Transcriptome aberration in marine microalgae Phaeodactylum tricornutum induced by commercial naphthenic acids

Naphthenic acids (NAs) are cycloalkyl linear carboxylic acids primarily originating from oil sand tailings water (OSTW), and the exposure to NAs affects the photosynthesis of marine microalgaes. However, the transcriptional response upon the stress of NAs remains unclear. Herein, we investigate the transcriptome alterations of marine Phaeodactylum tricornutum induced by NAs using RNA-sequencing. In total 70 differentially expressed genes (DEGs) are enriched in seven biological process pathways, and 48 DEGs are enriched in four molecular functions. Differentially expressed genes of P. tricornutum are primarily concentrated in three photosynthesis-related pathways including the porphyrin and chlorophyll metabolism pathway, the photosynthesis pathway, and the carbon fixation pathway in photosynthetic organisms. Five DEGs such as hemE, chlM, TPI/GapC3, FbaC5, and CHLH are validated using quantitative real-time PCR assay. NAs at low concentrations affect the material energy conversion efficiency of P. tricornutum, such as chlorophyll synthesis, electron transfer efficiency, and carbon assimilation.