The UV-B photoreceptor UVR8 promotes photosynthetic efficiency in Arabidopsis thaliana exposed to elevated levels of UV-B

Davey, Matthew and Susanti, Novata and Wargent, Jason and Findlay, Jane and Quick, Paul and Paul, Nigel and Jenkins, Gareth (2012) The UV-B photoreceptor UVR8 promotes photosynthetic efficiency in Arabidopsis thaliana exposed to elevated levels of UV-B. Photosynthesis Research, 114 (2). pp. 121-131. ISSN 0166-8595

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Abstract

The UV-B photoreceptor UVR8 regulates expression of genes in response to UV-B, some encoding chloroplast proteins, but the importance of UVR8 in maintaining photosynthetic competence is unknown. The maximum quantum yield of PSII (Fv/Fm) and the operating efficiency of PSII (ΦPSII) were measured in wild-type and uvr8 mutant Arabidopsis thaliana. The importance of specific UVR8-regulated genes in maintaining photosynthetic competence was examined using mutants. Both Fv/Fm and ΦPSII decreased when plants were exposed to elevated UV-B, in general more so in uvr8 mutant plants than wild-type. UV-B increased the level of psbD-BLRP (blue light responsive promoter) transcripts, encoding the PSII D2 protein. This increase was mediated by the UVR8-regulated chloroplast RNA polymerase sigma factor SIG5, but SIG5 was not required to maintain photosynthetic efficiency at elevated UV-B. Levels of the D1 protein of PSII decreased markedly when plants were exposed to elevated UV-B, but there was no significant difference between wild-type and uvr8 under conditions where the mutant showed increased photoinhibition. The results show that UVR8 promotes photosynthetic efficiency at elevated levels of UV-B. Loss of the DI polypeptide is probably important in causing photoinhibition, but does not entirely explain the reduced photosynthetic efficiency of the uvr8 mutant compared to wild-type.

Item Type:
Journal Article
Journal or Publication Title:
Photosynthesis Research
Uncontrolled Keywords:
/dk/atira/pure/subjectarea/asjc/1300/1307
Subjects:
ID Code:
61396
Deposited By:
Deposited On:
26 Dec 2012 14:33
Refereed?:
Yes
Published?:
Published
Last Modified:
01 Jan 2020 08:16