Floodproof mustards: Adaptation strategies in wild Brassicaceae

Climate change is intensifying hydrological extremes, reshaping water availability across ecosystems and threatening both agriculture and natural plant communities. While flooding tolerance has been extensively studied in crops and model species such as Arabidopsis thaliana and rice, wild plants naturally adapted to water-rich habitats remain underexplored. This review summarizes anatomical, physiological, and molecular strategies of flooding adaptation in wild Brassicaceae, with a focus on the ecologically diverse tribe Cardamineae. We further highlight other water-associated lineages, including Arabis, Cakile, Cochlearia and Subularia, as well as the related family Limnanthaceae inhabiting seasonal wetlands. Importantly, flooding in natural habitats rarely represents a single stress factor. Besides limited gas diffusion leading to hypoxia and carbon limitation, additional constraints such as salinity, mechanical disturbance, or low temperature may occur. The taxa reviewed here exhibit convergent morphological traits, including schizogenic aerenchyma, adventitious roots, heterophylly, and growth modulation under submergence. Although whole-genome duplication is frequent among water-associated Brassicaceae, it does not universally predict flooding tolerance and is best viewed as a context-dependent modifier of adaptive potential. This review highlights that flooding adaptation in Brassicaceae has evolved through multiple evolutionary routes and underscores wild relatives as a valuable, yet underutilized, resource for improving flooding resilience in crops.