Identifiction of signaling components in the response to excess light in Arabidopsis thaliana
Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
Even though light is essential for photosynthesis, it can also cause oxidative stress if theplant is exposed to high irradiances. Excess light results in redox changes in the chloroplastwhich can be sensed in order to mediate the information to the nucleus and adapt nucleargene expression. However, little is known about the mechanisms behind the redox sensingand light adaptive response. To investigate components involved in these pathways, twodifferent approaches were used in this study: a biochemical analysis of the transcriptionfactor bZIP16 and characterization of redox insensitive mutants isolated by a forwardgenetics approach. bZIP16 was confirmed by EMSA to interact with the G-box cis elementwhich is present in the promoters of redox/high light regulated genes, and a bZIP16:CFPfusion protein was shown to be localized to the nucleus. Characterization of the redoxinsensitive mutant rin5 revealed that these plants were unable to sense the redox changesassociated with high light exposure and adjust expression of LHCB. These results indicatethat the RI5 protein is a putative sensor of the redox changes in the chloroplast and acomponent in the signaling pathway to mediate information about light intensity to thenucleus. The bZIP16 is localized in the nucleus and binds to the G-box present in thepromoter of LHCB and possibly bZIP16 responds to the RI5 mediated plastid signal.
Place, publisher, year, edition, pages
2010. , 34 p.
IdentifiersURN: urn:nbn:se:umu:diva-36821OAI: oai:DiVA.org:umu-36821DiVA: diva2:356440
2010-06-22, KBF30, UPSC, Umeå, 10:00 (English)
UppsokLife Earth Science
Strand, Åsa, Univ lekt