Transcriptome profiling and RXR gene family identification reveals the molecular mechanism of rapid aging after spawning of cuttlefish Sepiella japonica

Sepiella japonica is a worldwide marine cuttlefish species of high economic value. S. japonica routinely modifying behaviors in reproductive life, such as rapid aging until death after spawning, has been recognized in artificial breeding. However, reproductive behavior at the level of genes is rarely reported, thus, the research on the genetic basis of behavior, reproduction, and artificial breeding was limited. We applied RNA-seq in different stages of reproduction to investigate the reason of rapid aging after spawning, pre-maturity, pre-spawning after maturity, and post-spawning. The retinoid X receptor (RXR) gene family in S. japonica was identified, and 1 343–1 452 differentially expressed genes (DEGs) in all 3 stages of reproductive life were identified from pairwise mRNA comparisons. Furthermore, through the GO term and KEGG analysis, S. japonica could handle neuronal development and network formation before maturity and have a functional degradation of neural communication, signal transduction, vision, and gene expression after spawning. Eight SjRXRαs have been identified and they played different roles in growth development or reproduction. Therefore, the regulation of several channels and receptors is the intrinsic molecular mechanism of rapid aging after spawning in S. japonica. This study revealed the survival strategy and provided fundamental data on the level of genes for understanding the reproductive behavior and the reproduction of S. japonica.