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ARS Home » Southeast Area » Byron, Georgia » Fruit and Tree Nut Research » Research » Publications at this Location » Publication #316451

Research Project: Breeding Stone Fruit Adapted to the Production Environment of the Southeastern United States

Location: Fruit and Tree Nut Research

Title: Identification of genes associated with low furanocoumarin content in grapefruit

item Chen, Chunxian
item YU, OIBIN - University Of Florida
item WEI, XU - University Of Florida
item CANCALON, PAUL - Florida Department Of Citrus
item GMITTER JR., FRED - University Of Florida

Submitted to: Genome
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/26/2014
Publication Date: 1/30/2015
Publication URL:
Citation: Chen, C., Yu, O., Wei, X., Cancalon, P.F., Gmitter Jr., F.G. 2015. Identification of genes associated with low furanocoumarin content in grapefruit. Genome. 57(10):537-545.

Interpretive Summary: Grapefruit juice effect, caused by the interaction of some furanocoumarins (FC) with human drugs, has a negative impact on grapefruit marketing and consumption. Identification of genes controlling the biosynthesis of these furanocoumarins may facilitate selection of low FC grapefruit cultivars, which may eliminate the interaction and allow grapefruits to be consumed by these concerned people.

Technical Abstract: Some furanocoumarins in grapefruit (Citrus paradisi) are associated with the so-called grapefruit juice effect. Previous phytochemical quantification and genetic analysis suggested that the synthesis of these furanocoumarins may be controlled by a single gene in the pathway. In this study, cDNA-amplified fragment length polymorphism (cDNA-AFLP) analysis of fruit tissues was performed to identify the candidate gene(s) likely associated with low furanocoumarin content in grapefruit. Fifteen tentative differentially-expressed fragments were cloned through the cDNA-AFLP analysis of ‘Foster’ grapefruit and its spontaneous low-furanocoumarin mutant, ‘Low Acid Foster’. Sequence analysis revealed a cDNA-AFLP fragment, Contig 6, was homologous to a substrate-proved psoralen synthase CYP71A22, and was part of citrus unigenes Cit.3003 and Csi.1332, and predicted genes Ciclev10004717m in mandarin and orange1.1g041507m in sweet orange. The two predicted genes contained the highly conserved motifs at one of the substrate recognition sites of CYP71A22. Digital gene expression profile showed the unigenes were expressed only in fruit and seed. Quantitative real-time PCR also proved Contig 6 was down-regulated in ‘Low Acid Foster’. These results showed the differentially expressed Contig 6 was related to the reduced furanocoumarin in the mutant. The identified fragment, homologs, unigenes and genes may facilitate further furanocoumarin genetic study and grapefruit variety improvement.