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Oryza sativa ObgC1 Acts as a Key Regulator of DNA Replication and Ribosome Biogenesis in Chloroplast Nucleoids

Authors :
Ji Chen
Li Wang
Xiaowan Jin
Jian Wan
Lang Zhang
Byoung Il Je
Ke Zhao
Fanlei Kong
Jin Huang
Mengliang Tian
Source :
Rice, Vol 14, Iss 1, Pp 1-18 (2021)
Publication Year :
2021
Publisher :
SpringerOpen, 2021.

Abstract

Abstract Background The Spo0B-associated GTP-binding protein (Obg) GTPase, has diverse and important functions in bacteria, including morphological development, DNA replication and ribosome maturation. Homologs of the Bacillus subtilis Obg have been also found in chloroplast of Oryza sativa, but their primary roles remain unknown. Results We clarify that OsObgC1 is a functional homolog of AtObgC. The mutant obgc1-d1 exhibited hypersensitivity to the DNA replication inhibitor hydroxyurea. Quantitative PCR results showed that the ratio of chloroplast DNA to nuclear DNA in the mutants was higher than that of the wild-type plants. After DAPI staining, OsObgC1 mutants showed abnormal nucleoid architectures. The specific punctate staining pattern of OsObgC1-GFP signal suggests that this protein localizes to the chloroplast nucleoids. Furthermore, loss-of-function mutation in OsObgC1 led to a severe suppression of protein biosynthesis by affecting plastid rRNA processing. It was also demonstrated through rRNA profiling that plastid rRNA processing was decreased in obgc1-d mutants, which resulted in impaired ribosome biogenesis. The sucrose density gradient profiles revealed a defective chloroplast ribosome maturation of obgc1-d1 mutants. Conclusion Our findings here indicate that the OsObgC1 retains the evolutionarily biological conserved roles of prokaryotic Obg, which acts as a signaling hub that regulates DNA replication and ribosome biogenesis in chloroplast nucleoids.

Details

Language :
English
ISSN :
19398425 and 19398433
Volume :
14
Issue :
1
Database :
Directory of Open Access Journals
Journal :
Rice
Publication Type :
Academic Journal
Accession number :
edsdoj.6fd13146e5c04af18c7dfc32689ba023
Document Type :
article
Full Text :
https://doi.org/10.1186/s12284-021-00498-5