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The fruit is a hierarchically organized organ composed of cells from different tissues. Its quality, defined by traits such as fruit size and composition, is the result of a complex chain of biological processes. In order to progress in our understanding of quality development, it is necessary to analyze the fruit as a system, in which processes interact at different organizational levels (Génard et al., 2007).

To this aim a Virtual Fruit Model is currently developed in the team.

Model description

In its basic version, the fruit is represented as a single compartment that exchange resources and information with the plant and the external environment. Within the fruit, a number of processes control the acquisition and redistribution of such resources towards metabolic functions, giving rise to a large panel of possible emerging phenotypes in terms of fruit size and composition.

The current version of the model includes 5 modules, mostly developed for peach fruit, corresponding to the main processes involved in the build-up of fruit quality:

• GROWTH= biophysical model of fruit expansion. It exists in two slightly different versions, one for peach and one for tomato (Fishman & Génard, 1998; Liu et al., 2007)
• SUGAR = carbon partitioning into main sugars (Génard & Souty, 1996; Génard et al., 2003)                                                                                                                                
• CITRATE = citrate synthesis (Lobit et al., 2003)
• MALATE = malic acid accumulation (Lobit et al., 2006)                                                                                                                                                                                    
• ETHYLENE = ethylene emission (Génard & Gouble, 2005)                                                                                                                                                                              

Modules can be launched independently or combined together into an integrated model of fruit functioning. All modules are driven by environmental factors, like temperature, humidity or plant status (water potential and sugar concentration in the phloem) that are given as inputs to the modules.

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The virtual fruit as a tool for agronomists and geneticists

The virtual fruit can be used to simulate the effects of agronomical and environmental factors on fruit development and quality (Génard et al., 2010) and to analyze genotype-by-environment interactions in the control of complex phenotypic traits (Bertin et al., 2010).

Towards a multi-scale fruit model

A multi-cellular, multi-scale version of the virtual fruit model, explicitly integrating cell division, endoreduplication  and expansion process, is currently under the way, in the perspective of “crop-system-biology” (Baldazzi et al., 2012a,b).  

Connection of the Virtual Fruit to a plant architectural model has also been recently realized, allowing an in-depth analysis of the consequences of water deficit and carbon limitation on fruit growth as function of fruit position and developmental stage, in tomato (Baldazzi et al., 2013)

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Contacts:

For more information, please contact:

Michel Génard: michel.genard@avignon.inra.fr

Dario Constantinescu : dario.constantinescu@inrae.fr