Mushroom genes lit up tobacco plants

Written by: Saradhi Attuluri

The concept of autoluminescent plants is not new. Most of the previous studies used genes from bacteria or firefly to produce transgenic autoluminescent plants.

With the old technology, plants required a continuous supply of a chemical known as luciferin. Moreover, the glow they generate is too low and invisible to the human eye.

Supplying luciferin for lighting up the plants would be okay in a laboratory set up. But it is definitely a setback if such plants must be used for commercial applications. Who has the time to spray luciferin from a bottle in their gardens to enjoy the light show?

A transgenic plant that can generate light which is perceivable to the human eye and yet does not need a supply of external chemicals is certainly a welcoming step. The present study led by Dr. Karen Sarkisyan and Ilia Yampolsky carried out by nine research laboratories spread across Russia, UK and Austria made it possible.

The glow of their plants is visible! and it does not require supplements. To put it in another way, sustainable visible glow! But how did they achieve this?

Instead of using the genes from firefly or a bacterium, the research team borrowed four genes from Neonothopanus nambi, a fungus (mushroom) and incorporated them into the tobacco genome.

With the currently available technology, a single gene insertion would never make the plants illuminate all by themselves. The four genes that the team has used made the technology sustainable.

The four genes produce enzymes (biological catalysts) that convert caffeic acid, a natural substance present in plants, into luciferin and then convert luciferin, back to caffeic acid. Of course, one of the steps is to use luciferin to generate light. The whole process is much like recycling of materials (paper and other stuff) in our day to day life.

The light they generate is yellowish-green. This colour of light is particularly advantageous in this case, as plants do not absorb light of this range much and thus, most of it is emitted out.

Caffeic acid is a natural substance present in plants which is used as a raw material for the synthesis of lignin, a component of the cell wall. Luckily, diverting some portion of the energy and material to produce luminescence does not tax the plants much. This was confirmed by the assessment of the seed germination rate and growth patterns of the plants in the laboratory.

Imagine, how beautiful a glowing flower would appear amidst darkness!

All parts of this transgenic plant glow, but the most intense glow is produced by the flowers. They emit about 1010 photons per minute. Although the number appears to be big, the light is just sufficient to see them in the dark. Fun fact, this amount of light might not be sufficient enough for you to read a book in the dark!

Who knows, further advancements in this technology may one day replace our table lamps and streetlights. They might even be used to light up airstrips and helipads in remote localities. Let’s hope for a bright and ‘luminous’ future.

Acknowledgement:

Our sincere thanks to Dr Karen S. Sarkisyan for providing visual elements.

Primary reference: Plants with genetically encoded autoluminescence.

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