Living with high potassium: Balance between nutrient acquisition and K-induced salt stress signaling

High potassium (K) in the growth medium induces salinity stress in plants. However, the molecular mechanisms underlying plant responses to K-induced salt stress are virtually unknown. We examined Arabidopsis (Arabidopsis thaliana) and its extremophyte relative Schrenkiella parvula using a comparative multiomics approach to identify cellular processes affected by excess K and understand which deterministic regulatory pathways are active to avoid tissue damages while sustaining growth. Arabidopsis showed limited capacity to curb excess K accumulation and prevent nutrient depletion, contrasting to S. parvula which could limit excess K accumulation without restricting nutrient uptake. A targeted transcriptomic response in S. parvula promoted nitrogen uptake along with other key nutrients followed by uninterrupted N assimilation into primary metabolites during excess K-stress. This resulted in larger antioxidant and osmolyte pools and corresponded with sustained growth in S. parvula. Antithetically, Arabidopsis showed increased reactive oxygen species levels, reduced photosynthesis, and transcriptional responses indicative of a poor balance between stress signaling, subsequently leading to growth limitations. Our results indicate that the ability to regulate independent nutrient uptake and a coordinated transcriptomic response to avoid nonspecific stress signaling are two main deterministic steps toward building stress resilience to excess K+-induced salt stress. The ability to decouple potassium uptake from nitrogen uptake is important for surviving high potassium-induced salinity stress in plants.

Automated summary

Research found that high potassium concentration in the growth medium leads to salinity stress in plants. Comparing Arabidopsis and its extremophyte relative Schrenkiella parvula, it was discovered that S. parvula can limit excess potassium accumulation while sustaining growth, by promoting nitrogen uptake and assimilation. On the other hand, Arabidopsis showed growth limitations due to poor balance between stress signaling, increased reactive oxygen species levels, and reduced photosynthesis. The ability to regulate nutrient uptake and coordinate transcriptomic responses are crucial for plants to survive high potassium-induced salinity stress.