Expression of MYB transcription factors and target genes and its association with phenolic content and antioxidant activity of selected Solanum lycopersicum var. cerasiforme accessions from Mexico

Eight Solanum lycopersicum var. cerasiforme accessions from Mexico were evaluated for total phenolics (TP) and flavonoids (TF), phenolic profiles (UPLC-DAD-MS), antioxidant capacity (AC) (ABTS, DPPH, and FRAP), and expression of transcription factors (MYB12 and MYB14) and target genes (PAL, CHS and CHI) by RT-qPCR. The AC (mmol TE/kg fw; TE, Trolox Equivalents) by ABTS (5.27–11.81), DPPH (1.43–3.67), and FRAP (4.41–9.22) correlated with TP (0.53–1.20 g GAE/kg fw; GAE, Gallic Acid Equivalents), TF (1.03–2.10 g QE/kg; QE, Quercetin Equivalents), and the levels of chlorogenic and dicaffeoylquinic acids and rutin. The expression of MYB12 and MYB14 correlated with that of PAL and CHS, while CHI was only associated with MYB12. The accessions Tumbisca and Kilim showed the highest gene expression, phenolics content, and AC, suggesting they can be used in breeding programs to produce tomatoes with better AC.