Communication between chloroplasts and the endoplasmic reticulum in plants under abiotic stress

Chloroplasts and the endoplasmic reticulum (ER) are vital organelles for plant cellular function, yet their communication remains relatively underexplored. Beyond photosynthesis and protein folding, both organelles serve as metabolic hubs and stress sensors, and their crosstalk represents a crucial missing link in plant stress biology. The discovery of membrane contact sites (MCSs) underscores this interdependence, revealing exchanges of biomolecules such as lipids that sustain cellular homeostasis. Evidence also points to stress metabolites, secondary messengers, and hormones as possible mediators in communication, particularly under adverse conditions. By discussing established and putative signals and pointing to emerging technologies, we show that ER-chloroplast communication is critical to understanding abiotic stress adaptation and may open new avenues for improving crop resilience in a changing climate.