From Wikipedia the free encyclopedia

Black arrow: the nitroplast inside B. bigelowii (with coccoliths removed)

A nitroplast is an organelle found in certain species of algae, particularly in the marine algae Braarudosphaera bigelowii.[1] It plays a crucial role in nitrogen fixation, a process previously thought to be exclusive to bacteria and archaea.[1][2] The discovery of nitroplasts has significant implications for both cellular biology and agricultural science.


In 1998, Jonathan Zehr, an ocean ecologist at the University of California, Santa Cruz, found an unknown DNA sequence that appeared to be for an unknown nitrogen-fixing cyanobacterium in the Pacific Ocean, which they called UCYN-A (unicellular cyanobacterial group A).[3] At the same time, Kyoko Hagino, a paleontologist at Kochi University, was working to culture the host organism, B. bigelowii.[4]

The existence of nitroplasts was first proposed by researchers studying the interaction between B. bigelowii and UCYN-A in 2012. Initially, it was hypothesized that UCYN-A facilitated nitrogen fixation, providing compounds like ammonia to the algae. However, subsequent studies led by Jonathan Zehr reported that UCYN-A were organelles.[1]

Structure and function[edit]

Nitroplasts exhibit typical organelle characteristics, meeting two key criteria: they are inherited during cell division and rely on proteins provided by the host cell.[1] Through imaging studies, researchers observed that nitroplasts divide along with the host cell, ensuring their passage to daughter cells.[1]


The discovery of nitroplasts challenges previous notions about the exclusivity of nitrogen fixation to prokaryotic organisms. Understanding the structure and function of nitroplasts opens up possibilities for genetic engineering in plants.[1] By incorporating genes responsible for nitroplast function, researchers aim to develop crops capable of fixing their own nitrogen, potentially reducing the need for nitrogen-based fertilizers and mitigating environmental damage.[1]


  1. ^ a b c d e f g Wong, Carissa (11 April 2024). "Scientists discover first algae that can fix nitrogen — thanks to a tiny cell structure". Archived from the original on 14 April 2024. Retrieved 16 April 2024.
  2. ^ "This marine alga is the first known eukaryote to pull nitrogen from air". 2024-04-11. Retrieved 2024-04-21.
  3. ^ Zehr, Jonathan P.; Mellon, Mark T.; Zani, Sabino (September 1998). "New nitrogen-fixing microorganisms detected in oligotrophic oceans by amplification of nitrogenase (nifH) genes". Applied and Environmental Microbiology. 64 (9): 3444–3450. doi:10.1128/AEM.64.9.3444-3450.1998. PMC 106745.
  4. ^ "Introducing the "nitroplast" -- The first nitrogen-fixing organelle". Retrieved 2024-04-21.

Further reading[edit]

  • Coale, Tyler H; Loconte, Valentina; Turk-Kubo, Kendra A; Vanslembrouck, Bieke; Mak, Wing Kwan Esther; Cheung, Shunyan; Ekman, Axel; Chen, Jian-Hua; Hagino, Kyoko; Takano, Yoshihito; Nishimura, Tomohiro; Adachi, Masao; Le Gros, Mark; Larabell, Carolyn; Zehr, Jonathan P (April 2024). "Nitrogen-fixing organelle in a marine alga". Science. 384 (6692): 217–222.

External links[edit]