Transgenic expression of pear PGIP in tomato limits fungal colonization.

POWELL AL, VAN KAN J, TEN HAVE A, VISSER J, GREVE LC, BENNETT AB, LABAVITCH JM

MOLECULAR PLANT-MICROBE INTERACTIONS

Año: 2000 vol. 13 p. 942 - 950

0894-0282

Transgenic tomato plants expressing the pear fruit poly-galacturonase inhibitor protein (pPGIP) were used todemonstrate that this inhibitor of fungal pathogen endo-polygalacturonases (endo-PGs) influences disease devel-opment. Transgenic expression of pPGIP resulted inabundant accumulation of the heterologous protein in alltissues and did not alter the expression of an endogenoustomato fruit PGIP (tPGIP). The pPGIP protein was de-tected, as expected, in the cell wall protein fraction in alltransgenic tissues. Despite differential glycosylation invegetative and fruit tissues, the expressed pPGIP was ac-tive in both tissues as an inhibitor of endo-PGs from Bo-trytis cinerea. The growth of B. cinerea on ripe tomatofruit expressing pPGIP was reduced, and tissue break-down was diminished by as much as 15%, compared withnontransgenic fruit. In transgenic leaves, the expression ofpPGIP reduced lesions of macerated tissue approximately25%, a reduction of symptoms of fungal growth similar tothat observed with a B. cinerea strain in which a singleendo-PG gene, Bcpg1, had been deleted (A. ten Have, W.Mulder, J. Visser, and J. A. L. van Kan, Mol. Plant-Microbe Interact. 11:1009-1016, 1998). Heterologous ex-pression of pPGIP has demonstrated that PGIP inhibitionof fungal PGs slows the expansion of disease lesions andthe associated tissue maceration.