I guess we all are familiar with the term photosynthesis. Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy that can later be released to fuel the organisms’ activities. It requires a special cell organelle called chloroplast (green plastid) which has the pigment chlorophyll to absorb sunlight. (Duh? Who doesn’t know that?)

Now, interestingly, a study conducted by Rutgers University has shown that the mollusc Elysia Chlorotica has the ability to survive like a plant via photosynthesis! It shows Kleptoplasty or kleptoplastidy which is a symbiotic phenomenon whereby plastids, notably chloroplasts from algae, are sequestered by host organisms. It has come to be known as solar powered sea slugs!

The sea slug is mostly found in the intertidal zone between Nova Scotia, Canada, and Martha’s Vineyard, Massachusetts, as well as in Florida. This sea slug feeds on the brown algae Vaucheria litorea and becomes photosynthetic for the next 6-8 months after stealing and retaining the algal plastids. It punctures the algal cell wall and sucks in the contents like a straw and stores these plastids in their gut lining. There’s a reason why this specific type of algae works as food for the slug. The algae don’t have any cell wall between its adjoining cells and hence makes it easy for the slug to suck the contents once it has punctured the outer wall with its radula.

Scientists have also studied other slugs and found that some of them retain the plastids only to be used as food during hard times. But clearly, the case with Elysia Chlorotica is different.

Another interesting fact is that, the algal nuclei sucked in by the mollusc don’t survive! It is still a mystery as to how the slugs maintain the plastids without the help of the algal nuclei which is necessary to control their function.

In the words of Debashish Bhattacharya, senior author of the study and distinguished professor in the Department of Biochemistry and Microbiology at Rutgers-New Brunswick, “The broader implication is in the field of artificial photosynthesis. That is, if we can figure out how the slug maintains stolen, isolated plastids to fix carbon without the plant nucleus, then maybe we can also harness isolated plastids for eternity as green machines to create bio products or energy. The existing paradigm is that to make green energy, we need the plant or alga to run the photosynthetic organelle, but the slug shows us that this does not have to be the case.”

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Images sources: Google, Wikipedia.

Raibat Sarker

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Author: Raibat Sarker

A BS-MS (Chemistry) student and a KVPY fellow at IISER Bhopal who founded The Qrius Rhino in March 2018.. He was associated with the IISER Bhopal iGEM 2020 team which went on to win the gold medal in the jamboree. He is passionate about trekking and camping, apart from being a foodie and die-hard FCB fan. When not sciencing, eating, or complaining about his bad luck, you will find him hooked into novels or planning his next trek!