The Pentratricopeptide Repeat Protein Pigment-Defective Mutant2 is Involved in the Regulation of Chloroplast Development and Chloroplast Gene Expression in Arabidopsis.
The development of functional chloroplasts, which is assisted by a series of nuclear-encoded auxiliary protein factors, is essential for plant autotrophic growth and development. To understand the molecular mechanisms underlying chloroplast development, we isolated and characterized a pigment-defective mutant, pdm2, and its corresponding variegated RNA interference (RNAi) lines in Arabidopsis. Sequence analysis revealed that PDM2 encodes a pentatricopeptide repeat protein that belongs to the P subgroup. Confocal microscopic analysis and immunoblotting of the chloroplast protein fraction showed that PDM2 was located in the stroma. In RNAi plants, protein-related photosynthesis was severely compromised. Furthermore, analysis of the transcript profile of chloroplast genes revealed that plastid-encoded polymerase-dependent transcript levels were markedly reduced, while nuclear-encoded polymerase-dependent transcript levels were increased, in RNAi plants. In addition, PDM2 affects plastid RNA editing efficiency in most editing sites, apparently by directly interacting with multiple organellar RNA editing factor 2 (MORF2) and MORF9. Thus, our results demonstrate that PDM2 is probably involved in the regulation of plastid gene expression required for normal chloroplast development.
College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, China.
Liang
L
Du
College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, China.
Jian
J
Zhang
College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, China.
Shaofeng
S
Qu
College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, China.
Yuanyuan
Y
Zhao
College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, China.
Bodan
B
Su
College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, China.
Xueqin
X
Lv
College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, China.
Ruili
R
Li
College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, China.
Yinglang
Y
Wan
College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, China.
Jianwei
J
Xiao
D017360:Arabidopsis / Q000235:genetics / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D002736:Chloroplasts / Q000235:genetics* / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D055785:Gene Knockdown Techniques; D061125:Genes, Chloroplast; D009154:Mutation; D030821:Plants, Genetically Modified; D018087:Plastids / Q000235:genetics; D017393:RNA Editing; D012639:Seeds / Q000235:genetics
D029681:Arabidopsis Proteins; C000623408:PDM2 protein, Arabidopsis
Arabidopsis; Chloroplast; Development; Pentatricopeptide repeat protein; Pigment-Defective Mutant2