Phenotypic characterization of tomato plants (Solanum lycopersicum) knockdown for phytochrome interactions proteins (PIF1b and PIF4)

Abstract

Beyond photosynthesis, light is crucial to many plants metabolic processes, such as photomorphogenesis, circadian cycle signaling and movement of organs and organelles. Therefore, the perception and adaptation to light conditions become essential for vegetal development. The light signal is perceived by photoreceptors and the responses include a complex signaling network in which phytochrome interaction proteins (PIFs) play a central role. These proteins are transcription factors that negatively regulate the light response, participating in several physiological processes during plant lifetime, from germination to senescence. In particular, PIFs induce expression of ORE1 gene, which encodes a transcription factor that triggers foliar senescence. Through the activation of several SAGs (senescence-associated genes), ORE1 induces, among other processes, the degradation of chloroplasts. Once the plastidial activity is strongly related to the productivity and nutritional quality of fruits, it is interesting to explore the effects of PIF genes manipulation on fleshy fruits metabolism. For this purpose, tomato transgenic lines silenced for the PIF1b and PIF4 genes were obtained. This project aims to perform an extensive phenotypic characterization of these transgenic lines, including aspects of carbon metabolism, nutraceutical compounds (carotenoids and tocopherols) and productivity. The results obtained will improve the knowledge regarding PIF's regulation in tomato and how its manipulation can affect fruit quality and development.