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When plants, remediation, and microorganisms meet    Nov 27, 2018

When plants, remediation, and microorganisms meet
Nov 27, 2018





Today Clarivate Analytics released their 2018 Highly Cited Researchers list. An annual list of researchers that have distinguished themselves by publishing a high number of papers that rank in the top 1 % of most cited articles within their respective field in the last decade. This showcases that their scientific work is judged by their peers to be of great significance and that they are leading the way in solving the big challenges of our world. Only very few researchers earn this distinction and among them is UHasselt professor Jaco Vangronsveld.


“Microorganisms will give you anything you want if you know how to ask them.” – Kinichiro Sakaguchi.  

When Prof. Vangronsveld arrived at Hasselt University, research into soil pollution in the northern part of Limburg with heavy metals was already ongoing. More specifically, UHasselt researchers where investigating the biochemical and physiological effects of heavy metals on plants. Later on, they also started to study the molecular mechanisms.

“In the late 80s, there was a large demand for soil remediation. We were looking for new ways to ensure that crops could be grown safely. In order to achieve this, we evaluated two different approaches. The first one was to use plants as a tool to extract the heavy metals out of the soil and store them in the parts of the plant above the soil surface, after which they would be harvested, leaving behind a sanitized piece of land. The use of plants to clean up the environment is also known as phytoremediation. The second method was to simply minimize the uptake of these heavy metals in plants, such as agricultural crops.”


“We realized very soon that the extraction of these pollutants was not as straightforward as it seems. However, we did come across something interesting during our research efforts: plant-associated microorganisms. Just like us humans, plants have a microbiome, a massive collection of symbiotic microbial cells that are vital to the health and productivity of the plant. We got particularly interested in a specific part of that community, those who are residing within the internal tissues of the plant, better known as the endosphere. We call these microbial inhabitants that live inside the leaves, stem, and roots of the plant the endophytes.”

“At the time, not much research was conducted within this field and the potential of these tiny organisms was still rather unexplored. So I followed my hinge and refocused my research. We started studying whether these endophytes could influence the uptake of heavy metals and were able to book some nice progress. Yet the idea for our biggest breakthrough came during a conference in Berkeley California. There the concern was voiced that when you use poplars to remove organic pollutants from the soil or groundwater, like benzene or toluene, they are actually pumped into the atmosphere through the leaves of the trees. So we came up with the idea to use the endophytes to break down these substances when transported through the vascular system of the plant.”

From that moment on, prof. Vangronsveld research really gained momentum. “We were able to obtain a prestigious European research grant while simultaneously collaborate with the car company FORD, as they were dealing with groundwater pollution by such organic pollutants. This allowed us to do fundamental research, develop a proof of concept and test our hypothesis directly in the field. A unique combination that allowed us to publish in top journals and become a leader in the field.”


“Over the past few years, this field of research has really become a hot topic. While in the early 2000’s it was difficult to find a presentation about it at a conference there are now multiple conferences organized solely around this topic. One of the reasons for this is the vast potential and importance that endophytes possess. They can establish neutral, detrimental or beneficial associations of various degrees with their host plants. These interactions can be used for a wide variety of applications extending far beyond phytoremediation, like combatting plant diseases and thus reducing the need for the use of chemicals, decreasing the emission of greenhouse gasses and increasing agricultural production as well as making it more sustainable.”

“However, we are not there yet. Still, a lot of fundamental research is required as we do not fully understand a lot of the mechanisms behind the interactions between plants and endophytes. Before we can make solid predictions about the usability of a certain endophyte for an application we must be able to explain our observations and answer questions like: What happens when we spray these endophytes onto plants? How do they get inside the plant? And how do they manage to overcome the competition of microorganisms that are already residing inside the endosphere? However, the fact that there is still a lot left to discover and that the progress made within the next decades might have major implications on society makes it such an interesting field of study. I am certainly looking forward to what lies ahead.”


Professor Jaco Vangronsveld is the director of the Centre for Environmental Sciences at UHasselt.