Methionine-mediated trade-off between plant growth and salt tolerance.

This article investigates the role of the amino acid methionine in mediating a trade-off between plant growth and salt tolerance. The study demonstrates that salt stress induces the upregulation of methionine biosynthesis genes—specifically homocysteine S-methyltransferases (HMTs) and methionine synthases (MSs)—through abscisic acid (ABA) and reactive oxygen species (ROS) signaling pathways, leading to methionine accumulation. Methionine enhances salt tolerance by activating ABA signaling and salt-responsive genes, while concurrently inhibiting primary root growth via suppression of auxin and cytokinin signaling and cell cycle progression. These findings reveal methionine as a pivotal signaling molecule that balances energy allocation between growth and stress adaptation, offering a potential strategy to improve crop performance in saline soils.