Lingyu Hu, Kun Zhou, Yuan Liu, Shulin Yang, Jingyun Zhang, Xiaoqing Gong, Fengwang Ma.Overexpression of MdMIPS1 enhances salt tolerance by improving osmosis, ion balance, and antioxidant activity in transgenic apple

Overexpression of MdMIPS1 enhances salt tolerance by improving osmosis, ion balance, and antioxidant activity in transgenic apple

Lingyu Hu, Kun Zhou, Yuan Liu, Shulin Yang, Jingyun Zhang, Xiaoqing Gong, Fengwang Ma

Plant Science

DOI: 10.1016/j.plantsci.2020.110654

Abstract

Myo-inositol and its derivatives play vital roles in plant stress tolerance. Myo-inositol-1-phosphate synthase (MIPS) is the rate-limiting enzyme of myo-inositol biosynthesis. However, the role of apple MIPS-mediated myo-inositol biosynthesis in stress tolerance remains elusive. In this study, we found that ectopic expression of MdMIPS1 from apple increased myo-inositol content and enhanced tolerance to salt and osmotic stresses in transgenic Arabidopsis lines. In transgenic apple lines over-expressing MdMIPS1, the increased myo-inositol levels could promote accumulation of other osmoprotectants such as glucose, sucrose, galactose, and fructose, to alleviate salinity-induced osmotic stress. Also, it was shown that overexpression of MdMIPS1 enhanced salinity tolerance by improving the antioxidant system to scavenge ROS, as well as Na+ and K+ homeostasis. Taken together, our results revealed a protective role of MdMIPS1-mediated myo-inositol biosynthesis in salt tolerance by improving osmotic balance, antioxidant defense system, and ion homeostasis in apple.