The violet color of the first tomatoes was due to the presence of antioxidant substances called anthocyanins, the same ones that color grapes and blackberries, but then changed to red due to a genetic mutation that occurred spontaneously and was now reconstructed by the two researches. The starting point was the analysis of a variety of very rare and known purple tomatoes from the 70s, of the variety called Aft (Anthocyanin Fruit) and with purple streaks on the peel. By crossing this variety with another, called ATV (Atroviolacea), tomatoes are obtained with a color similar to that of aubergines.
Identified the gene that made the tomatoes purple (source: PlantLab of the Institute of Life Sciences of the Scuola Superiore Sant’Anna)
This has allowed us to identify, among the more than 30,000 genes of the tomato, the one that colors the skin of the Aft variety with violet. The Italian group led by Pierdomenico Perata, with Sara Colanero, Silvia Gonzali, has discovered that this is not an exclusive super-gene of that variety, but that it is the common tomato that has lost it, silencing it with a process similar to that which occurred in 'grape, which was originally only black. Having identified this gene will speed up the selection of varieties with a higher content of antioxidants, such as anthocyanins.
Originally the tomatoes were purple (source: PlantLab of the Institute of Life Sciences of the Scuola Superiore Sant’Anna)
Getting this result "took many years of work, in a context of strong competition with some groups of Chinese scientists, particularly active on this research topic," observed Perata. "China – he added – invests over 3% of GDP in research, while Italy just 1.3%: it is clear that competition will become increasingly difficult, considering the different availability of funding for scientific research" .