Light and hormonal regulation of nutritional quality in Solanum lycopersicum

Abstract

Due to the high consumption and the biochemical profile, tomato fruit is an important component of the human diet contributing significant amounts of antioxidant compounds, such as carotenoids and tocopherols. Since these nutraceuticals are synthesized in the plastids, plastidial abundance and activity directly impact in the nutricional quality of the fruits. The differentiation and activity of chloroplasts are strictly controlled by light through a complex signal transduction cascade where phytochromes participate as receptors and phytochrome interacting factors are negative regulators of light response. This signal transduction pathway finally activates transcription factors, such as GLKs (GOLDEN LIKE) that induce plastid development and the expression of nuclear transcripts related to photosynthesis. Additionally, phytohormones and other signaling factors, including oxygen and nitrogen reactive species, also affect plastid differentiation. Particularly, nitric oxide (NO) is responsible for hormonal balance adjustments in response to phytochrome-mediated light signal. In this context, by applying functional genomic and biochemical approaches, this project proposes to improve the understanding of light, phytohormones and NO role in plastidial differentiation and activity aiming to identify genes and mechanisms that control the metabolism of nutraceutical compound in tomato. (AU)