A MULTI-LEVEL OMIC APPROACH OF TOMATO FRUIT QUALITY

Improvement of fruit quality traits is a major goal for tomato breeding. Deciphering the genetic diversity and inheritance of fruit quality components is thus necessary. For this purpose, we carried out a large multi-level omic experiment. Eight contrasted lines and 4 of their F₁ hybrids were phenotyped for fruit development traits. Fruit pericarp samples were analysed at 2 stages (cell expansion and orange ripe) and different scales: (1) untargeted profiling of major polar metabolites, (2) activities of 28 enzymes involved in primary metabolism, (3) proteome profiles revealed by 2D-PAGE and identification of 470 protein spots showing quantitative variations and (4) gene expression analysis by Digital Gene Expression. In parallel, the 8 lines were resequenced and more than 3 million SNPs identified when aligned on the reference tomato genome. This experiment allowed us to assess and compare the range of variability and inheritance mode of the metabolic traits and expression data. Correlation networks were constructed within and between levels of analysis to identify regulatory networks. Diversity of candidate genes could thus be analysed, relating the polymorphisms at the sequence levels with their expression.