Sap Flow Disruption in Grapevine Is the Early Signal Predicting the Structural, Functional, and Genetic Responses to Esca Disease

Abstract

Fungal species involved in Esca cause the formation of grapevine wood necroses. It results in the deterioration of vascular network transport capacity and the disturbance of the physiological processes, leading to gradual or sudden grapevine death. Herein, for two consecutive growing seasons, a detailed analysis of the structural (wood necrosis and leaf discoloration) and physiological parameters related to the water use of healthy and esca-symptomatic grapevines was conducted. Measurements were carried out on 17-year-old grapevines that expressed, or not, Esca-leaf symptoms in a vineyard of the Bordeaux region (France). Whole-plant transpiration was recorded continuously from pre-veraison to harvest, using noninvasive sap flow sensors. Whole-plant transpiration was systematically about 40–50% lower in Esca-diseased grapevines compared with controls, and this difference can be observed around 2 weeks before the first Esca-foliar symptoms appeared in the vineyard. Unlike grapevine sap flow disruption, structural (e.g., leaf discolorations), functional (e.g., stomatal conductance, photosynthetic activity, phenolic compounds), and genetic (e.g., expression of leaf-targeted genes) plant responses were only significantly impacted by Esca at the onset and during leaf symptoms development. We conclude that sap flow dynamic, which was related to a high level of a white-rot necrosis, provides a useful tool to predict plant disorders due to Esca-grapevine disease.

Minimal versus Intensive: How the Pruning Intensity Affects Occurrence of Grapevine Leaf Stripe Disease, Wood Integrity, and the Mycobiome in Grapevine Trunks

“…This probably leads to additional wood formation and callusing in the trunk’s head, thereby increasing the circumference. The annual restructuring of the vascular system caused by intensive pruning also provokes disturbance in the sap flow and induces occlusion, both of which are associated with external esca symptoms, i.e., GLSD and apoplexy [ 6 , 67 , 68 ]. However, for minimally pruned vines, omitting intensive head pruning can minimize restructuring and maintain vessel integrity.…”

The microbiota of the grapevine holobiont: A key component of plant health

“…In the case of woody plants, the symptoms of decline can often be linked to problems with the storage and the management of reserves – e.g., a lower photosynthesis rate or vascular system degradation [23] , [180] . The quality and quantity of root exudates are directly linked to the physiological state of the plant (including the quality and quantity of its reserves; Fig.…”

Activity of Trichoderma asperellum Strain ICC 012 and Trichoderma gamsii Strain ICC 080 Toward Diseases of Esca Complex and Associated Pathogens

“…Foliar symptom expression shows almost unique peculiarities, as their intermittent occurrence in the vineyard (Marchi et al, 2006;Guerin-Dubrana et al, 2019) is a very rare phenomenon that has been observed in another wood disease, the "decay of kiwi fruit" that has many common factors with ECDs (Di Marco and Osti, 2008). The erratic nature of foliar symptom expression could be associated with phytotoxins produced by tracheomycotic pathogens, alterations of phytoalexins and photosynthetic functions, and disorders of sap flow or hydraulic failures (Claverie et al, 2020;Calzarano et al, 2021;Ouadi et al, 2021) modulated by environmental and meteorological factors, such as rainfall and temperature (Marchi et al, 2006;. Nevertheless, the deterioration of the wood by pathogens and the correlation between incidence and severity of foliar symptom expression and yield losses are unquestionable.…”