Plants glowing in the dark – By Prof. Kirthi Tennakone

Plants glowing in the dark – By Prof. Kirthi Tennakone

Plants glowing in the dark

Source : island

When Rama’s brother Lakshmana fell unconscious, hit by an arrow from Indrajit, the son of Ravana, Hanuman appealed to Sushena, the genius Sri Lankan physician, for intervention. Vaidya Sushena said, “Rush to Dronagiri Parvat in the Himalayas and fetch the herb, Sanjeevani. I will resuscitate the wounded instantly. As the plant emanates light all the time and glows in the dark! You will make no mistake in identification.” (Ramayana).

In 2016, the Ministry of Alternative Medicine, State of Uttarakhand, India proposed spending 250 million rupees to search for the herb. An ayurvedic adviser claimed the herb had been seen growing in the slopes of Dronagiri endowed with a unique fragrance and lights up in the night.

Expeditions to the Himalayas have returned accompanying samples claimed to be Sanjeevani, but none glowed in the dark.

Although animals and fungi glowing in the dark exist, plants exhibiting the same quality are not found in nature. Nature may forbid the appearance of such plants in the wilderness for some unknown reason. Or perhaps an inadvertently long overdue. Yet if the laws of nature do not rule out their existence, man will someday invent them, somehow?

Starting in the early days of genetic engineering, attempts were made to modify plants to glow in the dark with little success. In 2017, the Russian chemist Zinaida Kazakova described the situation as: It can be done but may be as challenging as going to Mars. Things happen sooner than expected. The first plant to glow in the dark was engineered in 2020.

If a plant glowing evolved naturally, the trait would undoubtedly be a tremendous advantage for the species, because man certainly jumps to propagate. Presumably, the task that took a few decades for human intelligence to achieve, nature’s method of random mutations needs eons.

Recently a live herb emitting light constantly and blooming flowers luminescent at night was created artificially, making Valmiki’s imagination a reality.

 A synthetic biology startup Light Bio in the United States engineered a novel variety of flowering plants. And named it Firefly Petunia, because at night, the irradiance of flower buds resembles fireflies. After clearance from the United States Department of Agriculture, the transgenic ornamental was released for propagation (only in the United States) this year.

The phenomenon of light emission by living things is referred to as bioluminescence. Bioluminescent organisms live on land and more abundantly in the ocean. The familiar light sources, sun and fire are extremely hot. In the days before the advent of LEDs, people pondered how tender living objects emit light without getting burnt.

 The flashing lights of fireflies, familiar to us, fascinate the curious. For those reasons, all cultures have folklore and myths connected to fireflies. Later firefly curiosity inspired research revealing the science behind the mystery. Applications followed, notably around advanced medical research.

The seas around the Islands of Maldives frequently glitters at night owing to the bioluminescence of algae. In the olden days, the islanders revered and feared, considering the happening as an omen. Today the sight attracts tourists.

A species of jellyfish displays brilliant green bioluminescence. In 1961, the biochemist Osamu Shimomura found that when he extracted the active components, the luminescence appeared blue. Continuing experiments, Shimomura concluded a protein in the jellyfish, absorbs blue light and re-emits as green. Finding enabled devising a way of monitoring in real time, how cancer and virus diseases progress in living animals at the cellular level.

 Equally mysterious are the bioluminescent mushrooms and fungi.  In 1840 the English botanist George Gardner visiting Brazil was startled to see a group of boys playing with a luminous object. He identified it to be a mushroom growing at the base of coconut trees, subsequently named Neonothopanus Gardeneri to honor the discoverer. The same species occurs in Sri Lanka, growing on decaying exposed roots of coconut trees. We too as children played with it and read newspapers at night holding the mushroom.

One day, seven decades ago, the people of my ancestral village were agitated after seeing an avatar. Something as lengthy as a tall man in a thicket beside a footpath glowed at night, scaring passersby. Those days, it was normal for a man to walk along a footpath at night in the neighborhood, without a light source in hand. My father, who didn’t believe in ghosts, found the avatar to be a rotting bamboo pole. A mold (microscopic fungus) breeding on the pole caused luminance.

The phenomenon of bioluminescence intrigued humans since time immemorial is now understood as a sustained chemical reaction liberating energy, as light. Bioluminescent organisms carry two chemical substances: luciferin and luciferase. The former reacts with oxygen emitting light and the latter fastens the rate of the reaction without undergoing any change. Light emission sustains itself replenishing luciferin by biochemical synthesis. A remarkable way of converting the metabolic energy of an organism into light, generating very little heat and consuming oxygen.

Perhaps bioluminescence evolved more than 300 million years ago as a response of organisms to the danger posed by the increased oxygen in the atmosphere. In the carboniferous period, plants grew vigorously on land, releasing excessive amounts of oxygen. Bioluminescence afforded a way of eliminating oxygen without generating too much heat. Later organisms found other advantages of the process; to deter predators, communicate with their mates, and in the case of mushrooms attract insects and disperse spores.

Firefly petunia was designed by incorporating four genes from a Neonothopanus species mushroom and one gene from a fungus to the common, white-flowered petunia DNA. A strategy more involved than conventional genetic engineering, but a more advanced version termed synthetic biology.

Science examines nature – seeking explanations, correlations and generalizations and foresees innovations. Engineering turns innovative ideas derived from science into practicalities. During the past five decades, molecular biology and genetics have advanced tremendously. Synthetic biology aims to utilise knowledge gained to modify existing life forms or design new organisms, beneficial to the world, with the help of advanced instrumentation and computational facilities. Firefly petunia stands out as a step in this direction readily appreciated by laymen.

It is a realization of an imagination written down in one of the greatest epics of all time. And of particular interest to Sri Lankans. In the East, we mix up myth and imagination and fool ourselves. Whereas in the West, imagination inspires innovation.

In the future, you will walk on streets lit by trees. These engineered trees emit carbon dioxide at night and capture it during the daytime harvesting sunlight .Net zero carbon emissions!The author was motivated to write this essay after taking care of a Firefly Petunia plant and seeing how it glows at night.

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