Funktionelle Analyse des Hypoxie-induzierbaren Transkriptionsfaktors AtLBD41 und seiner Homologe
Zusammenfassung der Projektergebnisse
In times of climate change, severe weather conditions strongly impact crop cultures as well as ecosystems. Besides prolonged drought periods, also heavy rainfall and the subsequent soil flooding lead to drastic reductions in crop yield. Although the knowledge on acclimation responses of plants to flooding and low-oxygen stress and their regulation is increasing from year to year, there are still many open questions. In this project, one of the most highly induced transcriptional regulators under hypoxia, LBD41, was analyzed in the model plant Arabidopsis thaliana. With the help of different experimental approaches, several putative target genes of this transcriptional repressor and its two homologs, LBD40 and LBD42, were identified. However, a general and clear function could not be associated with these target genes. Overexpression and knockout lines were created and characterized at the biochemical and molecular level. These experiments did not reveal obvious phenotypes that were associated with the lack or enhancement of LBD41 protein levels. Three hypotheses have been developed as a basis for future experiments. (1) LBD41 has no important function in plants under hypoxic stress; (2) in sensitive Arabidopsis plants, this protein is not produced under hypoxia due to lack of energy; (3) the knockout lines produced a truncated, but still partially functional protein. A predicted post-translational regulation by SUMOylation was demonstrated, but so far no evidence could be presented that this SUMOylation has a biological function in plants under hypoxia. Therefore, more experiments and additional transgenic lines are needed to decipher the function of LBD41.
