scholarly journals Fine Mapping and Identification of BnaC06.FtsH1, a Lethal Gene That Regulates the PSII Repair Cycle in Brassica napus

2021 ◽  
Vol 22 (4) ◽  
pp. 2087
Author(s):  
Kai Xu ◽  
Yujin Wu ◽  
Jurong Song ◽  
Kaining Hu ◽  
Zengxiang Wu ◽  
...  
Keyword(s):  
Brassica Napus ◽  
Biomass Accumulation ◽  
Genomic Region ◽  
Functional Verification ◽  
Homologous Gene ◽  
Temperature Sensitive ◽  
Lethal Gene ◽  
Lethal Mutant ◽  
Recessive Genes ◽  
Repair Cycle

Photosystem II (PSII) is an important component of the chloroplast. The PSII repair cycle is crucial for the relief of photoinhibition and may be advantageous when improving stress resistance and photosynthetic efficiency. Lethal genes are widely used in the efficiency detection and method improvement of gene editing. In the present study, we identified the naturally occurring lethal mutant 7-521Y with etiolated cotyledons in Brassica napus, controlled by double-recessive genes (named cyd1 and cyd2). By combining whole-genome resequencing and map-based cloning, CYD1 was fine-mapped to a 29 kb genomic region using 15,167 etiolated individuals. Through cosegregation analysis and functional verification of the transgene, BnaC06.FtsH1 was determined to be the target gene; it encodes an filamentation temperature sensitive protein H 1 (FtsH1) hydrolase that degrades damaged PSII D1 in Arabidopsis thaliana. The expression of BnaC06.FtsH1 was high in the cotyledons, leaves, and flowers of B. napus, and localized in the chloroplasts. In addition, the expression of EngA (upstream regulation gene of FtsH) increased and D1 decreased in 7-521Y. Double mutants of FtsH1 and FtsH5 were lethal in A. thaliana. Through phylogenetic analysis, the loss of FtsH5 was identified in Brassica, and the remaining FtsH1 was required for PSII repair cycle. CYD2 may be a homologous gene of FtsH1 on chromosome A07 of B. napus. Our study provides new insights into lethal mutants, the findings may help improve the efficiency of the PSII repair cycle and biomass accumulation in oilseed rape.

Glutamyl and Glutaminyl-tRNA Synthetases Are a Promising Target for the Design of Threonine-Producing Strain

2019 ◽  
Vol 35 (6) ◽  
pp. 39-50
Author(s):  
T.V. Yuzbashev ◽  
A.S. Fedorov ◽  
F.V. Bondarenko ◽  
A.S. Savchenko ◽  
T.V. Vybornaya ◽  
...  
Keyword(s):  
Biomass Accumulation ◽  
Trna Synthetase ◽  
Temperature Sensitive ◽  
Original Strain ◽  
Trna Synthetases ◽  
Resource Center ◽  
Promising Target ◽  
The Russian Federation ◽  
Increase In Productivity ◽  
Culture Growth

The present work describes an approach that improves the properties of the strain producing L-threonine via the reduction in the biomass accumulation during fermentation. Glutamyl- and glutaminyl-tRNA synthetases were chosen as targets. Mutants carrying temperature-sensitive alleles were obtained. It was shown that the used system caused the suppression of the function of tRNA synthetases which led to a rapid arrest of the culture growth, and an increase in productivity and yield of the L-threonine synthesis. One of the temperature-sensitive strains was used to obtain under non-permissive conditions of mutants with the suppressed above phenotype. Some of these mutants accumulate less biomass and produce by 10-12% more threonine than the original strain. Escherichia coli, producing strain, threonine, aminoacyl-tRNA synthetase, ts-mutation This work was supported by the Ministry of Science and Higher Education of the Russian Federation (project code RFMEFI61017X0011), and it was carried out using the equipment of the National Bio-Resource Center All-Russian Collection of Industrial Microorganisms, NRC «Kurchatov Institute» - GosNIIgenetika.

scholarly journals Regulation of asparagine synthetase gene expression by amino acid starvation

1991 ◽  
Vol 11 (12) ◽  
pp. 6059-6066
Author(s):  
S S Gong ◽  
L Guerrini ◽  
C Basilico
Keyword(s):  
Gene Expression ◽  
Amino Acid ◽  
Transcription Initiation ◽  
Rna Stability ◽  
Genomic Region ◽  
Amino Acid Starvation ◽  
Asparagine Synthetase ◽  
Temperature Sensitive ◽  
Mrna Levels ◽  
Regulation Of Expression

We have studied the regulation of expression of the asparagine synthetase (AS) gene in ts11 cells, a mutant of BHK hamster cells which encodes a temperature-sensitive AS and therefore does not produce endogenous asparagine at 39.5 degrees C. Incubation of ts11 cells at the nonpermissive temperature drastically increases the level of AS mRNA, and the stimulation of AS mRNA expression is effectively suppressed by the addition of asparagine to the medium. We show here that regulation of AS gene expression involves cis-acting elements which are contained in the mRNA as well as in the 5' genomic region. When a plasmid containing the human AS cDNA under the control of the human AS promoter region was stably transfected into ts11 cells, the expression of human AS RNAs was regulated as that of the endogenous hamster transcripts, indicating that this construct contained all cis elements necessary for regulation. Expression of the AS cDNA in ts11 cells under the control of a constitutive foreign promoter was also regulated by the concentration of asparagine, and this regulation required translation. When we introduced by mutagenesis a number of stop codons in the AS cDNA, the mutant mRNAs with short open reading frames were expressed at low levels that were not increased by asparagine deprivation. Inhibition of protein and RNA synthesis also prevented down-regulation of AS mRNA levels by high concentrations of asparagine. In a parallel series of experiments, we showed that an AS DNA fragment including the promoter and first exon can also regulate RNA expression in response to asparagine concentration. Furthermore, similar increases in the levels of AS RNAs are produced not only by asparagine deprivation in ts11 cells but also by deprivation of human and wild-type BHK cells of leucine, isoleucine, or glutamine. Thus, regulation of AS gene expression is a response to amino acid starvation through mechanisms which appear to involve both changes in RNA stability and change in the rates of transcription initiation or elongation.

Characterization of a new temperature-sensitive male sterile line SP2S in rapeseed (Brassica napus L.)

Euphytica ◽  
2015 ◽  
Vol 206 (2) ◽  
pp. 473-485 ◽  
Author(s):  
Chengyu Yu ◽  
Yingfen Guo ◽  
Juan Ge ◽  
Yumei Hu ◽  
Jungang Dong ◽  
...  
Keyword(s):  
Brassica Napus ◽  
Temperature Sensitive ◽  
Male Sterile ◽  
Male Sterile Line ◽  
Brassica Napus L

A lack of aerenchyma and high rates of radial oxygen loss from the root base contribute to the waterlogging intolerance of Brassica napus

1999 ◽  
Vol 26 (1) ◽  
pp. 87 ◽  
Author(s):  
L.A.C.J. Voesenek ◽  
W. Armstrong ◽  
G.M. Bögemann ◽  
T.D. Colmer ◽  
M.P. McDonald
Keyword(s):  
Brassica Napus ◽  
Lateral Roots ◽  
Biomass Accumulation ◽  
Radial Oxygen Loss ◽  
Low Oxygen ◽  
Root Porosity ◽  
Oxygen Loss ◽  
Basal Portion ◽  
Pre Treatment ◽  
Oxygen Profiles

The morphology and physiology of the response of two cultivars of Brassica napus to an anaerobic root medium was investigated. The cultivars Chikuzen and Topas showed a large reduction in growth rate when their roots were exposed to a de-oxygenated stagnant nutrient solution containing 0.1% w/v agar. Older seedlings (11 d old) were more sensitive to stagnant agar, expressed as biomass accumulation, than younger ones (5 d old). Brassica napus was characterized by a constitutively low root porosity (3–5%), typical for plant species with a low tolerance to waterlogging. A hypoxia pre- treatment (16 h; 2.25% O2) before exposure to de-oxygenated stagnant agar had no effect on the final number or length of lateral roots and adventitious roots. Brassica napus cv. Chikuzen is characterized by radial oxygen loss being most at the basal portion of the root, when a strong oxygen sink surrounds the root. Oxygen profiles through laterals of Brassica napus cv. Chikuzen show a typical pattern with low oxygen concentrations in the stele and somewhat higher levels in the cortex. Despite the continuum of intercellular air spaces in the root cortical tissue the lack of aerenchyma and therefore low rates of internal oxygen diffusion restricts root growth in anaerobic media and presumably contributes to the sensitivity of Brassica napus to waterlogging.

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