ATML1 and PDF2 regulate cuticle formation and protect the plant body from environmental stresses in Arabidopsis thaliana seedlings

A sessile lifestyle compels plants to endure an array of environmental stressors in the location where they grow. To cope with environmental stresses, plants have developed specialized cell wall structures called cuticles at the interface between the plant and the environment. In Arabidopsis thaliana seedlings, cuticles cover and protect aerial organs and young roots. However, the precise assembly of the molecular machinery required for cuticle formation on the surface of distinct organs that exhibit entirely different functions and developmental contexts remains unknown. Here, we demonstrate that a paralogous gene pair, ARABIDOPSIS THALIANA MERISTEM LAYER1 (ATML1) and PROTODERMAL FACTOR2 (PDF2), regulates precise cuticle formation in Arabidopsis thaliana seedlings. We found that the expression of ATML1 and PDF2 spatially overlapped with cuticle deposition in Arabidopsis thaliana seedlings. Furthermore, the loss of ATML1 and PDF2 activity resulted in a significant downregulation of the expression of genes required for cuticle formation and compromised cuticle formation in different organs. Seedlings with impaired activities of ATML1 and PDF2 exhibited higher susceptibility to environmental stress. In particular, PDF2 plays a predominant role in tolerance to environmental stress rather than ATML1 in the roots. Collectively, our study provides new insights into the regulatory mechanisms of cuticle formation and the developmental strategies plants use to protect their bodies from environmental stresses.