Evaluation of the alkalinity stress tolerance of three Brassica rapa CAX1 TILLING mutants Navarro León, Eloy Atero Calvo, Santiago Ríos Ruiz, Juan José Blasco León, Begoña Brassica rapa CaCO3 Mineral elements Oxidative stress Photosynthesis TILLING Alkalinity is an important environmental factor that affects crop production and will be exacerbated in the current climate change scenario. Thus, the presence of carbonates and high pH in soils negatively impacts nutrient assimilation and photosynthesis and causes oxidative stress. A potential strategy to improve tolerance to alkalinity could be the modification of cation exchanger (CAX) activity, given that these transporters are involved in calcium (Ca2+) signaling under stresses. In this study, we used three Brassica rapa mutants (BraA. cax1a-4, BraA.cax1a-7, and BraA.cax1a-12) from the parental line ‘R-o-18’ that were generated by Targeting Induced Local Lesions in Genomes (TILLING) and grown under control and alkaline conditions. The objective was to assess the tolerance of these mutants to alkalinity stress. Biomass, nutrient accumulation, oxidative stress, and photosynthesis parameters were analyzed. The results showed that BraA.cax1a-7 mutation was negative for alkalinity tolerance because it reduced plant biomass, increased oxidative stress, partially inhibited antioxidant response, and lowered photosynthesis performance. Conversely, the BraA.cax1a-12 mutation increased plant biomass and Ca2+ accumulation, reduced oxidative stress, and improved antioxidant response and photosynthesis performance. Hence, this study identifies BraA.cax1a-12 as a useful CAX1 mutation to enhance the tolerance of plants grown under alkaline conditions. 2023-06-23T06:59:52Z 2023-06-23T06:59:52Z 2023-04-18 journal article E. Navarro-León et al. Evaluation of the alkalinity stress tolerance of three Brassica rapa CAX1 TILLING mutants. Plant Physiology and Biochemistry 198 (2023) 107712[https://doi.org/10.1016/j.plaphy.2023.107712] https://hdl.handle.net/10481/82749 10.1016/j.plaphy.2023.107712 eng http://creativecommons.org/licenses/by-nc-nd/4.0/ open access Attribution-NonCommercial-NoDerivatives 4.0 Internacional Elsevier