1.D.7 The Beticolin (Beticolin) Family

Beticolins are non-host-specific toxins produced by the phytopathogenic fungus, Cercospora beticola which causes leap spot disease in sugar beets. Fifteen non-peptide compounds are known which share the same polycyclic skeleton and have a chlorine atom and partially hydrogenated anthraquinone and xanthone moieties. They are named beticolin 0 to 14. They are not only phytotoxic but also bactericidal and anti tumorigenic. They chelate Mg2+ to form an electrically neutral dimeric complex consisting of two beticolins and two Mg2+. Mg2+ increases partitioning into the bilayer where in plants they induce loss of solutes, depolarize the membrane potential, and inhibit H+ extrusion and K+ uptake. They form poorly selective ion channels permeable to K+, Na+, Ca2+ and Cl-. They are the only sequenced pore-forming elicitors of plant defense reactions.



Ducrot, P.H., J. Einhorn, L. Kerhoas, J.Y. Lallemand, M.-L. Milat, J.P. Blein, A. Neuman and T. Prange (1996). Cercospora beticola toxins. PartXI. Isolation and structure of beticolin 0. Tetrahedron Lett. 37: 3121-3124.

Goudet, C., A.-A. Vèry, M.-L. Milat, M. Ildefonse, J.-B. Thibaud, J. Sentenac and J.-P. Blein (1998). Magnesium ions promote assembly of channel-like structures from beticolin 0, a non-peptide fungal toxin purified from Cercospora beticola. Plant J. 14: 359-364.

Klüsener, B. and E.W. Weiler (1999). Pore-forming properties of elicitors of plant defense reactions and cellulolytic enzymes. FEBS Lett. 459: 263-266.


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