DNA-Free genome editing confers disease resistance in grapevine

Damage during the budbreak period due to spring season frosts remains one of the most significant weather-related challenges to viticulture around the world. For example, in 2021, €2bn of estimated damage was reported in france while >50% of vineyards were badly affected in the UK in 2017.

Root system architecture (RSA) is important for soil exploration and edaphic resources acquisition by the plant, and thus contributes largely to its productivity and adaptation to environmental stresses, particularly soil water deficit. In grafted grapevine, while the degree of drought tolerance induced by the rootstock has been well documented in the vineyard, information about the underlying physiological processes, particularly at the root level, is scarce, due to the inherent difficulties in observing large root systems in situ. The objectives of this study were to determine genetic differences in the root architectural traits and their relationships to water uptake in two Vitis rootstocks genotypes (RGM, 140Ru) differing in their adaptation to drought. Young rootstocks grafted upon the Riesling variety were transplanted into cylindrical tubes and in 2D rhizotrons under two conditions, well watered and moderate water stress. Root traits were analyzed by digital imaging and the amount of transpired water was measured gravimetrically twice a week. Root phenotyping after 30 days reveal substantial variation in RSA traits between genotypes despite similar total root mass; the drought-tolerant 140Ru showed higher root length density in the deep layer, while the drought-sensitive RGM was characterised by shallow-angled root system development with more basal roots and a larger proportion of fine roots in the upper half of the tube. Water deficit affected canopy size and shoot mass to a greater extent than root development and architectural-related traits for both 140Ru and RGM, suggesting vertical distribution of roots was controlled by genotype rather than plasticity to soil water regime. The deeper root system of 140Ru as compared to RGM correlated with greater daily water uptake and sustained stomata opening under water-limited conditions but had little effect on above-ground growth. Our results highlight that grapevine rootstocks have constitutively distinct RSA phenotypes and that, in the context of climate change, those that develop an extensive root network at depth may provide a desirable advantage to the plant in coping with reduced water resources.

Berry texture and seed size are major components of grapevine fruit quality, influencing both consumer perception and technological performance; however, the genetic bases of these traits remain incompletely understood.

The impact of viticulture on soil can be determined by comparing the biophysical properties that represent soil health at a particular site and depth with those same properties in soil considered to represent the ‘pre-vineyard’ state (the headland). Information gathered by this method shows the changes in soil properties following the change to viticulture depend on individual vineyard management and environment.

Effective control with fungicides is essential to protect grapevine from downy mildew, a devastating disease caused by the oomycete Plasmopara viticola. Managing this disease faces challenges in maintaining fungicide efficacy as the number of modes of action decreases and the risk of fungicide resistance increases. Long-term measures should address strains resistant to multiple modes of action, that can be selected by the repeated use of single-site fungicides. For these reasons, a precision management of the disease, that considers the selection of the best fungicide schedule according to the sensitivity profile of the pathogen population, is needed.