Location: Plant, Soil and Nutrition ResearchTitle: Genetic networks influencing fruit ripening Author
Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 3/10/2013
Publication Date: 6/1/2013
Citation: Ampofo, B., Chapman, N., Seymour, G., Giovannoni, J.J. 2013. Regulatory Networks Controlling Ripening. In: Graham B. Seymour, Mervin Poole, James J. Giovannoni, Gregory A. Tucker, editors. The Molecular Biology and Biochemistry of Fruit Ripening. New Delhi, India:Wiley-Blackwell. p189-200. Interpretive Summary:
Technical Abstract: Tomato is a model for ripening control and the basis of many characterized genes underlying this process. Cloning of the CNR, RIN and NOR genes defined the first ripening-specific transcription factors and provided insight into a ripening control system upstream of ethylene. RIN is a central player in the developmental regulation of fruit ripening (and acts upstream of both ethylene and non-ethylene-mediated ripening control. Interestingly, a RIN homolog was shown to be necessary for ripening in non-climacteric strawberry fruit suggesting conservation of molecular regulatory systems of fruit exhibiting both ripening physiologies. In the rin mutant, CNR expression is reduced, indicating that it may act downstream of RIN in the regulatory hierarchy, though clearly the relationship among these regulators and ethylene is not linear as indicated by the complex interactions of RIN with its own and promoters of additional regulatory genes. Targets of CNR include MADS-box genes such as FRUITFUL (FUL). The tomato ortholog of the FUL, TDR4, has substantially reduced mRNA accumulation in the Cnr mutant. While TDR4 does not have a clear effect on tomato fruit maturation, possibly due to redundancy in the genome, repression of a homologous gene in bilberry resulted in ripening inhibition and reduced fruit pigment accumulation suggesting an important regulatory function downstream of CNR. Here we summarize these ripening genes and provide a model for their interactions toward mediating regulated ripening control.