Molecular evidence for the adaptive evolution in euryhaline bivalves

Marine bivalves inhabiting intertidal and estuarine areas are frequently exposed to salinity stress due to persistent rainfall and drought. Through prolonged adaptive evolution, numerous bivalves have developed eurysalinity, which are capable of tolerating a wide range of salinity fluctuations throu...

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Bibliographic Details
Published in:Marine Environmental Research
Main Authors: Zhou, Cong, Yang, Mei-jie, Hu, Zhi, Shi, Pu, Li, Yong-ren, Guo, Yong-jun, Zhang, Tao, Song, Hao
Format: Report
Language:English
Published: ELSEVIER SCI LTD 2023
Subjects:
Adaptive evolution
Euryhaline bivalves
Osmoregulation
Energy metabolism
ROS scavenging
Environmental Sciences & Ecology
Marine & Freshwater Biology
Toxicology
Environmental Sciences
OXIDATIVE STRESS
CRASSOSTREA-GIGAS
MACOMA-BALTHICA
PACIFIC OYSTER
SALINITY
RESPONSES
TRANSPORTER
MERCENARIA
ACIDIFICATION
Pacific
Crassostrea gigas
Pacific oyster
Online Access:http://ir.qdio.ac.cn/handle/337002/184043
http://ir.qdio.ac.cn/handle/337002/184044
https://doi.org/10.1016/j.marenvres.2023.106240
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Summary:Marine bivalves inhabiting intertidal and estuarine areas are frequently exposed to salinity stress due to persistent rainfall and drought. Through prolonged adaptive evolution, numerous bivalves have developed eurysalinity, which are capable of tolerating a wide range of salinity fluctuations through the sophisticated regulation of physiological metabolism. Current research has predominantly focused on investigating the physiological responses of bivalves to salinity stress, leaving a significant gap in our understanding of the adaptive evolutionary characteristics in euryhaline bivalves. Here, comparative genomics analyses were performed in two groups of bivalve species, including 7 euryhaline species and 5 stenohaline species. We identified 24 significantly expanded gene families and 659 positively selected genes in euryhaline bivalves. A significant coexpansion of solute carrier family 23 (SLC23) facilitates the transmembrane transport of ascorbic acids in euryhaline bivalves. Positive selection of antioxidant genes, such as GST and TXNRD, augments the capacity of active oxygen species (ROS) scavenging under salinity stress. Additionally, we found that the positively selected genes were significantly enriched in KEGG pathways associated with carbohydrates, lipids and amino acids metabolism (ALDH, ADH, and GLS), as well as GO terms related to transmembrane transport and inorganic anion transport (SLC22, CLCND, and VDCC). Positive selection of MCT might contribute to prevent excessive accumulation of intracellular lactic acids during anaerobic metabolism. Positive selection of PLA2 potentially promote the removal of damaged membranes lipids under salinity stress. Our findings suggest that adaptive evolution has occurred in osmoregulation, ROS scavenging, energy metabolism, and membrane lipids adjustments in euryhaline bivalves. This study enhances our understanding of the molecular mechanisms underlying the remarkable salinity adaption of euryhaline bivalves.

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