Journal Article

The enhancement of tolerance to salt and cold stresses by modifying the redox state and salicylic acid content via the cytosolic malate dehydrogenase gene in transgenic apple plants

Sun, Hong, Wang, Qing‐Jie, Hao, Yu‐Jin, Sun, Tian‐Yu, Yao, Yu‐Xin, Jin, Zhong‐Xin, Dong, Qing‐Long

2016

Overview

Summary In this study, we characterized the role of an apple cytosolic malate dehydrogenase gene (MdcyMDH) in the tolerance to salt and cold stresses and investigated its regulation mechanism in stress tolerance. The MdcyMDH transcript was induced by mild cold and salt treatments, and MdcyMDH‐overexpressing apple plants possessed improved cold and salt tolerance compared to wild‐type (WT) plants. A digital gene expression tag profiling analysis revealed that MdcyMDH overexpression largely altered some biological processes, including hormone signal transduction, photosynthesis, citrate cycle and oxidation–reduction. Further experiments verified that MdcyMDH overexpression modified the mitochondrial and chloroplast metabolisms and elevated the level of reducing power, primarily caused by increased ascorbate and glutathione, as well as the increased ratios of ascorbate/dehydroascorbate and glutathione/glutathione disulphide, under normal and especially stress conditions. Concurrently, the transgenic plants produced a high H2O2 content, but a low O2·− production rate was observed compared to the WT plants. On the other hand, the transgenic plants accumulated more free and total salicylic acid (SA) than the WT plants under normal and stress conditions. Taken together, MdcyMDH conferred the transgenic apple plants a higher stress tolerance by producing more reductive redox states and increasing the SA level; MdcyMDH could serve as a target gene to genetically engineer salt‐ and cold‐tolerant trees.

• Publisher: John Wiley & Sons, Inc,John Wiley and Sons Inc
• Subject: Abiotic stress / Acids / apple (Malus domestica B.) / Apples / Arabidopsis thaliana / Ascorbic acid / Biological activity / Chloroplasts / citrates / Citric acid / Cold / cold stress / Cold tolerance / Cytosol - enzymology / cytosolic malate dehydrogenase gene / Dehydrogenase / Dehydrogenases / Fruits / Gene expression / Gene Expression Regulation, Plant - genetics / gene overexpression / Genes / Genetic engineering / Genetically modified plants / Genomes / Genomics / Glutathione / Homeostasis / Hormones / Hydrogen peroxide / Malate dehydrogenase / Malate Dehydrogenase - genetics / Malate Dehydrogenase - metabolism / Malus - enzymology / Malus - genetics / Malus - metabolism / Malus domestica / Menopause / Mitochondria / overexpression / Oxidases / Oxidation / Oxidation-Reduction / Oxidative stress / Phenols / Photosynthesis / Photosynthesis - genetics / Plant Proteins - genetics / Plant Proteins - metabolism / Plants, Genetically Modified - enzymology / Plants, Genetically Modified - genetics / Plants, Genetically Modified - metabolism / Proteins / Redox properties / redox state / Respiration / Salicylic acid / Salicylic Acid - metabolism / salt and cold tolerance / Salt tolerance / Salt-Tolerance - genetics / Signal processing / signal transduction / stress tolerance / Stress, Physiological - genetics / Stresses / sulfides / superoxide anion / Transcription / Transduction / Transgenic plants / trees