Fig. 6

Schematic showing genetic variations on the coding sequence of MdRGLG3 and functional validation of these variations via callus transgenesis and genotype–phenotype association. a: Schematic diagram showing single nucleotide polymorphisms on the coding region and variations in the amino acid sequences of MdRGLG3. b: Images showing in vitro growth of transformed apple callus overexpressing variants of MdRGLG3 and the MdRGLG3-RNAi line on media containing high levels of NaCl, Na₂CO₃, or NaCl + Na₂CO₃. C and D: Column blots showing differences in apple callus fresh weight (c) and malondialdehyde (MDA) content (d) 14 days after treatment with NaCl, Na₂CO₃, or NaCl + Na₂CO₃, among transformants overexpressing variants of MdRGLG3 or the MdRGLG3-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 MdRGLG3 SNP168, SNP182, SNP932, and SNP936. 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