Thanks to a recent discovery regarding marine algae, scientists have developed crop plants that absorb a fuller spectrum of sunlight, resulting in better growth. The finding could also lead to increased production of biofuels.
Because seawater absorbs the red spectrum of sunlight fairly close to the surface, marine algae are left to make do with the blue-green spectrum that reaches down to them. In order to use that light to perform photosynthesis, they produce a special blue-green-light-absorbing chlorophyll known as chlorophyll c.
Because terrestrial (land-based) plants have ready access to the red spectrum, they don't bother making chlorophyll c. Instead, they produce chlorophyll a and chlorophyll b, which mainly absorb violet-blue and orange-red light, respectively. Neither a nor b are particularly good at absorbing blue-green light.
So, what would happen if a terrestrial plant could produce a, b and c? Well, that's where the new study comes in.
Led by Asst. Prof. Tingting Xiang, a team at the University of California Riverside was recently able to identify the gene that allows dinoflagellates (a type of marine algae) to produce chlorophyll c. The researchers then implanted that gene in tobacco plants, which proceeded to synthesize chlorophyll c along with the usual a and b.
This ability allowed the genetically modified plants to absorb a wider spectrum of sunlight than a conventional control group, resulting in significantly increased growth. And while tobacco plants were used for the study, it is believed that the technology should work with any kind of crop plant.
The scientists also think that their findings could lead to increased production of algae-oil-derived biofuels. This is because there are already some species of aquatic algae that naturally produce chlorophyll a and b but not c, just like terrestrial plants. If those algae could be modified to also produce c, then they would presumably grow faster and produce more oil.
"The identification of the biosynthetic pathway for chlorophyll c is more than a scientific curiosity; it's a potential game-changer for sustainable energy and food security," said Prof. Robert Jinkerson, co-author of a paper on the study. "We're not only gaining insights into the lifeblood of marine ecosystems but also pioneering a path towards developing more robust crops and efficient biofuels."
The paper was published in the journal Current Biology.