Paper accepted: “The non-sulfated ulvanobiuronic acid of ulvans is the smallest active unit able to induce an oxidative burst in dicot cells”

Today, a manuscript from our former doctoral candidates Roberta Paulert and Rebecca Melcher has finally been accepted for publication in the journal “Carbohydrate Polymers”. The first part of the work reported was already done ten years ago, towards the end of Roberta’s doctoral project. Over the years, the manuscript grew, with NMR and MS data from our postdocs Dr. Fabrice Brunel and Dr. Stefan Cord-Landwehr, MS with support from our doctoral candidate Anna Niehues and Dr. Michael Mormann from the Institute for Hygiene of our university. We submitted it once, years ago, but then had nobody to perform the final experiments requested by the referees until Roberta returned for a few months last year. This allowed her to finalize everything and resubmit, and after another round of peer review and re-submission, it is now going to print. In this paper, we describe the depoylmerization of the complex, highly sulfated green algal cell wall polysaccharide ulvan into small oligomers, their separation and characterization, and finally the determination of their elicitor activities in different plant species. Surprisingly, oligomers as small as the dimer building block of ulvan are still elicitor-active, not even requiring any sulfation. This raises the possibility to use this small molecule as a biopesticide inducing the plant’s immune system. We had shown in the past that this works with the ulvan polymer, but the dimer would be much easier to formulate into an agro-biologic product.