Chloride channels play important role in salt tolerance of plants

Increased soil salinity is a growing challenge for crop production, which adversely affects crop yields in ~20 % of cultivable land worldwide. This problem is predicted to affect >40 % of agricultural lands in the coming decades and major threat to food security globally. The excess accumulation of soluble salts, especially sodium chloride (NaCl), in the roots severely impedes plant growth, reducing crop productivity. Previous efforts to identify solutions for mitigating salinity stress have focused primarily on cations such as sodium (Na+) and its transport. It is important to explore the effects of counter-anions such as chloride (Cl-) on root growth and understand the uptake and transport of Cl- in plants. This knowledge could be used to improve salinity tolerance in crops in the future. 

Our study shows how Arabidopsis chloride channel, AtCLCf plays an important role in salt tolerance. Our findings show that WRKY9 transcription factor regulates the expression of AtCLCf under salt stressed conditions and the increased intracellular NaCl levels induce the translocation of AtCLCf from the Golgi apparatus to the plasma membrane via trans-Golgi network using an AtRABA1b (BEX5)-mediated pathway. The electrophysiological studies (patch clamp) with Human Embryonic Kidney 293 (HEK293FT) cells show that AtCLCf functions in efflux of Cl- from the cells. The subcellular translocation of this CLC in the root cortex tissue and epidermis represents an essential salt tolerance mechanism in Arabidopsis.