Malate Dehydrogenase Function in Plant Stress Responses

Malate dehydrogenases (MDHs) are a family of ubiquitous oxidoreductase enzymes that catalyse the reversible conversion of oxaloacetate to malate. In plants, multiple MDH isoforms localised in mitochondria, plastids, cytosol and peroxisomes play central roles in the tricarboxylic acid cycle, redox homeostasis, organic acid transport and energy metabolism. Under abiotic stresses such as salinity, cold, nutrient deficiency and heavy metal exposure, MDH activity influences cellular redox balance, organic acid secretion and cofactor regeneration, thereby modulating stress signalling, ion homeostasis and metabolic flexibility. Recent advances have revealed that differential expression and subcellular targeting of MDH isoforms underpin adaptive responses, regulating processes from root exudation of malate to scavenge toxic ions, to adjustment of salicylic acid levels and pyridoxine content during salt stress. Genetic manipulation of specific MDH genes has demonstrated potential to enhance crop tolerance to a variety of environmental challenges, indicating broad agronomic applications.

Research from Nature Portfolio

A foundational study uncovered that the mitochondrial MDH1 gene from cotton enhances phosphorus acquisition under deficiency by increasing root exudation of malate. Transgenic lines overexpressing MDH1 exhibited elevated malate secretion in roots, longer root systems and improved biomass when cultivated with insoluble phosphate sources, while MDH1 knockdown plants showed reduced growth and P uptake. This work established a mechanistic link between MDH-driven organic acid production, rhizosphere solubilisation of mineral nutrients and adaptation to low-phosphorus soils, highlighting a strategy for engineering nutrient-efficient crops.

Malate Dehydrogenase Function in Plant Stress Responses publication trend

The graph below shows the total number of articles in malate dehydrogenase function in plant stress responses across all publications each year (not limited to Nature Index journals).

Technical terms

Malate dehydrogenase (MDH): An oxidoreductase enzyme catalysing the interconversion of oxaloacetate and malate in central metabolism.

Abiotic stress: Environmental challenges such as salinity, drought, temperature extremes or nutrient deficiency impacting plant growth.

Redox state: The relative balance of oxidised and reduced forms of cellular metabolites that reflects oxidative and metabolic status.

Cofactor: A non-protein chemical compound, such as NAD(H), essential for enzyme activity and electron transfer.

References

1. 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. Plant Biotechnology Journal (2016).
2. Rice plastidial NAD‐dependent malate dehydrogenase 1 negatively regulates salt stress response by reducing the vitamin B6 content. Plant Biotechnology Journal (2019).
3. The mitochondrial malate dehydrogenase 1 gene GhmMDH1 is involved in plant and root growth under phosphorus deficiency conditions in cotton. Scientific Reports (2015).
4. Genome-Wide Identification of MDH Family Genes and Their Association with Salt Tolerance in Rice. Plants (2022).
5. Genome-Wide Characterization and Gene Expression Analyses of Malate Dehydrogenase (MDH) Genes in Low-Phosphorus Stress Tolerance of Chinese Fir (Cunninghamia lanceolata). International Journal of Molecular Sciences (2023).
6. Genome-Wide Identification of AhMDHs and Analysis of Gene Expression under Manganese Toxicity Stress in Arachis hypogaea. Genes (2023).