The building of impactful science careers
Two decades of effort
Science articles present us with fascinating glimpses into our world or visions of future possibilities. Yet when we get a science story from NPR or social media, the backstory behind discovery takes the backseat. It is like watching a movie montage where an ordinary person turns into a martial arts master in no time, with barely a glimpse into the effort it took to get good.
Science is actually a long-haul project and often starts with basic, sometimes unexpected discoveries. The latest publication involving the Benning lab and its collaborators describes one such endeavor that took over two decades to complete.
The study, published in the Proceedings of the National Academy of Sciences USA, examines a protein – called DGD1 – involved in making one of the most abundant lipids in the world. These same lipids are used to build the membranes inside chloroplasts which are responsible for photosynthesis, the process that converts sun light into much of the planet’s usable energy.
“These lipids provide the glue that holds the photosynthetic machinery together in membranes. Losing a set of these lipids, the machinery will be damaged,” says Dr. Christoph Benning, plant lipid expert.
The DGD1 protein is made of two parts. One was demonstrated decades ago to make the lipid. The other part, the subject of this latest study, has been found to shuttle the produced lipids from the outer parts of the chloroplast to its inner parts so that they build the photosynthetic membranes.
For a single protein, DGD1 holds much sway over the plant’s well-being. In lab experiments, plants that missed either half of the two-piece production and delivery system didn’t grow well or got sick.
Germany, 1995: discovering DGD1
“This is a story of a collaborative effort that has taken a long time, from the discovery to figuring out how an important plant protein works. I feel proud about having been part of this effort since a number of people have built their careers around this research,” says Benning.
This all started in 1995, when Benning was running his first lab at the Institut für Genbiologische Forschung Berlin GmbH in his native Germany.
“We did somewhat of a brute-force genetic mutant screen and stumbled on an Arabidopsis plant (Arabidopsis is the ‘lab rat’ of plants) that was missing 90% of this very important lipid. We didn’t know the responsible gene or protein or how either worked to produce the lipid, but we knew the lipid was relevant to photosynthesis, because the mutant plants were smaller and bushier than usual.”
Right from the outset, the group figured out that the mutant plant missed a protein for making the lipid. They christened it DGD1, after the scientific name of the missing lipid.
“We published the mutant in Plant Cell. People in the scientific community just thought it was amazing that missing one type of lipid could have such an effect, and I truly believe that this paper was key in getting me my job at MSU.” The first author was Peter Dörmann, a post doc working with Benning.
MSU, 1999: identifying the DGD1 protein
Three years later, the Benning group, now at MSU, identified the gene behind the defective protein and missing lipid in the mutant. This was a three-year genetic mapping feat, since the Arabidopsis genome was not yet fully deciphered.
“It was a big deal at the time, because without the genome as reference, we didn’t have the resources to easily identify the gene defective in the mutant. When the genome became available in 2000, we had a basis to confirm our findings against a larger reference library, where we immediately found a second protein similar to ours.”
With the gene identified, the group was now able to isolate the protein and see how it worked. “We knew right away that one part of the protein was important for building the membrane of the photosynthetic machinery. But the other part, we had to speculate. We came up with a hypothesis that it was important for transporting these lipids, but we couldn’t prove it.”
Benning, Ilse Balbo, the marvelous technician who found the mutant and was involved in mapping the gene, and Dörmann, who had followed his mentor to MSU, published the new findings in a Science paper in 1999.
“This second paper on finding the DGD1 gene and protein contributed much to my promotion to Associate professor with tenure at MSU. We speculated on how the two protein parts might work together, but we got it wrong, because we didn’t know enough about it at the time”, Benning reminisces.
A new career flourishes
With a Science paper under his belt, Dörmann left the Benning lab to pursue his own career in Germany.
“Before students or post docs leave my lab, I often let them be a corresponding author on a research paper so they get mentored on the publishing process, a cornerstone of scientific careers.”
“I also have handed down projects to my postdoctoral researchers so that they can continue the research on their own. At some point, mentors have to stop being involved in their mentees’ work so that they can develop their own careers, much like weening your kids.”
That is exactly what Dörmann did, starting his own lab and continuing the work on DGD1, while Benning moved on to new research topics.
“Dörmann and his students have published a number of papers on this protein. He corrected the error we made in the 1999 Science paper and showed how the protein correctly works. His lab also demonstrated how a plant deficient in DGD1 ended up sick because of defects in photosynthesis,” Benning adds.
This latest publication is the culmination of 15 years of research to prove the original hypothesis that DGD1 is also responsible for the transport of the lipid it produces.
“Dörmann and I have built a career with the research we started back in 1995 (Dörmann is now at the University of Bonn in Germany and Benning is now director of the PRL). Many others, including PRL’s own John Froehlich, collaborated on this subject. It’s an example of how big – and in this case accidental – discoveries lead to big publications, which are crucial to growing scientific careers.”
2016 and beyond: movie montage moment
In the large scheme of things, this is the story of the discovery of one protein among thousands that exist in every plant cell. The twenty years it took to tease out DGD1’s function is not an unusual timeframe for scientists.
But it is incremental basic discoveries that set the foundations for future applications that change society - in this case, perhaps how to increase photosynthetic efficiency or even how to replicate nature and build an artificial photosynthetic membrane in the test tube.
Given that plants are not perfect at harnessing the sunlight and converting it into useful things, increasing their production capacity, even in small increments, has huge consequences on food security and renewable energy solutions for the 21st century.
Additional contributors to the study include Amely Kelly and Barbara Kalisch, both first authors. Photographs courtesy of Christoph Benning.
Similar to how chameleons can change colors to blend into their surroundings, cyanobacteria can tune their coloring to better absorb light in different environments.
Plant gene regulation dictates how plants grow under differing environmental conditions, and researchers from the MSU-DOE Plant Research Laboratory are looking at how different genes control light-dependent processes in Arabidopsis thaliana.
Jianping Hu, professor at the MSU-DOE Plant Research Laboratory (PRL) and the Department of Plant Biology, received a $900,000 grant from the National Science Foundation (NSF) to study the motility of cellular energy organelles, peroxisomes and mitochondria in particular, along the cytoskeleton in Arabidopsis thaliana.