title: CitAP2.10 activation of the terpene synthase CsTPS1 is associated with the synthesis of (+)-valencene in 'Newhall' orange.
abstract: Aroma is a vital characteristic that determines the quality and commercial value of citrus fruits, and characteristic volatiles have been analyzed in different citrus species. In sweet orange, Citrus sinensis, the sesquiterpene (+)-valencene is a key volatile compound in the fruit peel. Valencene synthesis is catalyzed by the terpene synthase CsTPS1, but the transcriptional mechanisms controlling its gene expression are unknown. Here, the AP2/ERF (APETALA2/ethylene response factor) transcription factor, CitAP2.10, is characterized as a regulator of (+)-valencene synthesis. The expression pattern of CitAP2.10 was positively correlated with (+)-valencene content and CsTPS1 expression. Dual-luciferase assays indicated that CitAP2.10 could trans-activate the CsTPS1 promoter. Ethylene enhanced expression of CitAP2.10 and this effect was abolished by the ethylene antagonist 1-methylcyclopropene. The role and function of CitAP2.10 in (+)-valencene biosynthesis were confirmed using the Arabidopsis homolog (AtWRI1), which also transiently activated the CsTPS1 promoter. Furthermore, transient over-expression of CitAP2.10 triggered (+)-valencene biosynthesis in sweet orange fruit. These results indicate that CitAP2.10 regulates (+)-valencene synthesis via induction of CsTPS1 mRNA accumulation.
authors.affiliation: College of Agriculture & Biotechnology, Zhejiang University, Zijingang Campus, Hangzhou 310058, PR China Zhejiang Provincial Key Laboratory of Horticultural Plant Integrative Biology, Zhejiang University, Zijingang Campus, Hangzhou 310058, PR China The State Agriculture Ministry Laboratory of Horticultural Plant Growth, Development and Quality Improvement, Zhejiang University, Zijingang Campus, Hangzhou 310058, PR China.
authors.forename: Shu-Ling
authors.initials: SL
authors.lastname: Shen
authors.affiliation: College of Agriculture & Biotechnology, Zhejiang University, Zijingang Campus, Hangzhou 310058, PR China Zhejiang Provincial Key Laboratory of Horticultural Plant Integrative Biology, Zhejiang University, Zijingang Campus, Hangzhou 310058, PR China The State Agriculture Ministry Laboratory of Horticultural Plant Growth, Development and Quality Improvement, Zhejiang University, Zijingang Campus, Hangzhou 310058, PR China.
authors.forename: Xue-Ren
authors.initials: XR
authors.lastname: Yin
authors.affiliation: College of Agriculture & Biotechnology, Zhejiang University, Zijingang Campus, Hangzhou 310058, PR China Zhejiang Provincial Key Laboratory of Horticultural Plant Integrative Biology, Zhejiang University, Zijingang Campus, Hangzhou 310058, PR China The State Agriculture Ministry Laboratory of Horticultural Plant Growth, Development and Quality Improvement, Zhejiang University, Zijingang Campus, Hangzhou 310058, PR China.
authors.forename: Bo
authors.initials: B
authors.lastname: Zhang
authors.affiliation: College of Agriculture & Biotechnology, Zhejiang University, Zijingang Campus, Hangzhou 310058, PR China.
authors.forename: Xiu-Lan
authors.initials: XL
authors.lastname: Xie
authors.affiliation: College of Agriculture & Biotechnology, Zhejiang University, Zijingang Campus, Hangzhou 310058, PR China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Jiang
authors.affiliation: College of Agriculture & Biotechnology, Zhejiang University, Zijingang Campus, Hangzhou 310058, PR China School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, LE12 5RD, UK.
authors.forename: Donald
authors.initials: D
authors.lastname: Grierson
authors.affiliation: College of Agriculture & Biotechnology, Zhejiang University, Zijingang Campus, Hangzhou 310058, PR China Zhejiang Provincial Key Laboratory of Horticultural Plant Integrative Biology, Zhejiang University, Zijingang Campus, Hangzhou 310058, PR China The State Agriculture Ministry Laboratory of Horticultural Plant Growth, Development and Quality Improvement, Zhejiang University, Zijingang Campus, Hangzhou 310058, PR China akun@zju.edu.cn.
authors.forename: Kun-Song
authors.initials: KS
authors.lastname: Chen
mesh_terms: D019883:Alkyl and Aryl Transferases / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000378:metabolism / Q000502:physiology; D032084:Citrus sinensis / Q000201:enzymology* / Q000378:metabolism; D004789:Enzyme Activation; D005638:Fruit / Q000254:growth & development / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D011401:Promoter Regions, Genetic; D060888:Real-Time Polymerase Chain Reaction; D012717:Sesquiterpenes / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism / Q000502:physiology*
chemical_list: D029681:Arabidopsis Proteins; D012717:Sesquiterpenes; D014157:Transcription Factors; C495665:WRINKLED1 protein, Arabidopsis; C506706:valencene; D019883:Alkyl and Aryl Transferases; C108877:terpene synthase
keywords: CitAP2/ERF; Citrus sinensis; TPS; citrus volatile; ethylene; sweet orange; terpene synthase; transcriptional regulation; valencene.