scholarly journals Genetic Analysis of Organ Fusion in Arabidopsis thaliana

Genetics ◽  
1998 ◽  
Vol 149 (2) ◽  
pp. 607-619
Author(s):  
Susan J Lolle ◽  
Wendy Hsu ◽  
Robert E Pruitt
Keyword(s):  
Reproductive Development ◽  
Floral Organ ◽  
Growth Responses ◽  
Wild Type ◽  
Multiple Alleles ◽  
Aerial Parts ◽  
Complementation Groups ◽  
Pollen Growth ◽  
Mutant Lines

Abstract Postgenital organ fusion occurs most commonly during reproductive development and is important in many angiosperms during genesis of the carpel. Although a number of mutants have been described that manifest ectopic organ fusion, little is known about the genes involved in regulating this process. In this article we describe the characterization of a collection of 29 Arabidopsis mutants showing an organ fusion phenotype. Mapping and complementation analyses revealed that the mutant alleles define nine different loci distributed throughout the Arabidopsis genome. Multiple alleles were isolated for the four complementation groups showing the strongest organ fusion phenotype while the remaining five complementation groups, all of which show only weak floral organ fusion, have a single representative allele. In addition to fusion events between aerial parts of the shoot, some mutants also show abnormal ovule morphology with adjacent ovules joined together at maturity. Many of the fusion mutants isolated have detectable differences in the rate at which chlorophyll can be extracted; however, in one case no difference could be detected between mutant and wild-type plants. In three mutant lines pollen remained unresponsive to contact with the mutant epidermis, demonstrating that organ fusion and pollen growth responses can be genetically separated from one another.

scholarly journals Genetic analysis of the Arabidopsis TIR1/AFB auxin receptors reveals both overlapping and specialized functions

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Michael J Prigge ◽  
Matthieu Platre ◽  
Nikita Kadakia ◽  
Yi Zhang ◽  
Kathleen Greenham ◽  
...  
Keyword(s):  
Genetic Analysis ◽  
Early Embryo ◽  
Wild Type ◽  
The Family ◽  
Dependent Inhibition ◽  
Root Gravitropism ◽  
Specialized Function ◽  
Mutant Lines

The TIR1/AFB auxin co-receptors mediate diverse responses to the plant hormone auxin. The Arabidopsis genome encodes six TIR1/AFB proteins representing three of the four clades that were established prior to angiosperm radiation. To determine the role of these proteins in plant development we performed an extensive genetic analysis involving the generation and characterization of all possible multiply-mutant lines. We find that loss of all six TIR1/AFB proteins results in early embryo defects and eventually seed abortion, and yet a single wild-type allele of TIR1 or AFB2 is sufficient to support growth throughout development. Our analysis reveals extensive functional overlap between even the most distantly related TIR1/AFB genes except for AFB1. Surprisingly, AFB1 has a specialized function in rapid auxin-dependent inhibition of root growth and early phase of root gravitropism. This activity may be related to a difference in subcellular localization compared to the other members of the family.

scholarly journals The Arabidopsis ALDP protein homologue COMATOSE is instrumental in peroxisomal acetate metabolism

2007 ◽  
Vol 406 (3) ◽  
pp. 399-406 ◽  
Author(s):  
Mark A. Hooks ◽  
James E. Turner ◽  
Elaine C. Murphy ◽  
Katherine A. Johnston ◽  
Sally Burr ◽  
...  
Keyword(s):  
Glyoxylate Cycle ◽  
Sequence Length ◽  
Acetate Metabolism ◽  
Soluble Carbohydrate ◽  
Wild Type ◽  
Abc Protein ◽  
Atp Binding Cassette Transporter ◽  
Mutant Lines ◽  
Simple Sequence

The Arabidopsis acn (acetate non-utilizing) mutants were isolated by fluoroacetate-resistant germination and seedling establishment. We report the characterization of the acn2 mutant. Physiological analyses of acn2 showed that it possessed characteristics similar to those of the mutants cts (COMATOSE)-1 and pxa [peroxisomal ABC (ATP-binding-cassette) transporter]1. The acn2 locus was mapped to within 3 cM of the CTS gene on the bottom arm of chromosome IV using CAPS (cleavage amplification polymorphism) and SSLP (simple sequence-length polymorphism) markers. Crossing acn2 and cts-1 failed to restore the fluoroacetate-sensitive phenotype, suggesting that these mutations were allelic. Sequencing of the ACN2 locus revealed a C→T nonsense mutation in exon 13, which would have resulted in the elimination of the C-terminal hemitransporter domain of the encoded protein. Neither the full-length CTS protein nor the truncated protein was detected on immunoblots using either C-terminal- or N-terminal-specific anti-CTS antibodies respectively, demonstrating the absence of the entire CTS protein in acn2 mutants. Emerged seedlings of both cts-1 and pxa1 alleles displayed increased resistance to FAc (monofluoroacetic acid) compared with the corresponding wild-type seedlings. Complementation studies showed that mutation of the CTS gene was responsible for the FAc-resistant phenotype, as when the wild-type protein was expressed in both the cts-1 and pxa1 mutant lines, the strains became FAc-sensitive. Feeding studies confirmed that both acn2 and cts-1 mutants were compromised in their ability to convert radiolabelled acetate into soluble carbohydrate. These results demonstrate a role for the ABC protein CTS in providing acetate to the glyoxylate cycle in developing seedlings.

scholarly journals Cycloheximide-resistant temperature-sensitive lethal mutations of Saccharomyces cerevisiae.

Genetics ◽  
1988 ◽  
Vol 119 (2) ◽  
pp. 303-315
Author(s):  
J H McCusker ◽  
J E Haber
Keyword(s):  
Inhibitory Concentration ◽  
Temperature Sensitive ◽  
Nonpermissive Temperature ◽  
Wild Type ◽  
Lethal Mutations ◽  
New Methods ◽  
Similar Temperature ◽  
Complementation Groups ◽  
Wild Type Yeast

Abstract We describe the isolation and preliminary characterization of a set of pleiotropic mutations resistant to the minimum inhibitory concentration of cycloheximide and screened for ts (temperature-sensitive) growth. These mutations fall into 22 complementation groups of cycloheximide resistant ts lethal mutations (crl). None of the crl mutations appears to be allelic with previously isolated mutations. Fifteen of the CRL loci have been mapped. At the nonpermissive temperature (37 degrees), these mutants arrest late in the cell cycle after several cell divisions. Half of these mutants are also unable to grow at very low temperatures (5 degrees). Although mutants from all of the 22 complementation groups exhibit similar temperature-sensitive phenotypes, an extragenic suppressor of the ts lethality of crl3 does not relieve the ts lethality of most other crl mutants. A second suppressor mutation allows crl10, crl12, and crl14 to grow at 37 degrees but does not suppress the ts lethality of the remaining crl mutants. We also describe two new methods for the enrichment of auxotrophic mutations from a wild-type yeast strain.

scholarly journals Isolation and Functional Analysis of a PISTILLATA-like MADS-Box Gene from Argan Tree (Argania spinosa)

Plants ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1665
Author(s):  
Marwa Louati ◽  
Blanca Salazar-Sarasua ◽  
Edelín Roque ◽  
José Pío Beltrán ◽  
Amel Salhi Hannachi ◽  
...  
Keyword(s):  
Phylogenetic Analyses ◽  
Functional Characterization ◽  
Reproductive Development ◽  
Genetic Network ◽  
Floral Organ ◽  
Local Economy ◽  
Mads Box ◽  
Argania Spinosa ◽  
Mads Box Gene

Argan trees (Argania spinosa) belong to a species native to southwestern Morocco, playing an important role in the environment and local economy. Argan oil extracted from kernels has a unique composition and properties. Argan trees were introduced in Tunisia, where hundreds of trees can be found nowadays. In this study, we examined reproductive development in Argan trees from four sites in Tunisia and carried out the functional characterization of a floral homeotic gene in this non-model species. Despite the importance of reproductive development, nothing is known about the genetic network controlling flower development in Argania spinosa. Results obtained in several plant species established that floral organ development is mostly controlled by MADS-box genes and, in particular, APETALA3 (AP3) and PISTILLATA (PI) homologs are required for proper petal and stamen identity. Here, we describe the isolation and functional characterization of a MADS-box gene from Argania spinosa. Phylogenetic analyses showed strong homology with PI-like proteins, and the expression of the gene was found to be restricted to the second and third whorls. Functional homology with Arabidopsis PI was demonstrated by the ability of AsPI to confer petal and stamen identity when overexpressed in a pi-1 mutant background. The identification and characterization of this gene support the strong conservation of PI homologs among distant angiosperm plants.

scholarly journals Spontaneous Root-Nodule Formation in the Model Legume Lotus japonicus: A Novel Class of Mutants Nodulates in the Absence of Rhizobia

2006 ◽  
Vol 19 (4) ◽  
pp. 373-382 ◽  
Author(s):  
Leïla Tirichine ◽  
Euan K. James ◽  
Niels Sandal ◽  
Jens Stougaard
Keyword(s):  
Root Nodule ◽  
Lotus Japonicus ◽  
Nodule Development ◽  
Nodule Formation ◽  
Wild Type ◽  
Model Legume ◽  
Isolation And Characterization ◽  
Mutant Lines ◽  
Spontaneous Nodules

Root-nodule development in legumes is an inducible developmental process initially triggered by perception of lipochitin-oligosaccharide signals secreted by the bacterial microsymbiont. In nature, rhizobial colonization and invasion of the legume root is therefore a prerequisite for formation of nitrogen-fixing root nodules. Here, we report isolation and characterization of chemically induced spontaneously nodulating mutants in a model legume amenable to molecular genetics. Six mutant lines of Lotus japonicus were identified in a screen for spontaneous nodule development under axenic conditions, i.e., in the absence of rhizobia. Spontaneous nodules do not contain rhizobia, bacteroids, or infection threads. Phenotypically, they resemble ineffective white nodules formed by some bacterial mutants on wild-type plants or certain plant mutants inoculated with wild-type Mesorhizobium loti. Spontaneous nodules formed on mutant lines show the ontogeny and characteristic histological features described for rhizobia-induced nodules on wild-type plants. Physiological responses to nitrate and ethylene are also maintained, as elevated levels inhibit spontaneous nodulation. Activation of the nodule developmental program in spontaneous nodules was shown for the early nodulin genes Enod2 and Nin, which are both upregulated in spontaneous nodules as well as in rhizobial nodules. Both monogenic recessive and dominant spontaneous nodule formation (snf) mutations were isolated in this mutant screen, and map positions were determined for three loci. We suggest that future molecular characterization of these mutants will identify key plant determinants involved in regulating nodulation and provide new insight into plant organ development.

scholarly journals Identification and Characterization of Autosomal Genes That Interact With glass in the Developing Drosophila Eye

Genetics ◽  
1996 ◽  
Vol 142 (4) ◽  
pp. 1199-1213
Author(s):  
Chaoyong Ma ◽  
Hui Liu ◽  
Ying Zhou ◽  
Kevin Moses
Keyword(s):  
Photoreceptor Cell ◽  
Autosomal Dominant ◽  
Compound Eye ◽  
Photoreceptor Cells ◽  
Genetic Screens ◽  
Morphogenetic Furrow ◽  
Multiple Alleles ◽  
Complementation Groups ◽  
Identification And Characterization

Abstract The glass gene encodes a zinc finger, DNA-binding protein that is required for photoreceptor cell development in Drosophila melanogaster. In the developing compound eye, glass function is regulated at two points: (1) the protein is expressed in all cells' nuclei posterior to the morphogenetic furrow and (2) the ability of the Glass protein to regulate downstream genes is largely limited to the developing photoreceptor cells. We conducted a series of genetic screens for autosomal dominant second-site modifiers of the weak allele glass3, to discover genes with products that may regulate glass function at either of these levels. Seventy-six dominant enhancer mutations were recovered (and no dominant suppressors). Most of these dominant mutations are in essential genes and are associated with recessive lethality. We have assigned these mutations to 23 complementation groups that include multiple alleles of Star and hedgehog as well as single alleles of Delta, roughened eye, glass and hairy. Mutations in 18 of the complementation groups are embryonic lethals, and of these, 13 show abnormal adult retinal phenotypes in homozygous clones, usually with altered numbers of photoreceptor cells in some of the ommatidia.

scholarly journals A SUPPRESSOR OF snf1 MUTATIONS CAUSES CONSTITUTIVE HIGH-LEVEL INVERTASE SYNTHESIS IN YEAST

Genetics ◽  
1984 ◽  
Vol 107 (1) ◽  
pp. 19-32
Author(s):  
Marian Carlson ◽  
Barbara C Osmond ◽  
Lenore Neigeborn ◽  
David Botstein
Keyword(s):  
Genetic Characterization ◽  
Glucose Repression ◽  
Invertase Activity ◽  
Complementation Group ◽  
Regulatory Function ◽  
Wild Type ◽  
Suppressor Mutations ◽  
Complementation Groups ◽  
High Level

ABSTRACT The SNF1 gene product of Saccharomyces cerevisiae is required to derepress expression of many glucose-repressible genes, including the SUC2 structural gene for invertase. Strains carrying a recessive snf1 mutation are unable to ferment sucrose. We have isolated 30 partial phenotypic revertants of a snf1 mutant that were able to ferment sucrose. Genetic characterization of these revertants showed that the suppressor mutations were all recessive and defined eight complementation groups, designated ssn1 through ssn8 (suppressor of snf1). The revertants were assayed for secreted invertase activity, and although activity was detected in members of each complementation group, only the ssn6 strains contained wild-type levels. Synthesis of secreted invertase in ssn6 strains was found to be constitutive, that is, insensitive to glucose repression; moreover, the ssn6 mutations also conferred constitutivity in a wild-type (SNF1) genetic background and are, therefore, not merely suppressors of snf1. Pleiotropic defects were observed in ssn6 mutants. Genetic analysis suggested that the ssn6 mutations are allelic to the cyc8 mutation isolated by R. J. Rothstein and F. Sherman, which causes increased production of iso-2-cytochrome c. The data suggest a regulatory function for SSN6.

scholarly journals Characterization of triosephosphate isomerase mutants with reduced enzyme activity in Mus musculus.

Genetics ◽  
1989 ◽  
Vol 123 (4) ◽  
pp. 837-844 ◽  
Author(s):  
S Merkle ◽  
W Pretsch
Keyword(s):  
Enzyme Activity ◽  
Triosephosphate Isomerase ◽  
Hematological Parameters ◽  
Glucose Consumption ◽  
Dominant Mode ◽  
Metabolic Energy ◽  
Wild Type ◽  
Total Lack ◽  
Mutant Lines

Abstract Four heterozygous triosephosphate isomerase (TPI) mutants with approximately 50% reduced activity in blood compared to wild type were detected in offspring of 1-ethyl-1-nitrosourea treated male mice. Breeding experiments displayed an autosomal, dominant mode of inheritance for the mutations. All mutations were found to be homozygous lethal at an early postimplantation stage of embryonic development, probably due to a total lack of TPI activity and consequently to the inability to utilize glucose as a source of metabolic energy. Although activity alteration was also found in liver, lung, kidney, spleen, heart, brain and muscle the TPI deficiency in heterozygotes has no influence on the following physiological traits: hematological parameters, plasma glucose, glucose consumption of blood cells, body weight and organo-somatic indices of liver, spleen, heart, kidney and lung. Biochemical investigations of TPI in the four mutant lines indicated no difference of physicochemical properties compared to the wild type. Results from immunoinactivation assays indicate that the decrease of enzyme activity corresponds to a decrease in the level of an immunologically active moiety. It is suggested that the mutations have affected the Tpi-1 structural locus and resulted in alleles which produce no detectable enzyme activity and no immunologically cross-reacting material. The study furthermore suggests one functional TPI gene per haploid genome in the erythrocyte and seven other tested organs of the mouse.

scholarly journals (296) Genetic and Molecular Characterization of Putative Ethylene Mutants in Antirrhinum majus

HortScience ◽  
2006 ◽  
Vol 41 (4) ◽  
pp. 1079B-1079
Author(s):  
Leslie Heffron ◽  
Emily Jordan ◽  
Jackie Nugent ◽  
Schuyler Korban
Keyword(s):  
Gene Expression ◽  
Culture Medium ◽  
Regulation Of Gene Expression ◽  
Acc Synthase ◽  
Antirrhinum Majus ◽  
Cdna Clones ◽  
Complementation Groups ◽  
Exogenous Ethylene ◽  
Mutant Lines

Sixteen putative ethylene mutant Antirrhinum majus (snapdragon) lines, derived from 1-aminocyclopropane-1-carboxylic acid (ACC) screening, were crossed in a full diallel that included the wild-type line to determine allelism/complementation groups. Seeds from these crosses were screened on a tissue culture medium containing 5 μM ACC to elucidate the response to exogenous ethylene treatment. Additionally, five of the mutant lines along with an inbred control, from which the mutants were derived, were analyzed using RT-PCR to determine regulation of gene expression in vegetative (roots, shoots, leaves, and sepals) and floral (six stages of flowering, from green bud to post-pollination) tissues using six different ACC synthase (ACS) cDNA clones and two different ethylene receptor (ETR) cDNA clones, all derived from Antirrhinum majus, as probes. Differential regulation of gene expression for ACS and ETR were observed in some tissues and at different stages of floral development.

scholarly journals Characterization of wheat lacking B-type starch granules

2021 ◽  
Author(s):  
Benedetta Saccomanno ◽  
Pierre Berbezy ◽  
Kim Findlay ◽  
Jennifer Shoesmith ◽  
Cristobal Uauy ◽  
...  
Keyword(s):  
Starch Granule ◽  
Starch Content ◽  
Starch Granules ◽  
Wild Type ◽  
Bread Making ◽  
Wheat Varieties ◽  
Alcohol Production ◽  
Mutant Lines ◽  
B Granules

ABSTRACTThe physicochemical and agronomical properties of a new form of bread wheat, lacking B-type starch granules (BlessT) was assessed. Three BlessT mutant lines, made by combining homoeologous deletions of BGC1, a gene responsible for the control of B-granule content were compared with two sibling lines with normal starch phenotype and the parent line, cv. Paragon. Quantification of starch granule size and number in developing grain confirmed the lack of small, B-type starch granules throughout development in BlessT. Most starch, flour, grain and loaf characteristics did not vary between BlessT and the wild type sibling controls. However, BlessT starches had higher water absorption, reduced grain hardness and higher protein content, and dough made from BlessT flour required more water and had increased elasticity. Despite the lack of B-granules, BlessT lines do not display a significant decrease in total starch content suggesting that it should be possible to produce commercial wheat varieties that lack B-type starch granules without compromising yield. These findings support the potential utility of this novel type of wheat as a specialist crop in applications ranging from bread making and alcohol production to improved industrial starch products.

Sign in / Sign up

Export Citation Format

Share Document