Over-expression of a high-affinity phosphate transporter in transgenic barley plants does not enhance phosphate uptake rates

2004 ◽  
Vol 31 (2) ◽  
pp. 141 ◽  
Author(s):  
Anne L. Rae ◽  
Janine M. Jarmey ◽  
Stephen R. Mudge ◽  
Frank W. Smith
Keyword(s):  
Phosphate Uptake ◽  
Phosphate Concentration ◽  
Phosphate Transporter ◽  
Control Line ◽  
Wild Type ◽  
Gene Encoding ◽  
Over Expression ◽  
Transgenic Barley ◽  
Uptake Rates ◽  
Homozygous Line

Transgenic barley plants that over-express the gene encoding a phosphate transporter were generated and used to test the hypothesis that manipulation of transporters may lead to improved phosphate uptake by plant roots. Replicate T2 seedlings from a homozygous line with a single locus insertion were grown in dilute flow culture. The phosphate contents and uptake rates of these plants were compared with control transgenic and wild-type plants. When external phosphate concentration was maintained at 10 μM, all plants including the transgenic over-expressing line displayed low rates of phosphate uptake and contained high levels of phosphate in the shoot tissue. When external phosphate concentration was maintained at 2 μM, the uptake rates increased to a similar level in all plant lines. Three transgenic over-expressing lines were then grown in soil at a range of phosphate concentrations and the dry weights and total phosphorus contents of the shoots were measured and compared to a transgenic control line. The results showed that over-expression of the gene encoding a phosphate transporter did not improve the uptake of phosphate under any of the conditions tested. Transporter activity is likely to be influenced by post-transcriptional mechanisms and will require further investigation before this strategy can be applied to improving plant nutrition.

Effects of an Autoregulatory Senescence-inhibitor Gene Construct on Nicotiana alata Link and Otto.

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 519d-519 ◽  
Author(s):  
Kenneth R. Schroeder ◽  
Dennis P. Stimart
Keyword(s):  
Agrobacterium Tumefaciens ◽  
Plant Height ◽  
Dry Weight ◽  
Nicotiana Alata ◽  
Wild Type ◽  
Gene Encoding ◽  
Delayed Senescence ◽  
Gene Construct ◽  
Shoot Dry Weight ◽  
Inhibitor System

Nicotiana alata Link and Otto. was transformed via Agrobacterium tumefaciens encoding a senescence-specific promoter SAG12 cloned from Arabidopsis thaliana fused to a Agrobacterium tumefaciens gene encoding isopentenyl transferase (IPT) that catalyzes cytokinin synthesis. This was considered an autoregulatory senescence-inhibitor system. In 1996, we reported delayed senescence of intact flowers by 2 to 6 d and delayed leaf senescence of transgenic vs. wild-type N. alata. Further evaluations in 1997 revealed several other interesting effects of the SAG12-IPT gene construct. Measurement of chlorophyll content of mature leaves showed higher levels of both chlorophyll a and b in transgenic material under normal fertilization and truncated fertilization regimes. At 4 to 5 months of age transgenic plants expressed differences in plant height, branching, and dry weight. Plant height was reduced by 3 to 13 cm; branch counts increased 2 to 3 fold; and shoot dry weight increased up to 11 g over wild-type N. alata. These observations indicate the system is not tightly autoregulated and may prove useful to the floriculture industry for producing compact and more floriferous plants.

scholarly journals UNEQUAL CROSSING OVER AT THE rRNA TANDON AS A SOURCE OF QUANTITATIVE GENETIC VARIATION IN DROSOPHILA

Genetics ◽  
1980 ◽  
Vol 95 (3) ◽  
pp. 727-742 ◽  
Author(s):  
R Frankham ◽  
D A Briscoe ◽  
R K Nurthen
Keyword(s):  
Genetic Variation ◽  
Selection Response ◽  
Crossing Over ◽  
Wild Type ◽  
X Chromosomes ◽  
Unequal Crossing Over ◽  
Quantitative Genetic ◽  
Y Chromosomes ◽  
Homozygous Line ◽  
Minimum Estimate

ABSTRACT Abdominal bristle selection lines (three high and three low) and controls were founded from a marked homozygous line to measure the contribution of sex-linked "mutations" to selection response. Two of the low lines exhibited a period of rapid response to selection in females, but not in males. There were corresponding changes in female variance, in heritabilities in females, in the sex ratio (a deficiency of females) and in fitness, as well as the appearance of a mutant phenotype in females of one line. All of these changes were due to bb alleles (partial deficiencies for the rRNA tandon) in the X chromosomes of these lines, while the Y chromosomes remained wild-type bb+. We argue that the bb alleles arose by unequal crossing over in the rRNA tandon.—A prediction of this hypothesis is that further changes can occur in the rRNA tandon as selection is continued. This has now been shown to occur.—Our minimum estimate of the rate of occurrence of changes at the rRNA tandon is 3 × 10-4. As this is substantially higher than conventional mutation rates, the questions of the mechanisms and rates of origin of new quantitative genetic variation require careful re-examination.

scholarly journals Expression and function of the cdgD gene, encoding a CHASE–PAS-DGC-EAL domain protein, in Azospirillum brasilense

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
José Francisco Cruz-Pérez ◽  
Roxana Lara-Oueilhe ◽  
Cynthia Marcos-Jiménez ◽  
Ricardo Cuatlayotl-Olarte ◽  
María Luisa Xiqui-Vázquez ◽  
...  
Keyword(s):  
Azospirillum Brasilense ◽  
Type Strain ◽  
Wild Type Strain ◽  
Soil Conditions ◽  
Wild Type ◽  
Gene Encoding ◽  
Wheat Roots ◽  
Genes Encoding ◽  
In The Wild ◽  
Plant Growth Promoting

AbstractThe plant growth-promoting bacterium Azospirillum brasilense contains several genes encoding proteins involved in the biosynthesis and degradation of the second messenger cyclic-di-GMP, which may control key bacterial functions, such as biofilm formation and motility. Here, we analysed the function and expression of the cdgD gene, encoding a multidomain protein that includes GGDEF-EAL domains and CHASE and PAS domains. An insertional cdgD gene mutant was constructed, and analysis of biofilm and extracellular polymeric substance production, as well as the motility phenotype indicated that cdgD encoded a functional diguanylate protein. These results were correlated with a reduced overall cellular concentration of cyclic-di-GMP in the mutant over 48 h compared with that observed in the wild-type strain, which was recovered in the complemented strain. In addition, cdgD gene expression was measured in cells growing under planktonic or biofilm conditions, and differential expression was observed when KNO3 or NH4Cl was added to the minimal medium as a nitrogen source. The transcriptional fusion of the cdgD promoter with the gene encoding the autofluorescent mCherry protein indicated that the cdgD gene was expressed both under abiotic conditions and in association with wheat roots. Reduced colonization of wheat roots was observed for the mutant compared with the wild-type strain grown in the same soil conditions. The Azospirillum-plant association begins with the motility of the bacterium towards the plant rhizosphere followed by the adsorption and adherence of these bacteria to plant roots. Therefore, it is important to study the genes that contribute to this initial interaction of the bacterium with its host plant.

scholarly journals Ectopic Overexpression of Histone H3K4 Methyltransferase CsSDG36 from Tea Plant Decreases Hyperosmotic Stress Tolerance in Arabidopsis thaliana

2021 ◽  
Vol 22 (10) ◽  
pp. 5064
Author(s):  
Qinghua Chen ◽  
Linghui Guo ◽  
Yanwen Yuan ◽  
Shuangling Hu ◽  
Fei Guo ◽  
...  
Keyword(s):  
Drought Stress ◽  
Transmembrane Domain ◽  
Tea Plant ◽  
Microtubule Assembly ◽  
Pcr Analysis ◽  
Drought Response ◽  
Stomatal Development ◽  
Wild Type ◽  
Over Expression ◽  
Histone H3k4

Histone methylation plays an important regulatory role in the drought response of many plants, but its regulatory mechanism in the drought response of the tea plant remains poorly understood. Here, drought stress was shown to induce lower relative water content and significantly downregulate the methylations of histone H3K4 in the tea plant. Based on our previous analysis of the SET Domain Group (SDG) gene family, the full-length coding sequence (CDS) of CsSDG36 was cloned from the tea cultivar ‘Fuding Dabaicha’. Bioinformatics analysis showed that the open reading frame (ORF) of the CsSDG36 gene was 3138 bp, encoding 1045 amino acids and containing the conserved structural domains of PWWP, PHD, SET and PostSET. The CsSDG36 protein showed a close relationship to AtATX4 of the TRX subfamily, with a molecular weight of 118,249.89 Da, and a theoretical isoelectric point of 8.87, belonging to a hydrophilic protein without a transmembrane domain, probably located on the nucleus. The expression of CsSDG36 was not detected in the wild type, while it was clearly detected in the over-expression lines of Arabidopsis. Compared with the wild type, the over-expression lines exhibited lower hyperosmotic resistance by accelerating plant water loss, increasing reactive oxygen species (ROS) pressure, and increasing leaf stomatal density. RNA-seq analysis suggested that the CsSDG36 overexpression caused the differential expression of genes related to chromatin assembly, microtubule assembly, and leaf stomatal development pathways. qRT-PCR analysis revealed the significant down-regulation of stomatal development-related genes (BASL, SBT1.2(SDD1), EPF2, TCX3, CHAL, TMM, SPCH, ERL1, and EPFL9) in the overexpression lines. This study provides a novel sight on the function of histone methyltransferase CsSDG36 under drought stress.

scholarly journals A BAFF-R mutation associated with non-Hodgkin lymphoma alters TRAF recruitment and reveals new insights into BAFF-R signaling

2010 ◽  
Vol 207 (12) ◽  
pp. 2569-2579 ◽  
Author(s):  
Joanne M. Hildebrand ◽  
Zhenghua Luo ◽  
Michelle K. Manske ◽  
Tammy Price-Troska ◽  
Steven C. Ziesmer ◽  
...  
Keyword(s):  
B Cell ◽  
Hodgkin Lymphoma ◽  
Novel Mutation ◽  
B Cell Development ◽  
Signaling Cascades ◽  
Binding Motif ◽  
Wild Type ◽  
Immunoglobulin Production ◽  
Gene Encoding ◽  
Non Hodgkin Lymphoma

The cytokine B cell activating factor (BAFF) and its receptor, BAFF receptor (BAFF-R), modulate signaling cascades critical for B cell development and survival. We identified a novel mutation in TNFRSF13C, the gene encoding human BAFF-R, that is present in both tumor and germline tissue from a subset of patients with non-Hodgkin lymphoma. This mutation encodes a His159Tyr substitution in the cytoplasmic tail of BAFF-R adjacent to the TRAF3 binding motif. Signaling through this mutant BAFF-R results in increased NF-κB1 and NF-κB2 activity and increased immunoglobulin production compared with the wild-type (WT) BAFF-R. This correlates with increased TRAF2, TRAF3, and TRAF6 recruitment to His159Tyr BAFF-R. In addition, we document a requirement for TRAF6 in WT BAFF-R signaling. Together, these data identify a novel lymphoma-associated mutation in human BAFF-R that results in NF-κB activation and reveals TRAF6 as a necessary component of normal BAFF-R signaling.

scholarly journals A Regulator of G Protein Signaling-containing Kinase Is Important for Chemotaxis and Multicellular Development inDictyostelium

2003 ◽  
Vol 14 (4) ◽  
pp. 1727-1743 ◽  
Author(s):  
Binggang Sun ◽  
Richard A. Firtel
Keyword(s):  
Protein Kinase ◽  
G Protein ◽  
Kinase Activity ◽  
Site Directed Mutagenesis ◽  
Membrane Localization ◽  
Pleckstrin Homology Domain ◽  
G Protein Signaling ◽  
Protein Signaling ◽  
Wild Type ◽  
Gene Encoding

We have identified a gene encoding RGS domain-containing protein kinase (RCK1), a novel regulator of G protein signaling domain-containing protein kinase. RCK1 mutant strains exhibit strong aggregation and chemotaxis defects. rck1 null cells chemotax ∼50% faster than wild-type cells, suggesting RCK1 plays a negative regulatory role in chemotaxis. Consistent with this finding, overexpression of wild-type RCK1 reduces chemotaxis speed by ∼40%. On cAMP stimulation, RCK1 transiently translocates to the membrane/cortex region with membrane localization peaking at ∼10 s, similar to the kinetics of membrane localization of the pleckstrin homology domain-containing proteins CRAC, Akt/PKB, and PhdA. RCK1 kinase activity also increases dramatically. The RCK1 kinase activity does not rapidly adapt, but decreases after the cAMP stimulus is removed. This is particularly novel considering that most other chemoattractant-activated kinases (e.g., Akt/PKB, ERK1, ERK2, and PAKa) rapidly adapt after activation. Using site-directed mutagenesis, we further show that both the RGS and kinase domains are required for RCK1 function and that RCK1 kinase activity is required for the delocalization of RCK1 from the plasma membrane. Genetic evidence suggests RCK1 function lies downstream from Gα2, the heterotrimeric G protein that couples to the cAMP chemoattractant receptors. We suggest that RCK1 might be part of an adaptation pathway that regulates aspects of chemotaxis in Dictyostelium.

scholarly journals Enlarged Peroxisomes Are Present in Oleic Acid–grown Yarrowia lipolytica Overexpressing the PEX16 Gene Encoding an Intraperoxisomal Peripheral Membrane Peroxin

1997 ◽  
Vol 137 (6) ◽  
pp. 1265-1278 ◽  
Author(s):  
Gary A. Eitzen ◽  
Rachel K. Szilard ◽  
Richard A. Rachubinski
Keyword(s):  
Oleic Acid ◽  
Yarrowia Lipolytica ◽  
Consensus Sequence ◽  
Wild Type ◽  
Gene Encoding ◽  
Peroxisomal Membrane ◽  
Peripheral Protein ◽  
The Matrix ◽  
Peroxisomal Targeting ◽  
Targeting Signal

Pex mutants of the yeast Yarrowia lipolytica are defective in peroxisome assembly. The mutant strain pex16-1 lacks morphologically recognizable peroxisomes. Most peroxisomal proteins are mislocalized to a subcellular fraction enriched for cytosol in pex16 strains, but a subset of peroxisomal proteins is localized at, or near, wild-type levels to a fraction typically enriched for peroxisomes. The PEX16 gene was isolated by functional complementation of the pex16-1 strain and encodes a protein, Pex16p, of 391 amino acids (44,479 D). Pex16p has no known homologues. Pex16p is a peripheral protein located at the matrix face of the peroxisomal membrane. Substitution of the carboxylterminal tripeptide Ser-Thr-Leu, which is similar to the consensus sequence of peroxisomal targeting signal 1, does not affect targeting of Pex16p to peroxisomes. Pex16p is synthesized in wild-type cells grown in glucose-containing media, and its levels are modestly increased by growth of cells in oleic acid–containing medium. Overexpression of the PEX16 gene in oleic acid– grown Y. lipolytica leads to the appearance of a small number of enlarged peroxisomes, which contain the normal complement of peroxisomal proteins at levels approaching those of wild-type peroxisomes.

scholarly journals The Synechococcus Strain PCC 7942glnN Product (Glutamine Synthetase III) Helps Recovery from Prolonged Nitrogen Chlorosis

2000 ◽  
Vol 182 (19) ◽  
pp. 5615-5619 ◽  
Author(s):  
Jörg Sauer ◽  
Ulrike Dirmeier ◽  
Karl Forchhammer
Keyword(s):  
Glutamine Synthetase ◽  
Transcriptional Start Site ◽  
Binding Motif ◽  
Class Iii ◽  
Wild Type ◽  
Cloning And Sequencing ◽  
Gene Encoding ◽  
Low Concentrations ◽  
Synechococcus Strain ◽  
Pcc 7942

ABSTRACT We report the cloning and sequencing of the glnN gene encoding a class III glutamine synthetase from the cyanobacteriumSynechococcus strain PCC 7942. Mapping of the transcriptional start site revealed a DNA sequence in the promoter region that resembles an imperfect NtcA binding motif. Expression ofglnN is impaired in NtcA- and PII-deficient mutants. The only parameter which was negatively affected in theglnN mutant compared to the wild type was the recovery rate of prolonged nitrogen-starved cells with low concentrations of combined nitrogen.

scholarly journals Characterization of the Gene Encoding the Major Secreted Lysophospholipase A of Legionella pneumophila and Its Role in Detoxification of Lysophosphatidylcholine

2002 ◽  
Vol 70 (11) ◽  
pp. 6094-6106 ◽  
Author(s):  
Antje Flieger ◽  
Birgid Neumeister ◽  
Nicholas P. Cianciotto
Keyword(s):  
Fatty Acids ◽  
Legionella Pneumophila ◽  
Lipolytic Activity ◽  
Cholesterol Acyltransferase ◽  
Phospholipase A ◽  
Wild Type ◽  
Gene Encoding ◽  
Acyltransferase Activity ◽  
Lipolytic Enzymes ◽  
Cloned Gene

ABSTRACT We previously showed that Legionella pneumophila secretes, via its type II secretion system, phospholipase A activities that are distinguished by their specificity for certain phospholipids. In this study, we identified and characterized plaA, a gene encoding a phospholipase A that cleaves fatty acids from lysophospholipids. The plaA gene encoded a 309-amino-acid protein (PlaA) which had homology to a group of lipolytic enzymes containing the catalytic signature GDSL. In Escherichia coli, the cloned gene conferred trypsin-resistant hydrolysis of lysophosphatidylcholine and lysophosphatidylglycerol. An L. pneumophila plaA mutant was generated by allelic exchange. Although the mutant grew normally in standard buffered yeast extract broth, its culture supernatants lost greater than 80% of their ability to release fatty acids from lysophosphatidylcholine and lysophosphatidylglycerol, implying that PlaA is the major secreted lysophospholipase A of L. pneumophila. The mutant's reduced lipolytic activity was confirmed by growth on egg yolk agar and thin layer chromatography and was complemented by reintroduction of an intact copy of plaA. Overexpression of plaA completely protected L. pneumophila from the toxic effects of lysophosphatidylcholine, suggesting a role for PlaA in bacterial detoxification of lysophospholipids. The plaA mutant grew like the wild type in U937 cell macrophages and Hartmannella vermiformis amoebae, indicating that PlaA is not essential for intracellular infection of L. pneumophila. In the course of characterizing plaA, we discovered that wild-type legionellae secrete a phospholipid cholesterol acyltransferase activity, highlighting the spectrum of lipolytic enzymes produced by L. pneumophila.

scholarly journals IC138 Defines a Subdomain at the Base of the I1 Dynein That Regulates Microtubule Sliding and Flagellar Motility

2009 ◽  
Vol 20 (13) ◽  
pp. 3055-3063 ◽  
Author(s):  
Raqual Bower ◽  
Kristyn VanderWaal ◽  
Eileen O'Toole ◽  
Laura Fox ◽  
Catherine Perrone ◽  
...  
Keyword(s):  
Double Mutant ◽  
Essential Role ◽  
Null Allele ◽  
Flagellar Motility ◽  
Wild Type ◽  
Gene Encoding ◽  
Radial Spoke ◽  
Mutant Strains ◽  
Dynein Arms ◽  
Image Averaging

To understand the mechanisms that regulate the assembly and activity of flagellar dyneins, we focused on the I1 inner arm dynein (dynein f) and a null allele, bop5-2, defective in the gene encoding the IC138 phosphoprotein subunit. I1 dynein assembles in bop5-2 axonemes but lacks at least four subunits: IC138, IC97, LC7b, and flagellar-associated protein (FAP) 120—defining a new I1 subcomplex. Electron microscopy and image averaging revealed a defect at the base of the I1 dynein, in between radial spoke 1 and the outer dynein arms. Microtubule sliding velocities also are reduced. Transformation with wild-type IC138 restores assembly of the IC138 subcomplex and rescues microtubule sliding. These observations suggest that the IC138 subcomplex is required to coordinate I1 motor activity. To further test this hypothesis, we analyzed microtubule sliding in radial spoke and double mutant strains. The results reveal an essential role for the IC138 subcomplex in the regulation of I1 activity by the radial spoke/phosphorylation pathway.

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