SLU news

Thomas Wieloch wants to release the brakes on photosynthesis

Published: 12 July 2023
Portrait photo of Thomas Wieloch in front of a blue-grey background

Formas, the Swedish governmental research council for sustainable development, awarded Thomas Wieloch, postdoc at Umeå Plant Science Centre and SLU, a mobility grant for early-career researchers. He will investigate which processes hinder carbon assimilation in wheat and try to identify possible ways to improve productivity. His project will be in collaboration with his current supervisor Totte Niittylä and with Alex Sessions from the California Institute of Technology.

Congratulations to your mobility grant! Are you excited to start your project?

Thank you! Absolutely! This is the next step in my academic career. In addition to developing my own research, which I am already familiar with, I will now also have to manage project funds. A great responsibility I have not had before. I am very grateful to Formas for their trust and support.

You plan to identify processes that inhibit photosynthesis and carbon assimilation in C3 plants focusing on wheat. Why did you choose to work with wheat?

I would like to work with wheat because wheat is an extremely important crop both nationally and globally. It is actually one of the so-called ‘big three’ cereal crops feeding the world which means that it contributes substantially to the diet of several billions of people. In my opinion, these are very good reasons to try and better understand how this plant works at the metabolic level and to improve it.

Why is it important to identify processes that inhibit photosynthesis?

Ultimately, my project is all about releasing the brakes on photosynthesis. Biochemical mathematical models suggest that plants in general do not usually achieve their full photosynthetic potential. I believe that identifying inhibitory processes will provide the scientific basis for efforts aimed at optimising photosynthesis genetically, and this has enormous potential for improving agricultural productivity and food security.

You plan to work with stable isotopes which are naturally occurring, non-radioactive forms of a chemical element that are often used as tracers in biological systems. How can isotope technologies help to understand photosynthesis and carbon assimilation in plants, especially in C3 plants?

Stable isotopes can tell us how plants utilise their resources. Using isotope technologies, we may obtain information on where, within a metabolic network, resources get lost or where they are not used in the best possible way. This is not especially true for C3 plants, but for plants in general.

You are currently working as postdoc in Totte Niittylä’s group at UPSC and plan to continue there during the first two years of the project. Why did you choose to join UPSC and Totte Niittylä’s group in the first place and how will the group’s expertise contribute to your research project?

UPSC is one of the strongest research environments in experimental plant biology in Europe. It is home to excellent research groups covering a broad range of topics and very well equipped with basically everything I need to conduct my experiments. While I am quite proficient in modelling biochemical processes based on isotope data, Totte Niittylä’s group has longstanding experience in conducting isotope tracer experiments and biochemical analyses which means that our skillsets are complementing each other in very good ways. Besides, Totte is very supportive, and this is making a real difference especially for an early-career researcher. He is going out of his way to help me advance my career, and I am extremely grateful for that.

The third and fourth year of your project you plan to spend with Alex Sessions at the California Institute of Technology in Pasadena. What do you hope to learn in his group and how will this benefit your project?

Alex Sessions’ group is working on solving highly challenging problems within the stable isotope field that many other groups seemingly tend to stay away from. Recently, his group developed software for modelling isotope changes in complex networks. I believe this software constitutes an important breakthrough since it allows estimations of carbon fluxes based on natural-abundance isotope data in a convenient way. Sooner or later, everyone in the stable isotope field will want to implement these software capabilities in their research to obtain the best results possible, and I would like to be at the forefront of this development. I have great respect for this group’s dedication to pushing current boundaries.

Why did you choose to apply at Formas for the mobility grant for early-career researchers?

Formas provides a great mobility grant package. This package enables young scientists to independently develop their own line of research and visit research environments outside of Sweden where they may learn new methods, expand their research network, and get inspired by what others do. The package not only includes the awardee’s salary, but also covers additional living costs for the time spent at research institutes outside of Sweden, project-related costs, pension benefits and so on. To sum it up, Formas offers early-career researchers an entirely fair framework in which to advance their careers.

Do you have some tips for other early-career researchers applying for similar grants?

I am not feeling entirely comfortable about giving advice on what to do to get a research grant because my experience in this area is still quite limited. I think what helped me though was a longer list of published first- and corresponding-author papers which show that I have successfully and independently completed research projects before. I have also tried to make sure that my proposed project clearly addresses societal needs and asked Totte, Alex, and our Grants Office for advice as I developed my application which I believe made it a lot more competitive.

Project title: Releasing the brakes on photosynthesis – Identifying processes impeding photosynthesis in wheat leaves by cutting-edge isotope techniques

More information about Formas’ mobility grants for early-career researchers


What are C3 plants?

Plants have evolved different photosynthetic pathways to assimilate carbon from the atmosphere. The vast majority, about 85 percent of all plants on Earth, uses the so-called C3 pathway named after its first product, a three-carbon molecule. In C3 photosynthesis, the bifunctional enzyme rubisco can incorporate either atmospheric carbon dioxide or oxygen into organic molecules. Incorporating oxygen results in photorespiration, a process causing major carbon losses, and there are several other respiratory processes which cause additional losses. Overall, C3 photosynthesis is regarded by many as comparably inefficient.

How can stable isotopes help to understand photosynthesis?

Stable isotopes are the non-radioactive atom species of a given chemical element. Their nuclei contain the same number of protons but different numbers of neutrons. Consequently, different stable isotopes of a chemical element exhibit different masses. For instance, 12C is a comparably light carbon isotope containing six protons and six neutrons while 13C contains an additional neutron and is therefore somewhat heavier. Furthermore, heavier isotopes form stronger bonds with other atoms. These physical differences lead to isotope changes in plant compounds as carbon fluxes vary during plant growth. Researchers analyse these isotope changes to learn how plants adjust their carbon fluxes, for instance, in response to environmental changes.

Researchers use stable carbon isotopes also in so-called isotope tracer experiments. In these experiments, plants are grown inside chambers that initially contain normal air in which the carbon dioxide contains only very little 13C. The air in these chambers is then replaced by air containing carbon dioxide that is highly 13C enriched. As plants assimilate this carbon dioxide, the 13C is incorporated into plant compounds. By analysing how fast and where the 13C is incorporated, researchers can estimate plant carbon fluxes.