Anitroplast is anorganelle found in certain species ofalgae, particularly in the marine algaeBraarudosphaera bigelowii.[1] It plays a crucial role innitrogen fixation, a process previously thought to be exclusive tobacteria andarchaea.[1][2] The discovery of nitroplasts has significant implications for both cellular biology andagricultural science.
In 1998, Jonathan Zehr, an ocean ecologist at theUniversity of California, Santa Cruz, and his colleagues found an unknown DNA sequence that appeared to be for an unknown nitrogen-fixingcyanobacterium in thePacific Ocean, which they calledUCYN-A (unicellular cyanobacterial group A).[3] At the same time, Kyoko Hagino, a paleontologist atKochi University, was working to culture the host organism,B. bigelowii.[4][5]
The existence of nitroplasts was first proposed by researchers studying the interaction betweenB. bigelowii and UCYN-A in 2012. Initially, it was hypothesized that UCYN-A facilitated nitrogen fixation, providing compounds likeammonia to the algae. However, subsequent studies led by Jonathan Zehr reported that UCYN-A were organelles.[1]
Nitroplasts exhibit typical organelle characteristics, meeting two key criteria: they are inherited duringcell division and rely onproteins provided by the host cell.[1] Throughimaging 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 toprokaryotic organisms. Understanding the structure and function of nitroplasts opens up possibilities forgenetic 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]