Transcriptional survey of the light-induced anthocyanin pathway in non-GM purple tomatoes

Tomato MicroTom plants of the genotypes Aft/Aft x atv/atv (Aft/atv) and Aft/Aft x atv/atv x hp2/hp2 (Aft/atv/hp2) were used. Fruits showing purple anthocyanin pigmentation in the skin were collected at at the mature green (MG) and mature red (MR) stages to compare the transcriptomes of exocarp and mesocarp between the two developmental stages and the two genotypes with the objective to highlight the mechanisms through which light induces anthocyanin synthesis in tomato skin and impede it in mesocarp and other internal parts of the fruits. Aft/atv and Aft/atv/hp2 plants were cultivated in a growth chamber with 23°/20°C of day/night temperature, 12h photoperiod, 150 µmol photons m-2 s−1, and 40% relative humidity. Fruit samples were collected at MG and MR stages and divided into exocarp and mesocarp. Four biological replicates were collected for each of the following sample: 1. Aft/atv MG exocarp, 2. Aft/atv MG mesocarp, 3. Aft/atv/hp2 MG exocarp, 4. Aft/atv/hp2 MG mesocarp, 5. Aft/atv MR exocarp, 6. Aft/atv MR mesocarp, 7. Aft/atv/hp2 MR exocarp, 8. Aft/atv/hp2 MR mesocarp. Each sample was subjected to qPCR and gene expression analysis starting from same amount of total RNA.