Detailed sphingolipid profile responded to salt stress in cotton root and the GhIPCS1 is involved in the regulation of plant salt tolerance

Sphingolipids are major structural components of membrane and active signaling molecules and play an important role in plant developmental processes and stress responses. As land salinization has increased globally, salinity has compromised the growth and productivity of crops such as cotton. Understanding the mechanisms of plant adaptation to salt stress is essential for breeding salt-tolerant crops. In this study, we explored the comprehensive metabolic profile of sphingolipids in cotton root under salt stress using lipidomics. 118 sphingolipid molecular species were identified, of which PhytoSph, PhytoCer, PhytoCer-OHFA, IPC, and GIPC were relatively high in content, and PhytoSph, PhytoCer, PhytoCer-OHFA, Phyto-GluCer, and IPC showed significant changes after salt stress, especially inositol phosphatidyl ceramide (IPC), which was significantly upregulated after salt treatment. Subsequently, we identified the genes encoding IPC synthase (IPCS), and ectopic expression of GhIPCS1 enhanced salt sensitivity in Arabidopsis, which might result from the disruption on the balance between various sphingolipid classes and/or molecular species. Overall, this study reveals key lipids and genes response to salt stress in cotton and provides a theoretical basis for the use of genetic engineering to improve cotton stress resistance.