Deciphering how miRNAs control cluster root development in white lupin – MicroLUP

White lupin can form cluster roots as an adaptation to low phosphate, allowing an efficient acquisition of this fundamental nutrient for plant growth. Transferring this ability to other crops would help sparing the limited stocks of phosphorus. Indeed, experts predict that massive use of fertilizers will lead to an exhaustion of rock phosphorus stocks in the coming decades. In order to better understand the molecular mechanisms controlling cluster root formation, the MicroLUP project will study the role of microRNAs during the development of this organ. The project gathers a consortium of 3 partners including the team of Benjamin Péret (Scientific coordinator – root development specialist – B&PMP unit), Martin Crespi (miRNA specialist – IPS2 unit) and Adnane Boualem (TILLING platform – IPS2). Based on preliminary data and analysis, we have identified potential miRNAs targeting known genes, including transcription factors from the GRAS family. The MicroLUP project will analyse and create gene/miRNA networks supported by the study of organ-deregulated mutants (identified by Partner 1) to help selecting regulatory miRNA candidates involved in cluster root formation (Partner 2). Functional analysis of these candidates will be performed in planta using transient transformation, expression studies and mutant production (Partner 1). In parallel, the generation of a TILLING population using EMS-mutagenized seeds produced by Partner 1 will be amplified and screened to find additional white lupin mutants (Partner 3). This project will combine the development of gene regulatory networks involving miRNAs and their target genes and the generation of genetic resources through TILLING that can be used to improve our understanding of cluster root development as well as for field applications. We predict that MICROLUP will open wide perspectives to improve other crop root systems through translational biology in the future.