title: Targeted transcriptomic and metabolic profiling reveals temporal bottlenecks in the maize carotenoid pathway that may be addressed by multigene engineering.
abstract: Carotenoids are a diverse group of tetraterpenoid pigments found in plants, fungi, bacteria and some animals. They play vital roles in plants and provide important health benefits to mammals, including humans. We previously reported the creation of a diverse population of transgenic maize plants expressing various carotenogenic gene combinations and exhibiting distinct metabolic phenotypes. Here we performed an in-depth targeted mRNA and metabolomic analysis of the pathway to characterize the specific impact of five carotenogenic transgenes and their interactions with 12 endogenous genes in four transgenic lines representing distinct genotypes and phenotypes. We reconstructed the temporal profile of the carotenoid pathway during endosperm development at the mRNA and metabolic levels (for total and individual carotenoids), and investigated the impact of transgene expression on the endogenous pathway. These studies enabled us to investigate the extent of any interactions between the introduced transgenic and native partial carotenoid pathways during maize endosperm development. Importantly, we developed a theoretical model that explains these interactions, and our results suggest genetic intervention points that may allow the maize endosperm carotenoid pathway to be engineered in a more effective and predictable manner.
authors.affiliation: Department of Plant Production and Forestry Science, School of Agrifood and Forestry Science and Engineering-ETSEA, University of Lleida/Agrotecnio Center, Avenida Alcalde Rovira Roure 191, 25198 Lleida, Spain.
authors.forename: Gemma
authors.initials: G
authors.lastname: Farré
authors.forename: Sol
authors.initials: S
authors.lastname: Maiam Rivera
authors.forename: Rui
authors.initials: R
authors.lastname: Alves
authors.forename: Ester
authors.initials: E
authors.lastname: Vilaprinyo
authors.forename: Albert
authors.initials: A
authors.lastname: Sorribas
authors.forename: Ramon
authors.initials: R
authors.lastname: Canela
authors.forename: Shaista
authors.initials: S
authors.lastname: Naqvi
authors.forename: Gerhard
authors.initials: G
authors.lastname: Sandmann
authors.forename: Teresa
authors.initials: T
authors.lastname: Capell
authors.forename: Changfu
authors.initials: C
authors.lastname: Zhu
authors.forename: Paul
authors.initials: P
authors.lastname: Christou
mesh_terms: D002338:Carotenoids / Q000235:genetics* / Q000378:metabolism*; D056625:Endosperm / Q000254:growth & development / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D005818:Genetic Engineering / Q000379:methods; D055442:Metabolome; D030821:Plants, Genetically Modified; D060888:Real-Time Polymerase Chain Reaction / Q000379:methods; D024341:Xanthophylls / Q000378:metabolism; D003313:Zea mays / Q000235:genetics* / Q000378:metabolism*
chemical_list: D024341:Xanthophylls; D002338:Carotenoids
keywords: Zea mays; carotenoids; endosperm development; ketocarotenoids; metabolic engineering; metabolic profiling; transcriptomic analysis