Author
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WEN, YA-QIN - China Agricultural University |
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Zhong, Gan-Yuan |
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GAO, YUAN - China Agricultural University |
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LAN, YI-BIN - China Agricultural University |
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DUAN, CHANG-QING - China Agricultural University |
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PAN, QIU-HONG - China Agricultural University |
Submitted to: BMC Plant Biology
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 9/29/2015 Publication Date: 10/6/2015 Citation: Wen, Y., Zhong, G., Gao, Y., Lan, Y., Duan, C., Pan, Q. 2015. Using the combined analysis of transcripts and metabolites to propose key genes for differential terpene accumulation across two regions. Biomed Central (BMC) Plant Biology. 15:240. DOI: 10.1186/s12870-015-0631-1. Interpretive Summary: Terpenes are of great interest to winemakers because of their extremely low perception thresholds and pleasant floral odors. The biochemical profiles of terpenes could be substantially different for the berries of the same grapevine variety grown in different environments. Recently a series of genes required for terpene biosynthesis were biochemically characterized in grape berries. However, genes that control differential terpene accumulation in different growing environments have yet to be identified. In this study, ‘Muscat Blanc a Petits Grains’ berries were collected from two wine-producing regions with strikingly different climates, Gaotai (GT) in Gansu Province and Changli (CL) in Hebei Province in China, at four developmental stages for two consecutive years. GC-MS and RNA expression analyses revealed that differential accumulation of free and glycosidically-bound terpenes in grape berries across GT and CL regions were related to the expression of both VvHDR and VvGT14 genes. Through analysis of the expression patterns of both transcription factors and maturity-related genes, we concluded that less rainfall and stronger sunshine in the GT region triggered earlier expression of ripening-related genes, which in turn accelerated maturation and limit the accumulation of terpene volatiles in the berries harvested from the region. Technical Abstract: Terpenes are an important contributor to wine odors and their accumulation in grape berries is subject to environmental conditions under which the vines are grown. ‘Muscat Blanc a Petits Grains’ berries were collected from two wine-producing regions with strikingly different climates, Gaotai (GT) in Gansu Province and Changli (CL) in Hebei Province in China, at four developmental stages for two consecutive years. GC-MS analysis demonstrated that both free and glycosidically bound terpenes accumulated primarily after veraison and that mature grape berries from CL contained significantly higher concentrations of free and glycosidically bound terpenes than the berries from GT. Transcriptome analysis revealed that some key genes involved in terpene synthesis were significantly up-regulated in the CL region. Interestingly in the MEP pathway, the expression of VvHDR (1-hydroxy-2-methyl-2-butenyl 4-diphosphate reductase) paralleled with the accumulation of terpenes. We also found that glycosidically bound monoterpenes accumulated synchronously with the expression of a monoterpene glucosyltransferase gene (VvGT14) and several other genes during berry maturation. In addition, we found that the genes involved in abscisic acid and ethylene signal responses were expressed earlier and at higher levels in GT grapes than in CL grapes. Furthermore some transcription factors which might be involved in regulating terpene synthesis were predicted through gene co-expression network analysis. We hypothesized that less rainfall and stronger sunshine in the GT region triggered earlier expression of ripening-related genes, which in turn accelerated maturation and limited the accumulation of terpene volatiles in the berries harvested from the region. |