Research Article: Effects of temperature stress on genome-wide DNA methylation levels in the sea cucumber, Apostichopus japonicus

Sea cucumber Apostichopus japonicus lives in the lower temperature of the seawater and will enter the state of aestivation when the temperature is high. In recent years, the continuous high temperatures in summer have brought great loss to the production of sea cucumber in north China. To study the epigenetic regulating mechanism of A. japonicus and guide the temperature-controlled culture, the methylation level of A. japonicus genome was detected. Breeding imitation A. japonicus under different temperature conditions for a period of time, the difference of methylation level between the set temperature group and the control group was detected and verified. The methylation levels of A. japonicus in different temperature groups were detected. The methylation sites ranged from ۸۴,۷۶۶ to ۹۶,۲۲۵, and the sequencing depth was between ۴۲.۳۳ and ۱۵۳.۲۱. Under the temperature stress, more than ۶۰% of the differentiated methylated genes in different groups were down-regulated, the HBW group had the most differentiated methylated genes (۱,۴۰۵), and the SBW group had the least differentiated methylated genes (۶۴۳). Gene function classification and enrichment analysis were carried out, and a total of ۳,۵۱۲ differential genes were found, mostly related to immunity and metabolism. The results showed that temperature can change the gene methylation level of A. japonicus, affecting its expression level, and ultimately changing the metabolic and immune processes of A. japonicus.

Keywords:

Apostichopus japonicus , Temperature stress , Genomic methylation , Methylated differential genes