title: PRDA1, a novel chloroplast nucleoid protein, is required for early chloroplast development and is involved in the regulation of plastid gene expression in Arabidopsis.
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.
authors.affiliation: National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070, China.
authors.forename: Jiangwei
authors.initials: J
authors.lastname: Qiao
authors.forename: Jun
authors.initials: J
authors.lastname: Li
authors.forename: Wen
authors.initials: W
authors.lastname: Chu
authors.forename: Meizhong
authors.initials: M
authors.lastname: Luo
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D002736:Chloroplasts / Q000235:genetics / Q000378:metabolism*; D018087:Plastids / Q000378:metabolism*; D034622:RNA Interference; D036226:Seedlings / Q000378:metabolism*; D013879:Thioredoxins / Q000235:genetics / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; C000589129:At4g28590 protein, Arabidopsis; D013879:Thioredoxins
keywords: Chloroplast; FSD2; MRL7; PEP; PRDA1; Plastid gene expression