Optimizing disease management in the Rioja wine region: a study on Erisiphe necator and the Gubler-Thomas model

Recent advances in phenomics and transcriptomics have the enhanced capacity for understanding how clonally propagated perennial crops like grapevines respond to their environments seasonally and over the course of multiple years. Because most grapevines are grafted, above-ground grapevine traits reflect scion genotype and its interaction with the local environment. In addition, traits expressed by the scion reflect rootstock genotype and how that rootstock is interacting with its environment seasonally and across years. To investigate rootstock x environment interaction on shoot systems in grafted grapevines we characterized comprehensive phenotypic variation in an experimental vineyard in Mount Vernon, Missouri, USA where the grapevine cultivar ‘Chambourcin’ is growing on its own roots and is grafted to three different rootstocks (‘1103P’, ‘3309C’, ‘SO4’).

From a fertility standpoint, the vine has to extract from the soil mineral substances necessary for its existence. However, the amount of certain available nutrients does not always correspond to a proportional increase in quality.

Since the arrival of Phyloxera (Daktulosphaira vitifolia) in Europe at the end of the 19th century, grafting has become essential to cultivate Vitis vinifera. Today, grafting provides not only resistance to this aphid, but it used to adapt the cultivars according to the type of soil, environment, or grape production requirements by using a panel of rootstocks. As part of vineyard decline, it is often mentioned the importance of producing quality grafted grapevine to improve vineyard longevity, but, to our knowledge, no study has been able to demonstrate that grafting has a role in this context. However, some scion/rootstock combinations are considered as incompatible due to poor graft union formation and subsequently high plant mortality soon after grafting. In a context of climate change where the creation of new cultivars and rootstocks is at the centre of research, the ability of new cultivars to be grafted is therefore essential. The early identification of graft incompatibility could allow the selection of non-viable plants before planting and would have a beneficial impact on research and development in the nursery sector. For this reason, our studies have focused on the identification of metabolic and transcriptomic markers of poor grafting success during the first days/week after grafting; we have identified some correlations between some specialized metabolites, especially stilbenes, and grafting success, as well as an accumulation of some amino acids in the incompatible combination. The study of the metabolome and the transcriptome allowed us to understand and characterise the processes involved during graft union formation.

Challenging conditions created by limited water supply and changes in the climate require an understanding of the physiological status of table grapes along the whole value chain. This is critical to develop tools for regulatory management of growth balances and grape quality. This study aimed to determine the impact of different amounts of water and an altered micro-climate (complete covering of vineyards with plastic) on the physiological reaction of the grapevine during the growth season.

One cultivar could produce distinct wines with typical properties and qualities different depending on its cultivated and its mesoclimatic conditions.