Plastid Deficient 1 Is Essential for the Accumulation of Plastid-Encoded RNA Polymerase Core Subunit β and Chloroplast Development in <i>Arabidopsis</i>
Plastid-encoded RNA polymerase (PEP)-dependent transcription is an essential process for chloroplast development and plant growth. It is a complex event that is regulated by numerous nuclear-encoded proteins. In order to elucidate the complex regulation mechanism of PEP activity, identification and...
| Main Authors: | , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2021-12-01
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| Series: | International Journal of Molecular Sciences |
| Subjects: | |
| Online Access: | https://www.mdpi.com/1422-0067/22/24/13648 |
| Summary: | Plastid-encoded RNA polymerase (PEP)-dependent transcription is an essential process for chloroplast development and plant growth. It is a complex event that is regulated by numerous nuclear-encoded proteins. In order to elucidate the complex regulation mechanism of PEP activity, identification and characterization of PEP activity regulation factors are needed. Here, we characterize Plastid Deficient 1 (PD1) as a novel regulator for PEP-dependent gene expression and chloroplast development in <i>Arabidopsis</i>. The <i>PD1</i> gene encodes a protein that is conserved in photoautotrophic organisms. The <i>Arabidopsis</i> <i>pd1</i> mutant showed albino and seedling-lethal phenotypes. The plastid development in the <i>pd1</i> mutant was arrested. The PD1 protein localized in the chloroplasts, and it colocalized with nucleoid protein TRXz. RT-quantitative real-time PCR, northern blot, and run-on analyses indicated that the PEP-dependent transcription in the <i>pd1</i> mutant was dramatically impaired, whereas the nuclear-encoded RNA polymerase-dependent transcription was up-regulated. The yeast two-hybrid assays and coimmunoprecipitation experiments showed that the PD1 protein interacts with PEP core subunit β (PEP-β), which has been verified to be essential for chloroplast development. The immunoblot analysis indicated that the accumulation of PEP-β was barely detected in the <i>pd1</i> mutant, whereas the accumulation of the other essential components of the PEP complex, such as core subunits α and β′, were not affected in the <i>pd1</i> mutant. These observations suggested that the PD1 protein is essential for the accumulation of PEP-β and chloroplast development in <i>Arabidopsis</i>, potentially by direct interaction with PEP-β. |
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| ISSN: | 1661-6596 1422-0067 |