Chloride is an essential plant nutrient but under saline conditions it becomes part of the problem for plants. Interestingly during the work for the HALO project chloride is steadily emerging as a key player in the response of quinoa to salinity stress. Yet, most work on salinity tolerance has focused on sodium and potassium. Furthermore, the majority of the information that we have on chloride in the context of salinity tolerance comes from work on non-halophytes (i.e. plants that don’t like salt). Together with Prof Tim Colmer (University of Western Australia) and Dr. Tracey Ann Cuin (UTas), in this opinion paper published in Trends in Plant Science we look at how halophytes could deal with excess chloride under saline conditions. In particular we challenge the traditional view that breeding for reduced chloride uptake would benefit plant salinity tolerance, especially for halophytes that have evolved to use it to thrive in saline soils. We also propose that salinity tolerance could be achieved by looking at traits that control chloride uptake rather than its efflux from the roots. Here is the link to the opinion paper.
Also if you want more information regarding ion transport under saline conditions (including of course chloride) you can also look at this other review that we wrote roughly at the same time.