Insights into two rare types of photosynthesis could boost crop production

Researchers studied how certainbacteria use low-energy light to make food.

The trade-offs that the twobacteria make when using lower-energy light have been discovered by the Imperial researchers. The aim of plant genetic engineering is to make production more efficient.

Plants, algae and cyanobacteria convert light and carbon dioxide into sugars and oxygen. The photosystem II uses light to extract electrons from water and feed them into the photosynthetic machinery.

The majority of organisms use visible light to process food. For a long time, the minimum energy needed to do the hard chemistry of removing electrons from water has been considered.

There are some cyanobacteria that use red light for photosynthesis. Giving plants and algae the ability to use far-red light could make their production more efficient.

The ability to use both visible and far-red light in different conditions is a desirable property for crop plants, but the researchers need to understand if there are any trade-offs or compromises in systems that can do this.

It's far-red.

The team studied how the cyanobacteria use red light to make food. Acaryochloris marina lives under a green sea-squirt, shaded from visible light but exposed to stable far-red light, that it collects using the pigment chlorophyll-d.

When visible light is present and shaded from it, other recently discovered cyanobacteria can do photosynthesis with the help of the pigment chlorophyll-f.

In a study published in eLife, researchers led by the same team at Imperial have shown that the photo system II of cyanobacteria using the pigment chlorophyll-f is less efficient than the photo system II of those using chlorophyll-d.

The Department of Life Sciences at Imperial is led by Professor Bill Rutherford.

The first step in understanding the trade-offs between efficiency and resilience is our study. Researchers can use these insights to determine which features are beneficial.

Calculating the amount of carbon dioxide in the air.

The photosystem II of Acaryochloris marina is an efficient way to collect and use far red light. Excess light can cause it to be overwhelmed and produce harmful oxygen species which can kill the cells.

The photo system of Acaryochloris marina uses far-red light more efficiently than the photo system of the thermalis. Exposure to excess light doesn't produce harmful oxygen species.

Compared to the chlorophyll-d photo system of Acaryochloris marina, the chlorophyll-f photo system is less efficient and has better stability.

The research suggests that the two types of far-red photosystem II pay a different price for being able to work with less energy.

The next step is to understand how the two types of far-red photo system differ.

More information: Stefania Viola et al, Impact of energy limitations on function and resilience in long-wavelength Photosystem II, eLife (2022). DOI: 10.7554/eLife.79890 Journal information: eLife