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 language | English |
|---|---|
| Pages (from-to) | 124-132 |
| Number of pages | 9 |
| Journal | Plant Journal |
| Volume | 52 |
| Issue number | 1 |
| DOIs | |
| Publication status | Published - 2007 Oct |
| Externally published | Yes |
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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 journal › Article
}
TY - JOUR
T1 - The plastid sigma factor SIG1 maintains photosystem I activity via regulated expression of the psaA operon in rice chloroplasts
AU - Tozawa, Yuzuru
AU - Teraishi, Masayoshi
AU - Sasaki, Tadamasa
AU - Sonoike, Kintake
AU - Nishiyama, Yoshitaka
AU - Itaya, Mitsuhiro
AU - Miyao, Akio
AU - Hirochika, Hirohiko
PY - 2007/10
Y1 - 2007/10
N2 - 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.
AB - 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.
KW - Chloroplast
KW - Photosystem I
KW - Rice
KW - RNA polymerase
KW - Sigma factor
KW - Transcription
UR - http://www.scopus.com/inward/record.url?scp=34748918975&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=34748918975&partnerID=8YFLogxK
U2 - 10.1111/j.1365-313X.2007.03216.x
DO - 10.1111/j.1365-313X.2007.03216.x
M3 - Article
VL - 52
SP - 124
EP - 132
JO - Plant Journal
JF - Plant Journal
SN - 0960-7412
IS - 1
ER -