Genetic "Master Switch" Discovered to Control Tomato Ripening

Scientists at the Centre for Research in Agricultural Genomics (CRAG) have identified a key genetic regulator that controls tomato ripening. The study identifies a specific regulatory network that governs the transition of the fruit from the growing to the ripening stage. By focusing on the master switches within the plant's DNA, the team has mapped how different genes interact to control the timing and quality of the fruit's maturation process, offering a precise blueprint for future agricultural improvements.

The team, led by IRTA researcher at CRAG, Igor Florez-Sarasa, with Ariadna Iglesias-Sanchez as first author, published in Plant Physiology the discovery that a specific mitochondrial route, known as the alternative oxidase pathway (AOX), is the main engine enabling this transformation. They discovered that AOX pathway activity spikes when the tomato starts changing color, becoming the main support of fruit respiration. Using CRISPR‑Cas9 gene editing, the team deactivated the AOX1a gene in tomato plants, resulting in mutant tomatoes that took much longer to ripen. The researchers observed altered ripening-related metabolites in the mutants. Fruit with a deficiency in the AOX pathway was unable to accumulate key amino acids, such as aspartate and methionine, which are essential for the synthesis of ethylene.

This breakthrough holds transformative potential for the global food supply chain and the fight against food waste. By using this genetic information, breeders and biotechnologists can develop new fruit varieties with extended shelf lives and enhanced resilience during transport. Such innovations could significantly reduce the volume of produce lost to over-ripening before it reaches consumers, while simultaneously improving the sensory qualities of store-bought fruit. As the agricultural sector faces increasing pressure from climate change, these "smart" ripening traits represent a vital tool for ensuring sustainable and efficient food production.

For more details, read the article in CRAG News.