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Researchers have discovered a type of organelle, a fundamental cellular structure, that can turn nitrogen gas into a form that is useful for cell growth.
The discovery of the structure, called a nitroplast, in algae could bolster efforts to genetically engineer plants to convert, or ‘fix’, their own nitrogen, which could boost crop yields and reduce the need for fertilizers. The work was published in Science on 11 April.
“The textbooks say nitrogen fixation only occurs in bacteria and archaea,” says ocean ecologist Jonathan Zehr at the University of California, Santa Cruz, a co-author of the study. This species of algae is the “first nitrogen-fixing eukaryote”, he adds, referring to the group of organisms that includes plants and animals.
In 2012, Zehr and his colleagues reported that the marine algae Braarudosphaera bigelowii interacted closely with a bacterium called UCYN-A that seemed to live in, or on, the algal cells. The researchers hypothesised that UCYN-A converts nitrogen gas into compounds that the algae use to grow, such as ammonia. In return, the bacteria were thought to gain a carbon-based energy source from the algae.
But in the latest study, Zehr and his colleagues conclude that UCYN-A should be classed as organelles inside the algae, rather than as a separate organism. According to genetic analysis from a previous study, ancestors of the algae and bacteria entered a symbiotic relationship around 100 million years ago, says Zehr. Eventually, this gave rise to the nitroplast organelle, now seen in B. bigelowii.
www.nature.com
The discovery of the structure, called a nitroplast, in algae could bolster efforts to genetically engineer plants to convert, or ‘fix’, their own nitrogen, which could boost crop yields and reduce the need for fertilizers. The work was published in Science on 11 April.
“The textbooks say nitrogen fixation only occurs in bacteria and archaea,” says ocean ecologist Jonathan Zehr at the University of California, Santa Cruz, a co-author of the study. This species of algae is the “first nitrogen-fixing eukaryote”, he adds, referring to the group of organisms that includes plants and animals.
In 2012, Zehr and his colleagues reported that the marine algae Braarudosphaera bigelowii interacted closely with a bacterium called UCYN-A that seemed to live in, or on, the algal cells. The researchers hypothesised that UCYN-A converts nitrogen gas into compounds that the algae use to grow, such as ammonia. In return, the bacteria were thought to gain a carbon-based energy source from the algae.
But in the latest study, Zehr and his colleagues conclude that UCYN-A should be classed as organelles inside the algae, rather than as a separate organism. According to genetic analysis from a previous study, ancestors of the algae and bacteria entered a symbiotic relationship around 100 million years ago, says Zehr. Eventually, this gave rise to the nitroplast organelle, now seen in B. bigelowii.
Scientists discover first algae that can fix nitrogen — thanks to a tiny cell structure
A newly discovered ‘organelle’ that converts nitrogen gas into a useful form could pave the way for engineered plants that require less fertilizer.
www.nature.com
