Paper accepted: “Transcriptomics reveal a mechanism of niche defense: two beneficial root endophytes deploy a host-protective antimicrobial GH18-CBM5 chitinase”

Today, Ruben Eichfeld’s paper describing how a fungal endophyte of plant roots influences the interaction of the roots with the rhizosphere microbiome as well as with a fungal pathogen, was accepted for publication in the renowned journal “New Phytologist”. Ruben had done his Bachelor thesis with us before joining Dr. Alga Zuccaro’s team at the University of Cologne as a PhD candidate. Thus, when he found that the endophyte secretes an unusual chitinase which appears to be important for its complex interactions, he knew that he would find the experts to more deeply characterize this enzyme - Margareta Hellmann and Dr. Stefan Cord-Landwehr - in our group. Ruben spent some time in Münster last year to perform these analyses, using our newly developed one-step technique for the characterization of chitosan hydrolases. What makes this chitinase special is the unusual presence of a CBM5 chitin binding domain. Ruben was able to show that this chitinase, which is induced in the endophyte by the presence of the pathogen, has antimicrobial properties, reducing growth of the pathogenic fungus and protecting the plant roots from infection. Clearly, this enzyme plays a crucial role in the endophyte’s support of the plant’s immune system - suggesting ways to exploit the enzyme for sustainable plant protection. But one mystery remains: How does the endophytic fungus protects its own chitinous cell wall from the action of the chitinase? Does the CBM5 domain come into play here? Or does the endophyte use the chemical camouflage strategy to convert its chitin into chitosan? As always: one question answered, more questions to be answered!