Nov 2017: In the 5th round of the Graduate School Tuinbouw & Uitgangsmaterialen, the proposal of Sara Abdou and Julian Verdonk was granted.
It is a collaboration with Francesca Quattrocchio of the University of Amsterdam and Teemu Teeri from the university of Helsinki, and industry partners from Deliflor, Dümmen Orange, Florensis, Gene Twister and Hudson River Biotechnology.
Can we manipulate colour in ornamental crops beyond the current available palette? We are interested in the biosynthesis of yellow-orange pigments, the carotenoids. Although present in many species; they are not very abundant in petunia, a model to study the biosynthesis of the other important pigments: the purple-pink-red-blue anthocyanins. It is hard to understand the absence of carotenoids from most petunia cultivars, especially when it is taken in consideration that the close relative calibrachoa accumulates high amounts of carotenoids. Presence of both anthocyanins and carotenoids in the same tissue is rare, and this could mean that there is a mechanism that prevents overlap. Recent work in monkeyflower (Mimulus spp), identified a transcription factor (TF), that could be the key in understanding this possible mechanism. Reduced carotenoid pigmentation 1 (RCP1) represses the anthocyanin pathway in tissues that produces carotenoids. This year, it was revealed that all orange petunia varieties on the market contain a maize version of the anthocyanin pathway gene DFR. The interest to produce alternative ways to orange petunias, is huge. Petunia is able to produce and accumulate carotenoids in the petals as indicated by few yellow-orange petunia varieties for which the presence of carotenoids has been defined. These varieties offer the possibility to identify non-transgenic strategies to get to orange petunias. The many tools that are available in petunia, genome sequence, mutant libraries, simple transformation protocols, CRISPR-cas9, will be employed to unravel carotenoid regulation, and will then be applied to other ornamental species, such as chrysanthemum, and calibrachoa.
Sara Abdou, Francesca Quattrocchio, Teemu Teeri, and Julian Verdonk