Solanum lycopersicum Transcriptome or Gene expression. Solanum lycopersicum

Ascorbic acid (AsA), important for plant cell protection against oxidative stresses, is useful for human health. Among vegetables, tomato is the most important specie due to its significant consumption at worldwide level. Although AsA metabolism has been characterized in detail, the genetic mechanisms controlling AsA accumulation in tomatoes are poorly understood. We used an introgression line (IL 10-1) containing a QTL inducing a reduced AsA accumulation in the fruit and carried out a comparative transcriptomic analysis in fruit tissues using a parental cultivar (M82) with normal fruit AsA levels as a reference. We identified 233 differentially expressed genes, indicating that AsA accumulation in IL 10-1 reflects modification in the peroxisomal metabolism and reduced glutathione biosynthesis. Evidences coming from the experiment suggest that the lower AsA accumulation in IL10-1 fruit is mainly achieved by increasing ROS generation through a NAD+-dependent isocitrate dehydrogenase and promoting an increase in aminoacid catabolism, which is driven by a stress response and may lead to lower glutathione pool. Overall design: Comparative microarray analysis between a tomato introgression line (IL10-1) expressing lower level of fruit ascorbic acid and its parental cultivar M82 (reference) was performed. In particular, samples were generated by pooling red-ripe fruit from the same plant and discarding the seeds, jelly parenchyma, columella and placenta tissues. Three plant replica were used for each line (IL10-1 and M82) and the experiment was replicated over two consecutive years.