Transcriptomic Analysis Provides New Insights into Papillae Regeneration of the Sea Cucumber Apostichopus Japonicus

Abstract

The sea cucumber (Apostichopus japonicus), belonging to the phylum Echinodermata and the class Holothuroidea, is highly esteemed for its nutritional value and economic significance among echinoderms. This study involved the excision of papillae from sea cucumbers, followed by morphological, histological and transcriptomic analyses at 1, 3-, 7-, 14-, and 21-days post-experiment. Morphological analysis indicated that by 21 days post-regrowth, the appearance of the sea cucumber papillae was nearly indistinguishable from its pre-regrowth state. Histological analysis revealed that the tissues had largely reverted to their normal state by the 21st day of regeneration. Thus, the regeneration period of papillae is probably 21 days.An Illumina transcriptome analysis was performed on the sea cucumbers at 1, 3-, 7-, 14-, and 21-days after the papillae were cut. Differentially expressed genes were classified and enriched through GO and KEGG databases. These results suggest that the regeneration of sea cucumber papillae associates with the reconstruction of the extracellular matrix, and the ECM-receptor interaction signaling pathway plays a pivotal role in this process. Several key genes, such as COL1A2, DMBT1, fibropellin-ia, TNXB, and Kcp, were identified as collective regulators of papillae regeneration in sea cucumbers. Sea cucumbers exhibit an extraordinary capacity to regenerate damaged or lost tissues and organs. The regeneration of their economically significant papillae remains poorly understood. This study offers new insights into the mechanisms of sea cucumber papillae regeneration, and the critical genes identified in this study provides substantial theoretical support for the future application of molecular breeding in sea cucumbers.

Keywords: Transcriptomic, Apostichopus japonicus, papillae, regeneration, mechanism