Analysis of Impacts of Smoke Exposure on Grape (Vitis vinifera) Berry Development

In regions traditionally suitable for the cultivation and processing of wine grapes (Vitus vinifera), climate change has resulted in increasingly hotter and drier grape harvest seasons. A significant consequence this is the rising incidence of wildfires, which release phenolic compounds into the atmosphere through combustion of wood and other lignin-rich plants. Unfortunately, these compounds find their way into wine grapes, negatively affecting their flavor profile and drastically reducing the production value of entire vineyards. The annual smoke-exposure-associated loss in the wine grape industry amounts to hundreds of millions of dollars for vineyard owners. The mechanism by which smoke-associated compounds enter and are stored within the grape berries remains a poorly understood.To address this knowledge gap, we employed RNA sequencing (RNA-seq) to observe changes in gene expression over time of grape berries in response to smoke exposure at pre-veraison and version stages of development. We observed a significant upregulation of genes associated with redox stress responses to toxic compounds. Based on these observations, we hypothesize that the activation of redox stress pathways leads to the accumulation of unwanted sulfur compounds, specifically thiol phenols, within the grape berry vacuoles as a detoxification mechanism employed by the plant.