Title: Windows of Opportunity: Developmental Niches and Epigenetic Control of Transposon Transmission

Speaker: Dr. Leandro QuadranaInstitute of Plant Science. University Paris-Saclay, CNRS, France

Abstract: 
Transposable elements (TEs) are mobile DNA sequences whose proliferation is normally restrained by epigenetic silencing, which in plants includes DNA methylation in different cytosine contexts as well as small RNA pathways. Yet how these defenses cooperate to prevent heritable mobilization, and when during development this control is most critical, remains poorly understood. 
Here, I will present our efforts using the model plant Arabidopsis thaliana to dissect how distinct DNA methylation pathways constrain germline transposition, and I will show that TE mobilization is developmentally structured, with specific TE families concentrating transposition in defined cellular niches linked to germline differentiation and reproduction. I will discuss how these families hijack these windows to achieve successful proliferation, and the implications of such developmentally focused mobilization preferences for TE fitness, including their capacity to spread and invade across natural populations under ongoing host repression.