2024-01-03 22:45:44
On Earth, some living beings are capable of carrying out a strange photosynthesis that allows them to use almost infrared red light.
Red light with a wavelength between 700 and 800 nanometers (nm), barely visible to the human eye, is near-infrared and beyond the range typically used for photosynthesis because it contains less energy than the standard visible light range. , between normal blue and red (400 to 700 nm).
A new study has delved into this unique photosynthesis, used by cyanobacteria. There is growing interest in this photosynthesis due to the possibility of artificially adding it to agricultural vegetables and thus increasing their yield. The species thus improved could maintain good productivity in light conditions that would be too poor for non-genetically modified species.
The new research is the work of a team including, among others, Tanai Cardona, from Queen Mary University of London in the United Kingdom, and Christopher Gisriel, from Yale University in the United States.
The findings made in the study not only provide new and revealing data on the evolutionary history of photosynthesis with near-infrared red light, but they will also have great implications for the search for life in the cosmos. Red dwarf stars (spectral class M), the most common type of star in the universe, emit much more red near-infrared light than light in the rest of the band visible to the human eye. That makes any habitable planet around one of those stars the perfect setting to make the most of this rare near-infrared red light photosynthesis. In other words, that photosynthesis there would not be exotic but rather the most common or the only one.
The authors of the study have determined that in our world the ability to use near-infrared red light appeared in two different stages of evolutionary history.
In the first stage, cyanobacteria developed a new pigment, chlorophyll f, which allowed the photosystem to capture red, near-infrared light for the first time. Additionally, they developed a modified photosystem that could use this pigment to fuel the oxygen release reaction using only the lower energy red light. This stage possibly occurred in ancestral forms of cyanobacteria and probably began about 3 billion years ago.
Cyanobacteria. (Photo: Thomas Angus)
The second stage, which took place approximately 2 billion years ago, further optimized the ability to harness red near-infrared light through the emergence in evolutionary history of a second modified photosystem that incorporated chlorophyll f at critical points. This phase coincided with the diversification of cyanobacteria that led to the lineages that exist today.
The study also found evidence that the ability to photosynthesize with near-infrared red light may be acquired by a cyanobacteria through horizontal gene transfer. This discovery indicates that this complex trait could be feasibly transferred to a photosynthetic individual not previously adapted to the use of near-infrared red light.
Horizontal gene transfer is a rare but important form of gene transfer between species. It occurs when a portion of DNA from one species is introduced into that of another. The idea was ridiculed when it was first proposed more than sixty years ago, but the advent of antibiotic-resistant bacteria and several subsequent discoveries have led to its widespread acceptance in recent times.
The study is titled “Molecular diversity and evolution of far-red light-acclimated photosystem I.” And it has been published in the academic journal Frontiers in Plant Science. (Source: NCYT from Amazings)
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