Host: Professor Brande Wulff

Abstract:  
The execution of developmental programs requires genetic control exerted both at transcriptional and post-transcriptional levels. Two key mechanisms of post-transcriptional gene regulation involve small non-coding RNAs and mRNA methylation. Small non-coding RNAs are produced by DICER-LIKE ribonucleases and act to program RNA Induced Silencing Complexes to repress complementary mRNAs. In addition to its key role in developmental control, the small RNA machinery is essential for basal antiviral defense that requires the DICER-LIKE ribonucleases DCL2 and DCL4 in higher plants. mRNA methylation acts by generating binding sites for specialized RNA binding proteins that stimulate cell division in organ primordia in largely unknown ways. Viral RNA can also be methylated and can serve to limit viral infectivity. I will discuss evidence that advances our understanding of how both post-transcriptional regulatory systems work in the crossroads of growth and defense regulation. Particular focus will be given to evidence indicating that basal antiviral defense mediated by DICER-LIKE proteins is brought about by combining direct small RNA-mediated targeting of viral RNA with sensing of double-stranded RNA to switch on innate immune responses. I will also discuss our advances on understanding the principles underlying RNA-methylation-dependent basal antiviral defense in plants.

BIO: 
Principal investigator at the University of Copenhagen, Denmark, since 2011, full professor since 2020. Research focus on gene regulation via small non-coding RNAs and covalent mRNA modifications in plants, including links to control of the innate immune system. Post doctoral researcher and senior scientist at the Institut de Biologie Moléculaire des Plantes du CNRS, Strasbourg, France, 2004-2010. Research focus on mechanisms of microRNA function in plants.