RRC ID 75831
著者 Arango J, Jourdan M, Geoffriau E, Beyer P, Welsch R.
タイトル Carotene Hydroxylase Activity Determines the Levels of Both α-Carotene and Total Carotenoids in Orange Carrots.
ジャーナル Plant Cell
Abstract The typically intense carotenoid accumulation in cultivated orange-rooted carrots (Daucus carota) is determined by a high protein abundance of the rate-limiting enzyme for carotenoid biosynthesis, phytoene synthase (PSY), as compared with white-rooted cultivars. However, in contrast to other carotenoid accumulating systems, orange carrots are characterized by unusually high levels of α-carotene in addition to β-carotene. We found similarly increased α-carotene levels in leaves of orange carrots compared with white-rooted cultivars. This has also been observed in the Arabidopsis thaliana lut5 mutant carrying a defective carotene hydroxylase CYP97A3 gene. In fact, overexpression of CYP97A3 in orange carrots restored leaf carotenoid patterns almost to those found in white-rooted cultivars and strongly reduced α-carotene levels in the roots. Unexpectedly, this was accompanied by a 30 to 50% reduction in total root carotenoids and correlated with reduced PSY protein levels while PSY expression was unchanged. This suggests a negative feedback emerging from carotenoid metabolites determining PSY protein levels and, thus, total carotenoid flux. Furthermore, we identified a deficient CYP97A3 allele containing a frame-shift insertion in orange carrots. Association mapping analysis using a large carrot population revealed a significant association of this polymorphism with both α-carotene content and the α-/β-carotene ratio and explained a large proportion of the observed variation in carrots.
巻・号 26(5)
ページ 2223-2233
公開日 2014-5-1
DOI 10.1105/tpc.113.122127
PII tpc.113.122127
PMID 24858934
PMC PMC4079379
IF 9.618
リソース情報
シロイヌナズナ / 植物培養細胞・遺伝子 pda05376