HKT1;1 and HKT1;2 Na+ Transporters from Solanum galapagense Play Different Roles in the Plant Na+ Distribution under Salinity Asins, Maria J. Espinosa, Jesús González Fernández, Paloma Traverso Gutiérrez, José Ángel Belver, Andrés Tomato S. cheesmaniae Salt tolerance Rootstock breeding Yield Fruit quality K+ and Na+ homeostasis Long-distance transport The study was funded by the Spanish Ministerio de Ciencia e Innovacion/Agencia Estatal de Investigacion, grants AGL2017-82452-C2-1R (A.B.) and AGL2017-82452-C2-2R (M.J.A) both from the, MCIN/AEI/10.13039/501100011033, the European Union (H2020 SFS-28-2020), contract number 101000716 (HARNESSTOM), and FEDER "Una manera de hacer Europa". J.E. was supported by a JAE Intro-CSIC grant, JAEINT_19_00566. Salt tolerance is a target trait in plant science and tomato breeding programs. Wild tomato accessions have been often explored for this purpose. Since shoot Na+/K+ is a key component of salt tolerance, RNAi-mediated knockdown isogenic lines obtained for Solanum galapagense alleles encoding both class I Na+ transporters HKT1;1 and HKT1;2 were used to investigate the silencing effects on the Na and K contents of the xylem sap, and source and sink organs of the scion, and their contribution to salt tolerance in all 16 rootstock/scion combinations of non-silenced and silenced lines, under two salinity treatments. The results show that SgHKT1;1 is operating differently from SgHKT1;2 regarding Na circulation in the tomato vascular system under salinity. A model was built to show that using silenced SgHKT1;1 line as rootstock would improve salt tolerance and fruit quality of varieties carrying the wild type SgHKT1;2 allele. Moreover, this increasing effect on both yield and fruit soluble solids content of silencing SgHKT1;1 could explain that a low expressing HKT1;1 variant was fixed in S. lycopersicum during domestication, and the paradox of increasing agronomic salt tolerance through silencing the HKT1;1 allele from S. galapagense, a salt adapted species. 2022-06-01T11:36:09Z 2022-06-01T11:36:09Z 2022-05-04 journal article Asins, M.J... [et al.]. HKT1;1 and HKT1;2 Na+ Transporters from Solanum galapagense Play Different Roles in the Plant Na+ Distribution under Salinity. Int. J. Mol. Sci. 2022, 23, 5130. [https://doi.org/10.3390/ijms23095130] http://hdl.handle.net/10481/75165 10.3390/ijms23095130 eng http://creativecommons.org/licenses/by/3.0/es/ open access Atribución 3.0 España MDPI