Arabidopsis Chloroplast protein for Growth and Fertility1 (CGF1) and CGF2 are essential for chloroplast development and female gametogenesis

Camellia sinensis cv. ‘Yanlingyinbiancha’ is a leaf-variegated mutant with stable genetic traits. The current study aimed to reveal the differences between its albino and green tissues, and the molecular mechanism underlying the variegation. Anatomic analysis showed the chloroplasts of albino tissues to have no intact lamellar structure. Photosynthetic pigment in albino tissues was significantly lower than that in green tissues, whereas all catechin components were more abundant in the former. Transcriptome analysis revealed most differentially expressed genes involved in the biosynthesis of photosynthetic pigment, photosynthesis, and energy metabolism to be downregulated in albino tissues while most of those participating in flavonoid metabolism were upregulated. In addition, it was found cryptochrome 1 (CRY1) and phytochrome B (PHYB) genes that encode blue and red light photoreceptors to be downregulated. These photoreceptors mediate chloroplast protein gene expression, chloroplast protein import and photosynthetic pigment biosynthesis. Simultaneously, SUS gene, which was upregulated in albino tissues, encodes sucrose synthase considered a biochemical marker for sink strength. Collectively, we arrived to the following conclusions: (1) repression of the biosynthesis of photosynthetic pigment causes albinism; (2) destruction of photoreceptors in albino tissues suppresses photomorphogenesis, leading to abnormal chloroplast development; (3) albino tissues receive sucrose from the green tissues and decompose their own storage substances to obtain the energy needed for survival; and (4) UV-B signal and brassinosteroids promote flavonoid biosynthesis.

Download Full-text

A Nucleus-Encoded Chloroplast Protein YL1 Is Involved in Chloroplast Development and Efficient Biogenesis of Chloroplast ATP Synthase in Rice

Scientific Reports ◽

10.1038/srep32295 ◽

2016 ◽

Vol 6 (1) ◽

Cited By ~ 13

Author(s):

Fei Chen ◽

Guojun Dong ◽

Limin Wu ◽

Fang Wang ◽

Xingzheng Yang ◽

...

Keyword(s):

Atp Synthase ◽

Chloroplast Development ◽

Chloroplast Atp Synthase ◽

Chloroplast Protein

Download Full-text

Osj10gBTF3-Mediated Import of Chloroplast Protein Is Essential for Pollen Development in Rice

Frontiers in Plant Science ◽

10.3389/fpls.2021.713544 ◽

2021 ◽

Vol 12 ◽

Author(s):

Xue-jiao Liu ◽

Jiaqi Sun ◽

Yuqing Huang ◽

Chao Li ◽

Peng Zheng ◽

...

Keyword(s):

Fatty Acids ◽

Transcription Factors ◽

Plant Development ◽

Pollen Development ◽

Chloroplast Development ◽

Membrane Channel ◽

Chloroplast Import ◽

Chloroplast Protein ◽

Chloroplast Stroma

Chloroplasts are crucial organelles for the generation of fatty acids and starch required for plant development. Nascent polypeptide-associated complex (NAC) proteins have been implicated in development as transcription factors. However, their chaperone roles in chloroplasts and their relationship with pollen development in plants remain to be elucidated. Here, we demonstrated that Osj10gBTF3, a NAC protein, regulates pollen and chloroplast development in rice by coordinating with a Hsp90 family chaperone OsHSP82 to mediate chloroplast import. Knockout of Osj10gBTF3 affects pollen and chloroplast development and significantly reduces the accumulation of fertility-related chloroplast protein OsPPR676. Both Osj10gBTF3 and OsHSP82 interact with OsPPR676. Interestingly, the interaction between OsHSP82 and OsPPR676 is only found in the cytoplasm, while the interaction between Osj10gBTF3 and OsPPR676 also occurs inside the chloroplast. The chloroplast stroma chaperone OsCpn60 can also be co-precipitated with Osj10gBTF3, but not with OsHSP82. Further investigation indicates that Osj10gBTF3 enters the chloroplast stroma possibly through the inner chloroplast membrane channel protein Tic110 and then recruits OsCpn60 for the folding or assembly of OsPPR676. Our results reveal a chaperone role of Osj10gBTF3 in chloroplast import different from Hsp90 and provide a link between chloroplast transport and pollen development in rice.

Download Full-text

Crosstalk between chloroplast protein import and the SUMO system revealed through genetic and molecular investigation

10.1101/2020.07.21.213355 ◽

2020 ◽

Author(s):

Samuel Watson ◽

Na Li ◽

Feijie Wu ◽

Qihua Ling ◽

R. Paul Jarvis

Keyword(s):

Protein Import ◽

Chloroplast Development ◽

Nuclear Genome ◽

Chloroplast Protein Import ◽

Chloroplast Protein ◽

Sumo Conjugation ◽

Molecular Investigation ◽

Regulatory Link ◽

The Stability ◽

Chloroplast Proteome

AbstractThe chloroplast proteome contains thousands of different proteins that are encoded by the nuclear genome. These proteins are imported into the chloroplast via the action of the TOC translocase and associated downstream systems. Our recent work has revealed that the stability of the TOC complex is dynamically regulated via the ubiquitin-dependent chloroplast-associated protein degradation (CHLORAD) pathway. Here, we demonstrate that the stability of the TOC complex is also regulated by the SUMO system. Arabidopsis mutants representing almost the entire SUMO conjugation pathway can partially suppress the phenotype of ppi1, a pale yellow mutant lacking the Toc33 protein. This suppression is linked to increased stability of TOC proteins and enhanced chloroplast development. In addition, we demonstrate using molecular and biochemical experiments that the SUMO system directly targets TOC proteins. Thus, we have identified a regulatory link between the SUMO system and chloroplast protein import.

Download Full-text

Crosstalk between the chloroplast protein import and SUMO systems revealed through genetic and molecular investigation in Arabidopsis

eLife ◽

10.7554/elife.60960 ◽

2021 ◽

Vol 10 ◽

Author(s):

Samuel Watson ◽

Na Li ◽

Yiting Ye ◽

Feijie Wu ◽

Qihua Ling ◽

...

Keyword(s):

Protein Import ◽

Chloroplast Development ◽

Nuclear Genome ◽

Chloroplast Protein Import ◽

Chloroplast Protein ◽

Sumo Conjugation ◽

Molecular Investigation ◽

Regulatory Link ◽

The Stability ◽

Chloroplast Proteome

The chloroplast proteome contains thousands of different proteins that are encoded by the nuclear genome. These proteins are imported into the chloroplast via the action of the TOC translocase and associated downstream systems. Our recent work has revealed that the stability of the TOC complex is dynamically regulated by the ubiquitin-dependent chloroplast-associated protein degradation (CHLORAD) pathway. Here, we demonstrate that the TOC complex is also regulated by the SUMO system. Arabidopsis mutants representing almost the entire SUMO conjugation pathway can partially suppress the phenotype of ppi1, a pale-yellow mutant lacking the Toc33 protein. This suppression is linked to increased abundance of TOC proteins and improvements in chloroplast development. Moreover, data from molecular and biochemical experiments support a model in which the SUMO system directly regulates TOC protein stability. Thus, we have identified a regulatory link between the SUMO system and the chloroplast protein import machinery.

Download Full-text