Abstract Detail

Crops and Wild Relatives

Williams, Brigette [1], Edwards, Christine [2], Miller, Allison [3].

Epigenomic variation in the grapevine cultivar 'Chambourcin' in response to grafting and irrigation treatments.

Self-fertilization and clonality result in the loss or stagnation of genetic diversity over time. One mechanism that can potentiate survival, particularly in long-lived organisms, is phenotypic plasticity. This ability of organisms to express a range of phenotypes in response to spatial and temporal variation has been documented in biological literature since the early twentieth century. However, while our ability to document plasticity has improved, our explanatory power of the phenomenon itself has been limited until now. Recent advances in the fields of molecular biology and genetics have facilitated characterization of the epigenome; a system of chemical modifications to DNA and DNA-associating proteins, known as histones, mediated by small RNAs. These epigenetic modifications alter gene expression without changing the DNA sequence, which can have phenotypic consequences. Extensive variation in patterns of epigenetic modifications has been observed across many plant taxa; some of these epigenetic changes can be stably inherited across generations, while others are reversible. The epigenome can also be environmentally responsive with varying sensitivity. Although evolutionary models have shown support for environmentally driven epigenomic variation, empirical research that demonstrates a link is still lacking. In this study, we investigate impacts of grafting and irrigation on the epigenome (DNA methylation and small RNAs) in 12 replicates of a single, clonal individual of the wine grapevine ‘Chambourcin’ (a Vitis vinifera derived French-American hybrid). Our experimental design is balanced among ungrafted and grafted vines, with replicate sets exposed to full versus no irrigation. Early results from differential methylation analysis indicate that clonally replicated ‘Chambourcin’ display unique signatures in its methylome and corresponding small RNAs in response to both grafting and irrigation treatments. We have also identified putative micro RNAs and small interfering RNAs that may underpin this epigenomic response observed in grapevine. Not only did we uncover diverse epigenomic responses in clonal replicates under different irrigation treatments, we show that a single genome in the same space and time displays a dynamic response to its environment as potentially mediated by a genome-genome interaction between a grafted scion (‘Chambourcin’) and its hybrid rootstock (V. ruparia x V. rupestris). This work broadens our understanding of the role of the epigenome in organismal response to its environment and may have important consequences for understanding how clonal organisms such as grapevines can be cultivated across a wide range of habitats worldwide.

Related Links:
Perennial Plant Diversity

1 - Saint Louis University, Dept. Of Biology, 1 N. Grand Blvd., Saint Louis, MO, 63103, United States
2 - Missouri Botanical Garden, 4344 Shaw Ave., St. Louis, MO, 63110, United States
3 - Saint Louis University/Danforth Plant Science Center, Biology, 3507 Laclede Avenue, Macelwane Hall, St. Louis, MO , 63110, USA

Keywords:
Grapevine
epigenome
rootstock
DNA methylation
small RNA
irrigation effects.

Presentation Type: Oral Paper
Session: CWR1, Crops and Wild Relatives
Location: Tucson D/Starr Pass
Date: Wednesday, July 31st, 2019
Time: 10:45 AM
Number: CWR1011
Abstract ID:1036
Candidate for Awards:None