Lord of the factories

Portrait Matthijs Hölscher

At the Max Planck Institute of Molecular Plant Physiology, Matthijs Hölscher is modifying tobacco plants so that they produce vital medicinal substances. Read in our portrait how he is pushing the boundaries of molecular farming.

Matthijs Hölscher is 29 years old and has just completed his PhD – and is already the owner of hundreds of factories. That said, his factories are not quite like the factories one would normally imagine: they are less than one metre in size, and aren’t buildings but living, growing organisms.

An active substance that could protect against HIV

For his doctoral thesis at the Max Planck Institute of Molecular Plant Physiology (MPI-MP), Matthijs Hölscher has spent the past four years gradually modifying the genome of tobacco plants. The modified plants produce certain quantities of various antimicrobial proteins, i.e. proteins that are harmful to microorganisms. One of these proteins is called griffithsin, which has an antiviral effect. It binds with specific structures in viruses, preventing them from causing infection in the body. Matthijs Hölscher has been able to demonstrate that griffithsin is a good way of preventing HIV infection in particular.

This would require sufficient quantities of the active substance to be made available. Matthijs Hölscher has made an important contribution to achieving this, and published his findings in the journal Plant Molecular Biology. At the same time, he is using his “plant factories” to produce other active substances, including antimicrobial proteins that could prove suitable for combating multidrug-resistant bacteria. “Among other things, we modified the genomes such that the chloroplasts in the plant cells began to produce the desired proteins. This was a time-consuming process because changing the genes can of course disrupt the metabolic processes in the plants to the point where they no longer grow properly. We also had to find a solution for this in order to have something to harvest at the end of the day”, says Matthijs Hölscher.

Opportunities of molecular farming

His molecular farming required a lot of patience, in other words: Hölscher cannot even count the number of times he would go to the greenhouse, tear a leaf off a plant, pulverise it and then examine it in the lab, using for example separation methods such as gel electrophoresis. His persistence and patience paid off: finally, Matthijs Hölscher managed to grow tobacco plants that produced the desired proteins. One factor that helped him remain optimistic during the many highs and lows of his projects was the good support he received from his team, especially from his doctoral supervisor Dr Joachim Forner.

Last autumn Matthijs Hölscher was finally presented with his PhD certificate. “I had several options after that. I believe it is crucial to be guided first and foremost by my interests, because then things are bound to work out in the end”, says Matthijs Hölscher. That’s how it has almost always been for him.

Matthijs Hölscher was already fascinated by plants while studying for his degree in biology in the Dutch city of Utrecht – which is why he decided to specialise in plant genetics and molecular plant biotechnology during his master’s degree at the university in Wageningen. He also focused on molecular farming, which involves adapting plants through genetic modification and cultivation so that they produce medicinal substances. It was more of a coincidence – and a fortunate side effect – that this field happens to be one of the major trends in biology.

From internship to PhD

This interest is also what motivated him to apply to the MPI-MP: “I’ve long been fascinated by the concept of molecular farming, so I looked into places where research in this field is carried out. I found the papers published by Professor Ralph Bock’s research group at the MPI-MP really interesting. Ultimately, however, the MPI-MP was a good fit not only on account of its excellent reputation and publications, but also thanks to its outstanding equipment”, explains Matthijs Hölscher. Besides the equipment needed to conduct molecular biological analyses, the institute also boasted the personnel – including technicians, gardeners and many other professions – necessary to pursue research efficiently in this highly sophisticated field. Matthijs Hölscher already discovered these many advantages when he did a six-month internship at the institute shortly before beginning his PhD. This soon made him want to spend longer and do his doctorate there. So he applied for a grant from the Max-Planck-Gesellschaft that is also available to researchers from abroad: the scholarship of the International Max Planck Research Schools (IMPRS) – and was successful!

After his PhD, Matthijs Hölscher decided that his next step would be to accept a postdoc position at the university in Utrecht. “This brought me back full circle to my homeland, though it’s probable that I will return to Germany in the medium term.”

During the five years he spent in Germany, Matthijs Hölscher became better acquainted not only with the institute and the work of a professional scientist, but also with Germany itself. “Though Dutch and German are closely related, it was still hard work at first to improve my German”, he admits. After making a lot of new friends, however, he soon found that German came naturally to him. These days Matthijs Hölscher speaks German most of the time, both before and after his time at the MPI-MP – because he married a German.

Author: Christian Heinrich