Alteration of Photosynthesis in Grapevines Affected by Esca

Abstract

To further understand the development of esca disease in grapevine, its physiological impact on plants grown in the vineyard was characterized, focusing mainly on photosynthesis. For this purpose, the state of the photosynthetic apparatus was evaluated in symptomatic and asymptomatic leaves in esca-infected grape plants, and wood carbohydrates stored in annual canes were assayed. In symptomatic leaves, esca greatly affected grapevine physiology. Foliar symptoms were associated with both stomatal closure and alteration of the photosynthetic apparatus as revealed by (i) a decrease in CO(2) assimilation, transpiration, and a significant increase in intercellular CO(2) concentration; (ii) a strong drop in both the maximum fluorescence yield and the effective Photosystem II quantum yield; and (iii) a reduction of total chlorophyll but a stable carotenoid content. On symptomatic canes, all these variables were affected more on leaves with symptoms than without symptoms, suggesting a gradation in photosynthesis disruptions in the plant according to the degree of symptom severity. In addition, canes of symptomatic plants had reduced carbohydrate reserves during the winter rest, whether they exhibit symptoms or not. The following year, the lower pool of reserves may contribute to a significant decrease in plant development, as well as a global loss in plant vigor.

Gas Exchange, Stem Water Potential and Xylem Flux on Some Grapevine Cultivars Affected by Esca Disease

“…Similar effects were reported by Petit et al (2006). These results suggest that esca foliar symptoms do not seem to be due to water stress.…”

“…As yet there is no effective treatment and the use of the only chemical treatment (sodium arsenite) has been forbidden. Thus, characterising the impact of esca on grapevine physiology represents a key step in pointing out a target that could enable control of this disease (Petit et al, 2006).…”

An Overview of Plant Photosynthesis Modulation by Pathogen Attacks

“…Foliar symptoms were associated with stomatal closure and alteration of the photosynthetic apparatus. A decrease in CO 2 assimilation, transpiration, a significant increase in intercellular CO 2 concentration, a strong drop in the maximum fluorescence yield and the effective Photosystem II quantum yields, and a reduction of total chlorophyll but a stable carotenoid content were reported (Petit et al, 2006).…”

“…It is suggested that plants switch off photosynthesis and other assimilatory metabolism to initiate respiration and other processes required for defence (Berger et al, 2007). Recently, Petit et al (Petit et al, 2006) characterized the photosynthetic apparatus of grape leaves infected with esca disease. Foliar symptoms were associated with stomatal closure and alteration of the photosynthetic apparatus.…”

Botryticides affect grapevine leaf photosynthesis without inducing defense mechanisms

“…EVects of fungicides on photosynthesis have been already revealed by modiWcations of photosynthetic activity, chlorophyll Xuorescence, pigment contents or thylakoid function and integrity (Van Iersel and Bugbee 1996;Benton and Cobb 1997;Saladin et al 2003b;Alaoui-Sossé et al 2004;Xia et al 2006). An alteration of photosynthesis may disturb the whole carbon balance of the plant aVecting both restitution of reserves to storage organs (Petit et al 2006) and carbon nutrition in annual leaves and inXorescences (Saladin et al 2003a, b;Lebon et al 2005).…”