Functional characterization of grapevine MLO genes to define their roles in Powdery mildew susceptibility by CRISPR/Cas9 genome editing

Throughout the growing season, grapevine frequently encounters environmental challenges associated with heat and light radiation stress, especially during the ripening stage, thereby constraining the yield and quality of berries. MYB24 has been previously proposed to control light responses during late fruit ripening stages, and it has been found to require the co-factor MYC2. We have generated transcriptomic data from grapevine leaves transiently co-transformed with MYB24 and MYC2. Differential expression analysis revealed 179 up-regulated genes (URGs). Considering tissue specificity, where MYB24 is specifically and highly expressed in flowers and late-ripening berries, the expression of these URGs was explored using a previously published Berry Development Atlas gathering berry development data of cv. ‘Pinot Noir’ and ‘Cabernet Sauvignon’ in different vintages.

Cis-acting regulatory elements are DNA sequences that can be bound by transcription factors to regulate the expression of genes in a condition-dependent and tissue-specific way. It is nowadays possible to search for DNA motives and sequences that a given transcription factor is binding or at least can, but it is still hard to have a glance at all the transcription factors that are contemporaneously located at the same locus. Inspired by an existing technique that uses the CRISPR-Cas system in mammal cells, we are trying to develop a protocol to study such regulation in Vitis vinifera. Using the highly sequence-specific binding capacity of a catalytically inactive Cas9 protein (dCas9), our idea is to set up a system to target a desired sequence and precipitate all the crosslinked proteins and distantly interacting chromatin at this locus and analyze them.

The combined effect of soil moisture and soil temperature on grapevine physiology is gaining interest in the context of global warming.

As the climate warms, the focus of concern in viticulture often turns to how higher temperatures may shift growing regions, change the character of AVAs, and alter fruit quality. However, climate warming is increasing most quickly during the winter dormancy cycle, a critical and often underappreciated portion of the grapevine life cycle. In response to decreasing temperatures and decreasing daylength, grapes initiate a series of physiological changes to enter dormancy, acquire freeze resistance, and time spring phenology such that the growing season begins after threat of frost.

The definition of terroir has evolved throughout history, from something clearly negative in the XVIth-XVIIIth century to a complex multi-parametric construct with positive connotations but also with many scientific unknowns. Terroir has always been linked more or less explicitly to the sensory properties of the resulting products.