scholarly journals AtRsgA from Arabidopsis thaliana is important for maturation of the small subunit of the chloroplast ribosome

2018 ◽  
Vol 96 (2) ◽  
pp. 404-420 ◽  
Author(s):  
Marcin Janowski ◽  
Reimo Zoschke ◽  
Lars B. Scharff ◽  
Silvia Martinez Jaime ◽  
Camilla Ferrari ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Small Subunit

scholarly journals AtRsgA from Arabidopsis thaliana controls maturation of the small subunit of the chloroplast ribosome

2017 ◽  
Author(s):  
Marcin Janowski ◽  
Reimo Zoschke ◽  
Lars Scharff ◽  
Silvia Martinez Jaime ◽  
Camilla Ferrari ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Proteomic Analysis ◽  
Ribosome Biogenesis ◽  
Functional Characterization ◽  
Small Subunit ◽  
Signalling Pathways ◽  
Compensatory Mechanism ◽  
Transcriptional Responses ◽  
Retrograde Signalling ◽  
Assembly Factor

SummaryPlastid ribosomes are very similar in structure and function to ribosomes of their bacterial ancestors. Since ribosome biogenesis is not thermodynamically favourable at biological conditions, it requires activity of many assembly factors. Here, we have characterized a homolog of bacterial rsgA in Arabidopsis thaliana and show that it can complement the bacterial homolog. Functional characterization of a strong mutant in Arabidopsis revealed that the protein is essential for plant viability, while a weak mutant produced dwarf, chlorotic plants that incorporated immature pre-16S ribosomal RNA into translating ribosomes. Physiological analysis of the mutant plants revealed smaller, but more numerous chloroplasts in the mesophyll cells, reduction of chlorophyll a and b, depletion of proplastids from the rib meristem and decreased photosynthetic electron transport rate and efficiency. Comparative RNA-sequencing and proteomic analysis of the weak mutant and wild-type plants revealed that various biotic stress-related, transcriptional regulation and post-transcriptional modification pathways were repressed in the mutant. Intriguingly, while nuclear- and chloroplast-encoded photosynthesis-related proteins were less abundant in the mutant, the corresponding transcripts were upregulated, suggesting an elaborate compensatory mechanism, potentially via differentially active retrograde signalling pathways. To conclude, this study reveals a new chloroplast ribosome assembly factor and outlines the transcriptomic and proteomic responses of the compensatory mechanism activated during decreased chloroplast function.Significance statementAtRsgA is an assembly factor necessary for maturation of the small subunit of the chloroplast ribosome. Depletion of AtRsgA leads to dwarfed, chlorotic plants and smaller, but more numerous chloroplasts. Large-scale transcriptomic and proteomic analysis revealed that chloroplast-encoded and - targeted proteins were less abundant, while the corresponding transcripts were upregulated in the mutant. We analyse the transcriptional responses of several retrograde signalling pathways to suggest a mechanism underlying this compensatory response.

scholarly journals AIP1, Encoding the Small Subunit of Acetolactate Synthase, Is Partially Responsible for Resistance to Hypoxic Stress in Arabidopsis thaliana

Plants ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 2251
Author(s):  
Geunmuk Im ◽  
Dongsu Choi
Keyword(s):  
Arabidopsis Thaliana ◽  
Oxygen Deficiency ◽  
Acetolactate Synthase ◽  
Small Subunit ◽  
Fungal Species ◽  
Low Oxygen ◽  
Homologous Genes ◽  
Genes Encoding ◽  
Variable Success ◽  
Branched Chain

Flooding is a significant stress to land plants, depriving them of essential oxygen. Plants have evolved diverse strategies with variable success to survive flooding. Similar strategies have been described in organisms from other kingdoms. Several fungal species can successfully survive a low-oxygen environment by increasing their branched-chain amino acid (BCAA) contents. BCAAs may act as alternative electron acceptors in the respiratory chain under an oxygen-limited environment. The key and first enzyme for BCAA biosynthesis is acetolactate synthase (ALS). We identified two homologous genes encoding the small subunit of ALS in Arabidopsis (Arabidopsis thaliana). We determined that ALS INTERACTING PROTEIN1 (AIP1), which encodes the small subunit of ALS, is strongly expressed in all organs and highly expressed under submergence and low-oxygen stresses. We also showed that the overexpression of AIP1 confers tolerance to low-oxygen stress. These results indicate that ALS may play an essential role under prolonged flooding or oxygen deficiency in Arabidopsis.

Four genes in two diverged subfamilies encode the ribulose-1,5-bisphosphate carboxylase small subunit polypeptides of Arabidopsis thaliana

1988 ◽  
Vol 11 (6) ◽  
pp. 745-759 ◽  
Author(s):  
Enno Krebbers ◽  
Jef Seurinck ◽  
Lydia Herdies ◽  
Anthony R. Cashmore ◽  
Michael P. Timko
Keyword(s):  
Arabidopsis Thaliana ◽  
Small Subunit ◽  
Bisphosphate Carboxylase

scholarly journals Overlapping Functions of the Paralogous Proteins AtPAP2 and AtPAP9 in Arabidopsis thaliana

2021 ◽  
Vol 22 (14) ◽  
pp. 7243
Author(s):  
Renshan Zhang ◽  
Xiaoqian Guan ◽  
Meijing Yang ◽  
Yee-Song Law ◽  
Chia Pao Voon ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Small Subunit ◽  
Purple Acid Phosphatase ◽  
Bimolecular Fluorescence Complementation ◽  
Differential Growth ◽  
Outer Membranes ◽  
C Terminus ◽  
Specific Proteins ◽  
Hydrophobic Motif ◽  
High Seed Yield

Arabidopsis thaliana purple acid phosphatase 2 (AtPAP2), which is anchored to the outer membranes of chloroplasts and mitochondria, affects carbon metabolism by modulating the import of some preproteins into chloroplasts and mitochondria. AtPAP9 bears a 72% amino acid sequence identity with AtPAP2, and both proteins carry a hydrophobic motif at their C-termini. Here, we show that AtPAP9 is a tail-anchored protein targeted to the outer membrane of chloroplasts. Yeast two-hybrid and bimolecular fluorescence complementation experiments demonstrated that both AtPAP9 and AtPAP2 bind to a small subunit of rubisco 1B (AtSSU1B) and a number of chloroplast proteins. Chloroplast import assays using [35S]-labeled AtSSU1B showed that like AtPAP2, AtPAP9 also plays a role in AtSSU1B import into chloroplasts. Based on these data, we propose that AtPAP9 and AtPAP2 perform overlapping roles in modulating the import of specific proteins into chloroplasts. Most plant genomes contain only one PAP-like sequence encoding a protein with a hydrophobic motif at the C-terminus. The presence of both AtPAP2 and AtPAP9 in the Arabidopsis genome may have arisen from genome duplication in Brassicaceae. Unlike AtPAP2 overexpression lines, the AtPAP9 overexpression lines did not exhibit early-bolting or high-seed-yield phenotypes. Their differential growth phenotypes could be due to the inability of AtPAP9 to be targeted to mitochondria, as the overexpression of AtPAP2 on mitochondria enhances the capacity of mitochondria to consume reducing equivalents.

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