Like people, plants also have a sleep-wake cycle that we call the circadian rhythm . Cryptochromes are the proteins in crops and animals that help regulate sleep cycles. Now, a recent study has discovered that plants, thanks to these specific receptors, can react to bluish tones, making them perceive all wavelengths of light and even have better vision than humans themselves.
“Plants can see much better than we can,” says Itzan Shabek of the Department of Plant Biology of the Faculty of Biological Sciences, co-author of the work published in the journal Nature Communications Biology .
As you can see”?
Plants do not have organs dedicated to detecting light, like our eyes, but they do have a wide variety of dedicated receptors that can detect almost all wavelengths. One of them are blue light photoreceptors called cryptochromes, responsible for key processes such as seed germination, flowering time or the circadian clock. When cryptochrome detects an incoming photon, it reacts in a way that triggers a unique physiological response.
The scientists studied the specimen Arabidopsis thaliana, considered a model plant. It has a small genome, grows rapidly and produces many seeds, characteristics that make it a good example for study and analysis.
Thus, using advanced light source X-rays at the Lawrence Berkeley National Laboratory, they managed to identify the construction structure of cryptochrome-2.
When a part of the molecule detects light, a rearrangement occurs that transforms the molecular structure and releases proteins called transcriptional regulators that control the expression of specific genes in plants.
The scientists observed that the part of the molecule that detected light therefore changed its structure when it reacted with light particles, going from a single unit to a structure formed by four linked units, or tetramer.
“This rearrangement process, called photoinduced oligomerization, is also very intriguing because certain elements within the protein undergo changes when exposed to blue light. Our molecular structure suggests that these light-induced changes release transcriptional regulators that control the expression of specific genes in plants, “says Shabek.
The authors mention that this discovery is a further step in the direction of their more ambitious purpose of understanding detection mechanisms in crops. His team is eager to investigate the smooth signaling pathways and hormonal perceptions of plants.
“We are interested in hormone perceptions as well as light signaling pathways,” concludes Shabek.
The team first resolved the crystal structure of the blue light receptor two years ago, using X-ray crystallography and biochemical approaches.
Referencia: Malathy Palayam, Jagadeesan Ganapathy, Angelica M. Guercio, Lior Tal, Samuel L. Deck, Nitzan Shabek. Structural insights into photoactivation of plant Cryptochrome-2. Communications Biology, 2021; 4 (1) DOI: 10.1038/s42003-020-01531-x
