The Science
- What are the cellular bases of lateral root morphogenesis?
- What is the role played by small RNAs molecules in the regulation of lateral root growth?
Lateral root morphogenesis
The de novo formation of lateral roots (LRs) is an exquisite system to study the dynamics of 3D plant organ morphogenesis. LRs derive from a limited number of homogeneous founder cells that proliferate to form a primordium with stereotyped shape and tissue organisation. LR tissue organisation is similar to the one of the primary root which was specified during embryogenesis. In particular, a meristem is formed de novo which sustains the autonomous growth of the LR. Although the ontogeny of LRs has been described, how de novo pattern formation and outgrowth of LR is set up in an orthogonal axis to the original embryonic root axis remains an important question.
The lab uses light sheet fluorescence microscopy (LSFM) for live imaging of plant development in close-to-natural growth conditions and at the organ, cellular and sub-cellular scales. LSFM selectively illuminates a small portion of the specimen while collecting only the light emitted at the current focal resulting in lower phototoxicity and bleaching. LSFM has become increasingly popular in developmental studies as it provides detailed time-resolved information on the behaviour of all cells over the entire duration of the morphogenetic process. We study how TAS3 derived trans acting siRNAs (ta-siRNAs), a specific class of highly conserved small regulatory RNAs, can act in a non-cell autonomous manner to control root growth. TAS3 derived ta-siRNAs are produced by the initial ARGONAUTE7 (AGO7)/microRNA (miR390)-mediated cleavage of TAS3 RNAs which subsequently are processed by RDR6 to generate siRNAs. The ta-siRNA pathway is evolutionary ancient and has been implicated in several aspects of plant development including leaf patterning and root growth. The ta-siRNA pathway allows amplification of the effect of the miRNA and also of the propagation of its effects several cells away, as siRNA have been shown to be mobile. The laboratory is part of the Center for Organismal Studies of the University of Heidelberg. The lab is also a member of the Cluster of Excellence CellNetworks and has been created by endowments of the Schaller foundation and the Baden-Württemberg state. It is supported by grants from the Boehringer Ingelheim Foundation and the DFG. The lab is also part of the DFG Research Unit FOR2581 Quantitative Plant Morphodynamics.
RNA silencing and plant development
The Lab