Algae and bacterium merge to form a single organism for the first time in a billion years

Algae and bacterium merge to form a single organism for the first time in a billion years

Scientists have unveiled a phenomenon unseen for at least a billion years: the fusion of two distinct lifeforms into a singular organism in a groundbreaking revelation. This extraordinary process, termed primary endosymbiosis, has occurred merely twice in Earth’s history, marking pivotal moments in the evolution of complex life forms.

The first occurrence paved the way for the emergence of mitochondria, the powerhouse of cells, while the second gave rise to the plant kingdom.

Now, an international team of researchers has witnessed this evolutionary marvel unfolding between a species of oceanic algae and a bacterium. Tyler Coale, a postdoctoral researcher at the University of California, Santa Cruz, leading one of the recent studies delving into this phenomenon, told The Independent, “The first time we think it happened, it gave rise to all complex life… A billion years ago or so, it happened again with the chloroplast, and that gave us plants.”

This extraordinary process involves the algae engulfing the bacterium, endowing it with nutrients, energy, and protection, in exchange for novel functionalities—most notably, the ability to “fix” nitrogen from the air. Subsequently, the algae assimilates the bacterium as an internal organ, termed an organelle, crucial for the host organism’s survival and functioning.

Dr. Coale spoke about the transformative potential of this discovery, stating, “This system is a new perspective on nitrogen fixation, and it might provide clues into how such an organelle could be engineered into crop plants.” This breakthrough holds promise for revolutionising agriculture by offering novel insights into nitrogen fixation—a process vital for plant growth and ecosystem health.

Published in scientific journals Science and Cell, the research underscores a collaborative effort spanning institutions such as the Massachusetts Institute of Technology (MIT), University of Rhode Island, University of California, San Francisco, Lawrence Berkeley National Laboratory, Institut de Ciències del Mar in Barcelona, National Taiwan Ocean University, and Kochi University in Japan.