The characteristics of PtHSP40 gene family in Phaeodactylum tricornutum and its response to environmental stresses

Highlights

• Fifty-five heat shock protein 40 genes were identified in Phaeodactylum tricornutum.
• HSP40s contain HPD conserved motif and are distributed to 21 chromosomes.
• HSP40s are clustered into 4 independent clades in the phylogenetic tree.
• HSP40s show different response mechanisms to five environmental stresses.
• HSP40s are more sensitive to nickel than nutrient limit and ocean acidification.

Abstract

Diatom has evolved response mechanisms to cope with multiple environmental stresses. Heat shock protein 40 (HSP40) plays a key role in these response mechanisms. HSP40 gene family in higher plants has been well-studied. However, the HSP40 gene family has not been systematically investigated in marine diatom. In this study, the bioinformatic characteristics, phylogenetic relationship, conserved motifs, gene structure, chromosome distribution and the transcriptional response of PtHSP40 to different environmental stresses were analyzed in the diatom Phaeodactylum tricornutum, and quantitative real-time PCR was conducted. Totally, 55 putative PtHSP40 genes are distributed to 21 chromosomes. All PtHSP40 proteins can be divided into four groups based on their evolutionary relationship, and 54 of them contain a conserved HPD (histidine-proline-aspartic acid tripeptide) motif. Additionally, six, eleven, ten and four PtHSP40 genes were significantly upregulated under the treatments of nitrogen starvation, phosphorus deprivation, 2,2′,4,4′-tetrabrominated biphenyl ether (BDE-47) and ocean acidification, respectively. More interestingly, the expression level of 9 PtHSP40 genes was obviously upregulated in response to nickel stress, suggesting the sensitive to metal stress. The different expression models of PtHSP40 genes to environmental stresses imply the specificity of PtHSP40 proteins under different stresses. This study provides a systematic understanding of the PtHSP40 gene family in P. tricornutum and a comprehensive cognition in its functions and response mechanisms to environmental stresses.

Chen J., Gao G. & Liu X., 2024. The characteristics of PtHSP40 gene family in Phaeodactylum tricornutum and its response to environmental stresses. Marine Environmental Research 199: 106625. doi: 10.1016/j.marenvres.2024.106625. Article (subscription required).

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