Divergent Evolutionary Routes of Hypoxia Tolerance in Mangroves
Yulin Weng1, Taiping Chen1, Lichun Zhou1
1Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, College of the Environment and Ecology, Xiamen University, Xiamen, Fujian, China.
Molecular Ecology
|May 9, 2026
Summary
Two mangrove species adapted to hypoxia through different evolutionary paths. One species utilized whole-genome duplication (WGD) to expand gene families, while the other focused on regulatory elements for gene expression.
Area of Science:
- Plant evolutionary biology
- Genomics
- Environmental adaptation
Background:
- Extreme environments select for specialized adaptations.
- Understanding shared versus distinct evolutionary mechanisms in related species is crucial.
- Mangroves provide a model for studying adaptation to harsh intertidal conditions, particularly hypoxia.
Purpose of the Study:
- To investigate the genomic and regulatory strategies employed by two mangrove species, Kandelia obovata and Avicennia marina, to adapt to hypoxic intertidal zones.
- To determine if distinct lineages facing similar environmental stressors utilize shared or divergent adaptive mechanisms.
Main Methods:
- Phylogenomic analyses to reconstruct evolutionary history and identify whole-genome duplication (WGD) events.
- Comparative genomic analyses to assess gene family expansions and contractions, focusing on hypoxia-related genes.
- Transcriptomic profiling under controlled hypoxia gradients to compare gene expression responses.
Main Results:
- Kandelia obovata underwent an early whole-genome duplication (WGD) and shows gene family contraction with enriched cis-regulatory elements for hypoxia response.
- Avicennia marina experienced two rounds of WGD, retaining expanded hypoxia-responsive gene families.
- K. obovata exhibits rapid, stable gene expression responses to hypoxia, while A. marina displays delayed, hierarchical regulatory networks.
Conclusions:
- Plant lineages adapt to identical extreme selective pressures via distinct evolutionary trajectories.
- Genome evolution, including whole-genome duplication (WGD) events, significantly shapes adaptive potential.
- Differences in regulatory architecture underpin contrasting strategies for coping with environmental stress, such as hypoxia.
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