes involved in Mg deficiency response, we established screening methods to isolate mutants with altered response to Mg deficiency.
First, we examined conditions to see visual deficiency symptoms. When grown with agar medium, although Mg content in shoot was decreased under the deficiency condition, we could not get any symptoms/phenotypes. With the hydroponic culture, the growth of plants was severely inhibited under low Mg, indicating that agar is not suitable for screening based on visual symptoms.
Then, we established another screening method based on the expression of Mg-deficiency induced genes. We have identified Mg-deficiency induced genes by microarray. Those gene expression levels were high in mrs2-7 mutant, which has known to be involved in Mg homeostasis, compared with wild-type. This indicates that those genes could be used as marker for screening. Now we are generating transgenic plants carrying promoter-luciferase construct and confirming the response of luminescence to Mg.
