Data processing and statistical analysis of the metabolic profiles of Phaeodactylum tricornutum

Microalgae have evolved to face abiotic stresses by accumulating energy storage molecules such as lipids, which are also of interest for industries. A multidisciplinary approach was used to study the mechanisms involved in the transition from nitrogen-replete to nitrogen starvation conditions in the marine diatom. Metabolomic analysis resulted in the detection of 4267 compounds ranging from 0.1 and 2.8 kDa in size. In order to reduce the number of compounds to elucidate, the change in compound detected quantity was compared to the change in transcript abundance during the time course of the experiment. As a preliminary step, only compounds and transcripts which change in abundance compared to the control conditions are significant at least on a timepoint were retained. After this first screening, each compound pattern has been compared with each gene. In order to be as stringent as possible, only the combinations which display a significant direct correlation (|slope|=1, from 0.95 to 1.05; p>0.05). The results shown 419 compound-gene combinations which include 115 compounds. The 115 compounds were kept for further analyses and elucidation.