Metabolic Consequences of Infection of Grapevine (Vitis vinifera L.) cv. “Modra frankinja” with Flavescence Dorée Phytoplasma

Abstract

Flavescence dorée, caused by the quarantine phytoplasma FDp, represents the most devastating of the grapevine yellows diseases in Europe. In an integrated study we have explored the FDp–grapevine interaction in infected grapevines of cv. “Modra frankinja” under natural conditions in the vineyard. In FDp-infected leaf vein-enriched tissues, the seasonal transcriptional profiles of 14 genes selected from various metabolic pathways showed an FDp-specific plant response compared to other grapevine yellows and uncovered a new association of the SWEET17a vacuolar transporter of fructose with pathogens. Non-targeted metabolome analysis from leaf vein-enriched tissues identified 22 significantly changed compounds with increased levels during infection. Several metabolites corroborated the gene expression study. Detailed investigation of the dynamics of carbohydrate metabolism revealed significant accumulation of sucrose and starch in the mesophyll of FDp-infected leaves, as well as significant up-regulation of genes involved in their biosynthesis. In addition, infected leaves had high activities of ADP-glucose pyrophosphorylase and, more significantly, sucrose synthase. The data support the conclusion that FDp infection inhibits phloem transport, resulting in accumulation of carbohydrates and secondary metabolites that provoke a source-sink transition and defense response status.

Determination of the Activity Signature of Key Carbohydrate Metabolism Enzymes in Phenolic-rich Grapevine Tissues

“…2 Activity of SuSy significantly increased (from 0.10 to 0.53 nkat/g FW), in correlation with the gene expression of VvSuSy 2 and similar observations from grapevine infected with another taxonomically unrelated phytoplasma, 4 suggesting a specific role of SuSy in phytoplasma-infected grapevines.…”

“…The described adaptations may be useful for other plant species with inherently high levels of phenolic compounds or tissues that are enriched in phenolics due to exogenous factors or expression of specific transgenes. 33 This protocol provides a valuable platform for advanced metabolic fingerprinting of grapevine to complement determination of metabolites 4,[34][35][36] and will help narrow the knowledge gap between genome and phenotype in environment and agricultural management practice. …”

“…1 Therefore, proper regulation of their production, distribution, and allocation is essential for both plant development and plant responses to pathogens and abiotic stresses. Significant changes in carbohydrate metabolism are associated with development of disease symptoms on grapevine infected with phytoplasmas, [2][3][4] the causal agents of important crop and fruit tree diseases, including phytoplasmal grapevine diseases. 5 The changes of carbohydrate metabolism in grapevine infected with these phytopathogenic bacteria have been detected mainly as increased expression of genes encoding the key enzymes associated with carbohydrate production.…”

Statistical modeling of long-term grapevine response to ‘Candidatus Phytoplasma solani’ infection in the field

“…Based on the results of the model presented here, we have already tested the involvement of VvDMR6 in pathogenicity of flavescence dorée phytoplasma that causes the most devastating grapevine phytoplasma disease. VvDMR6 has shown similar pattern and has been suggested as a potential early marker in diagnosis of grapevine yellows (Prezelj et al 2016a).…”

“…VvAGPL was also exposed in the second decision tree, which predicts sanitary status of plants in late summer based on results from early growing season testing. It is of note that the increased expression of VvAGPL, the activity of AGPase, as well as starch concentration have been reported in grapevines infected with phytoplasma flavescence dorée (Prezelj et al 2016a) indicating that this pattern of expression is typical for GYand not for specific grapevine -phytoplasma interaction. The third gene in this group is VvGLC2, encoding an isoform of β-1,3-glucanases, a member of the class 2 pathogenesis related proteins (PR-2).…”