Transcriptomic profiling reveals the mechanisms underlying growth divergence in Apostichopus japonicus

Area of Science:

• Marine Biology
• Aquaculture
• Molecular Biology

Background:

• Sea cucumber (Apostichopus japonicus) exhibits significant growth rate variation under identical cultivation.
• A subset of sea cucumbers display a "growth stagnation" phenotype, resulting in dramatically reduced biomass.
• This divergence necessitates understanding the molecular mechanisms underlying differential growth.

Purpose of the Study:

• To investigate the molecular basis of growth divergence in Apostichopus japonicus.
• To identify differentially expressed genes (DEGs) associated with normal growth versus growth stagnation.
• To explore potential therapeutic targets for mitigating sea cucumber growth retardation.

Main Methods:

• Transcriptomic profiling of body wall tissues from normally growing (NG) and stunted-growing (SG) Apostichopus japonicus.
• Differential gene expression analysis to identify key molecular players.
• Histological examination of muscle tissue to correlate molecular findings with physical structure.

Main Results:

• 816 differentially expressed genes (DEGs) were identified between NG and SG individuals.
• NG individuals showed upregulation of growth-promoting genes (e.g., HGFR, RAS).
• SG individuals exhibited upregulation of muscle and cytoskeletal genes (e.g., ACTG1, MYHC, TITIN, FLNB), indicating abnormal tissue structure and compensatory mechanisms.

Conclusions:

• Growth divergence in sea cucumbers is linked to differential gene expression, particularly in growth-promoting and muscle/cytoskeletal pathways.
• Stunted growth in A. japonicus is associated with disordered cellular processes rather than productive growth.
• Traditional Chinese medicine compounds show potential for modulating key signaling pathways (HGFR, RAS) to address growth retardation in aquaculture.