TY  - JOUR
A1  - Graus, Dorothea
A1  - Li, Kunkun
A1  - Rathje, Jan M.
A1  - Ding, Meiqi
A1  - Krischke, Markus
A1  - Müller, Martin J.
A1  - Cuin, Tracey Ann
A1  - Al‐Rasheid, Khaled A. S.
A1  - Scherzer, Sönke
A1  - Marten, Irene
A1  - Konrad, Kai R.
A1  - Hedrich, Rainer
T1  - Tobacco leaf tissue rapidly detoxifies direct salt loads without activation of calcium and SOS signaling
JF  - New Phytologist
N2  - Salt stress is a major abiotic stress, responsible for declining agricultural productivity. Roots are regarded as hubs for salt detoxification, however, leaf salt concentrations may exceed those of roots. How mature leaves manage acute sodium chloride (NaCl) stress is mostly unknown.

To analyze the mechanisms for NaCl redistribution in leaves, salt was infiltrated into intact tobacco leaves. It initiated pronounced osmotically‐driven leaf movements. Leaf downward movement caused by hydro‐passive turgor loss reached a maximum within 2 h.

Salt‐driven cellular water release was accompanied by a transient change in membrane depolarization but not an increase in cytosolic calcium ion (Ca\(^{2+}\)) level. Nonetheless, only half an hour later, the leaves had completely regained turgor. This recovery phase was characterized by an increase in mesophyll cell plasma membrane hydrogen ion (H\(^{+}\)) pumping, a salt uptake‐dependent cytosolic alkalization, and a return of the apoplast osmolality to pre‐stress levels. Although, transcript numbers of abscisic acid‐ and Salt Overly Sensitive pathway elements remained unchanged, salt adaptation depended on the vacuolar H\(^{+}\)/Na\(^{+}\)‐exchanger NHX1.

Altogether, tobacco leaves can detoxify sodium ions (Na\(^{+}\)) rapidly even under massive salt loads, based on pre‐established posttranslational settings and NHX1 cation/H+ antiport activity. Unlike roots, signaling and processing of salt stress in tobacco leaves does not depend on Ca\(^{2+}\) signaling.
KW  - calcium signaling
KW  - cytosolic pH
KW  - leaf response
KW  - NaCl transport
KW  - NHX1
KW  - osmotic effects
KW  - Salt Overly Sensitive pathway
KW  - salt stress
Y1  - 2023
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-312152
VL  - 237
IS  - 1
SP  - 217
EP  - 231
ER  -