Transcriptomics Approach to Understand Phytonutrient Composition Differences in Plants Grown Under Different Nitrogen Regimes

Recent evidence suggests that organic soil management improves nutritional attributes of fruit, such as phytochemical concentrations and antioxidant capacity. In greenhouse studies of tomato (Solanum lycopersicum) plants grown with organic or inorganic fertilizers and exposed to herbivory by green peach aphids (Myzus persicae) we found positive links between soil fertility management and these crop quality parameters. Increases in phytochemcials and antioxidant capacity were found in tomato fruit that were grown using organic fertilizers, but sometimes these differences were cultivar dependent. Soluble solids and dry matter were usually higher in organic fruits, but this also varied by cultivar indicating an opportunity for selective breeding of genotypes amenable to organic production systems. Aphid populations were lower on organically grown tomatoes, while both organic fertility management and herbivory increased phenolics concentration in fruit. In order to gain an understanding of the genomic underpinnings of the observed biochemical and phenotypic differences, we conducted a transcriptomic analysis on fruit and leaves derived from samples grown under the two conditions. The recently published tomato genome and transcriptome data was utilized to map the RNAseq reads and determine the relative expression of genes involved in the analyzed biochemical pathways. Results from this analysis will be presented.