Interaction between light and ethylene signaling during plastid formation/differentiation and carotenoid accumulation in tomato fruits

• Grant number: 11/18498-0
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: November 01, 2011
• End date: October 31, 2012
• Field of knowledge: Biological Sciences - Botany - Pant Physiology
• Principal Investigator: Luciano Freschi
• Grantee: Michel Hans Silva
• Host Institution: Instituto de Biociências (IB). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

The signaling routes interconnecting light perception and plant metabolism and development are currently characterized as highly complex and dynamic processes, involving not only distinct photoreceptors and specific regulatory proteins, but also innumerous phytohormones and second messengers. However, the mechanisms through which plant hormones interact with the light signaling cascades are still little understood, especially regarding the control of photomorphogenic events such as plastidial biogenesis, chloroplast to chromoplast differentiation, and the biosynthesis and accumulation of nutraceutical compounds in fresh fruits. Therefore, studies focused on the role played by phytohormones and light signals in these important photomorphogenic responses could contribute significantly both for increasing the basic knowledge about this research field and for providing relevant subsides for directing future plant genetic improvement programs. Based on these circumstances, the present project aims to characterize, in an integrative way, the influence of both light signaling (photoreceptors and light signal transduction proteins) and the hormone ethylene on the plastid biogenesis and carotenoid accumulation in tomato fruits. For allowing more conclusive approaches in this research field, the plant material chosen was the cultivar Micro-Tom (MT), which displays a wide availability of mutants with alterations in light and hormonal signaling. Fruits of these mutants will be exposed to distinct light treatments, followed by harvest at several stages of development and subsequent quantification of antioxidant activities and levels of total chlorophylls and carotenoids and lycopene, as well as analyses of plastid abundance and size. Moreover, ethylene production in these mutants will be measured throughout distinct light treatments aiming to increase the current knowledge not only regarding the influence of light on ethylene production in tomato fruits, but also about the role played by this hormone during plastid biogenesis and carotenoid accumulation in this fresh fruit.(AU)