Fig. 2

Transcriptional responses of Neoporphyra haitanensis to cold stress. A Principal components analysis (PCA) of the transcriptomic profile. B Number of differentially expressed genes (DEGs) between different temperature groups. C Heatmaps of GO and KEGG enrichment of DEGs. D Scaled transcript profiles that were identified by the clustering analysis of N. haitanensis undergoing cold stress. The DEGs were clustered into six groups using the fuzzy c-means clustering method. The vertical axis shows the normalized FPKM expression values of DEGs. E The Heatmap describes significantly enriched KEGG pathways for each cluster of the transcriptome dataset. Thalli were cultured at − 4, 4, 10 and 20 °C (T-4, T4, T10 and T20) for 1, 2 or 7 days (D1, D2, or D7)