OsPLDα1 mediates cadmium stress response in rice by regulating reactive oxygen species accumulation and lipid remodeling

Lipid remodeling is crucial for various cellular activities and the stress tolerance of plants; however, little is known about the lipid dynamics induced by the heavy metal cadmium (Cd). In this study, we investigated the phospholipid profiles in rice (Oryza sativa) under Cd exposure. We observed a significant decline in the total amounts of phosphatidylcholine and phosphatidylserine, contrasted with an elevation in phosphatidic acid (PA) due to Cd stress. Additionally, Cd stress prompted the activation of phospholipase D (PLD) and induced the expression of PLD alpha 1. OsPLD alpha 1 knockout mutants (Ospld alpha 1) showed increased sensitivity to Cd, characterized by a heightened accumulation of hydrogen peroxide in roots and diminished PA production following Cd treatment. Conversely, PLD alpha 1-overexpressing (OsPLD alpha 1-OE) lines demonstrated enhanced tolerance to Cd, with suppressed transcription of the respiratory burst oxidase homolog (Rboh) genes. The transcription levels of genes associated with Cd uptake and transport were accordingly modulated in Ospld alpha 1 and OsPLD alpha 1-OE plants relative to the wild-type. Taken together, our findings underscore the pivotal role of OsPLD alpha 1 in conferring tolerance to Cd by modulating reactive oxygen species homeostasis and lipid remodeling in rice.