De novo transcriptome of the red alga Gracilariopsis tenuifrons (Gracilariales, Rhodophyta) in response to prolonged temperature stress.

Transcriptomic information is still scarce for seaweeds, especially for species from tropical regions. Laboratory-based physiological studies of some red algae have shown that they can tolerate temperatures that exceed those observed in their natural conditions. To understand the molecular mechanisms related to this tolerance, we chose as a model the agarophyte red alga Gracilariopsis tenuifrons and analyzed transcriptomic profiles at two different temperatures: 25°C (control temperature) and 33°C (stress temperature). Under the stress temperature conditions, only a relatively small percentage of genes were differentially expressed compared to the control temperature (5.75% were down-regulated and 5.25% were up-regulated at 33°C). Analysis of the predicted functions of the differentially regulated genes indicated enrichment in DNA-associated processes for the up-regulated genes and enrichment in gene ontogeny categories related to photosynthesis and membrane-associated processes for the down-regulated genes. The de novo transcriptome data provided in this study is a valuable scientific resource for future comparative research on red algae at stress conditions.