TY - JOUR

T1 - Potassium efflux and cytosol acidification as primary anoxia-induced events in wheat and rice seedlings

AU - Yemelyanov, Vladislav V.

AU - Chirkova, Tamara V.

AU - Shishova, Maria F.

AU - Lindberg, Sylvia M.

PY - 2020/9

Y1 - 2020/9

N2 - Both ion fluxes and changes of cytosolic pH take an active part in the signal transduction of different environmental stimuli. Here we studied the anoxia-induced alteration of cytosolic K+ concentration, [K+]cyt, and cytosolic pH, pHcyt, in rice and wheat, plants with different tolerances to hypoxia. The [K+]cyt and pHcyt were measured by fluorescence microscopy in single leaf mesophyll protoplasts loaded with the fluorescent potassium-binding dye PBFI-AM and the pH-sensitive probe BCECF-AM, respectively. Anoxic treatment caused an efflux of K+ from protoplasts of both plants after a lag-period of 300–450 s. The [K+]cyt decrease was blocked by tetraethylammonium (1 mM, 30 min pre-treatment) suggesting the involvement of plasma membrane voltage-gated K+ channels. The protoplasts of rice (a hypoxia-tolerant plant) reacted upon anoxia with a higher amplitude of the [K+]cyt drop. There was a simultaneous anoxia-dependent cytosolic acidification of protoplasts of both plants. The decrease of pHcyt was slower in wheat (a hypoxia-sensitive plant) while in rice protoplasts it was rapid and partially reversible. Ion fluxes between the roots of intact seedlings and nutrient solutions were monitored by ion-selective electrodes and revealed significant anoxia-induced acidification and potassium leakage that were inhibited by tetraethylammonium. The K+ efflux from rice was more distinct and reversible upon reoxygenation when compared with wheat seedlings.

AB - Both ion fluxes and changes of cytosolic pH take an active part in the signal transduction of different environmental stimuli. Here we studied the anoxia-induced alteration of cytosolic K+ concentration, [K+]cyt, and cytosolic pH, pHcyt, in rice and wheat, plants with different tolerances to hypoxia. The [K+]cyt and pHcyt were measured by fluorescence microscopy in single leaf mesophyll protoplasts loaded with the fluorescent potassium-binding dye PBFI-AM and the pH-sensitive probe BCECF-AM, respectively. Anoxic treatment caused an efflux of K+ from protoplasts of both plants after a lag-period of 300–450 s. The [K+]cyt decrease was blocked by tetraethylammonium (1 mM, 30 min pre-treatment) suggesting the involvement of plasma membrane voltage-gated K+ channels. The protoplasts of rice (a hypoxia-tolerant plant) reacted upon anoxia with a higher amplitude of the [K+]cyt drop. There was a simultaneous anoxia-dependent cytosolic acidification of protoplasts of both plants. The decrease of pHcyt was slower in wheat (a hypoxia-sensitive plant) while in rice protoplasts it was rapid and partially reversible. Ion fluxes between the roots of intact seedlings and nutrient solutions were monitored by ion-selective electrodes and revealed significant anoxia-induced acidification and potassium leakage that were inhibited by tetraethylammonium. The K+ efflux from rice was more distinct and reversible upon reoxygenation when compared with wheat seedlings.

KW - Acidification

KW - Anoxic signaling

KW - Fluorescence microscopy

KW - Oryza sativa

KW - PH

KW - Potassium

KW - Triticum aestivum

KW - OXYGEN DEFICIENCY

KW - H+-ATPASE ACTIVITY

KW - K+ RETENTION

KW - potassium

KW - ROOT TISSUES

KW - CYTOPLASMIC PH

KW - acidification

KW - fluorescence microscopy

KW - MOBILE ENERGY-SOURCE

KW - anoxic signaling

KW - BARLEY HORDEUM-VULGARE

KW - CALCIUM

KW - pH

KW - PLANTS

KW - ION CHANNELS

UR - http://www.scopus.com/inward/record.url?scp=85090969125&partnerID=8YFLogxK

UR - https://www.mendeley.com/catalogue/7dbe969e-cc7c-3a2b-8566-43aa35dd923f/

U2 - 10.3390/plants9091216

DO - 10.3390/plants9091216

M3 - Article

AN - SCOPUS:85090969125

VL - 9

SP - 1

EP - 15

JO - Plants

JF - Plants

SN - 2223-7747

IS - 9

M1 - 1216

ER -