This Week’s Discoveries | 2 April 2019
- Tuesday 2 April 2019
Niels Bohrweg 2
2333 CA Leiden
- De Sitterzaal
Unlocking the secrets of disease-suppressive soils
Víctor J. Carrión (IBL) obtained his PhD at the University of Málaga followed by postdocs at Wageningen University and The Netherlands Institute of Ecology. Currently, he is postdoctoral researcher at the Institute of Biology.
His research interest is to understand how microorganisms and plants interact and communicate to each other. More specifically, he uses “omics” approaches to study the diversity and functions of microorganisms associated with plants that suffer from emerging diseases
Microorganisms living inside plant tissues can promote plant growth and health, but their genomic diversity and functional potential remains largely elusive. Here, metagenomics of the endosphere microbiome of plants grown in soil naturally suppressive to infections by the fungal root pathogen Rhizoctonia solani, revealed specialized, novel metabolic diversity of 730 biosynthetic gene clusters and enrichment of Chitinophagaceae and Flavobacteriaceae. Following metagenomic reconstruction of multiple endophytic bacterial genomes and network analysis, bioassays showed that chitinase and novel NRPS and PKS genes were only activated in these endophytic bacterial families upon pathogen challenge and that disease was only suppressed by a consortium of these two families. Feeding endophytic Flavobacterium with N-acetylglucosamine, a degradation product of fungal chitin, triggered the expression of a specific NRPS-PKS hybrid gene cluster and restricted fungal growth. We conclude that endosphere microbiomes harbor a wealth of novel functional traits that, in concert, can protect the plant inside out.
A novel scanning tunneling microscope to visualize quantum mechanical waves
Irene Battisti (LION) is a PhD candidate at the Leiden Institute of Physics (LION). She is about to finish her PhD in experimental condensed-matter physics in the group of Milan Allan. During her PhD, she developed a novel, ultra-stiff scanning tunneling microscope and she studied the electronic properties of quantum materials such as iridates and cuprate unconventional superconductors.
Spectroscopic-imaging scanning tunneling microscopy can visualize the electronic properties of materials down to the atomic scales. Among other things, it enables the visualization of the wave functions of electrons that scatter off defects on the surface of a crystal.
Performing this type of measurement is not simple, and it requires the use of especially stable microscopes. In this talk, I will show how we developed and built a novel cryogenic scanning tunneling microscope that is one of the most stable in the world, and I will show examples of the type of measurements this microscope can perform.