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Endosymbiosis
Endosymbiosis
Background:
Background:
Endosymbiosis—the intimate partnership in which one organism lives inside another—is one of the most transformative innovations in the history of life. Endosymbiotic relationships have shaped the evolution of eukaryotic cells and continue to drive the ecology of many modern ecosystems. Understanding how these beneficial partnerships are established, maintained, and adapted is a fundamental question in biology.
Our laboratory studies coral-algal endosymbiosis, one of the best examples of beneficial symbiosis in nature. Reef-building corals form mutualistic partnerships with photosynthetic dinoflagellates in the family Symbiodiniaceae, which provide most of the energy required for coral growth and reef formation. Climate change is destabilizing this relationship, leading to coral bleaching and the decline of coral reef ecosystems worldwide.
Our laboratory studies coral-algal endosymbiosis, one of the best examples of beneficial symbiosis in nature. Reef-building corals form mutualistic partnerships with photosynthetic dinoflagellates in the family Symbiodiniaceae, which provide most of the energy required for coral growth and reef formation. Climate change is destabilizing this relationship, leading to coral bleaching and the decline of coral reef ecosystems worldwide.
By integrating molecular biology, genomics, synthetic biology, and bioengineering, we seek not only to understand the mechanisms governing symbiosis but also to develop new approaches for engineering more resilient host–microbe partnerships.
By integrating molecular biology, genomics, synthetic biology, and bioengineering, we seek not only to understand the mechanisms governing symbiosis but also to develop new approaches for engineering more resilient host–microbe partnerships.
Nutrient exchange
Nutrient exchange
Research Theme 1
Research Theme 1
Understanding Symbiosis at the Molecular Level
Our laboratory investigates the molecular mechanisms that establish, regulate, and maintain coral-algal symbiosis. We integrate functional genomics, transcriptomics, single-cell sequencing, molecular genetics, and computational biology to identify genes and pathways that control interactions between hosts and their algal symbionts.
By combining genome-scale analyses with experimental validation, we aim to move beyond gene discovery toward mechanistic understanding of symbiosis.
Representative approaches
Functional genomics
Single-cell RNA sequencing
Comparative transcriptomics
CRISPR and gene perturbation
Molecular and cell biology
Symbiosis establishment
Symbiosis establishment
Research Theme 2
Research Theme 2
Understanding Symbiosis at the Organismal Level
Understanding how symbiosis functions in living organisms requires connecting molecular mechanisms to organismal phenotypes. Our laboratory develops experimental model systems—including the sea anemone Aiptasia, reef-building corals, a single-celled ciliate, and their algal symbionts—to uncover the biological principles that govern symbiosis.
A major focus of our research is developing genetic resources for Symbiodiniaceae. We generated one of the first UV mutagenesis libraries in Breviolum minutum and isolated mutants with altered photosynthetic function. These mutants provide powerful tools for testing long-standing hypotheses about the role of photosynthesis in establishing and maintaining symbiosis.
Using these genetically defined mutants, we discovered that photosynthesis is not required for the initial establishment of symbiosis. Photosynthetically impaired Breviolum mutants can successfully infect host animals, demonstrating that symbiont uptake occurs independently of photosynthetic activity. However, we also found that the importance of photosynthesis after infection differs among host species. In the sea anemone Aiptasia and the upside-down jellyfish Cassiopea, photosynthetically defective symbionts fail to proliferate within host tissues. In contrast, the same mutants retain the ability to proliferate in juvenile polyps of the reef-building coral Acropora, revealing unexpected diversity in how different cnidarian hosts regulate and support their symbionts.
These findings challenge long-standing assumptions about the role of photosynthesis in coral symbiosis and illustrate how comparative experimental systems can reveal conserved and species-specific mechanisms governing beneficial endosymbiosis.
Current questions include:
How do Symbiodiniaceae proliferate during the establishment of symbiosis? We use a unique collection of Breviolum minutum mutants, including pigmented mutants, to quantify symbiont proliferation in different cnidarian hosts and identify the host and symbiont factors that regulate population expansion. In collaboration with Dr. Jia Gou (Dept. of Mathematics, UC Riverside), we are developing stochastic mathematical models to understand the dynamics of symbiont proliferation and predict how symbiont populations are regulated during symbiosis establishment.
How are symbionts eliminated from host tissues? We investigate the cellular and molecular mechanisms underlying symbiont loss during bleaching and the selective removal of dysfunctional symbionts.
Research Theme 3
Research Theme 3
Engineering Symbiosis
Understanding symbiosis is only the first step. Our long-term goal is to engineer more resilient symbioses that can contribute to coral reef conservation.
We develop synthetic biology, functional genomics, and bioengineering tools to improve algal performance, engineer beneficial traits, and create new technologies for coral restoration. Our laboratory is particularly interested in translating fundamental discoveries into practical solutions for reef resilience.
Current directions include:
Engineering thermally resilient Symbiodiniaceae
Developing algal delivery systems for coral restoration
Synthetic biology of symbiotic algae
High-throughput phenotyping and screening
Functional genomics-guided engineering
Toxin biosynthesis in red-tide dinoflagellates
Toxin biosynthesis in red-tide dinoflagellates
The red-tide dinoflagellate Karenia brevis causes harmful algal bloom and produces neurotoxins that poison marine animals as well as humans. The frequency of coral bleaching and red tide is increasing in the world.
The red-tide dinoflagellate Karenia brevis causes harmful algal bloom and produces neurotoxins that poison marine animals as well as humans. The frequency of coral bleaching and red tide is increasing in the world.
What are the metabolic pathways controlling the biosynthesis of the neurotoxins in red-tide dinoflagellate Karenia brevis?
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