Project description:In the production of seedless table grapes, it is conventional to use plant growth regulators including gibberellins. Little is known about the differences in aroma volatiles between seedless-treated grapes and nontreated (seeded) grapes. Therefore, in this study, the aroma volatile profiles of seedless-treated and nontreated ‘Shine Muscat’ grape berries during ripening were compared using gas chromatography-mass spectrometry. Measurements of volatiles during ripening showed 202 peaks in the seedless-treated and nontreated whole grape berries. According to two-way analysis of variance, the number of volatiles with differences between seedless-treated and nontreated berries and/or between ripening stages was 123, whereas those with no differences between treatments and between ripening stages was 79. Two-way hierarchical clustering analysis for the 123 volatiles showed that seedless-treated berries at the early ripening stages were separated from the other berries, and the seedless-treated and nontreated berries at the post-ripening stage were classified into the same cluster. At the early ripening stage, more lipoxygenase-pathway volatiles were produced in the seedless-treated berries than in the non-treated ones. Linalool compounds increased in both seedless-treated and nontreated berries with ripening. Gene expression profile comparisons using principal component analysis of RNA-sequencing data showed that the seedless-treated berries ripened earlier than the nontreated berries at the early ripening stage. The number of differentially expressed genes in the seedless-treated berries decreased during ripening. Using weighted gene co-expression network analyses, 12 modules and 24 modules were detected in berry skin and flesh, respectively. The correlation analysis revealed that 33 volatiles correlated with four modules in the skin and 50 volatiles correlated with nine modules in the flesh. Most of the volatiles correlated with these modules were those that showed significant differences between treatments and/or ripening stages by two-way analysis of variance. The differences in the aroma volatile profiles between seedless-treated and nontreated berries decreased as harvest was delayed, suggesting that delaying the harvest may make it possible to bring the aroma of seedless-treated ‘Shine Muscat’ berries closer to the original aroma of the seeded berries.
Project description:Somatic variation is a valuable source of trait diversity in clonally propagated crops. In grapevine, which has been clonally propagated worldwide for centuries, important phenotypes such as white berry colour are the result of genetic changes caused by transposable elements. Additionally, epiallele formation may play a role in determining geo-specific (‘terroir’) differences in grapes and thus ultimately in wine. This genomic plasticity might be co-opted for crop improvement via somatic embryogenesis, but that depends on a species-specific understanding of the epigenetic regulation of transposable element (TE) expression and silencing in these cultures. For this reason, we used whole-genome bisulphite sequencing, mRNA sequencing and small RNA sequencing to study the epigenetic status and expression of TEs in embryogenic callus, in comparison with leaf tissue.
Project description:Seedless varieties are of particular importance to the table-grape and raisin industries. Gibberellin (GA) application is widely used in the early stages of seedless berry development to increase berry size and economic value. However, the underlying mechanism of GA induction of berry enlargement is not well understood. Here, RNA-sequencing analysis of âCentennial Seedlessâ (Vitis vinifera L.) berries treated with GA3 12 days after flowering is reported.
Project description:Transcriptome analysis during seed development provides insights into co-regulated and altered gene expression between a seeded wine grape variety and it seedless somatic variant.
Project description:By implementing a leaf-removal treatment in the berry bunch zone, grapes were predominantly exposed to elevated light and their complete transcriptomes (as generated by RNASeq) were compared at four developmental stages.