Lysophosphatidylcholine acyltransferase (LPCAT) is a key enzyme of the Lands cycle that mediates the interconversion between phosphatidylcholine (PC) and lysophosphatidylcholine (LPC) to maintain lipid membrane fluidity and function. Wang et al. report that LPCATs are localized to the endoplasmic reticulum in Arabidopsis. Using a chemical phenocopying approach, they demonstrated that loss of LPCAT activity alters the LPC/PC ratio in roots, resulting in excessive vacuolation. The findings provide compelling evidence that LPCATs play a pivotal role in maintaining root growth under conditions that require dynamic adjustments in lipid homeostasis.