Tasting Light: New Type of Photoreceptor is 50 Times More Efficient than the Human Eye

A new type of receptor, 50 times more efficient at capturing light than the rhodospin in the human eye, was discovered among a family of taste receptors in roundworms.  This new receptor protein has unique properties that suggest potential future applications.  LITE-1 is extremely efficient at absorbing UV-A and UV-B light.  It is 10 - 100 times greater than opsins and cryptochromes.  The genetic code of these receptor proteins is far different from other types of photoreceptors found in plants, animals and microbes.  The chromophore in animal receptors retains some functionality when broken apart, but LITE-1 completely loses its ability to absorb light when denatured.  Scientists determined that having the tryptophan in two places was critical to the function of the protein.  They modified a nonlight-sensitive protein, GUR-3, with tryptophan and it reacted to UV light with a third the sensitivity to UV-B as LITE-1.  Scientists may be able to genetically engineer other photoreceptors.

http://www.ns.umich.edu/new/releases/24359-tasting-light-new-type-of-photoreceptor-is-50-times-more-efficient-than-the-human-eye
https://www.sciencedaily.com/releases/2016/11/161117134629.htm
http://www.cell.com/cell/fulltext/S0092-8674(16)31518-5

A single gene influences petunia pollinators

An international research team has discovered the mutations of the MYB-FL gene and the role it plays of floral UV absorbance and coloration in petunias. The MYB-FL gene is a single gene that accounts for the attraction of nocturnal pollinators. The variation of the gene allows for the fluctuations of Flavonol and anthocyanin. Flavonol controls the dimming or stimulation of the UV light intensity while anthocyanin is a pigment compound that controls flower color. 

            The mutation of the MYB-FL gene could mean the difference between which insect/animal pollinates the plant’s flower. Researchers found UV and pigment differences among three different petunia flowers correspond to differences in their pollinators. Some nocturnal moths had tended to draw near flowers with much UV absorption, such as the white flowers of P. axillaris. Bees enjoy the small, purple flowers of P. inflata. In the daytime, hummingbirds visit the bright red flower P. exserta that absorbs much less UV light.

            It was interesting to read how plants can pick their pollinators. Each petunia was different in their means of UV absorption and coloration. This, of course, depended upon the accumulation of flavonoid pigments in the plants. The P. exserta, for instance, primarily attracts hummingbirds. This bright red flower draws the bird to its stigmas and stamens for pollination.