Microorganisms living in the ocean play a key role in maintaining the health of our planet. Take SAR11-Earth's most abundant microbes, which are widely distributed throughout the ocean. These bacteria are vital for sustaining the planet's global nutrient cycles for carbon, sulfur, and other key elements. The latest research from OIST's Protein Engineering and Evolution Unit, led by Professor Paola Laurino, has shed new light on how SAR11 carries out these crucial functions. In a paper published in the scientific journal Nature in 2024, researchers improved our understanding of the world's most abundant microbes that have evolved to thrive in nutrient-poor ocean environments. Their findings, with important implications for planetary health and climate regulation, have earned them the prestigious 2025 Frontier Planet Prize National Championship for Japan.
Established by the Frontiers Research Foundation in 2022, the award recognizes scientific breakthroughs with the 'greatest potential to address the ecological crisis.' It is judged by a distinguished global panel of 100 sustainability experts, and the award comes with 1 million USD for the top three international champions to accelerate their research and advance the transformative breakthroughs they propose.
"Our work provides deeper insight into how SAR11 shapes marine carbon cycling and nutrient dynamics, an especially urgent need as climate change drives rapid shifts in ocean temperatures and nutrient availability. These findings offer a framework for predicting how these microbes-and the ecosystems they support-might respond to future environmental challenges," said Prof. Laurino.
By decoding how SAR11 adapted to nutrient-poor environments and how it thrives under extreme selective pressure, researchers have uncovered its remarkably efficient nutrient uptake capabilities. These tiny microbes have evolved specialized transport proteins to absorb dissolved organic matter in the oceans, enabling them to process up to 60% of surface ocean amino acids and other essential nutrients. "Remarkably, these transport proteins exhibit binding affinities in the picomolar (pM) range, the highest ever observed for bacterial nutrient uptake, which explains SAR11's extraordinary efficiency in scavenging scarce nutrients," commented Prof. Laurino.
These recent findings challenge previous assumptions about SAR11 bacteria, revealing that they are far more selective in their nutrient uptake than previously thought. Through biophysical adaptations, like enhanced nutrient binding affinity in nutrient-poor environments, they have achieved widespread dominance in marine ecosystems. These evolutionary adaptations have likely shaped the physiology of SAR11, a bacterial group that is now essential to marine ecosystems everywhere.
The implications are profound, as recognized by the Frontier Planet Prize. This research will inform marine conservation efforts, climate change mitigation strategies through carbon sequestration, and even biotechnological applications. It bridges the scale between the molecular function of tiny microbial proteins and their global ecological impact, exemplifying the transformative science urgently needed to tackle today's environmental challenges.
The Frontier Planet Prize was inspired by the swift scientific and policy response to the COVID-19 pandemic, with the hope of catalyzing similar urgent and coordinated action for planetary health. With more than 600 institutions from over 60 countries participating, this marks the second consecutive year that OIST research has been recognized for its significant global impact in addressing the challenges of the Anthropocene, following last year's award to Professor Evan Economo.
Read the thought piece behind the research HERE.
The three International Champions for the 2025 Frontier Planet Prize will be announced in June at the Villars Symposium in Switzerland.
