Abstract
Magnesium (Mg) is an essential nutrient element for plant growth and plays an important role in numerous physiological and biochemical processes. Mg deficiency inhibits plant growth and has become a growing problem for crop productions in agriculture. However, the molecular mechanisms for the resistance to Mg deficiency in plants were not well understood. In this study, we identified a Mg transporter gene OsMGT1 that confers resistance to Mg deficiency in rice (Oryza sativa). The expression of OsMGT1 was highly induced by Mg deficiency in shoots. Investigation of tissue expression patterns revealed that OsMGT1 was mainly expressed in the phloem region; however, Mg deficiency remarkably enhanced its expression in xylem parenchyma and mesophyll cells in shoots. Knockout of OsMGT1 resulted in a significant reduction in Mg content and biomass when grown at Mg-limited conditions. Furthermore, the sensitivity to low-Mg in mutants was intensified by excessive calcium supply. In addition, overexpression of OsMGT1 increased Mg content and biomass under low-Mg supply. In conclusion, our results indicate that OsMGT1 plays an important role in rice Mg import and is required for the resistance to Mg deficiency, which can be utilized for molecular breeding of low-Mg tolerant plants.
Highlights
Magnesium (Mg) is an essential element for plant growth, development and reproductive success [1,2,3], which plays an important role in numerous physiological and biochemical processes, such as chlorophyll biosynthesis and degradation, photosynthetic CO2 assimilation, carbohydrate allocation, energy metabolism and ribosome aggregation [4,5,6,7,8]
We firstly investigated the gene expression of all OsMGTs in both shoots and roots of rice, and observed that only the expression of OsMGT1 in the shoots was remarkably induced by Mg deficiency
Our results suggest that OsMGT1 plays an important role in rice growth under low-Mg stress
Summary
Magnesium (Mg) is an essential element for plant growth, development and reproductive success [1,2,3], which plays an important role in numerous physiological and biochemical processes, such as chlorophyll biosynthesis and degradation, photosynthetic CO2 assimilation, carbohydrate allocation, energy metabolism and ribosome aggregation [4,5,6,7,8]. Lack of Mg in plants reduces the photosynthetic rate, disrupts the distribution of carbohydrates from source to sink, inhibits the growth of plant organs and leads to a significant decline in crop productivity and quality [9,10]. Mg deficiency in plants may result from three following factors: First, Mg has a relatively larger hydrated radius in contrast to other cations, which makes it easier to be leached, in acidic soils and sandy soils with low cation exchange capacity [11,12,13]. Mg deficiency has become a growing problem for many crop productions in agriculture
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