Jan Zarzycki’s journey through photorespiration: from bacterial enzymes to field trials
What began as undergraduate fascination with potential ways to bypass photorespiration has evolved into a promising solution for helping crops thrive in our changing climate.
“My fascination with alternative CO₂ fixation pathways began as an undergraduate already. I was immediately fascinated by the topic,” recalls Zarzycki, now a postdoctoral researcher at the Max Planck Institute for Terrestrial Microbiology, where he assists and mentors students working on the CROP4CLIMA project. This European initiative is developing crops that can better tolerate arid conditions while capturing more carbon dioxide.
Exploring alternative pathways
During his doctoral work, Jan studied the 3-hydroxypropionate bi-cycle — a unique metabolic pathway found in bacteria that thrive in hot springs — that revealed enzymes with potential to address this persistent problem in plant productivity.
“I found that some of [the pathway’s] enzymes held great potential for bypassing photorespiration, a process that limits the photosynthetic efficiency of many plants. During my post-doc, I explored whether this bypass was a viable option, and my findings showed great promise,” he explains.
Building a better pathway
“In 2015, I joined Tobias Erb’s lab, and we started working on what would become the tartronyl-CoA (TaCo) pathway. We believed this new photorespiratory bypass had an even greater potential to boost agricultural yields,” Jan explains. “One of my first contributions was to engineer a new-to-nature carboxylase.”
Initially conceived through the FET Open project FutureAgriculture, the TaCo pathway is a photorespiration-bypass pathway that, instead of allowing photorespiration to waste CO₂, it captures and recycles it back into the plant’s carbon-fixing system.
Passing the baton
“Over the years, two students, Dr. Marieke Enderle and Dr. Daniel Marchal, took over the work and improved the enzyme many times over, assembled the whole pathway, and eventually earned their PhDs while working on the project. It’s been incredibly rewarding to be part of this work from the very beginning!”
While Jan’s main role is now supervision, advisory and administrative in nature, there are still chances to go back to his early days of pathway explorations. “I still enjoy getting hands-on and helping our students out with lab tasks and experiments whenever I can,” he confesses.
From concept to implementation
Now, nearly a decade later, the TaCo pathway has reached a significant milestone. “The TaCo pathway is now mature enough to be implemented directly into living plants,” Zarzycki notes. “This is precisely what is being done in the CROP4CLIMA project, and the early results are incredibly promising.”
The consortium is currently testing the pathway in rapeseed, with the Max Planck Institute providing analysis platforms to characterize enzyme performance and identify optimization opportunities. Their work involves both laboratory experiments and plant trials to ensure the pathway functions effectively under agricultural conditions.
The good weeks
Behind the promising results lie the day-to-day reality of research work. “I think there’s no such thing as a ‘typical’ week—for better or worse, something is always happening,” Zarzycki admits.
“In a good week, no instruments break down and need repairing or replacing: we get to see some exciting new results or come up with a brilliant idea for how to tackle a particular problem,” he says. “But sometimes it is good to step away for a moment, take a break, grab a coffee, talk to people, and then return to work with a new perspective.”
A group effort
The CROP4CLIMA project brings together expertise from across European institutions, each contributing specialized knowledge while sharing results and insights.
“While each partner contributes their own specific expertise and works independently on their tasks, we regularly share our results and observations to discuss progress, how to interpret our findings, and plan the next steps. These interactions are always rewarding.”
If successful, the results of this long journey could help farmers make use of land growing increasingly unsuitable to traditional crops, potentially reducing irrigation costs while maintaining productivity.