Understanding the mechanisms responsible for tomato plant flowering will enable new selection procedures to be developed in order to obtain even more productive varieties. Researchers in Liege and Louvain-la-Neuve demonstrate the importance of a gene in controlling the number of flowers within a tomato inflorescence. 

Originally from the north-west of South America where it was domesticated, the tomato rapidly conquered the entire world and arrived in Europe at the beginning of the 16th century. Today it is considered as one of the most important fruits/vegetables (depending on whether we use botanical or culinary language) in the human diet. Various forms and varieties of this plant exist. Thousands of cultivated varieties - called cultivars - in some 170 countries produced more than 125 million tonnes of tomatoes in 2007, according to FAO statistics (United Nations Food and Agriculture Organization). In Europe, each individual consumes around 13kg of fresh tomatoes per year, and 22kg of tomatoes in other forms (cans, sauces, concentrates, juices, etc.)!

In short, the economic, agronomic and gastronomic value of the tomato cannot be overstated.  However, to keep its place in the sun and retain its position as one of the top three most widely consumed vegetables in the world, after the potato and the sweet potato, the tomato needs to be able to respond to ever increasing demand.

To help it do so, scientists have been studying the flowering mechanisms of the tomato plant. To create cultivars producing ever more fruits, it is necessary to understand the genetic bases which lead to the fruits being formed. Claire Périlleux, lecturer and head of the ULg Laboratory of Plant Physiology is one scientist interested in that topic. "Understanding how any crop flowers is interesting because the underlying mechanisms can be used to increase the number of fruits produced by the plant."

From producing leaves to flowers

Before diving into the genetic mechanisms which control tomato plant flowering, it is important to understand the various stages of flowering in plants in general. "The part of the plant which develops the above ground organs, in other words the stem and the leaves, is called the shoot apical meristem. This tissue is made up of cells which retain a high potential for multiplication and differentiation. These are known as stem cells" explains Claire Périlleux. When the plant is growing, the apical meristem only produces leaves and stem segments. Then, generally following an environmental signal such as day length or light intensity, the plant shifts from the vegetative growing phase to the flowering phase. "This transition to flowering has become autonomous in tomato plants. It was originally a short day plant, but as the result of breeding carried out by horticulturalists, flowering has become independent of day length. However, the process is still accelerated by high light intensity," specifies the researcher.