IDENTIFICATION OF FLAVONOL GLYCOSIDES FROM PRUNUS AVIUM LEAVES WHICH INDUCE THE PRODUCTION OF SYRINGOMYCIN BY PSEUDOMONAS SYRINGAE PV. SYRINGAE

Pseudomonas syringae p.v. syringae causes leafspots and necrosis of the bark of Prunus cerasus and P. avium. The pathogen produces a potent phytotoxin called syringomycin that is estimated to nearly double its virulence.
A vital role in syringomycin synthesis is attributed to the syrB gene.
Certain phenolic glycosides activate expression of both the syrB gene and syringomycin biosynthesis, indicating that virulence is modulated by the perception of host plant signals.
Cherry leaves (P. avium) were analyzed and shown to contain high quantities of substances with signal activity.

This report describes the purification and identification of two flavonol signal molecules that are quercetin 3-rutinosyl-4′-glucoside and kaempferol 3-rutinosyl-4′-glucoside.
We also describe 3,4′-diglucosides of quercetin and kaempferol from cherry leaves.

Elucidation of the structures of the signal molecules is a significant step towards understanding the role of flavonoid glycosides in host-parasite interactions, and defining the specific functional groups required for signal activity.

International Symposium on Natural Phenols in Plant Resistance

M. GEIBEL, DENNIS C. GROSS, Y. MO, ROBERT F. BONSALL, H. GEIGER

https://doi.org/10.17660/ActaHortic.1994.381.93