Tylose Formation and Changes in Phenolic Compounds of Grape Roots Infected with «Phaeomoniella chlamydospora» and «Phaeoacremonium» Species

Ana Gonzalez, Ana Ortuño, José Del Rio, Juana M. Botia, María D. Fuster, Pedro Gomez, Victor Frias

Abstract


The role of phenolic compounds in strengthening resistance of grapevine to young grapevine decline was
analysed. The formation of tyloses has also been associated with this disease. A microscopic study showed that
tyloses originated in parenchyma cells associated with the xylem and from there invaded the xylem lumen. As tyloses
formed, there were changes in the cell wall, associated with the accumulation of crystalline structures. The cells
surrounding the blocked xylem contained more polyphenolic compounds than the cells of intact xylem. Changes in
the level and composition of polyphenolic compounds occurred in relation to the severity of infection. Tannin concentrations
also increased with increasing numbers of xylem vessels containing tyloses. Root extracts added to fungal
culture media inhibited mycelial growth of Phaeomoniella chlamydospora, Phaeoacremonium aleophilum and Pm.
inflatipes. Inhibition was greater with extracts from roots with tyloses, and was also correlated with polyphenol
content. Extracts of the leaves, stems and berries of vines treated with Brotomax, which increases the biosynthesis of
phenolic compounds, inhibited mycelial growth of the fungi compared to untreated control plants.

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DOI: http://dx.doi.org/10.14601/Phytopathol_Mediterr-1644



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