AtLTP12, a Non-Specific Lipid Transfer Protein, Enhances Abiotic and Biotic Stress Tolerance in Arabidopsis thaliana

Non-specific lipid transfer proteins (nsLTPs) are plant-specific proteins involved in lipid transport, cuticle formation, and responses to abiotic and biotic stresses. Here, we functionally characterized AtLTP12, a member of the nsLTP1 subfamily in Arabidopsis thaliana, using a T-DNA insertion knockout mutant. The atltp12 mutant exhibited reduced seed germination rates, increased leaf water loss, and enhanced sensitivity to salt, drought, osmotic, and oxidative stress. Additionally, the mutant plants also showed compromised basal resistance, while their response to inducing systemic acquired resistance remained unaffected. In vitro assays confirmed lipid-binding activity of recombinant AtLTP12, with a preference for phospholipids. Subcellular localization analysis indicated its targeting to the extracellular space. These results demonstrate that AtLTP12 positively regulates multi-stress tolerance through lipid homeostasis and ROS regulation and contributes to basal immune responses. AtLTP12, therefore, represents a potential target for improving stress-resilience in plants.