Fig. 7

Schematic diagram showing genetic variations of the coding sequence of MdKCAB and the functional validation of these variations via callus transgenesis and genotype–phenotype association. a: Schematic diagram showing single nucleotide polymorphisms on the coding region and the changes in the encoded amino acids of MdKCAB. b: Images showing in vitro growth of transformed apple callus overexpressing variants of MdKCAB and the MdKCAB-RNAi line 14 days after treatment with NaCl, Na₂CO₃, or NaCl + Na₂CO₃. c and d: Column blots showing differences in the fresh weight of the apple callus (c) and malondialdehyde (MDA) content (d) 14 days after treatment with NaCl, Na₂CO₃ or NaCl + Na₂CO₃ among transformants overexpressing variants of MdKCAB or the MdKCAB-RNAi line. E: Box-plot showing injury indices of salt, alkali, and salt–alkali stress in F1 hybrids of ‘Baleng Crab’ × ‘M9’ with different genotype combinations of MdKCAB SNP11 and SNP761. Data are means ± standard deviation of three biological replicates. *, **, and *** indicate statistically significant differences at P < 0.05, P < 0.01, and P < 0.001, respectively