PDM4, a Pentatricopeptide Repeat Protein, Affects Chloroplast Gene Expression and Chloroplast Development in Arabidopsis thaliana

Xinwei Wang; Lirong Zhao; Yi Man; Xiaojuan Li; Li Wang; Jianwei Xiao

doi:10.3389/fpls.2020.01198

PDM4, a Pentatricopeptide Repeat Protein, Affects Chloroplast Gene Expression and Chloroplast Development in Arabidopsis thaliana

Front Plant Sci. 2020 Aug 11:11:1198. doi: 10.3389/fpls.2020.01198. eCollection 2020.

Authors

Xinwei Wang^{1

2}, Lirong Zhao^{1

2}, Yi Man^{1

2}, Xiaojuan Li^{1

2}, Li Wang³, Jianwei Xiao^{1

2}

Affiliations

¹ Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing Forestry University, Beijing, China.
² College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing, China.
³ College of Horticulture and Plant Protection, Yangzhou University, Yangzhou, China.

Abstract

Extensive studies have been carried out on chloroplast gene expression and chloroplast development; however, the regulatory mechanism is still largely unknown. Here, we characterized Pigment-Defective Mutant4 (PDM4), a P-type PPR protein localized in chloroplast. The pdm4 mutant showed seedling-lethal and albino phenotype under heterotrophic growth conditions. Transmission electron microscopic analysis revealed that thylakoid structure was totally disrupted in pdm4 mutant and eventually led to the breakdown of chloroplasts. The levels of several chloroplast- and nuclear-encoded proteins are strongly reduced in pdm4 mutant. Besides, transcript profile analysis detected that, in pdm4 mutant, the expression of plastid-encoded RNA polymerase-dependent genes was markedly affected, and deviant chloroplast rRNA processing was also observed. In addition, we found that PDM4 functions in the splicing of group II introns and may also be involved in the assembly of the 50S ribosomal particle. Our results demonstrate that PDM4 plays an important role in chloroplast gene expression and chloroplast development in Arabidopsis.

Keywords: chloroplast; development; gene expression; pentatricopeptide repeat protein; pigment-defective mutant4.