Abstract
Salinity stress is an ongoing problem for global crop production. Schrenkiella parvula and Eutrema salsugineum are salt-tolerant extremophytes closely related to Arabidopsis thaliana. We investigated multi-omics salt stress responses of the two extremophytes in comparison to A. thaliana. Our results reveal that S. parvula limits Na accumulation while E. salsugineum shows high tissue tolerance to excess Na. Despite this difference, both extremophytes maintained their nutrient balance, while A. thaliana failed to sustain its nutrient content. The root metabolite profiles of the two extremophytes, distinct at control conditions, converged upon prolonged salt stress. This convergence was achieved by a dynamic response in S. parvula roots increasing its amino acids and sugars to the constitutively high basal levels observed in E. salsugineum. The metabolomic adjustments were strongly supported by the transcriptomic responses in the extremophytes. The predominant transcriptomic signals in all three species were associated with salt stress. However, root architecture modulation mediated by negative regulators of auxin and ABA signaling supported minimally affected root growth unique to each extremophyte during salt treatments. Overall, E. salsugineum exhibited more preadapted responses at the metabolome level while S. parvula showed predominant pre-adaptation at the transcriptome level to salt stress. Our work shows that while salt tolerance in these two species shares common features, they substantially differ in pathways leading to convergent adaptive traits.
Competing Interest Statement
The authors have declared no competing interest.
