Anyone who has watched the Avatar movie gets their breath taken in when the movie brings you through their beautiful world, especially with different varieties of glowing flora and fauna. Recent discoveries and findings have shown that it is not very far where people will be able to build something very similar in real life. In nature even at present, we can easily find a few animals, microbes like fireflies and mushrooms that can glow due to their bioluminescence. This phenomenon occurs when enzymes react on luciferins within the organism, resulting in releasing energy in the form of light. However, bioluminescence does not occur naturally in plants.
Scientists believe that these bioluminescent plants will not only take us to a gorgeous completely new world, bust also will aid tremendously in exploring and studying plants. This technology will help scientists to monitor how different hormones act inside plant tissues and will help in observing how plants respond to various abiotic (e.g., droughts, salinity) and biotic (e.g., pathogens, herbivores) stresses.
Previously, what researchers have done was, incorporating enzymes required for the synthesis of bioluminescence and luciferins into nanoparticles and insert them into plants. Also, several other researchers have tried inserting bacterial genes that cause bioluminescence into plants. However, those efforts were not successful because of the high cost entangled with the nanotechnology and the luminance being quite weak when using bacterial bioluminescence genes.
The latest research takes a different approach, which uses the process of which fungi illuminate. In 2018, it was discovered that a fungal species Neonothopanus nambi luciferase has a biochemical pathway that produce bioluminescence, similar to that of the firefly luciferase. Fungi use α-pyrone 3-hydroxyhispidin which is oxidized by luciferase in the presence of oxygen which results in the emission of green light (~ 520 nm). It was found that the expression of only a few genes (only 3) from the fungal bioluminescent system is sufficient to obtain considerable level of glowing in eukaryotes.

In the year 2019, Sarkisyan and the team had inserted four genes from the fungus into the DNA of tobacco plants. These genes are related to the enzymes that convert caffeic acid into a luciferin which emits energy as a green light visible to the naked eye. Also they had discovered that the light emitted was 10 times brighter than that of bacterial genes. According to them, the site of expression changes with the growth of the plant. They also had discovered that the brightness reduces with the senescence of the leaves, but there was an increase in the glow at sites where the leaves were damaged. The highest luminescence was observed in flowers.
Investigators hope to take these plants to the market after making the plants brighter and with approved safety regulations. The next target of this team is to insert the fungal genes into the plant’s genome that will be activated by certain hormones. Moreover, it is believed that the tissues at which the hormones are active at different times will show luminescence.

References:
Fleiss, A. and Sarkisyan, K.S., 2019. A brief review of bioluminescent systems (2019). Current genetics, 65(4), pp.877-882.

Image courtesy
Featured image:
https://sharebiology.com/wp-content/uploads/2020/05/glowing-tobacco.jpg
Figure 01: Planta/MRC London Institute of Medical Sciences https://www.theguardian.com/science/2020/apr/27/scientists-create-glowing-plants-using-mushroom-genes