Kassaw, T. K.; Morey, K. J.; Donayre-Torres, A. J.; Antunes, M.; Polito, J. T.; Pilon-Smits, E. A. H.; Lonergan, R.; Ternes, C. M.; Medford, J. I.

Salinity exerts a major constraint on global crop production while seawater intrusion impacts coastal aquifers and surface waters. Using a blueprint from nature, we produced highly salt tolerant Arabidopsis and rice. Endodermal-like barriers, duplicated to the root epidermis and distally expanded to protect sensitive regions, provide salt tolerance to 600 mM NaCl, levels comparable to seawater. Two additional genetic modules are added to reduce adverse effects on ion uptake and provide osmotic protection. Arabidopsis and rice containing all three genetic modules can survive 600 mM NaCl and set seed. RNA-seq analysis suggests that our rational engineering primes plants for salt tolerance, even without salt exposure, while our ionic analysis provides means for improvement. Our results, duplicating suberin and the Casparian Strip to the epidermis, adding symplastic transport and providing a means to address osmotic stress, provides a new approach to salt tolerance and insight to genes involved in salt responses.