Emerging role of phospholipase C mediated lipid signaling in abiotic stress tolerance and development in plants.

Environmental stimuli are primarily perceived at the plasma membrane. Stimuli perception leads to membrane disintegration and generation of molecules which trigger lipid signaling. In plants, lipid signaling regulates important biological functions however, the molecular mechanism involved is unclear. Phospholipases C (PLCs) are important lipid-modifying enzymes in eukaryotes. In animals, PLCs by hydrolyzing phospholipids, such as phosphatidylinositol-4,5-bisphosphate [PI(4,5)P2] generate diacylglycerol (DAG) and inositol- 1,4,5-trisphosphate (IP3). However, in plants their phosphorylated variants i.e., phosphatidic acid (PA) and inositol hexakisphosphate (IP6) are proposed to mediate lipid signaling. Specific substrate preferences divide PLCs into phosphatidylinositol-PLC (PI-PLC) and non-specific PLCs (NPC). PLC activity is regulated by various cellular factors including, calcium (Ca2+) concentration, phospholipid substrate, and post-translational modifications. Both PI-PLCs and NPCs are implicated in plants' response to stresses and development. Emerging evidences show that PLCs regulate structural and developmental features, like stomata movement, microtubule organization, membrane remodelling and root development under abiotic stresses. Thus, crucial insights are provided into PLC mediated regulatory mechanism of abiotic stress responses in plants. In this review, we describe the structure and regulation of plant PLCs. In addition, cellular and physiological roles of PLCs in abiotic stresses, phosphorus deficiency, aluminium toxicity, pollen tube growth, and root development are discussed.