Titel: The meiotic progression of Arabidopsis thaliana under elevated temperatures and towards an understanding of translational control in plant meiosis
Sprache: Englisch
Autor*in: De Jaeger-Braet, Joke
Erscheinungsdatum: 2021-10
Tag der mündlichen Prüfung: 2022-01-21
Zusammenfassung: 
Plant growth and fertility strongly depend on environmental conditions and previous work has demonstrated that meiosis is highly sensitive to temperature changes. To counteract the detrimental effects of high temperatures and adjust breeding programs, it is vital to comprehend the changes imposed by heat stress on yield-related traits at a cellular and molecular level. Thus, to better understand the impact of temperature on meiosis, I followed male meiocytes in Arabidopsis thaliana under three different temperature conditions using live cell imaging. This work led to a cytological framework of meiotic progression at elevated temperatures. A sudden increase to 34 C leads to a faster overall progression of meiosis compared to 21 C. However, the phase in which cross-overs mature is prolonged at 34 C and I could further show that this delay is recombination-dependent, since mutants in genes involved in meiotic recombination proceed faster through this phase at 34 C than wild type. Further analysis revealed that the DNA damage sensor kinase ATM is also involved in this heat stress induced prolongation, indicating the existence of a previously unrecognised pachytene checkpoint in plants.
Recent studies in yeast revealed that translational regulation is crucial in the control of protein abundance during meiosis. However, little is known about meiotic gene regulation at translational level in plants. To bridge this gap, I aimed at revealing evidence for meiotic translational control in dicotyledonous and monocotyledonous species, Arabidopsis thaliana and Zea mays, respectively. To this end, transcriptome and translatome analysis using isolated maize reproductive organs, i.e. spikelets and anthers, were conducted. This resulted in the establishment of a functional protocol to perform RNA-sequencing and ribosome profiling from these tissues and led to the discovery that whole anthers have distinct transcriptomes and translatomes at defined meiotic time points. Preliminary results of the first sequencing analysis suggest that several meiotic genes undergo translational regulation, as their mRNA levels and translation profiles significantly differ. In addition, to visualize temporal differences between the onset of transcription and translation at a cellular level in Arabidopsis thaliana, the meiotic genes ASY3, TAM and REC8 were analyzed using fluorescent mRNA and protein reporter based systems, i.e. MS2-system and TRICK. While these methods have been used in several species, they appear to be challenging for studying translational regulation during meiosis in Arabidopsis thaliana. However, a careful analysis of the encountered problems was carried out, which facilitates how and where this strategy can be used for future research.
URL: https://ediss.sub.uni-hamburg.de/handle/ediss/9471
URN: urn:nbn:de:gbv:18-ediss-98773
Dokumenttyp: Dissertation
Betreuer*in: Schnittger, Arp
Enthalten in den Sammlungen:Elektronische Dissertationen und Habilitationen

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