|Martel, Catherine - CORNELL UNIVERSITY|
Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: August 22, 2006
Publication Date: January 26, 2007
Citation: Martel, C., Giovannoni, J.J. 2007. Fruit ripening. In: Roberts, J., Gonzalez-Carranzas, Z., editors. Plant Cell Separation and Adhesion. Oxford, UK: Blackwell Publishing Ltd. p. 164-176. Technical Abstract: The exact nature of fruit modifications associated with ripening varies depending on the species examined. However, ripening generally includes modification of cell wall utltrastructure, conversion of starch to sugars, increase in susceptibility to post-harvest pathogens, changes in the accumulation and biosynthesis of pigments, and a rise in the production of aroma- and flavor-associated volatile compounds. Ethylene certainly represents a major regulator of climacteric fruit ripening, however it is itself insufficient to trigger this program as demonstrated by the inability of an immature fruit to ripen in the presence of exogenous ethylene. The initial cue responsible for timely induction of ethylene synthesis (thru increased expression of ethylene biosynthesis genes) and up-regulation of other signalling components (such as the NR ethylene receptor) has until recently been a complete mystery and remains an area of active investigation. A developmental ripening signal must necessarily be involved in the acquisition, by unripe mature fruit, of a competency to respond to ethylene. Ripening-impaired tomato mutants that fail to ripen in the presence of exogenous ethylene, yet possess fully functional ethylene signalling networks, have been identified. These mutants are believed to be impaired in ripening competency acquisition and therefore represent valuable tools for the elucidation of the developmental signalling network required for ethylene competency acquisition and subsequent climacteric ripening.