Florian Lelchat: Winner (2019) of a Best Article Award from FEMS Microbiology Ecology
Florian Lelchat, Researcher at Leo viridis lab in Plouzané (France), is the winner of a 2019 article award from FEMS Microbiology Ecology. He wins the award as the first author of the winning paper: Viral degradation of marine bacterial exopolysaccharides.
This is the first time that FEMS Microbiology Ecology has presented such awards and it has selcted four top papers to be the winners. We interviewed Florian to find out more about the inspiration behind this paper:
First, I would like to dedicate this prize to Dr Claire Boisset, one of the co-authors of this paper. She tragically passed-away last summer. During my Ph.D., she was my (wonderful) supervisor. She was a fantastic collaborator and a great Lady. Without her, this work would not have been done.
We miss her a lot.”
Could you provide a brief, simple overview of the topic your paper covers?
This paper highlights for the first time the presence of active polysaccharidases on virions of marine phages. We demonstrated that these viral enzymes can specifically and passively degrade solubilized polysaccharides which eventually speed-up their remineralization (and, maybe not only…). That’s huge because a large part of oceanic Dissolved Organic Matter (DOM) is constituted by polysaccharides.
In short, that simply means we probably have a new player in the game of the marine Carbon cycle and eventually others elemental cycles…”
Why is it important for us to learn about the role of viruses in the cycling of marine dissolved organic matter?
Since the description of the viral shunt 20 years ago, we know that marine phages are key players in oceanic fluxes of matter. This certitude has been reinforced with the metaviromic revolution. Despite these breakthroughs, and at the light of our preliminary study, it seems that their true role is still underestimated. In one mL of seawater we find an average abundance of around 10 million virus-like particles, they naturally outnumber bacteria by one order of magnitude. Moreover, their genomes remain largely silent, the major part of the proteins they code lack for described homologous in databank (the famous viral dark matter)!
We feel that we still only see the tip of the iceberg. Marine phages undoubtedly play a complex and fundamental role in the cycling of marine DOM. How to refine the extent and comprehension of this role? How could this role evolve in a context of global change? That’s the kind of questions which clearly point out why it is important for us to learn about the role of viruses in the cycling of marine dissolved organic matter.”
What encouraged you to perform research in this area of microbiology?
It was by pure serendipity. Initially, I was looking for an efficient preparative tool to elucidate the structure of complex marine exopolysaccharides for biotechnology purposes (The L6 exopolysaccharide of the study is one of them). The best tools we found were carbohydrate active enzymes (CAZymes) from marine phages. With Anne-Claire Baudoux, we decided to run over of the biotechnological scope and explore what could be the ecological implications of such enzymatic activitiI guees from an ecological point of view. We were not disappointed…
This story perfectly illustrates how it’s important to get out of our own comfort zone and take a look at other areas of the same discipline. I was a « simple » biotechnologist (and still, visit my lab page: www.leoviridis.fr We do great things, particularly with phages !), and now I’m some kind of hybrid researcher. Thank to this, I can feed my research with an extended scientific horizon, which often simplify things when a blocking point appears.”
What do you see as the next steps in this area of research?
The field of possibilities is enormous whether in biogeochemistry or biochemistry. One simple thing could be to evaluate the impact of viral polysaccharidases on the bioavailability of depolymerized EPS as a carbon source. But many other approaches are possible. We need to know more about these enzymes which don’t match so much with other polysaccharidases in databases. They must be finely characterized. Polysaccharides, and especially exopolysaccharides (EPS), are highly reactive secondary metabolites. For example, they exhibit great chelation properties with trace metal elements.
What could be the impact of the viral mediated depolymerization of polysaccharides on the chelative properties or bioavailability of such trace elements? Considering HNLC (High Nutrient, Low Chlorophyll) regions of the global ocean where iron is the main limiting element for the primary productivity (e.g. Southern Ocean), implications seem to be important. With Anne-Claire Baudoux, we are currently working on these topics (publications in progress). To conclude, we hope that our paper will encourage marine microbiologists and biogeochemists communities to explore with us this promising story of marine viral CAZymes.”
Read the 2019 award winning paper: Viral degradation of marine bacterial exopolysaccharides.