The Role of Pollination in Flower Senescence and the Expression of Ethylene Biosynthesis Genes in Tomato (Solanum lycopersicum)

Flower senescence is the end phase of flower development, leading to the termination of the flower, including flower wilting and the dehiscence of flower organs. Flower senescence and fruit ripening are the most important physiological responses that are controlled by ethylene as a major regulator. These phenomena require significant attention in terms of crop improvement, utilizing molecular genetics as well as conventional breeding approaches. We are exploring whether pollination-driven ethylene production is responsible for flower senescence in tomato (Solanum lycopersicum), a model crop plant, using flowers from ethylene insensitive mutants non-ripening (nor) and alcobaca (alc). qRT-PCR suggests that expression of ethylene biosynthetic genes is delayed in nor and alc post-pollination, relative to an ethylene sensitive control line, as a result of post pollination events occurring at different time points. Microscopic analysis of pollen tube growth confirms a positive correlation between the pollination event and SlACS (ethylene biosynthetic gene) expression. Our initial results, therefore, suggest that SlACS gene expression is crucial for the preliminary spurt of ethylene production which is eventually responsible for flower senescence.