Approaching the function of a Lipid transfer protein and various miRNAs in the formation of the Arabidopsis root periderm
ENG- This thesis aims to explore the two knowledge gaps exposed above. First, we identified a gene that codes for an LTP, which was overexpressed in phellem and other suberized structures of different plant species. To characterize this LTP we analysed Arabidopsis mutants deficient in this gene. The...
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| Tipo de recurso: | tesis doctoral |
| Estado: | Versión publicada |
| Fecha de publicación: | 2025 |
| País: | España |
| Institución: | CBUC, CESCA |
| Repositorio: | TDR. Tesis Doctorales en Red |
| OAI Identifier: | oai:www.tdx.cat:10803/695441 |
| Acceso en línea: | http://hdl.handle.net/10803/695441 |
| Access Level: | acceso embargado |
| Palabra clave: | Suberina Suberin Arrel Raiz Root Periderma Periderm LTP miRNA Arabidopsis Fel·lema Felema Phellem 58 |
| Sumario: | ENG- This thesis aims to explore the two knowledge gaps exposed above. First, we identified a gene that codes for an LTP, which was overexpressed in phellem and other suberized structures of different plant species. To characterize this LTP we analysed Arabidopsis mutants deficient in this gene. The root suberized tissues of these mutants showed a high and specific reduction of alkyl caffeates in suberin-associated waxes indicating that the LTP is required to deposit these compounds in the su-berized root tissues. We also observed a slight but increased permeability of the mutant seeds, in agreement with defects in their outer suberized seed coat. Unexpectedly, these mutant plants showed a variable but sometimes higher resistance to Ralstonia solanacearum, a pathogen that ini-tially colonizes the root. Although unexpected, this interesting result might indicate some metabolic rerouting and needs further assessment. Overall, while further research is needed, these results high-light the relationship between LTP and suberized tissues. Second, we identified the most relevant miRNA by comparing the miRNA expression profile of Quer-cus spp. barks exhibiting different kinds of periderm. Specifically, we classified them in cork-type barks and rhytidome-type barks, the former showing a thick and unique periderm consisting of sev-eral layers, and the latter showing several thin periderms mixed with other tissues. We selected a subset of miRNAs upregulated in cork-type barks and we identified their Arabidopsis orthologues. The promoters of some of these miRNAs were active in Arabidopsis root periderm. To uncover the molecular role of these miRNAs, we generated Arabidopsis plants specifically engineered to se-quester and block the activity of selected miRNAs in tissues involved in periderm formation or in the periderm itself. Some developmental defects were observed, particularly when secondary growth was stimulated by phytohormones. However, the results showed variability, and the effects were relatively modest. In summary, these results provide a set of candidate miRNAs for periderm for-mation and set the basis for the systematic characterization of miRNAs in the Arabidopsis root peri-derm |
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