ISHS Acta Horticulturae 528: VII International Symposium on Grapevine Genetics and Breeding
EUTYPA DIEBACK OF GRAPEVINE: EXPRESSION OF AN NADPH-DEPENDANT ALDEHYDE REDUCTASE WHICH DETOXIFIES EUTYPINE, A TOXIN FROM EUTYPA LATA |
| Authors: | J.P. Roustan, S. Colrat, S. Dalmayrac, P. Guillen, M. Guis, G. Martinez-Reina, C. Deswarte, M. Bouzayen, J. Fallot, J.C. Pech, A. Latché |
| Keywords: | Detoxifying gene, Eutypa dieback, eutypine reducing enzyme, toxin resistance, transgenic grape cells |
| Abstract:
Eutypa dieback, caused by the ascomycete fungus Eutypa lata, is currently the most serious disease of the grapevine. This disease affects a great number of vineyards throughout the world and its economic impact is very important. Furthermore, there is no remedy available for the destruction of parasitic fungus. Eutypa lata infects the vineyard through pruning wounds and colonizes trunk or arms. It has been found that the fungus synthesizes a toxin, 4-hydroxy-3-(3-methyl-3-butene-1-yny]) benzyl aldehyde, named cutypine. It is transported by the sap to the herbaceous parts of the grapevines and plays a prominent role in the expression of eutypa dieback symptoms. In the grapevine cells, eutypine is metabolized into an compound identified as 4-hydroxy-3-(3-methyl-3-butene-1-ynyl) benzylic alcohol, named eutypinol. This compound does not exhibit a toxic effect towards the grapevine. Furthermore, a relationship has been found between tolerance to this disease and the capacity of cells to convert eutypine to the corresponding alcohol. The progress made in the understanding eutypine mechanism of action has opened new prospects regarding development of efficient tools for stopping this disease. We described here the purification to homogeneity of a protein from Vigna radiata that exhibited eutypine reductase activity and the cloning of corresponding cDNA. VR-ERE (eutypine reducing enzyme) cDNA encodes an NADPH-dependent reductase of 36 kDa exhibiting a high affinity towards eutypine. Furthermore, it has been shown that expression of the VR-ERE cDNA in grapevine cells, transformed by Agrobacterium- mediated procedure, conferred resistance to the toxin. This discovery opens up new biotechnological approaches for the generation of grapevines resistant to eutypa dieback. | |
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