Aim 1 assesses how scion plasticity in foliar and reproductive traits is driven by the root system, the environment, and their interaction. Taking a step further, Aim 1 also addresses the molecular mechanism through which these factors act by testing the hypothesis that scion plasticity is driven via differential modification of the epigenome. We will start with characterizing leaf, fruit and wine traits in the cultivar 'Marquette' grown as a scion grafted on '3309C', '1103P' and 'SO4' rootstocks. This experimental vineyard is replicated in the climatically diverse locations of South Dakota, New York, Pennsylvania, and Missouri. Leaf and berry samples will be collected at corresponding phenological stages at the four locations. The samples will be analyzed for metabolite and elemental composition, and wine made from the fruit will be chemically characterized for its aroma and flavor components. To gain insight into the influence of the environment on the epigenome and gene expression in the scion, we will quantify DNA methylation, mRNA, miRNA and siRNA levels in subsets of the samples used for phenotypic analysis of the leaf and fruit in all four vineyards.
Commercial grape rootstocks represent a narrow sampling of the natural variation that exists in rootstock breeding resources. While scion phenotypes are known to be modulated by rootstock genotypes, it is yet to be determined if scion phenotypic plasticity can be further expanded by grafting the scion onto an expended array of rootstock genotypes. We previously established a unique experimental resource which enables us to address this question: We created a vineyard composed of 'Marquette' grafted on 140 different rootstock genotypes derived from a cross between Vitis rupestris and Vitis riparia, and replicated this vineyard at our in South Dakota, New York, and Missouri experimental fields. We will collect leaf and berry samples and analyze them for metabolite and elemental composition. Fruit will also be fermented into wine, which will then be analyzed for its chemical components. As genetic linkage maps were previously constructed for this V. rupestris X V. riparia progeny, each phenotype of the scion can be used as a trait in a multi-site QTL analysis to assess rootstock genotype X environment contributions to leaf, fruit and wine traits.
This aim will enable us to partition scion phenotypic plasticity between rootstock genotype and the environment across multiple years. DNA methylation, and mRNA, siRNA and miRNA abundance data will allow us to evaluate the impact of the environment on epigenomic changes and gene expression patterns in the scion. Overlaying the phenotypic and molecular data will offer an insight into how epigenomics and gene regulation correlate with environmental conditions and deepen our understanding of the biological basis of terroir.
This aim will enable us to partition scion phenotypic plasticity between rootstock genotype and the environment across multiple years. DNA methylation, and mRNA, siRNA and miRNA abundance data will allow us to evaluate the impact of the environment on epigenomic changes and gene expression patterns in the scion. Overlaying the phenotypic and molecular data will offer an insight into how epigenomics and gene regulation correlate with environmental conditions and deepen our understanding of the biological basis of terroir.
