A role for UV-B -induced DNA damage in photomorphogenic responses in etiolated Arabidopsis seedlings
2014-01
Loading...
View/Download File
Persistent link to this item
Statistics
View StatisticsJournal Title
Journal ISSN
Volume Title
Title
A role for UV-B -induced DNA damage in photomorphogenic responses in etiolated Arabidopsis seedlings
Authors
Published Date
2014-01
Publisher
Type
Thesis or Dissertation
Abstract
Ultraviolet (UV) radiation is a constituent of sunlight that influences plant morphology and growth. It induces photomorphogenic responses but also causes damage to DNA. Plant responses to DNA damage caused by UV-B light are often categorized as general mechanisms that get activated by other environmental stresses. Photodimers are formed through the direct absorption of UV-B light by DNA and are removed, in part, by nucleotide excision repair (NER). UV-B irradiation resulted in the accumulation of the two most common photodimers, cyclobutane pyrimidine dimers (CPDs) and pyrimidine-(6,4)-pyrimidinone dimers (6,4PPs), in etiolated wild type (wt) <italic>Arabidopsis</italic> seedlings. <italic>Arabidopsis</italic> mutants of the endonucleases that function in NER, <italic>xpf-3</italic> and <italic>uvr1-1</italic>, show hypersensitivity to UV-B (280-320 nm) in terms of hypocotyl growth inhibition. I hypothesized that the accumulation of UV-B-induced photodimers was responsible for the hypocotyl growth phenotype of these NER mutants after UV-B irradiation. It was also predicted that the accumulation of photodimers could ultimately trigger signaling pathways that result in cell-cycle arrest through stalled replication sites or double-strand breaks. This was tested using the <italic><underline>s</underline>uppressor <underline>o</underline>f <underline>g</underline>amma 1</italic> (<italic>sog1-1</italic>) mutant, which lacks a transcription factor responsible for gene induction and cell-cycle arrest after gamma irradiation, and a Col-0 line containing a CYCB1;1-GUS reporter construct. <italic>CYCB1;1</italic> encodes a cyclin that accumulates in response to cell-cycle arrest at the G2/M transition. The main conclusion from this work is that hypocotyl growth inhibition induced by UV-B light in etiolated <italic>Arabidopsis</italic> seedlings, which is a classic photomorphogenic response, is influenced by signals originating from UV-B light absorption by DNA that lead to cell-cycle arrest. Furthermore, this process is shown to occur independently of <italic>UVR8</italic> and its signaling pathway responsible for <italic>CHS</italic> induction. This work also demonstrates that UV-B-induced DNA damage can be responsible for specific photomorphogenic responses, at least in etiolated <italic>Arabidopsis</italic> seedlings, and does not simply induce general stress responses.
Description
University of Minnesota Ph.D. dissertation. January 2014. Major: Plant Biological Sciences. Advisor: Gary M. Gardner. 1 computer file (PDF); ix, 77 pages, appendices A-B.
Related to
Replaces
License
Collections
Series/Report Number
Funding information
Isbn identifier
Doi identifier
Previously Published Citation
Suggested citation
Biever, Jessica Jo. (2014). A role for UV-B -induced DNA damage in photomorphogenic responses in etiolated Arabidopsis seedlings. Retrieved from the University Digital Conservancy, https://hdl.handle.net/11299/162630.
Content distributed via the University Digital Conservancy may be subject to additional license and use restrictions applied by the depositor. By using these files, users agree to the Terms of Use. Materials in the UDC may contain content that is disturbing and/or harmful. For more information, please see our statement on harmful content in digital repositories.