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Abstract Flooding events are highly detrimental to most terrestrial plant species. However, there is an impressive diversity of plant species that thrive in flood-prone regions and represent a treasure trove of unexplored flood-resilience mechanisms. Here we surveyed a panel of four species from the Cardamineae tribe representing a broad tolerance range. This included the flood-tolerant Cardamine pratensis , Rorippa sylvestris and Rorippa palustris and the flood-sensitive species Cardamine hirsuta . All four species displayed a quiescent strategy, evidenced by the repression of shoot growth underwater. Comparative transcriptomics analyses between the four species and the sensitive model species Arabidopsis thaliana were facilitated via de-novo transcriptome assembly and identification of 16,902 universal orthogroups at a high resolution. Our results suggest that tolerance likely evolved separately in the Cardamine and Rorippa species. While the Rorippa response was marked by a strong downregulation of cell-cycle genes, Cardamine minimized overall transcriptional regulation. However, a weak starvation signature was a universal trait of tolerant species, potentially achieved in multiple ways. It could result from a strong decline in cell-cycle activity, but is also intertwined with autophagy, senescence, day-time photosynthesis and night-time fermentation capacity. Our dataset provides a rich source to study adaptational mechanisms of flooding tolerance.
Veen et al. (Mon,) studied this question.