According to a recent study published in Current Biology, researchers at Georgia Tech’s School of Biological Sciences have created one of the first strains of yeast in history that could be happy when the lights are on.
We were frankly shocked by how simple it was to turn the yeast into phototrophs.
All we needed to do was move a single gene, and they grew 2% faster in the light than in the dark. Without any fine-tuning or careful coaxing, it just worked.
Anthony Burnetti
Our knowledge of the origins of this feature and its potential applications in the research of biofuel generation, evolution, and cellular ageing may be greatly enhanced by the ease with which the yeast may be endowed with such an evolutionarily significant characteristic.
The team’s earlier studies into the development of multicellular life inspired this study. In their initial report on the Multicellularity Long-Term Evolution Experiment (MuLTEE), published in Nature last year, the team described how multicellularity evolved over 3,000 generations in their single-celled model organism, “snowflake yeast.”
Light is one way that organisms can receive an energy boost without the need for oxygen. However, from an evolutionary perspective, the process of converting light into useful energy might be challenging. For example, a variety of genes and proteins that are difficult to produce in the lab and transfer to other species spontaneously through evolution are part of the molecular machinery that enables plants to exploit light for energy. Fortunately, there are other living things besides plants that can transform light into energy.
Rhodopsins are proteins that, without extracellular machinery, may transform light into energy, providing organisms with a simpler means of using light.
Rhodopsins are found all over the tree of life and apparently are acquired by organisms obtaining genes from each other over evolutionary time.
Autumn Peterson
A rhodopsin gene synthesised from a parasitic fungus was introduced to common baker’s yeast by researchers in an attempt to test whether they could equip a single-celled creature with solar-powered rhodopsin. The rhodopsin variant that this particular gene codes for would be put into the cell’s vacuole, a structure that, like mitochondria, is capable of converting chemical gradients created by proteins like rhodopsin into energy.
Here we have a single gene, and we’re just yanking it across contexts into a lineage that’s never been a phototroph before, and it just works.
This says that it really is that easy for this kind of a system, at least sometimes, to do its job in a new organism.
Anthony Burnetti
The group has also started working together to investigate the possibility that rhodopsins might mitigate the ageing effects in yeast by controlling vacuolar activity, which may be linked to cellular ageing. A similar new yeast that runs on solar power is already being used by other researchers to examine improving bioproduction, which might lead to significant advancements in the production of biofuels, among other things.
However, Ratcliff and his team are primarily interested in investigating how this extra advantage can affect the single-celled yeast’s transition into a multicellular creature.
Source: Georgia Institute of Technology News
Journal Reference: Transforming yeast into a facultative photoheterotroph via expression of vacuolar rhodopsin, Current Biology (2024). DOI: 10.1016/j.cub.2023.12.044.
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