scholarly journals Genetic analysis of the barley variegation mutant, grandpa1.a

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Shengming Yang ◽  
Megan Overlander ◽  
Jason Fiedler
Keyword(s):  
Gene Cluster ◽  
Molecular Mechanisms ◽  
Chloroplast Development ◽  
Snp Array ◽  
Chloroplast Ultrastructure ◽  
Large Deletion ◽  
Chloroplast Biogenesis ◽  
Precise Position ◽  
Albino Plants ◽  
Transmission Electron

Abstract Background Providing the photosynthesis factory for plants, chloroplasts are critical for crop biomass and economic yield. However, chloroplast development is a complicated process, coordinated by the cross-communication between the nucleus and plastids, and the underlying biogenesis mechanism has not been fully revealed. Variegation mutants have provided ideal models to identify genes or factors involved in chloroplast development. Well-developed chloroplasts are present in the green tissue areas, while the white areas contain undifferentiated plastids that are deficient in chlorophyll. Unlike albino plants, variegation mutants survive to maturity and enable investigation into the signaling pathways underlying chloroplast biogenesis. The allelic variegated mutants in barley, grandpa 1 (gpa1), have long been identified but have not been genetically characterized. Results We characterized and genetically analyzed the grandpa1.a (gpa1.a) mutant. The chloroplast ultrastructure was evaluated using transmission electron microscopy (TEM), and it was confirmed that chloroplast biogenesis was disrupted in the white sections of gpa1.a. To determine the precise position of Gpa1, a high-resolution genetic map was constructed. Segregating individuals were genotyped with the barley 50 k iSelect SNP Array, and the linked SNPs were converted to PCR-based markers for genetic mapping. The Gpa1 gene was mapped to chromosome 2H within a gene cluster functionally related to photosynthesis or chloroplast differentiation. In the variegated gpa1.a mutant, we identified a large deletion in this gene cluster that eliminates a putative plastid terminal oxidase (PTOX). Conclusions Here we characterized and genetically mapped the gpa1.a mutation causing a variegation phenotype in barley. The PTOX-encoding gene in the delimited region is a promising candidate for Gpa1. Therefore, the present study provides a foundation for the cloning of Gpa1, which will elevate our understanding of the molecular mechanisms underlying chloroplast biogenesis, particularly in monocot plants.

scholarly journals Genetic Analysis of the Barley Variegation Mutant, Grandpa1.α

2020 ◽  
Author(s):  
Shengming Yang ◽  
Megan Overlander ◽  
Jason Fiedler
Keyword(s):  
Gene Cluster ◽  
Molecular Mechanisms ◽  
Chloroplast Development ◽  
Snp Array ◽  
Chloroplast Ultrastructure ◽  
Large Deletion ◽  
Chloroplast Biogenesis ◽  
Precise Position ◽  
Albino Plants ◽  
Transmission Electron

Abstract Background Providing the photosynthesis factory for plants, chloroplasts are critical for crop biomass and economic yield. However, chloroplast development is a complicated process, coordinated by the cross-communication between the nucleus and plastids, and the underlying biogenesis mechanism has not been fully revealed. Variegation mutants have provided ideal models to identify genes or factors involved in chloroplast development. Well-developed chloroplasts are present in the green tissue areas, while the white areas contain undifferentiated plastids that are deficient in chlorophyll. Unlike albino plants, variegation mutants survive to maturity and enable investigation into the signaling pathways underlying chloroplast biogenesis. The allelic variegated mutants in barley, grandpa 1 (gpa1), have long been identified but have not been genetically characterized. Results We characterized and genetically analyzed the grandpa1.a (gpa1.a) mutant. The chloroplast ultrastructure was evaluated using transmission electron microscopy (TEM), and it was confirmed that chloroplast biogenesis was disrupted in the white sections of gpa1.a. To determine the precise position of Gpa1, a high-resolution genetic map was constructed. Segregating individuals were genotyped with the barley 50k iSelect SNP Array, and the linked SNPs were converted to PCR-based markers for genetic mapping. The Gpa1 gene was mapped to chromosome 2H within a gene cluster functionally related to photosynthesis or chloroplast differentiation. In the variegated gpa1.a mutant, we identified a large deletion in this gene cluster that eliminates a putative plastid terminal oxidase (PTOX).Conclusions Here we characterized and genetically mapped the gpa1.a mutation causing a variegation phenotype in barley. The PTOX-encoding gene in the delimited region is a promising candidate for Gpa1. Therefore, the present study provides a foundation for the cloning of Gpa1, which will elevate our understanding of the molecular mechanisms underlying chloroplast biogenesis, particularly in monocot plants.

scholarly journals Albino seedling lethality 4; Chloroplast 30S Ribosomal Protein S1 is Required for Chloroplast Ribosome Biogenesis and Early Chloroplast Development in Rice

Rice ◽  
2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Kunneng Zhou ◽  
Caijuan Zhang ◽  
Jiafa Xia ◽  
Peng Yun ◽  
Yuanlei Wang ◽  
...  
Keyword(s):  
Rna Polymerase ◽  
Ribosomal Protein ◽  
Ribosomal Proteins ◽  
Ribosome Biogenesis ◽  
Molecular Mechanisms ◽  
Chloroplast Development ◽  
Phage Type ◽  
Chloroplast Biogenesis ◽  
Ribosomal Protein S1 ◽  
Seedling Lethality

Abstract Background Ribosomes responsible for transcription and translation of plastid-encoded proteins in chloroplasts are essential for chloroplast development and plant growth. Although most ribosomal proteins in plastids have been identified, the molecular mechanisms regulating chloroplast biogenesis remain to be investigated. Results Here, we identified albinic seedling mutant albino seedling lethality 4 (asl4) caused by disruption of 30S ribosomal protein S1 that is targeted to the chloroplast. The mutant was defective in early chloroplast development and chlorophyll (Chl) biosynthesis. A 2855-bp deletion in the ASL4 allele was verified as responsible for the mutant phenotype by complementation tests. Expression analysis revealed that the ASL4 allele was highly expressed in leaf 4 sections and newly expanded leaves during early leaf development. Expression levels were increased by exposure to light following darkness. Some genes involved in chloroplast biogenesis were up-regulated and others down-regulated in asl4 mutant tissues compared to wild type. Plastid-encoded plastid RNA polymerase (PEP)-dependent photosynthesis genes and nuclear-encoded phage-type RNA polymerase (NEP)-dependent housekeeping genes were separately down-regulated and up-regulated, suggesting that plastid transcription was impaired in the mutant. Transcriptome and western blot analyses showed that levels of most plastid-encoded genes and proteins were reduced in the mutant. The decreased contents of chloroplast rRNAs and ribosomal proteins indicated that chloroplast ribosome biogenesis was impaired in the asl4 mutant. Conclusions Rice ASL4 encodes 30S ribosomal protein S1, which is targeted to the chloroplast. ASL4 is essential for chloroplast ribosome biogenesis and early chloroplast development. These data will facilitate efforts to further elucidate the molecular mechanism of chloroplast biogenesis.

scholarly journals The 3' ends of the deletions of Spanish delta beta zero-thalassemia and black HPFH 1 and 2 lie within 17 kilobases

Blood ◽  
1987 ◽  
Vol 70 (2) ◽  
pp. 593-596 ◽  
Author(s):  
C Camaschella ◽  
A Serra ◽  
G Saglio ◽  
M Baiget ◽  
N Malgaretti ◽  
...  
Keyword(s):  
Gene Cluster ◽  
Molecular Mechanisms ◽  
Globin Gene ◽  
Adult Life ◽  
Fetal Hemoglobin ◽  
Large Deletion ◽  
Complete Characterization ◽  
Beta Globin ◽  
Beta Globin Gene ◽  
Globin Gene Cluster

Abstract Spanish delta beta zero-thalassemia, a mild thalassemic condition characterized by increased level of hemoglobin (Hb) F production during adult life, is known to be due to a large deletion starting within the beta globin gene cluster and extending beyond the 3′ breakpoint of any other similar deletional defects so far identified. By molecular cloning and by genomic mapping we now demonstrate that the deletion of Spanish delta beta zero-thalassemia ends at approximately 11 and 17 kilobases (kb) downstream to the 3′ endpoints of black hereditary persistence of fetal hemoglobin (HPFH) type 1 and 2, respectively. As suggested by the complete characterization of this and other deletional defects involving the beta globin gene cluster, the 5′ and 3′ breakpoints of several deletions cluster in rather restricted DNA areas, further strengthening the idea that common molecular mechanisms may operate in causing these deletions.

scholarly journals The 3' ends of the deletions of Spanish delta beta zero-thalassemia and black HPFH 1 and 2 lie within 17 kilobases

Blood ◽  
1987 ◽  
Vol 70 (2) ◽  
pp. 593-596 ◽  
Author(s):  
C Camaschella ◽  
A Serra ◽  
G Saglio ◽  
M Baiget ◽  
N Malgaretti ◽  
...  
Keyword(s):  
Gene Cluster ◽  
Molecular Mechanisms ◽  
Globin Gene ◽  
Adult Life ◽  
Fetal Hemoglobin ◽  
Large Deletion ◽  
Complete Characterization ◽  
Beta Globin ◽  
Beta Globin Gene ◽  
Globin Gene Cluster

Spanish delta beta zero-thalassemia, a mild thalassemic condition characterized by increased level of hemoglobin (Hb) F production during adult life, is known to be due to a large deletion starting within the beta globin gene cluster and extending beyond the 3′ breakpoint of any other similar deletional defects so far identified. By molecular cloning and by genomic mapping we now demonstrate that the deletion of Spanish delta beta zero-thalassemia ends at approximately 11 and 17 kilobases (kb) downstream to the 3′ endpoints of black hereditary persistence of fetal hemoglobin (HPFH) type 1 and 2, respectively. As suggested by the complete characterization of this and other deletional defects involving the beta globin gene cluster, the 5′ and 3′ breakpoints of several deletions cluster in rather restricted DNA areas, further strengthening the idea that common molecular mechanisms may operate in causing these deletions.

Albino seedling lethality 4 ; chloroplast 30S ribosomal protein S1 required for chloroplast ribosome biogenesis and early chloroplast development in rice

2021 ◽  
Author(s):  
Kunneng Zhou ◽  
Caijuan Zhang ◽  
Jiafa Xia ◽  
Peng Yun ◽  
Yuanlei Wang ◽  
...  
Keyword(s):  
Ribosomal Protein ◽  
Ribosomal Proteins ◽  
Ribosome Biogenesis ◽  
Molecular Mechanisms ◽  
Chloroplast Development ◽  
Chlorophyll Biosynthesis ◽  
Housekeeping Genes ◽  
Chloroplast Biogenesis ◽  
Ribosomal Protein S1 ◽  
Photosynthesis Genes

Abstract Background : Ribosomes responsible for transcription and translation of plastid-encoded proteins in chloroplasts are essential for chloroplast development and plant growth. Although most ribosomal proteins in plastids have been identified, the molecular mechanisms regulating chloroplast biogenesis remain to be investigated. Results: Here, we identified albinic seedling mutant asl4 caused by disruption of 30S ribosomal protein S1 that is targeted to the chloroplast . The mutant was defective in early chloroplast development and chlorophyll biosynthesis . A 2,855-bp deletion in the ASL4 allele was verified as responsible for the mutant phenotype by complementation tests. Expression analysis revealed that the ASL4 allele was highly expressed in leaf 4 sections and newly expanded leaves during early leaf development. Expression levels were increased by exposure to light following darkness. Some genes involved in chloroplast biogenesis were up-regulated and others down-regulated in asl4 mutant tissues compared to wild type. PEP-dependent photosynthesis genes and NEP-dependent housekeeping genes were separately down-regulated and up-regulated, suggesting that plastid transcription was impaired in the mutant. Transcriptome and western blot analyses showed that levels of most plastid-encoded genes and proteins were reduced in the mutant. The decreased contents of chloroplast rRNAs and ribosomal proteins indicated that chloroplast ribosome biogenesis was impaired in the asl4 mutant. Conclusion: Rice ASL4 encodes 30S ribosomal protein S1, which is targeted to the chloroplast. ASL4 is essential for chloroplast ribosome biogenesis and early chloroplast development. These data will facilitate efforts to further elucidate the molecular mechanism of chloroplast biogenesis.

scholarly journals Ivermectin induces autophagy-mediated cell death through the AKT/mTOR signaling pathway in glioma cells

2019 ◽  
Vol 39 (12) ◽  
Author(s):  
Jingjing Liu ◽  
Hongsheng Liang ◽  
Chen Chen ◽  
Xiaoxing Wang ◽  
Faling Qu ◽  
...  
Keyword(s):  
Cell Death ◽  
Molecular Mechanisms ◽  
Anticancer Agent ◽  
Glioma Cells ◽  
Mtor Signaling ◽  
Terminal Deoxynucleotidyl Transferase ◽  
Transmission Electron ◽  
Diphenyltetrazolium Bromide

Abstract Glioma is one of the most common types of primary brain tumors. Ivermectin (IVM), a broad-spectrum antiparasitic drug, has been identified as a novel anticancer agent due to its inhibitory effects on the proliferation of glioma cells in vitro and in vivo. However, the ability of IVM to induce autophagy and its role in glioma cell death remains unclear. The main objective of the present study was to explore autophagy induced by IVM in glioma U251 and C6 cells, and the deep underlying molecular mechanisms. In addition, we examined the effects of autophagy on apoptosis in glioma cells. In the present study, transmission electron microscopy (TEM), immunofluorescence, Western blot and immunohistochemistry were used to evaluate autophagy activated by IVM. Cell viability was measured by 3-(4,5-dimethylthiazol2-yl)-2, 5-diphenyltetrazolium bromide (MTT) and colony formation assay. The apoptosis rate was detected by flow cytometry and terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL). Meanwhile, autophagy inhibition was achieved by using chloroquine (CQ). U251-derived xenografts were established for examination of IVM-induced autophagy on glioma in vivo. Taken together, the results of the present study showed that autophagy induced by IVM has a protective effect on cell apoptosis in vitro and in vivo. Mechanistically, IVM induced autophagy through AKT/mTOR signaling and induced energy impairment. Our findings show that IVM is a promising anticancer agent and may be a potential effective treatment for glioma cancers.

Transcriptomic response ofRalstonia solanacearumto antimicrobialPseudomonas fluorescensSN15-2 metabolites

2018 ◽  
Vol 64 (11) ◽  
pp. 816-825 ◽  
Author(s):  
Haibo Lou ◽  
Xiaobing Wang ◽  
Jun Chen ◽  
Bozhi Wang ◽  
Wei Wang
Keyword(s):  
Oxidative Stress ◽  
Plant Pathogens ◽  
Molecular Mechanisms ◽  
Acid Metabolism ◽  
Iron Absorption ◽  
Fermentation Broth ◽  
Transcriptomic Response ◽  
Transmission Electron ◽  
Antimicrobial Metabolites ◽  
Tomato Wilt

To develop efficient biocontrol agents, it is essential to investigate the response of soil-borne plant pathogens to such agents. For example, the response of Ralstonia solanacearum, the tomato wilt pathogen, to antimicrobial metabolites of Pseudomonas fluorescens is unknown. Thus, we assessed the effects of P. fluorescens SN15-2 fermentation broth on R. solanacearum by transmission electron microscopy and transcriptome technology. RNA sequencing identified 109 and 155 genes that are significantly upregulated and downregulated, respectively, in response to P. fluorescens metabolites, many of which are associated with the cell membrane and cell wall, and with nucleotide acid metabolism, iron absorption, and response to oxidative stress. This study highlights the effectiveness of P. fluorescens metabolites against the tomato wilt pathogen and helps clarify the underlying molecular mechanisms.

The Beneficial Effect of Nanostructured Oligochitosan against Gamma Irradiation and/or Carbon Tetrachloride-Induced Hepatic Injury in Rats

2021 ◽  
pp. 2243-2257
Author(s):  
Enas A. Mohamed ◽  
Ahmed M. Elbarbary ◽  
Nashat M. M. Abd alaty ◽  
Nashwa K. Ibrahim ◽  
Mahmoud M. Said ◽  
...  
Keyword(s):  
Carbon Tetrachloride ◽  
Gamma Irradiation ◽  
Molecular Mechanisms ◽  
Interleukin 1 ◽  
Molecular Data ◽  
Male Rats ◽  
Transmission Electron ◽  
Ccl4 Intoxication ◽  
Hepatotoxic Effect ◽  
Bax Gene

The current study was undertaken to investigate the hepatoprotective potential of nanostructured oligochitosan (NOC) against the synergistic toxic effects of -irradiation exposure and carbon tetrachloride (CCl4) intoxication in male rats. Adult male rats were allocated into eight groups; control, NOC-administered, -irradiated, CCl4-intoxicated, NOC-pretreated -irradiated, NOC-pretreated CCl4-intoxicated, -irradiated and CCl4-intoxicated, NOC-pretreated CCl4-intoxicated and -irradiated. Dynamic light scattering (DLS) and transmission electron microscopy (TEM) results demonstrated that the oligochitosan prepared by exposure to gamma irradiation was in the range of nanoparticles. A synergistic hepatotoxic effect was demonstrated following the exposure of rats to -irradiation and CCl4 intoxication, along with the induction of oxidative stress, inflammation and apoptosis. NOC was able to protect the hepatocytes from the combined toxic insults through suppressing lipid and protein oxidations, maintaining hepatic functions, downregulating the expression of some inflammatory genes, including nuclear factor kappa B (NF-B) and interleukin 1 beta (IL-1β), as well as enhancing the expression of the antiapoptotic Bcl2 gene and suppressing the proapoptotic Bax gene expression. Histological findings of liver tissues verified the biochemical and molecular data. The study clarified some of the molecular mechanisms by which NOC protects the liver against the synergistic toxic effect of -irradiation and CCl4.

scholarly journals atToc159 is a selective transit peptide receptor for the import of nucleus-encoded chloroplast proteins

2004 ◽  
Vol 165 (3) ◽  
pp. 323-334 ◽  
Author(s):  
Matthew D. Smith ◽  
Caleb M. Rounds ◽  
Fei Wang ◽  
Kunhua Chen ◽  
Meshack Afitlhile ◽  
...  
Keyword(s):  
Plant Cell ◽  
Chloroplast Development ◽  
Transit Peptide ◽  
Chloroplast Biogenesis ◽  
Cross Link ◽  
Peptide Receptor ◽  
Chloroplast Proteins ◽  
Transit Peptides ◽  
Import Receptor

The members of the Toc159 family of GTPases act as the primary receptors for the import of nucleus-encoded preproteins into plastids. Toc159, the most abundant member of this family in chloroplasts, is required for chloroplast biogenesis (Bauer, J., K. Chen, A. Hiltbunner, E. Wehrli, M. Eugster, D. Schnell, and F. Kessler. 2000. Nature. 403:203–207) and has been shown to covalently cross-link to bound preproteins at the chloroplast surface (Ma, Y., A. Kouranov, S. LaSala, and D.J. Schnell. 1996. J. Cell Biol. 134:1–13; Perry, S.E., and K. Keegstra. 1994. Plant Cell. 6:93–105). These reports led to the hypothesis that Toc159 functions as a selective import receptor for preproteins that are required for chloroplast development. In this report, we provide evidence that Toc159 is required for the import of several highly expressed photosynthetic preproteins in vivo. Furthermore, we demonstrate that the cytoplasmic and recombinant forms of soluble Toc159 bind directly and selectively to the transit peptides of these representative photosynthetic preproteins, but not representative constitutively expressed plastid preproteins. These data support the function of Toc159 as a selective import receptor for the targeting of a set of preproteins required for chloroplast biogenesis.

scholarly journals Identification of Genes Required for Synthesis of the Adhesive Holdfast in Caulobacter crescentus

2003 ◽  
Vol 185 (4) ◽  
pp. 1432-1442 ◽  
Author(s):  
Chris S. Smith ◽  
Aaron Hinz ◽  
Diane Bodenmiller ◽  
David E. Larson ◽  
Yves V. Brun
Keyword(s):  
Outer Membrane ◽  
Gene Cluster ◽  
Xanthomonas Campestris ◽  
Caulobacter Crescentus ◽  
Sequence Similarity ◽  
Gram Negative ◽  
Transmission Electron ◽  
Polar Development ◽  
Transposon Insertions ◽  
Polar Organelle

ABSTRACT Adhesion to both abiotic and biotic surfaces by the gram-negative prothescate bacterium Caulobacter crescentus is mediated by a polar organelle called the “holdfast,” which enables the bacterium to form stable monolayer biofilms. The holdfast, a complex polysaccharide composed in part of N-acetylglucosamine, localizes to the tip of the stalk (a thin cylindrical extension of the cell wall and membranes). We report here the isolation of adhesion mutants with transposon insertions in an uncharacterized gene cluster involved in holdfast biogenesis (hfs) as well as in previously identified polar development genes (podJ and pleC), and the holdfast attachment genes (hfa). Clean deletions of three of the four genes in the hfs gene cluster (hfsDAB) resulted in a severe holdfast biogenesis phenotype. These mutants do not bind to surfaces or to a fluorescently labeled lectin, specific for N-acetylglucosamine. Transmission electron microscopy indicated that the hfsDAB mutants fail to synthesize a holdfast at the stalk tip. The predicted hfs gene products have significant sequence similarity to proteins necessary for exopolysaccharide export in gram-negative bacteria. HfsA has sequence similarity to GumC from Xanthomonas campestris, which is involved in exopolysaccharide export in the periplasm. HfsD has sequence similarity to Wza from Escherichia coli, an outer membrane protein involved in secretion of polysaccharide through the outer membrane. HfsB is a novel protein involved in holdfast biogenesis. These data suggest that the hfs genes play an important role in holdfast export.

Sign in / Sign up

Export Citation Format

Share Document