Comparative transcriptome analysis of four co-occurring Ulva species for understanding the dominance of Ulva prolifera in the Yellow Sea green tides

The last 12 years has seen the dominance of Ulva prolifera in the green tides occurring in the Yellow Sea. To gain a better understanding of the underlying molecular clues associated with the dominance pattern of the Yellow Sea green tides, we generated and compared the transcriptomes of four co-occurring Ulva species including U. prolifera, U. linza, U. flexuosa, and U. compressa under the same conditions. Our results revealed that the transcriptomes of four Ulva species shared a set of core genes, but varied in construction of GO term categories, transcription factor (TF) styles, and metabolism pathways. Based on the KEGG database, several growth-related genes including pyruvate kinase (PK) and nitrate transporter (NRT) have been identified to be enriched in U. prolifera compared with the other three Ulva species. This study provides novel transcriptionomic data for us to understand the species dominance pattern in the Yellow Sea green tides.