Transcriptional profiling of the tomato fruit pericarp tissue: fruits overexpressing yeast ySAMdc gene and controls

Experiment description: Fruits of transgenic tomato (Solanum lycopersicum) plants engineered with ripening-induced, yeast S-adenosylmethionine decarboxylase (ySAMdc) gene, accumulate the higher polyamines spermidine (Spd) and spermine (Spm) and demonstrate ameliorated phytonutrient content, juice quality, and prolonged vine life. Enhanced nitrogen-carbon interactions were revealed by comprehensive Nuclear Magnetic Resonance (NMR) spectroscopy-based metabolite profiling of the transgenics, suggesting that Spd and Spm are perceived as nitrogenous metabolites by the fruit cells (Mattoo et al., 2006). The recent work by our colleagues identified the effects of Spd/Spm accumulation on various functional classes of tomato genes affected during ripening by probing 1522 ESTs on a custom-made array (Srivastava et al., 2007). In this study we monitored alterations of genome-wide transcriptional patterns in pericarp of Spd/Spm-accumulating tomatoes by means of direct comparison with azygous controls using DNA-microarray technology. Consistent with the ySAMdc expression pattern, very minor transcriptional alterations were detected in mature green developmental stage. For both breaker and red stages, large mutual and unique gene sets displayed altered levels of transcript. Ontological term analysis of up- and down-regulated transcript groups revealed processes in cell metabolism that are regulated by increased levels of Spd/Spm in ripening tomato fruits. These processes mainly involve carbohydrate and amino acids metabolism and protein synthesis. Additionally, transcript levels of representative genes encoding structural enzymes for related biosynthetic pathways show strong relationship to specific metabolites that were identified as regulated in Spd/Spm-accumulating transgenics.

Author: Igor Michael Kolotili

Contact: Igor Michael Kolotilin (, Volcani inst.

External link: GEO