Transcriptome survey, molecular identification, and expression analysis of stress-responsive genes in the toxic dinoflagellate Alexandrium pacificum under algicidal agents and metal stresses

In this study we characterized the genome scale of the transcriptome of the marine dinoflagellate Alexandrium pacificum under various stresses, focusing on the identification of stress-responsive genes. RNA sequencing generated 18.1 Gb nucleotides that were assembled to 297,808 transcripts. Of them, 207 and 134 transcripts were assigned to the antioxidant enzyme system and heat shock protein (HSP) families, respectively. In addition, the carotenoid biosynthesis pathway and other typical stress-responsive genes (e.g., cold shock proteins and mitogen-activated protein kinases) were widely expressed under stresses. Phylogenetic analysis revealed that these genes might be acquired from different origins via separate evolutionary events. The A. pacificum CuZnSOD and HSP70 were evidently responded to algicides and metals. These findings clearly suggest that A. pacificum possesses many different stress-resistant genes from different sources, which are used for defense and/or adaptation in diverse environments. These may allow the organism to survive and develop when introduced to new environments.

Automated summary

The study characterized the transcriptome of marine dinoflagellate Alexandrium pacificum under various stresses, revealing numerous stress-responsive genes with potential diverse origins. Specifically, genes related to antioxidant enzymes, heat shock proteins, carotenoid biosynthesis, and other stress-responsive genes were identified. The findings suggest that A. pacificum possesses a range of stress-resistant genes that may aid in adaptation to new environments.