REDWINE project: use of Chlorella vulgaris to prevent biotic and abiotic stress in Palmela’s region, Portugal, vineyards

The South African Table grape industry has to expand to new markets with high quality niche products, but limited water availability threatens sustainable production. To overcome this challenge and to obtain high-quality products for the new markets, require constant technological advancement. Currently, limited available scientific information about growth balances and physiology and especially grape quality parameters, hinders technological advancement and thus efficient regulatory management of the morphological, chemical, and pathological status of table grapes, especially in response to abiotic factors.

Seven plots located in the commune of Montigny-lès-Arsures (Jura, 39), planted with grapevine varieties Trousseau and Savagnin, were chosen for a study of soil pits and a distribution of major and trace chemical elements in soils and wines. It was shown that the mineral matrix of the soil reflects the geological substratum and the sub-surface alteration process, while the organic soil matrix depends on agro-viticultural practices.

One of the main consequences of global warming is the rise of the mean temperature. Thus, the heat summation by the plants begins sooner in the early spring, and by cumulating growing degree-days, phenological development tends to happen earlier. However, spring frost is still a recurrent phenomenon causing serious damages to buds and therefore, threatening the harvests of the winegrowers. The wind machine is a solution to protect fruit crops against spring frost that is increasingly used. It is composed of a 10-m mast with a blowing fan at its peak. By tapping into the strength of the nocturnal thermal inversion, it sweeps the crop by propelling warm air above to the ground. Thus, stratification is momentarily suppressed. Furthermore, the continuous action of the machine, alone or in synergy, or the addition of a heater allow the bud to be bathed in a warmer environment. Also, the punctual action of the tower’s warm gust reaches the bud directly at each rotation period. All these actions allow the bud to continuously warm up, but with different intensities and over a different period. Although there is evidence of the effectiveness of the wind machines, the thermal transfers involved in those mechanisms raise questions about their true nature. Field measurements based on ultrasonic anemometers and fast responding thermocouples complemented by laboratory measurements on a reduced scale model allow to characterize both the airflow produced by the wind machine and the local temperature in its vicinity. Those experiments were realized in the vineyard of Quincy, in the framework of the SICTAG project. In the future paper, we will detail the aeraulic characterization of the wind machine and the thermal effects resulting from it and we will focus on how the wind machine warms up the local atmosphere and enables to reduce the freezing risk.

Tempranillo Tinto (TT) is the third-most planted red wine variety in the world, and it is mostly grown in the Iberian Peninsula. Spontaneous somatic variation appearing during vegetative propagation can be exploited to improve elite varieties as Tempranillo Tinto, including the selection of new phenotypes enhancing berry quality. We described previously that a somatic variant of TT with darker fruit color, the clone VN21, exhibits increased extractability of polyphenols during the winemaking process. To unravel the molecular mechanism underlying this phenomenon, we performed whole-genome resequencing to compare VN21 to other TT clones, revealing a 10 Mb deletion in chromosome 11 that likely affected only the L1 meristem cell layer of VN21 and tissues derived from it, such as external cell layers of berry skin.

Grapevine is a crop of great economic importance for several countries. The intensification of grapevine production has mostly been sustained by the increasing use of water resources at the expense of the environmental water balance. Moreover, in the last decades, climate change and the consequent expansion of drought have further compromised water availability, making current agricultural systems even more fragile both ecologically and economically. Recently, many research groups have highlighted the important role of endophytes in facilitating plant growth under optimal or stressful conditions. Within the framework of the PRIMA project, we aim to investigate the possible exploitation of the natural endophyte biodiversity as a sustainable tool to make grapevine plants more resilient to water deficit environmental conditions.