Mechanisms of grapevine resilience to a vascular disease: investigating stem radial growth, xylem development and physiological acclimation

Abstract

Background and Aims Plant vascular diseases significantly impact crop yield worldwide. Esca is a grapevine vascular disease found globally in vineyards which causes a loss of hydraulic conductance due to the occlusion of xylem vessels by tyloses. However, the integrated response of plant radial growth and physiology in maintaining xylem integrity in grapevine expressing esca symptoms remains poorly understood. Methods We investigated the interplay between variation in stem diameter, xylem anatomy, plant physiological response, and hydraulic traits in two widespread esca susceptible cultivars, ‘Sauvignon blanc’ and ‘Cabernet Sauvignon’. We used an original experimental design using naturally infected mature vines which were uprooted and transplanted into pots allowing for their study in a mini-lysimeter greenhouse phenotyping platform. Key Results Esca significantly altered the timing and sequence of stem growth periods in both cultivars, particularly the shrinkage phase following radial expansion. Symptomatic plants had a significantly higher density of occluded vessels and lower leaf- and whole-plant gas exchange. Esca-symptomatic vines showed compensation mechanisms, producing numerous small functional xylem vessels later in development suggesting a maintenance of stem vascular cambium activity. Stabilization or late recovery of whole plant stomatal conductance coincided with new healthy shoots at the top of the plant after esca symptoms plateaued. Conclusions Modified cropping practices, like avoiding late season topping, may enhance resilience in esca-symptomatic plants. These results highlight that integrating dendrometers, xylem anatomy, and gas exchange provides insights into vascular pathogenesis and its effects on plant physiology.

Large gradient of susceptibility to esca disease revealed by long-term monitoring of 46 grapevine cultivars in a common garden vineyard

“…There have been many studies of the impact of esca disease on grapevine physiology, including plant growth (Gramaje et al ., 2010; Dell’Acqua et al ., 2023), photosynthesis, water relations (Magnin-Robert et al ., 2011; Bortolami et al ., 2021a,b), and phenology (Andreini et al ., 2013), but very little effort has, as yet, been devoted to the opposite issue: the ecophysiological traits predicting esca incidence or severity. Here, we found that a low incidence of esca appeared to be associated with high water use efficiency and low vigour at the cultivar scale.…”

“…Foliar symptoms are associated with xylem hydraulic failure and impaired photosynthesis (Bortolami et al ., 2019, 2021a; Ouadi et al ., 2021; Dell’Acqua et al ., 2023). The incidence of esca foliar symptoms is probably affected by multiple factors (as reviewed in Claverie et al ., 2020), including plant age, pedoclimatic conditions, viticulture practices, the plant- and soil-associated microbiota, and the plant material.…”