Tryptophan-Requiring Mutants of the Plant Arabidopsis thaliana

Science ◽  
1988 ◽  
Vol 240 (4850) ◽  
pp. 305-310 ◽  
Author(s):  
ROBERT L. LAST ◽  
GERALD R. FINK
Keyword(s):  
Amino Acids ◽  
Arabidopsis Thaliana ◽  
Amino Acid ◽  
Second Step ◽  
Recessive Trait ◽  
Whole Plant ◽  
Tryptophan Pathway ◽  
Morphological Defects ◽  
Plant Level ◽  
Plant Arabidopsis Thaliana

Although amino acid auxotrophs are among the most frequently isolated mutations in microorganisms, no mutants that require amino acids have been isolated at the whole plant level. Tryptophan-requiring mutants of the cruciferous plant Arabidopsis thaliana have now been isolated by selecting for resistance to 5-methylanthranilic acid. The tryptophan requirement of one mutant, trpl-1, results from a defect in the second step of the tryptophan pathway catalyzed by anthranilate phosphoribosyl transferase. Mutant trpl-1 plants are highly fluorescent and aromatic because they accumulate anthranilic acid and anthranilate β-glucoside. Plants homozygous for the trpl-1 mutation exhibit a syndrome of morphological defects suggestive of a defect in the biosynthesis, metabolism, or localization of a tryptophan derivative such as auxin. All of these morphological phenotypes cosegregate with the tryptophan requirement as a simple Mendelian recessive trait.

Sucrose Transporter Gene AtSUC4 Responds to Drought Stress by Regulating the Sucrose Distribution and Metabolism in Arabidopsis thaliana

2013 ◽  
Vol 765-767 ◽  
pp. 2971-2975 ◽  
Author(s):  
Xue Gong ◽  
Ming Li Liu ◽  
Li Jun Zhang ◽  
Wei Liu ◽  
Che Wang
Keyword(s):  
Arabidopsis Thaliana ◽  
Drought Stress ◽  
Plant Stress ◽  
Homozygous Mutation ◽  
Transporter Gene ◽  
Wild Type ◽  
Sucrose Transporters ◽  
Whole Plant ◽  
Plant Stress Tolerance ◽  
Plant Level

Sucrose transporters (SUCs or SUTs) are considered as the important carriers and responsible for the loading, unloading and distribution of sucrose, but at present there is no report that SUCs are involved in sucrose distribution and metabolism under drought stress at the whole-plant level. AtSUC4, as the unique member of SUT4-clade inArabidopsis thaliana, may be important for plant stress tolerance. Here, by analyzing two homozygous mutation lines ofAtSUC4(Atsuc4-1andAtsuc4-2), we found drought stress induced higher sucrose, lower fructose and glucose contents in shoots, and lower sucrose, higher fructose and glucose contents in roots of these mutants compared with the wild-type (WT), leading to an imbalance of sucrose distribution, fructose and glucose (sucrose metabolites) accumulation changes at the whole-plant level. Thus we believe thatAtSUC4regulates sucrose distribution and metabolism in response to drought stress.

scholarly journals RESISTÊNCIA DE PLANTAS DANINHAS: SELEÇÃO OU INDUÇÃO À MUTAÇÃO PELOS HERBICIDAS INIBIDORES DE ACETOLACTATO

2002 ◽  
Vol 12 ◽  
Author(s):  
RIBAS ANTONIO VIDAL ◽  
LARISSA MACEDO WINKLER
Keyword(s):  
Amino Acids ◽  
Arabidopsis Thaliana ◽  
Amino Acid ◽  
Dna Replication ◽  
Branched Chain Amino Acids ◽  
Amino Acid Synthesis ◽  
Replication Errors ◽  
Resistance To Herbicides ◽  
Branched Chain ◽  
Weed Resistance

A resistência de plantas daninhas aos herbicidas, principalmente os inibidores da síntese de aminoácidos ramificados (isoleucina, leucina e valina), está se propagando no Brasil. A literatura propõem que a resistência aos herbicidas ocorre devido à seleção de indivíduos mutantes já presentes na comunidade vegetal aspergida pelo herbicida. Contudo, durante a replicação do DNA ocorrem erros que são corrigidos por diversas proteínas. Já foi identificada a composição de aminoácidos das proteínas do grupo MutS, responsáveis pela correção de erros replicativos em Arabidopsis thaliana. Com base na elevada composição dos aminoácidos ramificados nas proteínas do grupo MutS, este trabalho questiona se a ausência desses aminoácidos em momentos críticos da replicação do DNA pode estar prejudicando a correção dos erros do DNA das plantas daninhas. Comparações são feitas entre possíveis efeitos de inibidores de acetolactato sintase (ALS) e de enol-piruvil-shiquimatofosfato- sintase (EPSPS). Com base nessas informações sugere-se que herbicidas inibidores da síntese de aminoácidos ramificados podem propiciar o aparecimento de mais indivíduos mutantes resistentes aos mesmos. WEED RESISTANCE: SELECTION OR INDUCTION TO MUTATION BY INHIBITORS OF ACETO LACTATE SYNTASE HERBICIDES Abstract The weed resistance to herbicides is widely spread in Brazil, mainly for the compounds inhibitors of the synthesis of branched-chain amino acids, isoleucine, leucine and valine. The literature proposes that the resistance to herbicides appears as result of selection of mutant individual plants existent in the weed flora prior to herbicide application. However, during DNA replication occur replication errors, that are corrected by several proteins. It is already known the amino acid composition of the proteins from the group MutS, responsible for the correction of replication errors in Arabidopsis thaliana. Based on the high composition of branched-chain amino acids on the group MutS proteins, in this work it is hypothesized that the absence of these amino acids on critical moments of the DNA replication can be interfering on the correction of the DNA replication errors in weeds. Possible effect of aceto lactate syntase (ALS) and enolpyruvil- shiquimato-phosphate syntase (EPSPS) inhibithing herbicides are compared. This review suggests that herbicides inhibitor of branched chain amino acid synthesis can trigger the appearance of more mutant weeds resistant to the herbicides when sprayed by these compounds.

scholarly journals Identification of functional regions on the tail of Acanthamoeba myosin-II using recombinant fusion proteins. II. Assembly properties of tails with NH2- and COOH-terminal deletions.

1990 ◽  
Vol 111 (6) ◽  
pp. 2417-2426 ◽  
Author(s):  
J H Sinard ◽  
D L Rimm ◽  
T D Pollard
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Amino Acid Residue ◽  
Fusion Proteins ◽  
Divalent Cations ◽  
Myosin Ii ◽  
Coiled Coil ◽  
Second Step ◽  
Recombinant Fusion Proteins ◽  
Functional Regions

We used purified fusion proteins containing parts of the Acanthamoeba myosin-II tail to localize those regions of the tail responsible for each of the three steps in the successive dimerization mechanism (Sinard, J. H., W. F. Stafford, and T. D. Pollard. 1989. J. Cell Biol. 107:1537-1547) for Acanthamoeba myosin-II minifiliment assembly. Fusion proteins containing the terminal approximately 90% of the myosin-II tail assemble normally, but deletions within the last 100 amino acids of the tail sequence alter or prevent assembly. The first step in minifilament assembly, formation of antiparallel dimers, requires the COOH-terminal approximately 30 amino acids that are thought to form a nonhelical domain at the end of the coiled-coil. The second step, formation of antiparallel tetramers, requires the last approximately 40 residues in the coiled-coil. The final step, the association of two antiparallel tetramers to form the completed octameric minifilament, requires residues approximately 40-70 from the end of the coiled-coil. A region of the tail near the junction with the heads is important for tight packing of the tails in the minifilaments. Divalent cations induce the lateral aggregation of minifilaments formed from native myosin-II or fusion proteins containing a nonmyosin "head," but under the same conditions fusion proteins composed essentially only of myosin tail sequences with very little nonmyosin sequences form paracrystals. The region of the tail necessary for this paracrystal formation lies NH2-terminal to amino acid residue 1,468 in the native myosin-II sequence.

A model-based analysis of the dynamics of carbon balance at the whole-plant level in Arabidopsis thaliana

2008 ◽  
Vol 35 (11) ◽  
pp. 1147 ◽  
Author(s):  
Angélique Christophe ◽  
Véronique Letort ◽  
Irène Hummel ◽  
Paul-Henry Cournède ◽  
Philippe de Reffye ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Growth Analysis ◽  
Time Course ◽  
Strong Increase ◽  
Structural Development ◽  
Whole Plant ◽  
Use Efficiency ◽  
Plant Level ◽  
Source Sink ◽  
Radiation Use

Arabidopsis thaliana (L.) Heynh. is used as a model plant in many research projects. However, few models simulate its growth at the whole-plant scale. The present study describes the first model of Arabidopsis growth integrating organogenesis, morphogenesis and carbon-partitioning processes for aerial and subterranean parts of the plant throughout its development. The objective was to analyse competition among sinks as they emerge from patterns of plant structural development. The model was adapted from the GreenLab model and was used to estimate organ sink strengths by optimisation against biomass measurements. Dry biomass production was calculated by a radiation use efficiency-based approach. Organogenesis processes were parameterised based on experimental data. The potential of this model for growth analysis was assessed using the Columbia ecotype, which was grown in standard environmental conditions. Three phases were observed in the overall time course of trophic competition within the plant. In the vegetative phase, no competition was observed. In the reproductive phase, competition increased with a strong increase when lateral inflorescences developed. Roots and internodes and structures bearing siliques were strong sinks and had a similar impact on competition. The application of the GreenLab model to the growth analysis of A. thaliana provides new insights into source–sink relationships as functions of phenology and morphogenesis.

scholarly journals Cut and paste – Efficient cotyledon micrografting for Arabidopsis thaliana seedlings

2019 ◽  
Author(s):  
Kai Bartusch ◽  
Jana Trenner ◽  
Marcel Quint
Keyword(s):  
Arabidopsis Thaliana ◽  
Success Rates ◽  
Long Distance ◽  
Long Distance Transport ◽  
Light Intensities ◽  
Whole Plant ◽  
Plant Level ◽  
Distance Transport ◽  
Plant Seedlings

AbstractCotyledon micrografting represents a very useful tool for studying the central role of cotyledons during early plant development, especially their interplay with other plant organs with regard to long distance transport. While hypocotyl grafting methods are established, cotyledon grafting is still inefficient. By optimizing cotyledon micrografting, we aim for higher success rates and increased throughput in the model species Arabidopsis thaliana. We established a cut and paste cotyledon surgery procedure on a flat solid but moist surface which improved handling of small plant seedlings. Applying a specific cutting and joining pattern throughput was increased up to 40 seedlings per hour. The combination of short day conditions and low light intensities for germination and long day plus high light intensities and vertical plate positioning after grafting significantly increased ‘ligation’ efficiency. Together, we achieved up to 46 % grafting success in A. thaliana. Reconnection of vasculature was shown by successful transport of a vasculature-specific dye across the grafting site. On a whole plant level, plants with grafted cotyledons match plants with intact cotyledons in biomass production and rosette development. This cut and paste cotyledon-to-petiole grafting protocol simplifies the handling of plant seedlings in surgery, increases the number of grafted plants per hour and produces higher success rates for A. thaliana seedlings. The developed cotyledon micrografting method is also suitable for other plant species of comparable size.

Codon Signature Extremes In Eukaryote genomes

2006 ◽  
Vol 52 (3-4) ◽  
pp. 281-297 ◽  
Author(s):  
Samuel Karlin ◽  
Dorit Carmelli
Keyword(s):  
Amino Acids ◽  
Arabidopsis Thaliana ◽  
Amino Acid ◽  
Mammalian Species ◽  
Life Domains ◽  
Codon Site ◽  
Bacterial Genomes ◽  
Noncoding Regions ◽  
Genome Wide ◽  
Eukaryotic Genomes

Twenty-one complete eukaryotic genomes are compared for codon signature biases. The codon signature refers to the dinucleotide relative abundance values at codon sites {1, 2}, {2, 3}, and {3, 4} (4 = 1 of the next codon site). The genomes under study include human, mouse, chicken, three invertebrates, one plant species, eight fungi, and six protists. The dinucleotide CpG is significantly underrepresented at all contiguous codon sites and drastically suppressed in noncoding regions in mammalian species, in yeast-like genomes, in the dicot Arabidopsis thaliana, but not in the filamentous fungi Neurospora crassa and Asperigillus fumigatus, and in the protist Entamoeba histolytica. The dinucleotide TpA, probably due to DNA structural weaknesses, is underrepresented genome-wide and significantly underrepresented in the codon signature for all contiguous codon sites in mammals, inverterbrates, plants, and fungi, but somewhat restricted to codon sites {1, 2} among protists helping in avoidance of stop codons. The amino acid Ser, not of abundance in bacterial genomes, generally ranks among the two most used amino acids among eukaryotes ostensibly resulting from greater activity in the nucleus. The observed differences are linked to specifics of methylation, context-dependent mutation, DNA repair, and replication. For example, the amino acid Leu is broadly abundant in all life domains generally resulting from extra occurrences of the codon TTR, R purine. The malarial protist Plasmodium falciparum shows many codon signature extremes.

Sucrose Transporter Gene AtSUC4 Regulates Sucrose Distribution and Metabolism in Response to Salt Stress in Arabidopsis thaliana

2013 ◽  
Vol 726-731 ◽  
pp. 217-221 ◽  
Author(s):  
Xue Gong ◽  
Ming Li Liu ◽  
Che Wang ◽  
Li Jun Zhang ◽  
Wei Liu
Keyword(s):  
Arabidopsis Thaliana ◽  
Salt Stress ◽  
Stress Tolerance ◽  
Plant Stress ◽  
High Capacity ◽  
Sucrose Transporter ◽  
Homozygous Mutation ◽  
Glucose Content ◽  
Whole Plant ◽  
Plant Level

Sporadic reports indicated that salt stress induced the expression of sucrose transporter genes, and sucrose transporters (SUCs or SUTs) as the important carriers are responsible for the loading, unloading and distribution of sucrose, but the study that SUCs are involved in sucrose distribution and metabolism under salt stress at the whole-plant level has not been reported to date. AtSUC4, as the unique member of low affinity/high capacity SUT4-clade inArabidopsis thaliana, may play an important role in plant stress tolerance. Here, through analyzing two homozygous mutation lines ofAtSUC4(Atsuc4-1andAtsuc4-2), we found salt stress induced higher sucrose, fructose and glucose content in shoots and lower sucrose, fructose and glucose content in roots of these mutants compared with the wild-type (WT), resulting in an imbalance of sucrose distribution and fructose and glucose accumulation changes of sucrose metabolitesat the whole-plant level. Our results indicated thatAtSUC4is involved in salt stress tolerance by the regulation of sucrose distribution and metabolism.

scholarly journals The Impact of Photorespiratory Glycolate Oxidase Activity on Arabidopsis thaliana Leaf Soluble Amino Acid Pool Sizes during Acclimation to Low Atmospheric CO2 Concentrations

Metabolites ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 501
Author(s):  
Younès Dellero ◽  
Caroline Mauve ◽  
Mathieu Jossier ◽  
Michael Hodges
Keyword(s):  
Amino Acids ◽  
Arabidopsis Thaliana ◽  
Amino Acid ◽  
Atmospheric Co2 ◽  
Glycolate Oxidase ◽  
Wild Type ◽  
Low Co2 ◽  
Co2 Concentrations ◽  
Atmospheric Co2 Concentrations ◽  
The Impact

Photorespiration is a metabolic process that removes toxic 2-phosphoglycolate produced by the oxygenase activity of ribulose-1,5-bisphosphate carboxylase/oxygenase. It is essential for plant growth under ambient air, and it can play an important role under stress conditions that reduce CO2 entry into the leaf thus enhancing photorespiration. The aim of the study was to determine the impact of photorespiration on Arabidopsis thaliana leaf amino acid metabolism under low atmospheric CO2 concentrations. To achieve this, wild-type plants and photorespiratory glycolate oxidase (gox) mutants were given either short-term (4 h) or long-term (1 to 8 d) low atmospheric CO2 concentration treatments and leaf amino acid levels were measured and analyzed. Low CO2 treatments rapidly decreased net CO2 assimilation rate and triggered a broad reconfiguration of soluble amino acids. The most significant changes involved photorespiratory Gly and Ser, aromatic and branched-chain amino acids as well as Ala, Asp, Asn, Arg, GABA and homoSer. While the Gly/Ser ratio increased in all Arabidopsis lines between air and low CO2 conditions, low CO2 conditions led to a higher increase in both Gly and Ser contents in gox1 and gox2.2 mutants when compared to wild-type and gox2.1 plants. Results are discussed with respect to potential limiting enzymatic steps with a special emphasis on photorespiratory aminotransferase activities and the complexity of photorespiration.

scholarly journals Insertion of an endogenous Jaagsiekte sheep retrovirus element into the BCO2 - gene abolishes its function and leads to yellow discoloration of adipose tissue in Norwegian Spælsau (Ovis aries)

BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Matthew Kent ◽  
Michel Moser ◽  
Inger Anne Boman ◽  
Kristine Lindtveit ◽  
Mariann Árnyasi ◽  
...  
Keyword(s):  
Amino Acids ◽  
Adipose Tissue ◽  
Amino Acid ◽  
Nonsense Mutation ◽  
Ovis Aries ◽  
Splice Acceptor Site ◽  
Recessive Trait ◽  
Hybrid Protein ◽  
Jaagsiekte Sheep Retrovirus ◽  
Enzymatic Function

Abstract Background The accumulation of carotenoids in adipose tissue leading to yellow fat is, in sheep, a heritable recessive trait that can be attributed to a nonsense mutation in the beta-carotene oxygenase 2 (BCO2) gene. However, not all sheep breeds suffering from yellow fat have this nonsense mutation, meaning that other functional mechanisms must exist. We investigated one such breed, the Norwegian spælsau. Results In spælsau we detected an aberration in BCO2 mRNA. Nanopore sequencing of genomic DNA revealed the insertion of a 7.9 kb endogenous Jaagsiekte Sheep Retrovirus (enJSRV) sequence in the first intron of the BCO2 gene. Close examination of its cDNA revealed that the BCO2 genes first exon was spliced together with enJSRV-sequence immediately downstream of a potential -AG splice acceptor site at enJSRV position 415. The hybrid protein product consists of 29 amino acids coded by the BCO2 exon 1, one amino acid coded by the junction sequence, followed by 28 amino acids arbitrary coded for by the enJSRV-sequence, before a translation stop codon is reached. Conclusions Considering that the functional BCO2 protein consists of 575 amino acids, it is unlikely that the 58 amino acid BCO2/enJSRV hybrid protein can display any enzymatic function. The existence of this novel BCO2 allele represents an alternative functional mechanism accounting for BCO2 inactivation and is a perfect example of the potential benefits for searching for structural variants using long-read sequencing data.

scholarly journals Expression of AtAAP Gene Family and Endosperm-Specific Expression of AtAAP1 Gene Promotes Amino Acid Absorption in Arabidopsis thaliana and Maize

Agronomy ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 1668
Author(s):  
Zhanyu Chen ◽  
Yingying Zhang ◽  
Jiating Zhang ◽  
Bei Fan ◽  
Ying Zhou ◽  
...  
Keyword(s):  
Amino Acids ◽  
Arabidopsis Thaliana ◽  
Amino Acid ◽  
Transmembrane Protein ◽  
Expression Patterns ◽  
Reproductive Organs ◽  
Amino Acid Permease ◽  
Specific Expression ◽  
Vegetative Organs ◽  
Amino Acid Contents

The amino acid permease (AAP) is an important transmembrane protein that is involved in the absorption and transport of amino acids in plants. We investigated the expression patterns of AtAAP genes in Arabidopsis thaliana, based on quantitative real-time PCR. The results revealed differential expression patterns of eight AtAAP genes in different tissues, with five genes (AtAAP1, AtAAP2, AtAAP6, AtAAP7, and AtAAP8) expressed at relatively high levels in both flowers and siliques, suggesting their shared functions in the accumulation of amino acids. In transgenic plants, with endosperm-specific overexpression of AtAAP1, both AtAAP1 and AtAAP6 were up-regulated in both the roots and siliques, while AtAAP2, AtAAP3, AtAAP4, and AtAAP5 showed similar expression levels in the stems and siliques, whereas AtAAP7 and AtAAP8 were expressed at their highest levels in the stems and roots. The results of the amino acid affinity experiments revealed varied absorption capacities for different amino acids, by AtAAP1, and increased acid amino contents in the reproductive organs. These results were verified in transgenic maize plants, with the overexpression of AtAAP1, revealing higher amino acid contents in the reproductive organs than those of the vegetative organs. Our study clearly demonstrated that the endosperm-specific promoter increased the amino acid contents in the reproductive organs and improved the effective utilization of organic nitrogen in plants.

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