scholarly journals Mutations That Reduce Sinapoylmalate Accumulation in Arabidopsis thaliana Define Loci With Diverse Roles in Phenylpropanoid Metabolism

Genetics ◽  
2001 ◽  
Vol 159 (4) ◽  
pp. 1741-1749
Author(s):  
Max Ruegger ◽  
Clint Chapple
Keyword(s):  
Arabidopsis Thaliana ◽  
Secondary Metabolites ◽  
Plant Development ◽  
Phenylpropanoid Metabolism ◽  
Normal Plant ◽  
Wild Type ◽  
Developmentally Regulated ◽  
Recessive Mutations ◽  
Uv Illumination ◽  
Cell Specificity

Abstract The products of phenylpropanoid metabolism in Arabidopsis include the three fluorescent sinapate esters sinapoylglucose, sinapoylmalate, and sinapoylcholine. The sinapoylmalate that accumulates in cotyledons and leaves causes these organs to appear blue-green under ultraviolet (UV) illumination. To find novel genes acting in phenylpropanoid metabolism, Arabidopsis seedlings were screened under UV for altered fluorescence phenotypes caused by changes in sinapoylmalate content. This screen identified recessive mutations at four Reduced Epidermal Fluorescence (REF) loci that reduced leaf sinapoylmalate content. Further analyses showed that the ref mutations affected other aspects of phenylpropanoid metabolism and some led to perturbations in normal plant development. A second class of mutations at the Bright Trichomes 1 (BRT1) locus leads to modest reductions in sinapate ester content; however, the most notable phenotype of brt1 mutants is the development of hyperfluorescent trichomes that appear to contain elevated levels of sinapate esters when compared to the wild type. These results indicate that at least five new loci affecting the developmentally regulated accumulation of phenylpropanoid secondary metabolites in Arabidopsis, and the cell specificity of their distribution, have been identified by screening for altered UV fluorescence phenotypes.

Characterisation of three shoot apical meristem mutants of Arabidopsis thaliana

Development ◽  
1992 ◽  
Vol 116 (2) ◽  
pp. 397-403 ◽  
Author(s):  
H. M. Ottoline Leyser ◽  
I. J. Furner
Keyword(s):  
Arabidopsis Thaliana ◽  
Root Growth ◽  
Shoot Apical Meristem ◽  
Apical Meristem ◽  
Floral Development ◽  
Wild Type ◽  
Recessive Mutations ◽  
Phenotypic Characterisation ◽  
Dicotyledonous Plants ◽  
And Function

The shoot apical meristem of dicotyledonous plants is highly regulated both structurally and functionally, but little is known about the mechanisms involved in this regulation. Here we describe the genetic and phenotypic characterisation of recessive mutations at three loci of Arabidopsis thaliana in which meristem structure and function are disrupted. The loci are Clavata1 (Clv1), Fasciata1 (Fas1) and Fasciata2 (Fas2). Plants mutant at these loci are fasciated having broad, flat stems and disrupted phyllotaxy. In all cases, the fasciations are associated with shoot apical meristem enlargement and altered floral development. While all the mutants share some phenotypic features they can be divided into two classes. The pleiotropic fas1 and fas2 mutants are unable to initiate wild- type organs, show major alterations in meristem structure and have reduced root growth. In contrast, clv1 mutant plants show near wild-type organ phenotypes, more subtle changes in shoot apical meristem structure and wild-type root growth.

scholarly journals Analysis of secondary metabolism and total chlorophyll content provides new insights into the role of A-tocopherol for wild type and VTE4 mutant Arabidopsis thaliana under different abiotic stresses

Genetika ◽  
2016 ◽  
Vol 48 (2) ◽  
pp. 445-462 ◽  
Author(s):  
Amir Khalatbari ◽  
Hawa Jaafar ◽  
Amir Khalatbari ◽  
Maziah Mahmood ◽  
Radziah Othman
Keyword(s):  
Arabidopsis Thaliana ◽  
Salt Stress ◽  
Water Stress ◽  
Secondary Metabolites ◽  
Chlorophyll Content ◽  
Abiotic Stresses ◽  
Total Chlorophyll ◽  
Water Deficiency ◽  
Wild Type ◽  
Total Chlorophyll Content

Plants experience different abiotic stresses under natural conditions including salinity, water deficit, low temperature and high light. Once plants are exposed to these stresses they might have a variety of responses physiologically and biochemically. In this study, we test this hypothesis in wild type Col-0 and vte4 mutant of Arabidopsis thaliana by measuring major secondary metabolites alongside with total chlorophyll content under different abiotic stresses namely salt stress, water stress and prolonged water deficiency. These stresses were imposed to the plants in separate experiments in which each treatment was replicated three times in a complete randomized design with factorial arrangement. It was concluded that under all abiotic stresses wild type Col-0 Arabidopsis plants showed stronger performance in terms of all major metabolites compared to vte4 mutant. ?-tocopherol deficiency in vte4 mutant plants led to lower accumulation of proline, total protein and total amino acids as well as starch and total sugars in comparison with wild type A. thaliana. Furthermore, all five secondary metabolites obtained the highest value under 100mM NaCl concentration (Salt stress), under 50% of field capacity (water stress) and under 8 days of water withholding (prolonged water deficiency). Wild type Col-0 resulted in higher level of total chlorophyll content under all abiotic stresses compared to mutant plants. Therefore, our results suggested that the loss of ?-tocopherol in vte4 mutant A.thaliana under different abiotic stresses affected the efficiency and the stability of central metabolism and photosynthetic apparatus.

scholarly journals 5-Fluoroindole resistance identifies tryptophan synthase beta subunit mutants in Arabidopsis thaliana.

Genetics ◽  
1995 ◽  
Vol 140 (1) ◽  
pp. 303-313
Author(s):  
A J Barczak ◽  
J Zhao ◽  
K D Pruitt ◽  
R L Last
Keyword(s):  
Arabidopsis Thaliana ◽  
Protein A ◽  
Beta Subunit ◽  
Alpha Subunit ◽  
Anthranilate Synthase ◽  
Tryptophan Synthase ◽  
Wild Type ◽  
Recessive Mutations ◽  
The Stability

Abstract A study of the biochemical genetics of the Arabidopsis thaliana tryptophan synthase beta subunit was initiated by characterization of mutants resistant to the inhibitor 5-fluoroindole. Thirteen recessive mutations were recovered that are allelic to trp2-1, a mutation in the more highly expressed of duplicate tryptophan synthase beta subunit genes (TSB1). Ten of these mutations (trp2-2 through trp2-11) cause a tryptophan requirement (auxotrophs), whereas three (trp2-100 through trp2-102) remain tryptophan prototrophs. The mutations cause a variety of changes in tryptophan synthase beta expression. For example, two mutations (trp2-5 and trp2-8) cause dramatically reduced accumulation of TSB mRNA and immunologically detectable protein, whereas trp2-10 is associated with increased mRNA and protein. A correlation exists between the quantity of mutant beta and wild-type alpha subunit levels in the trp2 mutant plants, suggesting that the synthesis of these proteins is coordinated or that the quantity or structure of the beta subunit influences the stability of the alpha protein. The level of immunologically detectable anthranilate synthase alpha subunit protein is increased in the trp2 mutants, suggesting the possibility of regulation of anthranilate synthase levels in response to tryptophan limitation.

scholarly journals Temperature-Sensitive, Vitamin-Requiring Mutants of Arabidopsis Thaliana

1965 ◽  
Vol 18 (2) ◽  
pp. 311 ◽  
Author(s):  
J Langridge
Keyword(s):  
Arabidopsis Thaliana ◽  
High Temperatures ◽  
Temperature Sensitive ◽  
Wild Type ◽  
X Ray ◽  
Recessive Mutations ◽  
Naturally Occurring ◽  
Induced Mutant

Three mutants of Arabidopsi8 requiring specific vitamins for growth at certain temperatures are described. All are due to recessive mutations of single wild-type genes. One X-ray-induced mutant is unable to synthesize thiamine at low tempera-tures because of a block in the phosphorylation or coupling of the immediate precursors. Two mutants which require biotin for growth at high temperatures are determined by recessive alleles of the same gene. These mutants comprise naturally occurring ecotypes in Spain and Austria. Experiments indicate that an inability to make biotin at high temperatures may be adaptively advantageous. The consequent cessation in growth is a balanced one, readily reversible by a lowering of temperature, which allows the plant to escape the irreversible sterilizing effect of heat.

scholarly journals Inhibition of cell expansion enhances cortical microtubule stability in the root apex of Arabidopsis thaliana

2021 ◽  
Vol 28 (1) ◽  
Author(s):  
Veronica Giourieva ◽  
Emmanuel Panteris
Keyword(s):  
Arabidopsis Thaliana ◽  
Cell Wall ◽  
Cell Expansion ◽  
Cortical Microtubule ◽  
Root Apex ◽  
Cellulose Synthase ◽  
Cellulose Biosynthesis ◽  
Cortical Microtubules ◽  
Wild Type ◽  
Microtubule Stability

Abstract Background Cortical microtubules regulate cell expansion by determining cellulose microfibril orientation in the root apex of Arabidopsis thaliana. While the regulation of cell wall properties by cortical microtubules is well studied, the data on the influence of cell wall to cortical microtubule organization and stability remain scarce. Studies on cellulose biosynthesis mutants revealed that cortical microtubules depend on Cellulose Synthase A (CESA) function and/or cell expansion. Furthermore, it has been reported that cortical microtubules in cellulose-deficient mutants are hypersensitive to oryzalin. In this work, the persistence of cortical microtubules against anti-microtubule treatment was thoroughly studied in the roots of several cesa mutants, namely thanatos, mre1, any1, prc1-1 and rsw1, and the Cellulose Synthase Interacting 1 protein (csi1) mutant pom2-4. In addition, various treatments with drugs affecting cell expansion were performed on wild-type roots. Whole mount tubulin immunolabeling was applied in the above roots and observations were performed by confocal microscopy. Results Cortical microtubules in all mutants showed statistically significant increased persistence against anti-microtubule drugs, compared to those of the wild-type. Furthermore, to examine if the enhanced stability of cortical microtubules was due to reduced cellulose biosynthesis or to suppression of cell expansion, treatments of wild-type roots with 2,6-dichlorobenzonitrile (DCB) and Congo red were performed. After these treatments, cortical microtubules appeared more resistant to oryzalin, than in the control. Conclusions According to these findings, it may be concluded that inhibition of cell expansion, irrespective of the cause, results in increased microtubule stability in A. thaliana root. In addition, cell expansion does not only rely on cortical microtubule orientation but also plays a regulatory role in microtubule dynamics, as well. Various hypotheses may explain the increased cortical microtubule stability under decreased cell expansion such as the role of cell wall sensors and the presence of less dynamic cortical microtubules.

scholarly journals Mutants of downy mildew resistance in Lactuca sativa (lettuce).

Genetics ◽  
1994 ◽  
Vol 137 (3) ◽  
pp. 867-874
Author(s):  
P A Okubara ◽  
P A Anderson ◽  
O E Ochoa ◽  
R W Michelmore
Keyword(s):  
Molecular Marker ◽  
Downy Mildew ◽  
Genomic Dna ◽  
Spontaneous Mutation ◽  
Multigene Families ◽  
Downy Mildew Resistance ◽  
Bremia Lactucae ◽  
Wild Type ◽  
Mildew Resistance ◽  
Recessive Mutations

Abstract As part of our investigation of disease resistance in lettuce, we generated mutants that have lost resistance to Bremia lactucae, the casual fungus of downy mildew. Using a rapid and reliable screen, we identified 16 distinct mutants of Latuca sativa that have lost activity of one of four different downy mildew resistance genes (Dm). In all mutants, only a single Dm specificity was affected. Genetic analysis indicated that the lesions segregated as single, recessive mutations at the Dm loci. Dm3 was inactivated in nine of the mutants. One of five Dm 1 mutants was selected from a population of untreated seeds and therefore carried a spontaneous mutation. All other Dm1, Dm3, Dm5/8 and Dm7 mutants were derived from gamma- or fast neutron-irradiated seed. In two separate Dm 1 mutants and in each of the eight Dm3 mutants analyzed, at least one closely linked molecular marker was absent. Also, high molecular weight genomic DNA fragments that hybridized to a tightly linked molecular marker in wild type were either missing entirely or were truncated in two of the Dm3 mutants, providing additional evidence that deletions had occurred in these mutants. Absence of mutations at loci epistatic to the Dm genes suggested that such loci were either members of multigene families, were critical for plant survival, or encoded components of duplicated pathways for resistance; alternatively, the genes determining downy mildew resistance might be limited to the Dm loci.

scholarly journals Extended JAZ degron sequence for plant hormone binding in jasmonate co-receptor of tomato SlCOI1-SlJAZ

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Rina Saito ◽  
Kengo Hayashi ◽  
Haruna Nomoto ◽  
Misuzu Nakayama ◽  
Yousuke Takaoka ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Plant Development ◽  
Genetic Modification ◽  
Tomato Plant ◽  
Plant Hormone ◽  
Herbivorous Insects ◽  
Hormone Binding ◽  
Plant Body

Abstract(+)-7-iso-Jasmonoyl-l-isoleucine (JA-Ile) is a lipid-derived phytohormone implicated in plant development, reproduction, and defense in response to pathogens and herbivorous insects. All these effects are instigated by the perception of JA-Ile by the COI1-JAZ co-receptor in the plant body, which in Arabidopsis thaliana is profoundly influenced by the short JAZ degron sequence (V/L)P(Q/I)AR(R/K) of the JAZ protein. Here, we report that SlJAZ-SlCOI1, the COI1-JAZ co-receptor found in the tomato plant, relies on the extended JAZ degron sequence (V/L)P(Q/I)AR(R/K)XSLX instead of the canonical JAZ degron. This finding illuminates our understanding of the mechanism of ligand perception by JA-Ile in this plant, and will inform both efforts to improve it by genetic modification of the SlCOI1-SlJAZ co-receptor, and the development of the synthetic agonists/antagonists.

Comparative Quantitative Trait Loci Mapping of Aliphatic, Indolic and Benzylic Glucosinolate Production in Arabidopsis thaliana Leaves and Seeds

Genetics ◽  
2001 ◽  
Vol 159 (1) ◽  
pp. 359-370 ◽  
Author(s):  
Daniel J Kliebenstein ◽  
Jonathan Gershenzon ◽  
Thomas Mitchell-Olds
Keyword(s):  
Arabidopsis Thaliana ◽  
Secondary Metabolites ◽  
Plant Environment ◽  
Aliphatic Glucosinolates ◽  
Glucosinolate Concentration ◽  
Indolic Glucosinolates ◽  
The Individual ◽  
Concentration Mapping ◽  
Indolic Glucosinolate ◽  
Aliphatic Glucosinolate

Abstract Secondary metabolites are a diverse set of plant compounds believed to have numerous functions in plant-environment interactions. Despite this importance, little is known about the regulation of secondary metabolite accumulation. We are studying the regulation of glucosinolates, a large group of secondary metabolites, in Arabidopsis to investigate how secondary metabolism is controlled. We utilized Ler and Cvi, two ecotypes of Arabidopsis that have striking differences in both the types and amounts of glucosinolates that accumulate in the seeds and leaves. QTL analysis identified six loci determining total aliphatic glucosinolate accumulation, six loci controlling total indolic glucosinolate concentration, and three loci regulating benzylic glucosinolate levels. Our results show that two of the loci controlling total aliphatic glucosinolates map to biosynthetic loci that interact epistatically to regulate aliphatic glucosinolate accumulation. In addition to the six loci regulating total indolic glucosinolate concentration, mapping of QTL for the individual indolic glucosinolates identified five additional loci that were specific to subsets of the indolic glucosinolates. These data show that there are a large number of variable loci controlling glucosinolate accumulation in Arabidopsis thaliana.

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