Limits...
Using the combined analysis of transcripts and metabolites to propose key genes for differential terpene accumulation across two regions.

Wen YQ, Zhong GY, Gao Y, Lan YB, Duan CQ, Pan QH - BMC Plant Biol. (2015)

Bottom Line: Particularly in the MEP pathway, the expression of VviHDR (1-hydroxy-2-methyl-2-butenyl 4-diphosphate reductase) paralleled with the accumulation of terpenes, which can promote the flow of isopentenyl diphosphate (IPP) into the terpene synthetic pathway.Other genes were also found to be related to the differential accumulation of terpenes and monoterpene glycosides in the grapes between regions.Considering the expression patterns of both transcription factors and mature-related genes, we infer that less rainfall and stronger sunshine in the GT region could initiate the earlier expression of ripening-related genes and accelerate the berry maturation, eventually limiting the production of terpene volatiles.

View Article: PubMed Central - PubMed

Affiliation: Centre for Viticulture and Enology, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, 100083, China. wenyaqin1219@163.com.

ABSTRACT

Background: Terpenes are of great interest to winemakers because of their extremely low perception thresholds and pleasant floral odors. Even for the same variety, terpene profile can be substantially different for grapevine growing environments. Recently a series of genes required for terpene biosynthesis were biochemically characterized in grape berries. However, the genes that dominate the differential terpene accumulation of grape berries between regions have yet to be identified.

Methods: Free and glycosidically-bound terpenes were identified and quantified using gas chromatography-mass spectrometry (GC-MS) technique. The transcription expression profiling of the genes was obtained by RNA sequencing and part of the results were verified by quantitative real time PCR (QPCR). The gene co-expression networks were constructed with the Cytoscape software v 2.8.2 ( www.cytoscape.org).

Results: '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 berries from GT. Transcriptome analysis revealed that some key genes involved in terpene biosynthesis were markedly up-regulated in the CL region. Particularly in the MEP pathway, the expression of VviHDR (1-hydroxy-2-methyl-2-butenyl 4-diphosphate reductase) paralleled with the accumulation of terpenes, which can promote the flow of isopentenyl diphosphate (IPP) into the terpene synthetic pathway. The glycosidically bound monoterpenes accumulated differentially along with maturation in both regions, which is synchronous with the expression of a monoterpene glucosyltransferase gene (VviUGT85A2L4 (VviGT14)). Other genes were also found to be related to the differential accumulation of terpenes and monoterpene glycosides in the grapes between regions. Transcription factors that could regulate terpene synthesis were predicted through gene co-expression network analysis. Additionally, the genes involved in abscisic acid (ABA) and ethylene signal responses were expressed at high levels earlier in GT grapes than in CL grapes.

Conclusions: Differential production of free and glycosidically-bound terpenes in grape berries across GT and CL regions should be related at least to the expression of both VviHDR and VviUGT85A2L4 (VviGT14). Considering the expression patterns of both transcription factors and mature-related genes, we infer that less rainfall and stronger sunshine in the GT region could initiate the earlier expression of ripening-related genes and accelerate the berry maturation, eventually limiting the production of terpene volatiles.

No MeSH data available.


Change of total concentrations of free and glycosidically-bound volatiles. Columns indicate mean concentration (n = 3), and bars indicate standard error of the mean. Pound sign and asterisk represent significant difference of free and glycosidically-bound data between CL and GT region, respectively (p < 0.05). CL and GT is the abbreviation of Changli and Gaotai
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
getmorefigures.php?uid=PMC4595271&req=5

Fig2: Change of total concentrations of free and glycosidically-bound volatiles. Columns indicate mean concentration (n = 3), and bars indicate standard error of the mean. Pound sign and asterisk represent significant difference of free and glycosidically-bound data between CL and GT region, respectively (p < 0.05). CL and GT is the abbreviation of Changli and Gaotai

Mentions: Total soluble solid (°Brix) and titratable acid presented similar change patterns in developing grape berries between the two regions across two consecutive years. Nevertheless, the berries close to harvest (E-L 38) from GT contained significantly higher total soluble solid content and titratable acid compared with those from the CL region (Fig. 1). The total terpene concentration increased approximately 3-fold (CL) and 1.5 ~ 2-fold (GT), separately, along with ripening (Fig. 2). Statistically significant differences in the total concentrations of free and glycosidically bound terpenes were observed between CL and GT grapes, except for E-L 35 and E-L 36 in 2010. In particular, the difference in the concentration of the glycosidically bound form was much greater than the free form. Three evolutionary trends in the two-year time-course series could be clearly observed for free volatiles from the hierarchical heatmap clustering (Fig. 3a). In the first trend, volatiles such as geraniol, nerol, linalool, myrcene, cis-rose oxide generally presented an increase in their concentrations along with berry ripening (Additional file 1: Table S1A). Moreover, most compounds with the first evolutionary trend in mature grape berries had higher concentrations in the grapes grown in the CL region compared with the GT region. The compounds with the second evolutionary trend, such as terpinenols and cis/trans-furan linalool oxides, reached their highest levels at the pea-size period (E-L 31) or veraison (E-L 35) stage and subsequently reduced their levels in post-veraison grapes. At harvest, this group of volatile compounds did not display significant differences between the grapes from the CL and GT regions. The remaining compounds were grouped into the third evolutionary trend, including hotrienol, citronella and pyran linalool oxide. Their accumulation trends varied between regions and years. In the third group, hotrienol, a dehydrogenated form of linalool, displayed a downward trend as berry ripening processed, which was the opposite of the developmental accumulation of linalool. Among the detected free-form terpenes, linalool and geraniol had the highest concentrations, followed by nerol, mycene, citronellol and cis-rose oxide. Apart from citonellol, the other five terpenes presented higher concentration in mature grapes from the CL region than from the GT region (Fig. 3b). We must note that even in the same region, there was a great difference in the compound evolutionary trend between the two vintages. Because of this difference, we analyzed annual data instead of the mean of the two-year data. The findings indicate that the accumulation of free-from volatiles is easily altered by vintage.Fig. 1


Using the combined analysis of transcripts and metabolites to propose key genes for differential terpene accumulation across two regions.

Wen YQ, Zhong GY, Gao Y, Lan YB, Duan CQ, Pan QH - BMC Plant Biol. (2015)

Change of total concentrations of free and glycosidically-bound volatiles. Columns indicate mean concentration (n = 3), and bars indicate standard error of the mean. Pound sign and asterisk represent significant difference of free and glycosidically-bound data between CL and GT region, respectively (p < 0.05). CL and GT is the abbreviation of Changli and Gaotai
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4595271&req=5

Fig2: Change of total concentrations of free and glycosidically-bound volatiles. Columns indicate mean concentration (n = 3), and bars indicate standard error of the mean. Pound sign and asterisk represent significant difference of free and glycosidically-bound data between CL and GT region, respectively (p < 0.05). CL and GT is the abbreviation of Changli and Gaotai
Mentions: Total soluble solid (°Brix) and titratable acid presented similar change patterns in developing grape berries between the two regions across two consecutive years. Nevertheless, the berries close to harvest (E-L 38) from GT contained significantly higher total soluble solid content and titratable acid compared with those from the CL region (Fig. 1). The total terpene concentration increased approximately 3-fold (CL) and 1.5 ~ 2-fold (GT), separately, along with ripening (Fig. 2). Statistically significant differences in the total concentrations of free and glycosidically bound terpenes were observed between CL and GT grapes, except for E-L 35 and E-L 36 in 2010. In particular, the difference in the concentration of the glycosidically bound form was much greater than the free form. Three evolutionary trends in the two-year time-course series could be clearly observed for free volatiles from the hierarchical heatmap clustering (Fig. 3a). In the first trend, volatiles such as geraniol, nerol, linalool, myrcene, cis-rose oxide generally presented an increase in their concentrations along with berry ripening (Additional file 1: Table S1A). Moreover, most compounds with the first evolutionary trend in mature grape berries had higher concentrations in the grapes grown in the CL region compared with the GT region. The compounds with the second evolutionary trend, such as terpinenols and cis/trans-furan linalool oxides, reached their highest levels at the pea-size period (E-L 31) or veraison (E-L 35) stage and subsequently reduced their levels in post-veraison grapes. At harvest, this group of volatile compounds did not display significant differences between the grapes from the CL and GT regions. The remaining compounds were grouped into the third evolutionary trend, including hotrienol, citronella and pyran linalool oxide. Their accumulation trends varied between regions and years. In the third group, hotrienol, a dehydrogenated form of linalool, displayed a downward trend as berry ripening processed, which was the opposite of the developmental accumulation of linalool. Among the detected free-form terpenes, linalool and geraniol had the highest concentrations, followed by nerol, mycene, citronellol and cis-rose oxide. Apart from citonellol, the other five terpenes presented higher concentration in mature grapes from the CL region than from the GT region (Fig. 3b). We must note that even in the same region, there was a great difference in the compound evolutionary trend between the two vintages. Because of this difference, we analyzed annual data instead of the mean of the two-year data. The findings indicate that the accumulation of free-from volatiles is easily altered by vintage.Fig. 1

Bottom Line: Particularly in the MEP pathway, the expression of VviHDR (1-hydroxy-2-methyl-2-butenyl 4-diphosphate reductase) paralleled with the accumulation of terpenes, which can promote the flow of isopentenyl diphosphate (IPP) into the terpene synthetic pathway.Other genes were also found to be related to the differential accumulation of terpenes and monoterpene glycosides in the grapes between regions.Considering the expression patterns of both transcription factors and mature-related genes, we infer that less rainfall and stronger sunshine in the GT region could initiate the earlier expression of ripening-related genes and accelerate the berry maturation, eventually limiting the production of terpene volatiles.

View Article: PubMed Central - PubMed

Affiliation: Centre for Viticulture and Enology, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, 100083, China. wenyaqin1219@163.com.

ABSTRACT

Background: Terpenes are of great interest to winemakers because of their extremely low perception thresholds and pleasant floral odors. Even for the same variety, terpene profile can be substantially different for grapevine growing environments. Recently a series of genes required for terpene biosynthesis were biochemically characterized in grape berries. However, the genes that dominate the differential terpene accumulation of grape berries between regions have yet to be identified.

Methods: Free and glycosidically-bound terpenes were identified and quantified using gas chromatography-mass spectrometry (GC-MS) technique. The transcription expression profiling of the genes was obtained by RNA sequencing and part of the results were verified by quantitative real time PCR (QPCR). The gene co-expression networks were constructed with the Cytoscape software v 2.8.2 ( www.cytoscape.org).

Results: '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 berries from GT. Transcriptome analysis revealed that some key genes involved in terpene biosynthesis were markedly up-regulated in the CL region. Particularly in the MEP pathway, the expression of VviHDR (1-hydroxy-2-methyl-2-butenyl 4-diphosphate reductase) paralleled with the accumulation of terpenes, which can promote the flow of isopentenyl diphosphate (IPP) into the terpene synthetic pathway. The glycosidically bound monoterpenes accumulated differentially along with maturation in both regions, which is synchronous with the expression of a monoterpene glucosyltransferase gene (VviUGT85A2L4 (VviGT14)). Other genes were also found to be related to the differential accumulation of terpenes and monoterpene glycosides in the grapes between regions. Transcription factors that could regulate terpene synthesis were predicted through gene co-expression network analysis. Additionally, the genes involved in abscisic acid (ABA) and ethylene signal responses were expressed at high levels earlier in GT grapes than in CL grapes.

Conclusions: Differential production of free and glycosidically-bound terpenes in grape berries across GT and CL regions should be related at least to the expression of both VviHDR and VviUGT85A2L4 (VviGT14). Considering the expression patterns of both transcription factors and mature-related genes, we infer that less rainfall and stronger sunshine in the GT region could initiate the earlier expression of ripening-related genes and accelerate the berry maturation, eventually limiting the production of terpene volatiles.

No MeSH data available.