PhD defence by Alessandro Giannetti

RNA molecule

The Role of Micro RNAs in regulating Secondary Cell Wall Synthesis and Lignification in the Model Plant Arabidopsis thaliana

Micro RNAs (miRNAs) are small non-coding RNAs that play crucial roles in post-transcriptional regulation and are thought involved in numerous biological processes, including the regulation of secondary cell wall (SCW) synthesis. However, the precise function of miRNAs in this process remains elusive. This study focuses on the role of copper miRNAs (Cu-miRNAs) in the regulation of lignification and SCW biosynthesis. Here, a tissue-specific knockout (TSKO) of the miRNA-processing protein DCL1, targeting SCW-related cell types, was employed to elucidate the specific roles of this gene during SCW synthesis. Phenotypic alterations from these constructs are presented. Furthermore, the expression of specific miRNAs that are induced during SCW synthesis, and related to lignin synthesis, was targeted using Short Tandem Target Mimics (STTMs), and the resulting phenotypes are illustrated. Lastly, qPCR on the mutant lines was used to check the expression profiles of SCW related genes, mainly focusing on lignin biosynthesis. Overall, this study aims to explore the functions of Cu-miRNAs and DCL1 in the control of lignification and SCW production in Arabidopsis. By unraveling the regulatory roles of Cu-miRNAs and DCL1, this study lays the groundwork for potential novel approaches in lignin modification.

Supervisors

Professor Staffan Persson, PLEN

Assessment Committee

Professor Wout Boerjan, VIB Ghent, University of Ghent

Associate Professor Ulf Andersson Vang Ørum, Aarhus University

Associate Professor Bent L Petersen, PLEN (Chair)