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Effect of silencing the two major tomato fruit pectin methylesterase isoforms on cell wall pectin metabolism
Author(s) -
Wen B.,
Ström A.,
Tasker A.,
West G.,
Tucker G. A.
Publication year - 2013
Publication title -
plant biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.871
H-Index - 87
eISSN - 1438-8677
pISSN - 1435-8603
DOI - 10.1111/j.1438-8677.2012.00714.x
Subject(s) - pectin , ripening , pectinesterase , cell wall , biology , pectinase , lycopersicon , softening , gene isoform , biochemistry , gene silencing , enzyme , horticulture , gene , statistics , mathematics
Post‐harvest storage is largely limited by fruit softening, a result of cell wall degradation. Pectin methylesterase ( PE ) ( EC 3.1.1.11) is a major hydrolase responsible for pectin de‐esterification in the cell wall, a response to fruit ripening. Two major PE isoforms, PE 1 and PE 2, have been isolated from tomato ( S olanum lycopersicon ) pericarp tissue and both have previously been down‐regulated using antisense suppression. In this paper, PE 1 and PE 2 double antisense tomato plants were successfully generated through crossing the two single antisense lines. In the double antisense fruit, approximately 10% of normal PE activity remained and ripening associated pectin de‐esterification was almost completely blocked. However, double antisense fruit softened normally during ripening. In tomato fruit, the PE 1 isoform was found to contribute little to total PE activity and have little effect on the degree of esterification of pectin. In contrast, the other dominant fruit isoform, PE 2, has a major impact on de‐esterification of total pectin. PE 2 appears to act on non‐ CDTA ‐soluble pectin during ripening and on CDTA ‐soluble pectin before the start of ripening in a potentially block‐wise fashion.