The plastid sigma factor SIG1 maintains photosystem I activity via regulated expression of the psaA operon in rice chloroplasts

Yuzuru Tozawa, Masayoshi Teraishi, Tadamasa Sasaki, Kintake Sonoike, Yoshitaka Nishiyama, Mitsuhiro Itaya, Akio Miyao, Hirohiko Hirochika

Research output: Contribution to journalArticle

18 Citations (Scopus)

Abstract

Sigma factors encoded by the nucleus of plants confer promoter specificity on the bacterial-type RNA polymerase in chloroplasts. We previously showed that transcripts of OsSIG1, which encodes one such sigma factor in rice, accumulate relatively late during leaf development. We have now isolated and characterized two allelic mutants of OsSIG1, in which OsSIG1 is disrupted by insertion of the retrotransposon Tos17, in order to characterize the functions of OsSIG1. The OsSIG1-/- plants were found to be fertile but they manifested an approximately one-third reduction in the chlorophyll content of mature leaves. Quantitative RT-PCR and northern blot analyses of chloroplast gene expression revealed that the abundance of transcripts derived from the psaA operon was markedly reduced in OsSIG1-/- plants compared with that in wild-type homozygotes. This effect was accompanied by a reduction in the abundance of the core protein complex (PsaA-PsaB) of photosystem I. Analysis of chlorophyll fluorescence also revealed a substantial reduction in the rate of electron transfer from photosystem II to photosystem I in the OsSIG1 mutants. Our results thus indicate that OsSIG1 plays an important role in the maintenance of photosynthetic activity in mature chloroplasts of rice by regulating expression of chloroplast genes for components of photosystem I.

Original languageEnglish
Pages (from-to)124-132
Number of pages9
JournalPlant Journal
Volume52
Issue number1
DOIs
Publication statusPublished - 2007 Oct
Externally publishedYes

Fingerprint

sigma factors
Sigma Factor
Photosystem I Protein Complex
Plastids
photosystem I
operon
Chloroplasts
Operon
Chloroplast Genes
plastids
chloroplasts
Chlorophyll
rice
Bacterial RNA
Gene Components
Retroelements
Photosystem II Protein Complex
Homozygote
DNA-Directed RNA Polymerases
chlorophyll

Keywords

  • Chloroplast
  • Photosystem I
  • Rice
  • RNA polymerase
  • Sigma factor
  • Transcription

ASJC Scopus subject areas

  • Plant Science

Cite this

The plastid sigma factor SIG1 maintains photosystem I activity via regulated expression of the psaA operon in rice chloroplasts. / Tozawa, Yuzuru; Teraishi, Masayoshi; Sasaki, Tadamasa; Sonoike, Kintake; Nishiyama, Yoshitaka; Itaya, Mitsuhiro; Miyao, Akio; Hirochika, Hirohiko.

In: Plant Journal, Vol. 52, No. 1, 10.2007, p. 124-132.

Research output: Contribution to journalArticle

Tozawa, Yuzuru ; Teraishi, Masayoshi ; Sasaki, Tadamasa ; Sonoike, Kintake ; Nishiyama, Yoshitaka ; Itaya, Mitsuhiro ; Miyao, Akio ; Hirochika, Hirohiko. / The plastid sigma factor SIG1 maintains photosystem I activity via regulated expression of the psaA operon in rice chloroplasts. In: Plant Journal. 2007 ; Vol. 52, No. 1. pp. 124-132.
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