Transcriptome profiles of three Muscat table grape cultivars at three developmental stage
Ontology highlight
ABSTRACT: Vitis vinifera is widely grown worldwide for making wine and for use as table grapes. Of the existing cultivars, some have a floral and fruity flavour, referred to as a Muscat flavour. It is well-documented that this flavour originates from a series of terpene compounds, but the mechanism of terpene content differences among the Muscat-type cultivars remains unclear. Transcript and terpene metabolite profiles were integrated to elucidate the molecular mechanism of this phenomenon. In this research, three genotypes with different aromatic strengths were investigated by RNA sequencing. A total of 27 fruit samples from three biological replicates were sequenced on Illumina HiSeq 2000 at three stages, corresponding to the veraison; berries had intermediate Brix value and were harvest-ripe. After quality assessment and data clearance, a total of 254.18 Gb of data with more than 97% Q20 bases were obtained, approximately 9.41 Gb data were generated per sample. These results will provide a valuable dataset for the discovery of the mechanism of terpene biosynthesis.
Project description:Aroma is an important parameter for table grapes and wines; terpenes are typical compounds in Muscat-type grape cultivars and can be easily perceived by humans because of their low olfactory threshold. Volatile terpenes contribute directly to the aroma character, while glycoside-bound terpenes are potential aromatic compounds and can be changed to their volatile forms via hydrolysis. With gas chromatography-mass spectrometry and a solid-phase microextraction method, an automatic data analysis platform was constructed; terpene compounds were identified and quantified from three table grape cultivars at three stages during berry development, and the raw data were deposited in MetaboLights. Terpene metabolite accumulation profiles are presented in this article for integrative analysis with the transcriptome data and phenotypic data to elucidate the important candidate genes and mechanism for terpene biosynthesis. Our method has applications in the identification and quantification of terpene compounds with very low or trace concentrations.
Project description:Monoterpenes are typical aroma components of muscat grape cultivars. However, the molecular mechanism of monoterpene biosynthesis between muscat and non-muscat grape remains unclear. In this study, two F1 hybrids with different aroma profiles from the cross between 'Midknight Beauty' and 'Red Globe' grapes were chosen for comprehensive transcriptome and metabolome analysis to study the unique monoterpenoid accumulation pattern and related candidate genes. The results showed that in the hybrid progeny, the concentrations of most terpenoids differed at different times, and the concentration of most terpenoids increased from the pre-veraison to veraison, followed by a decreasing trend from veraison to maturity. In the F1 generation, the concentration of monoterpenes accumulated in Muscat grapes was significantly higher than that in Neutral grapes. Furthermore, linalool,α-terpineol, and L-α-terpineol may be important odorants that affect the floral characteristics of Muscat grapes because of their high odor activity values (OAVs). Transcriptional analysis identified 3 VvDXS (LOC100249323, LOC100268079, LOC100247834), 1 VvHDS (LOC100257071), 1 VvMVK (LOC100251148), 1 VvHMGR (LOC100265082), and 1 VvGGPPS (LOC100257234) in the MEP and MVA pathways. Meanwhile, 11 TPS genes that may be involved in the regulation of monoterpenes were identified. Among them, VvTPS (LOC100853562) showed consistency with the accumulation of monoterpenes and had a high expression level, MYB (LOC100255488), GATA (LOC100262474), and ERF (LOC100255943, LOC100260401) were selected as candidate transcription factors (TFs). The findings provide new insights for the subsequent functional validation and further investigation of genes related to monoterpene synthesis in Muscat aroma grapes.
Project description:Vitis vinifera is widely grown worldwide for making wine and for use as table grapes. Of the existing cultivars, some have a floral and fruity flavour, referred to as a Muscat flavour. It is well-documented that this flavour originates from a series of terpene compounds, but the mechanism of terpene content differences among the Muscat-type cultivars remains unclear. Transcript and terpene metabolite profiles were integrated to elucidate the molecular mechanism of this phenomenon. In this research, three genotypes with different aromatic strengths were investigated by RNA sequencing. A total of 27 fruit samples from three biological replicates were sequenced on Illumina HiSeq2000 at three stages, corresponding to the veraison; berries had intermediate Brix value and were harvest-ripe. After quality assessment and data clearance, a total of 254.18 Gb of data with more than 97% Q20 bases were obtained, approximately 9.41 Gb data were generated per sample. These results will provide a valuable dataset for the discovery of the mechanism of terpene biosynthesis.
Project description:Aroma is an important parameter for table grapes and wines; terpenes are typical compounds in Muscat-type grape cultivars and can be easily perceived by humans because of their low olfactory threshold. Volatile terpenes contribute directly to the aroma character, while glycoside-bound terpenes are potential aromatic compounds and can be changed to their volatile forms via hydrolysis. With gas chromatography-mass spectrometry and a solid-phase microextraction method, an automatic data analysis platform was constructed; terpene compounds were identified and quantified from three table grape cultivars at three stages during berry development, and the raw data were deposited in MetaboLights. Terpene metabolite accumulation profiles are presented in this article for integrative analysis with the transcriptome data and phenotypic data to elucidate the important candidate genes and mechanism for terpene biosynthesis. Our method has applications in the identification and quantification of terpene compounds with very low or trace concentrations.
Project description:Grape volatiles include a great number of compounds, among which monoterpenes, alcohols,esters and carbonyls were found.Grape may be divided into aromatic and non-aromatic varieties. ‘Shine Muscat’ belongs to the aromatic cultivar. The most abundant free compounds detected in Muscat grape were linalool, geraniol, citronellol, nerol. Grapevine (Vitis vinifera L.) is an economically important and widely cultivated fruit crop. Grape quality is important for its market value and is largely decided by its taste and aroma.Gas-chromatograph mass-spectrometry (GC-MS) was performed to observe changes of the volatile compounds.
Project description:To obtain an interpretation from the view of transcriptome on distinct metabolite accumulation between ecologically different regions in China, next-generation sequencing technology was performed on E-L 31, 35?36 and 38 stages of Muscat Blanc a Petits Grains grape berries from Changli (CL, eastern) and Gaotai (GT, western). Transcriptome analysis revealed that some key genes involved in terpene synthesis were markedly up-regulated in the CL region. Particularly in the MEP pathway, the expression of VvHDR (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 (VvGT14). 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. cDNA libraries generated from four developmental stages (E-L 31, 35, 36 and 38) of Muscat Blanc a Petits Grains grape berries in two consecutive years from Changli (CL) and Gaotai (GT) in China were sequenced using Illumina HiSeq™ 2000.Only one RNA-seq library was constructed for each of the E-L31 and E-L36 stage samples because of the small amount of high quality RNA acquired, whereas two libraries were constructed for each of the E-L35 and E-L38 stage samples. As a result, a total of 24 libraries were obtained for the two regions within two years.