Carnitine Metabolism and Stress Response in Plant Systems

Carnitine, traditionally recognised for its role in lipid transport and mitochondrial function in animals, has emerged as a key metabolite in plant systems, particularly under conditions of abiotic stress. In plants, carnitine and its derivatives facilitate the shuttling of fatty acids into mitochondria for β‐oxidation, thereby contributing to energy homeostasis when photosynthetic capacity is compromised. Beyond its metabolic shuttle, carnitine exerts osmoprotective and antioxidant effects, scavenging reactive oxygen species and stabilising membrane integrity. These properties underpin its capacity to ameliorate the impact of salinity, drought and temperature extremes.

Recent work has highlighted intricate crosstalk between carnitine metabolism and hormonal signalling pathways. Abscisic acid (ABA)–dependent networks modulate the expression of carnitine acyltransferases and transporter proteins, aligning lipid mobilisation with stomatal regulation and osmotic adjustment. Moreover, carnitine influences the activity of the ascorbate–glutathione cycle, reinforcing the cell’s redox buffering systems. Through this dual action—fuel provision and oxidative defence—carnitine contributes to the resilience of root and shoot tissues, preserving growth and reproductive success under stress.

In seed germination, carnitine stimulates the mobilisation of stored lipids, accelerating the onset of respiratory metabolism. Enhanced activity of lipases, carnitine acyltransferases and tricarboxylic acid cycle enzymes supports rapid energy generation and cell division. Concurrently, the induction of antioxidant enzymes such as superoxide dismutase and ascorbate peroxidase mitigates genotoxic damage during the critical phase of radicle protrusion. Collectively, these processes underscore the global importance of carnitine pathways in sustaining crop performance under increasingly variable climatic conditions.

Research from Nature Portfolio

Recent studies have demonstrated that exogenous application of L-carnitine to barley seeds under salt stress significantly enhances mitotic activity and reduces DNA damage. Pretreatment with a defined concentration of L-carnitine led to a higher mitotic index compared with untreated controls, even as salinity increased. The protective effect on chromosome structure suggests a potent antioxidant role that guards against genotoxic by-products of oxidative stress. These findings illustrate how carnitine can act as both a growth promoter and a safeguard of genome integrity during early seedling establishment under saline conditions.

Carnitine Metabolism and Stress Response in Plant Systems publication trend

The graph below shows the total number of articles in carnitine metabolism and stress response in plant systems across all publications each year (not limited to Nature Index journals).

Technical terms

Carnitine acyltransferase: An enzyme that catalyses the reversible transfer of acyl groups between CoA and carnitine, facilitating fatty acid transport into mitochondria.

Reactive oxygen species (ROS): Chemically reactive molecules containing oxygen that can damage proteins, lipids and DNA unless detoxified by antioxidants.

Ascorbate–glutathione cycle: A cellular antioxidant system that regenerates ascorbate and glutathione to neutralise hydrogen peroxide and maintain redox balance.

Mitotic index: The proportion of cells undergoing mitosis, used as a measure of cell division activity.

Osmolyte: A small organic compound that accumulates in cells to counteract osmotic stress without interfering with normal biochemical processes.

Abscisic acid (ABA): A plant hormone that regulates stomatal closure, gene expression and metabolic adjustments in response to water deficit and salinity.

References

1. Exogenous L-Carnitine Promotes Plant Growth and Cell Division by Mitigating Genotoxic Damage of Salt Stress. Scientific Reports (2019).
2. Carnitine modulates antioxidative defense in ABI2 mutant under salt stress. Plant Growth Regulation (2024).
3. The Regulatory Role of Exogenous Carnitine Applications in Lipid Metabolism, Mitochondrial Respiration, and Germination in Maize Seeds (Zea mays L.). Life (2025).