Transcriptomics and metabolomics reveal the molecular and metabolic adaptation to heat stress in Manila clam Ruditapes philippinarum

Abstract

Temperature is an important environmental factor affecting metabolism, growth and life activities of marine bivalves. To reveal the molecular and metabolic responses to heat stress, comparative transcriptomics and metabolomics were performed in the commercially important bivalve, Manila clam Ruditapes philippinarum. Comparative transcriptomics revealed a total of 3980 differential genes (DEGs) mainly involved in energy metabolism, protein processing, glycerolphospholipid metabolism, inoxidizability and anti-apoptosis. Comparative metabolomic analysis identified 293 differential metabolites (DEMs) in the heat-stressed clams, including Acetyl-CoA, Beta-D-Glucose, phosphatidylcholine and free amino acids. For the heat-stress clams, they showed the significantly increased enzyme activities of AKP and ACP, as well as antioxidant-related enzyme activities (SOD and CAT) and oxidative damage substance (MDA). The changes in gene expression of glycolysis-related genes (GLUT1, GLK, HK1 and GPI6) and metabolites (Beta-D-Glucose and Acetyl-CoA) reflect the adjusted energy metabolism in the heat-stressed clams. The protein processing in endoplasmic reticulum may play the important roles in the stability of cell membrane structure during heat adaptation. The increased contents of glycerophospholipid (PC) may be essential to maintain the stability and permeability of cell membrane in the heat-stressed clams. Molecular chaperones (HSP70 and HSP90) may participate in the degradation of misfolded proteins to maintain cell homeostasis during the heat stress. To defense the heat stress, clams also initiate the protection and defense mechanisms by activating antioxidant system, innate immune system and anti-apoptotic system. These findings will shed new lights on molecular and metabolic adaptation to heat stress in the intertidal mollusks in a warming climate at the global scale.

Transcriptome Analysis of Gill Tissues from Neptunea cumingii in Different Seasons

“…Temperature is an important environmental factor that affects the metabolism, growth, and life activities of marine bivalves [10]. When shellfish perceive short-term fluctuations in temperature or long-term seasonal changes, they will adapt to the change in the environmental temperature by actively adjusting their physiological and biochemical activities [11].…”

“…Previous studies have investigated the physical response mechanisms in various shellfish under changing environmental temperatures and have shown that the expression of heat shock proteins (HSPs) is stimulated in shellfish to maintain cell homeostasis under high temperature conditions, where the response to damage also involves the activation of immune cells and accelerated metabolism. Under low-temperature conditions, shellfish respond to oxidative stress by stimulating the production of glutathione S-transferases (GSTs), such as in Ruditapes philippinarum [10], Patinopecten yessoensis [12,13], and Chlamys farreri [13]. However, the regulatory mechanism that allows Neptunea cumingii to adapt to seasonal temperature changes has not been reported previously.…”