PRDA1, a novel chloroplast nucleoid protein, is required for early chloroplast development and is involved in the regulation of plastid gene expression in Arabidopsis

Plant Cell Physiol. 2013 Dec;54(12):2071-84. doi: 10.1093/pcp/pct148. Epub 2013 Oct 15.

Abstract

Chloroplast development requires accurate spatio-temporal expression of plastid genes. The regulation of plastid genes mediated by plastid-encoded RNA polymerase (PEP) is rather complex, and its related mechanism remains largely unclear. Here, we report the identification of a novel protein that is essential for plant development, PEP-Related Development Arrested 1 (PRDA1). Knock-out of PRDA1 in Arabidopsis (prda1 mutant) caused a seedling-lethal, albino phenotype and arrested the development of leaf chloroplasts. Localization analysis showed that PRDA1 was specifically targeted to chloroplasts and co-localized with chloroplast nucleoids, revealing that PRDA1 is a chloroplast nucleoid-associated protein. Gene expression analyses revealed that the PEP-dependent plastid transcript levels were greatly reduced in prda1. PRDA1 was co-expressed with most of the PEP-associated proteins. Protein interaction assays showed that PRDA1 clearly interacts with MRL7 and FSD2, both of which have been verified as essential for PEP-related chloroplast development. Reactive oxygen species scavenging through dimethylthiourea markedly alleviated the cotyledon-albino phenotypes of PRDA1 and MRL7 RNA interference seedlings. These results demonstrate that PRDA1 is required for early chloroplast development and involved in the regulation of plastid gene expression.

Keywords: Chloroplast; FSD2; MRL7; PEP; PRDA1; Plastid gene expression.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arabidopsis / genetics
  • Arabidopsis / metabolism*
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / metabolism
  • Chloroplasts / genetics
  • Chloroplasts / metabolism*
  • Plastids / metabolism*
  • RNA Interference
  • Seedlings / metabolism*
  • Thioredoxins / genetics
  • Thioredoxins / metabolism

Substances

  • Arabidopsis Proteins
  • At4g28590 protein, Arabidopsis
  • Thioredoxins