Groundbreaking Discovery: The Emergence of a Nitrogen-Fixing Organelle

In a remarkable breakthrough, scientists have uncovered a once-in-a-billion-years evolutionary event – the merger of two lifeforms into a single organism with unprecedented capabilities. This phenomenon, known as primary endosymbiosis, has only occurred twice before in Earth's history, leading to the evolution of mitochondria and chloroplasts. Now, researchers have discovered a third instance, involving an algae species called Braarudosphaera bigelowii and a cyanobacterium.

The cyanobacterium, engulfed by the algae, has evolved into a specialized organelle named the nitroplast. This unique organelle grants the algae the ability to fix nitrogen directly from the atmosphere, a feat that plants typically cannot accomplish without the help of symbiotic bacteria in root nodules. The discovery challenges the long-held belief that only bacteria can convert atmospheric nitrogen into a biologically usable form.

The identification of the nitroplast is the result of decades of research, beginning with the detection of an unknown nitrogen-fixing cyanobacterium's DNA sequence in Pacific Ocean seawater in 1998. Scientists spent years studying the mystery organism, leading to this groundbreaking revelation.

This discovery not only expands our understanding of the evolution of complex life but also provides valuable insights into ocean ecosystems and the nitrogen cycle. As researchers continue to study nitroplasts and their potential presence in other cells, the implications of this finding on our understanding of life on Earth are set to be profound.

newscenter.lbl.gov/2024/04/17/scientists-discover-first-nitrogen-fixing-organelle/