Drought tolerance assessment and differentiation of grapevine cultivars using physiological metrics: insights from field studies

Plant diseases are a major obstacle to crop production. The main approaches to battle plant diseases, consist of synthetic chemicals to attack infecting pathogens. However, concerns are increasing about the effects of chemicals in the environment, leading to an increase in the use of biocontrol agents (BCAs), due to their assets, such as, antagonism, and competition. In this study, we tested the hypothesis that the introduction of Bacillus subtilis PTA-271 (Bs PTA-271) and Trichoderma atroviride SC1 (Ta SC1) produce distinctive modifications in the composition and network structure of the grapevine rhizosphere microbial community, as well as grapevine induced defenses.

Grapevine cultivars can be unequivocally typed by both physical differences (ampelography) and genetic tests. However due to their very similar characteristics, the identification of clones within a cultivar relies on the accurate tracing of supply records to the point of origin. Such records are not always available or reliable, particularly for older accessions. Whole genome sequencing (WGS) provides the most highly detailed methodology for defining grapevine cultivars and more importantly, this can be extended to differentiating clones within those cultivars.

In the context of global change, the environmental conditions are expected to be more stressful for viticulture. The choice of the rootstock may play a crucial role to improve the adaptation of viticulture to new biotic and abiotic threats (Ollat et al., 2016). However, the selection of interesting traits in rootstock breeding programs is complex because of the combination of multiple targets in a same ideotype. In this sense, the integration of studies about the genetic architecture for desired biotic and abiotic response traits allow us to identify genomic regions to combine and those with interesting pleiotropic effects.

This study presents the preliminary results obtained in 2022, of the evaluation of three new crossbreed winegrape genotypes and their parental varieties, grown under controlled irrigation (60% ETc) and rainfed conditions in a wine-growing area with scarcity of water and high temperatures (Murcia, southeast Spain). The genotypes MC16 and MC80 were obtained from crosses between the varieties ‘Monastrell’ and ‘Cabernet Sauvignon’, and MS104 from crosses between ‘Monastrell’ and ‘Syrah’ [1]. The objective of this study was to analyse the physiological response and vegetative development of the 6 genotypes under the two irrigation conditions, and to study their effect on the content of soluble sugars and chlorophyll in the leaf.

Condensed grape tannins play a major role in the organoleptic properties and quality of red wine. Recently, a new sub-family of macrocyclic condensed tannins has been identified in red wine and named “crown tannins”. Indeed, the first compound of the family identified and characterised by NMR was the crown procyanidin tetramer which is composed of a macrocyclic structure composed of four (-)-epicatechins link together by B-type interflavanoid linkage in the following an alternative sequences of C4-C8 and C4-C6 linkage. The 3D structure of this unusual crown procyanidin family reveals a central cavity in the molecule [1].