PT  - JOURNAL ARTICLE
AU  - Pramod Pantha
AU  - Dong-Ha Oh
AU  - David Longstreth
AU  - Maheshi Dassanayake
TI  - Living with high potassium: an asset or a hindrance
AID  - 10.1101/2021.07.01.450778
DP  - 2021 Jan 01
TA  - bioRxiv
PG  - 2021.07.01.450778
4099  - http://biorxiv.org/content/early/2021/07/02/2021.07.01.450778.short
4100  - http://biorxiv.org/content/early/2021/07/02/2021.07.01.450778.full
AB  - K is more toxic than Na at similar concentrations but the molecular mechanisms governing excess K-induced salt stress responses, including excess K+ signaling and major cellular functions interrupted during K toxicity in plants are unknown. We used Arabidopsis thaliana and its extremophyte relative Schrenkiella parvula, to explore this interesting but vastly unexplored question using comparative physiological, ionomic, transcriptomic, and metabolomic approaches aimed at understanding how plants can develop resilience to excess K toxicity. Our results showed that the stress responses exhibited by the two plants diverged at a decisive step where the stress-sensitive A. thaliana could not limit excess K influx and suffered severe nutrient depletion. The stress adapted model, S. parvula, was able to independently regulate reduction in K uptake while sustaining uptake of other major nutrients including N. Upheld N uptake and uninterrupted assimilation into primary metabolites allowed S. parvula to sustain growth and concurrently boost its antioxidant capacity and osmolyte pools, facilitated by a targeted transcriptomic response. In contrast, A. thaliana descended into mismanaged transcriptional cascades including induction of both biotic and abiotic stress responses and autophagy accompanied by inhibited growth, photosynthesis, and induced accumulation of ROS. This study provides a basic framework to select key pathways to target in the development of building plant resilience towards non-canonical salt stress induced by excess K+.Competing Interest StatementThe authors have declared no competing interest.