Tiny organisms that live in water could hold the key to increasing agricultural yields, according to a Brock University researcher.
Assistant Professor of Chemistry Divya Kaur Matta and her international research team are examining photosynthesis in cyanobacteria, a single-celled organism that clumps together to form the blue-green algal blooms seen in many lakes.
Photosynthesis is the process of converting sunlight - which consists of visible light, ultraviolet light and infrared radiation - into chemical energy.
In a newly published paper, Matta's team reviewed 91 studies comparing how photosynthesis occurs in four cyanobacteria species: Thermosynechococcus elongatus, Acaryochloris marina, Halomicronema hongdechloris and Fischerella thermalis.
The wavelengths of visible light, ultraviolet light and infrared radiation vary and can change rapidly, posing a challenge for plants, bacteria and other organisms that undergo the process of photosynthesis.
Most plants can efficiently absorb visible light but are less able to absorb infrared radiation, which is invisible to the eye but felt as heat.
"Far-red, infrared light is usually underused by most crops," says Matta. "These cyanobacteria show us how to grab that low-energy light under shade, in murky water or at the bottom of a crop canopy and still turn it into useful chemical energy."
To better understand the four cyanobacteria species' use of different wavelengths of light, the researchers focused on photosystem I (PSI), which involves the transfer of electrons in the cell by proteins and chlorophyll, the pigment that gives plants their green colour.
"Our paper brings together what we know about four very different cyanobacteria and asks a simple question: how do they tune the same photosynthetic machine to run on different colours of light?" says Chemistry master's student Jimit Patel, the review's lead author.
"By comparing their strategies, we start to see practical design rules for using far-red light more efficiently," he says.
The team found that three of the species had minor differences in their protein and chemical structures, but Acaryochloris marina used a molecule called pheophytin as the substance aiding the transfer of electrons.
There are also "subtle differences" in the bonding of hydrogen molecules and the arrangement of water molecules, Matta says.
She says small, precise changes to pigments, protein environments and water networks are enough to keep electron transfer fast and efficient, providing a "roadmap for how nature already extends the solar spectrum."
These adjustments enable cyanobacteria to use low-energy, far-red light that, when replicated in plants, "will enable future crops to capture a broader range of sunlight, stay productive under shade or stress, and support more resilient, sustainable food and energy systems in a changing climate."
Matta says the team's review is paving the way for the next step in the research, which is to investigate the transfer of cyanobacteria photosynthetic process to crops.
With this knowledge, scientists could bioengineer crops and algae to grow in a wider range of environmental conditions, ultimately boosting global food security and sustainable energy production, she says.
As well as Matta and Patel, the research team includes Brock master's student Amen ElMasadef, Professor of Chemistry Art van der Est and researchers from India and the United States.
Their review, "Driving Electron Transfer in Photosystem I Using Far-Red Light: Overall Perspectives," was published Nov. 5 in the journal Plants.
Supporting Matta's research is a Discovery Grant from the Natural Sciences and Engineering Research Council, which is funded by the Government of Canada.
