Paper accepted: Transcriptome analysis of Solanum tuberosum genotype RH89-039-16 in response to chitosan

Today, Philipp Lemke’s paper describing our first transcriptomic analysis of chitosan-treated plants has been accepted for publication in the Journal “Frontiers in Plant Science”, with Prof. Bruno Moerschbacher as his supervisor and Dr. Ratna Singh as his mentor in bioinformatic analyses as co-authors. Given the multitude of papers describing biochemical and physiological responses of plants to treatments with chitosan, it is surprising how rarely modern transcriptomic tools such as RNAseq have been applied in this context. In fact, Philipp’s study is probably the first one conducted with a well-characterized chitosan which was applied at a low, physiologically and economically relevant dosage. Philipp had painstakingly prepared this study, with a series of preliminary experiments to define the best chitosan, the best concentration, the best application method, and the best harvesting times. We were expecting to see the induction of hundreds of genes like in previous studies performed with heavy amounts of poorly characterized bulk chitosan, but were surprised to find a rather specific up-regulation of just about one hundred genes. We were even more surprised that the vast majority of these were not primarily involved in plant disease defense, but rather in electron transport (“Elektronen sind wichtig!”), mostly in the chloroplast. We have a new working hypothesis now that these events are not only orchestrating the disease resistance reactions induced by chitosan treatment, but that these same events are also at the core of the chitosan-induced promotion of plant growth and development. We are indeed beginning to understand how chitosan can simultaneously trigger disease resistance and growth promotion – avoiding the infamous growth-resistance trade-off. More of this is to come!