Role of mRNA export in plant tolerance to abiotic stress conditions

• Applicant: Professor Dr. Klaus Grasser
• Subject Area: Plant Biochemistry and Biophysics ; Plant Genetics and Genomics ; Plant Cell and Developmental Biology
• Term: since 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 551150998

In eukaryotic organisms, protein-coding genes are transcribed by RNA polymerase II in the cell nucleus. The freshly synthesised pre-mRNAs are extensively processed by 5´-end capping, splicing and 3´-end cleavage/polyadenylation. Before mature mRNAs can be translated into protein in the cytosol, they must be exported from the nucleus through nuclear pore complexes. Nucleocytosolic transport is directed by various export factors (EFs) that bind the mRNAs to initiate the formation of export-competent ribonucleoprotein particles. A critical role at this process is performed by the TREX complex that links transcription and mRNA export. In recent years, several EFs have been characterised in the model plant Arabidopsis, demonstrating that impaired mRNA export causes defects in growth and development. Moreover, it became apparent that RNA-binding EFs are rather diversified in plants. In preliminary work, we have recently started exploring the involvement of EFs in plant responses to environmental cues, which hitherto has been hardly investigated. Our analyses so far reveal that compared to controls, mutant plants deficient in certain EFs exhibited distinct defects in their response to stressful conditions. Transcriptional reprogramming induced by stress conditions can only become biologically effective, if the synthesised mRNAs were efficiently exported to the cytosol for translation. However, it appears that under challenging conditions impaired nucleocytosolic transport of mRNAs has particularly adverse effects. Therefore, we propose provoking the potential of the mRNA export machinery by environmental stress as a tool to study the functionality of EFs in a meaningful biological context. We intend to assay mutants deficient in various EFs upon exposure to a set of stress conditions (e.g. heat, drought) to learn more about the molecular functionality of EFs as well as their contribution to plant stress tolerance. Beyond that our study will complement a more complete understanding of plant responses to environmental stress, which is also relevant in the light of progressing climate change.

• DFG Programme: Research Grants