scholarly journals Identification of an arabinopyranosyltransferase fromPhyscomitrella patensinvolved in the synthesis of the hemicellulose xyloglucan

2017 ◽  
Author(s):  
Lei Zhu ◽  
Murali Dama ◽  
Markus Pauly
Keyword(s):  
Arabidopsis Thaliana ◽  
Transgenic Plants ◽  
Linkage Analysis ◽  
Double Mutant ◽  
Physcomitrella Patens ◽  
Proper Function ◽  
Side Chain ◽  
Glycosidic Linkage ◽  
Nmr Analysis ◽  
Wild Type

AbstractThe hemicellulose xyloglucan consists of a backbone of a β-1,4 glucan substituted with xylosyl moieties and many other, diverse sidechains that are important for its proper function. Many, but not all glycosyltransferases involved in the biosynthesis of xyloglucan have been identified. Here, we report the identification of an hitherto elusive xyloglucan:arabinopyranosyltransferase. This glycosyltransferase was isolated from the mossPhyscomitrella patens, where it acts as aXyloglucan “D”-side-chainTransferase (XDT). Heterologous expression ofXDTin theArabidopsis thalianadouble mutantmur3.1 xlt2, where xyloglucan consists of a xylosylated glucan without further glycosyl substituents, results in the production of the arabinopyranose-containing “D” side chain as characterized by oligosaccharide mass profiling, glycosidic linkage analysis, and NMR analysis. In addition, expression of a relatedPhyscomitrellaglycosyltransferase hortholog ofXLT2leads to the production of the galactose-containing “L” side chain. The presence of the “D” and “L” xyloglucan side chains inPpXDT mur3.1 xlt2andPpXLT2 mur3.1 xlt2transgenic plants, respectively, rescue the dwarfed phenotype of untransformedmur3.1 xlt2mutants to nearly wild-type height. Expression ofPpXDTandPpXLT2in the Arabidopsismur3.1 xlt2mutant also enhanced root growth.

The early-flowering mutant efs is involved in the autonomous promotion pathway of Arabidopsis thaliana

Development ◽  
1999 ◽  
Vol 126 (21) ◽  
pp. 4763-4770 ◽  
Author(s):  
W.J. Soppe ◽  
L. Bentsink ◽  
M. Koornneef
Keyword(s):  
Arabidopsis Thaliana ◽  
Flowering Time ◽  
Double Mutant ◽  
Plant Size ◽  
Early Flowering ◽  
Wild Type ◽  
Late Flowering ◽  
Long Day ◽  
Short Days ◽  
Transition To Flowering

The transition to flowering is a crucial moment in a plant's life cycle of which the mechanism has only been partly revealed. In a screen for early flowering, after mutagenesis of the late-flowering fwa mutant of Arabidopsis thaliana, the early flowering in short days (efs) mutant was identified. Under long-day light conditions, the recessive monogenic efs mutant flowers at the same time as wild type but, under short-day conditions, the mutant flowers much earlier. In addition to its early-flowering phenotype, efs has several pleiotropic effects such as a reduction in plant size, fertility and apical dominance. Double mutant analysis with several late-flowering mutants from the autonomous promotion (fca and fve) and the photoperiod promotion (co, fwa and gi) pathways of flowering showed that efs reduces the flowering time of all these mutants. However, efs is completely epistatic to fca and fve but additive to co, fwa and gi, indicating that EFS is an inhibitor of flowering specifically involved in the autonomous promotion pathway. A vernalisation treatment does not further reduce the flowering time of the efs mutant, suggesting that vernalisation promotes flowering through EFS. By comparing the length of the juvenile and adult phases of vegetative growth for wild-type, efs and the double mutant plants, it is apparent that efs mainly reduces the length of the adult phase.

scholarly journals The conserved PFT1 tandem repeat is crucial for proper flowering in Arabidopsis thaliana

2014 ◽  
Author(s):  
Pauline Rival ◽  
Maximilian O Press ◽  
Jacob Bale ◽  
Tanya Grancharova ◽  
Soledad F Undurraga ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Transgenic Plants ◽  
Tandem Repeat ◽  
Allelic Diversity ◽  
Selective Constraint ◽  
Dependent Manner ◽  
Functional Requirements ◽  
Loss Of Function ◽  
Wild Type ◽  
Genomic Regions

It is widely appreciated that short tandem repeat (STR) variation underlies substantial phenotypic variation in organisms. Some propose that the high mutation rates of STRs in functional genomic regions facilitate evolutionary adaptation. Despite their high mutation rate, some STRs show little to no variation in populations. One such STR occurs in the Arabidopsis thaliana gene PFT1 (MED25), where it encodes an interrupted polyglutamine tract. Though the PFT1 STR is large (~270 bp), and thus expected to be extremely variable, it shows only minuscule variation across A. thaliana strains. We hypothesized that the PFT1 STR is under selective constraint, due to previously undescribed roles in PFT1 function. We investigated this hypothesis using plants expressing transgenic PFT1 constructs with either an endogenous STR or with synthetic STRs of varying length. Transgenic plants carrying the endogenous PFT1 STR generally performed best across adult PFT1-dependent traits. In stark contrast, transgenic plants carrying a PFT1 transgene lacking the STR entirely phenocopied a pft1 loss-of-function mutant for flowering time phenotypes, and were generally hypomorphic for other traits, establishing the functional importance of this domain. Transgenic plants carrying various synthetic constructs occupied the phenotypic space between wild-type and pft1-loss-of-function mutants. By varying PFT1 STR length, we discovered that PFT1 can act as either an activator or repressor of flowering in a photoperiod-dependent manner. We conclude that the PFT1 STR is constrained to its approximate wild-type length by its various functional requirements. Our study implies that there is strong selection on STRs not only to generate allelic diversity, but also to maintain certain lengths pursuant to optimal molecular function.

Non-destructive X-ray analysis of Arabidopsis embryo mutants

1993 ◽  
Vol 3 (3) ◽  
pp. 167-170 ◽  
Author(s):  
R. J. Bino ◽  
J. W. Aartse ◽  
W. J. van der Burg
Keyword(s):  
Arabidopsis Thaliana ◽  
Double Mutant ◽  
Embryo Morphology ◽  
Wild Type ◽  
X Ray ◽  
Non Destructive ◽  
Mature Seeds

AbstractX-radiography is a simple, rapid and non-destructive method for analysing the morphology of embryos in dry, mature seeds of Arabidopsis thaliana. In wild type seeds, the cotyledons, hypocotyl and radicle tip can be readily distinguished. In seeds of the mutant types knolle, keule, and the double mutant keulelgnom, aberrations in embryo morphology can be visualized. X-radiography may therefore be useful in the isolation of embryo mutants from Arabidopsis seed samples.

scholarly journals Involvement of THH1, an Arabidopsis thaliana homologue of the TOM1 gene, in tobamovirus multiplication

2006 ◽  
Vol 87 (8) ◽  
pp. 2397-2401 ◽  
Author(s):  
Koki Fujisaki ◽  
Gerald B. Ravelo ◽  
Satoshi Naito ◽  
Masayuki Ishikawa
Keyword(s):  
Arabidopsis Thaliana ◽  
Coat Protein ◽  
Double Mutant ◽  
Detectable Level ◽  
Expression Level ◽  
Wild Type ◽  
Homologous Proteins ◽  
Single Mutant ◽  
Mutant Lines

The TOM1 and TOM3 genes of Arabidopsis thaliana encode homologous proteins that are required for tobamovirus multiplication. Although the A. thaliana genome encodes another TOM1-like gene, THH1, the tobamovirus coat protein (CP) does not accumulate to a detectable level in the tom1 tom3 double mutant. Here, double and triple mutants of tom1, tom3 and thh1 were generated to investigate whether THH1 functions to support tobamovirus multiplication. In the tom1 thh1 double mutant, the tobamovirus CP accumulated to a level that was detectable, but lower than that in the tom1 single mutant. In tom1 tom3 double-mutant lines overexpressing THH1, the tobamovirus CP accumulated to a level similar to that observed in wild-type plants. These results suggest that THH1 supports tobamovirus multiplication, but to a lesser extent than TOM1 and TOM3. The expression level of THH1 is lower than that of TOM1 and TOM3, which might explain the smaller contribution of THH1 to tobamovirus multiplication.

Tolerance to, and Uptake and Degradation of 2,4,6-Trinitrotoluene (TNT) are Enhanced by the Expression of a Bacterial Nitroreductase Gene in Arabidopsis thaliana

2005 ◽  
Vol 60 (3-4) ◽  
pp. 272-278 ◽  
Author(s):  
Mami Kurumata ◽  
Misa Takahashi ◽  
Atsushi Sakamoto ◽  
Juan L. Ramos ◽  
Ales Nepovim ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Transgenic Plants ◽  
Degradation Products ◽  
Plant Genome ◽  
Pcr Analysis ◽  
Wild Type ◽  
In Planta ◽  
Gene Encoding ◽  
Plant Body ◽  
Wide Range

Abstract Arabidopsis thaliana was transformed with a gene encoding a nitroreductase (NTR, E.C. 1.6.99.7) with activity against a wide range of nitroaromatic compounds. The gene was transferred from Escherichia coli by an Agrobacterium-mediated in planta method. The ob­tained seeds were sowed to produce T1 plants, and they were assayed for the integration of the transgene in the plant genome. Transgenic plants that were positive with the PCR analysis were self-pollinated to produce T2 generation plants. Seven lines obtained were assayed for the NTR activity. While the noil-transformed wild-type plants showed no detectable NTR activity, the enzyme activity of the transgenic plant lines was approx. 20 times higher. Using the line with the highest NTR activity, the phytoremediation characteristics of plants against 2,4,6-trinitrotoluene (TNT) was investigated. While the wild-type plants did not grow in the presence of 0.1 mᴍ TNT, the transgenic plants grew almost normally in this condition. The uptake of TNT by seedlings of transgenic plants increased by 7 to 8 times when they were floated on TNT solution. HPLC analysis showed that the peak due to TNT taken up into plant body was much smaller in the transgenic plants as compared with that of the wild type, and that a number of peaks attributable to the degradation products of TNT, including 4-amino-2,6-dinitrotoluene, were detected in the extract from the transgenic plants. This indi­cates that the expression of bacterial NTR improved the capability of plants to degrade TNT.

A Study of Arabidopsis Cold Stress Tolerance Improvement via AthHOS1-Targeting HOS1-AmiRNA Approach

2021 ◽  
Author(s):  
Marzieh Karimi ◽  
Behrouz Shiran ◽  
Mohammad Rabei ◽  
Hossein Fallahi ◽  
Bojana Banović Đeri
Keyword(s):  
Gene Expression ◽  
Arabidopsis Thaliana ◽  
Circadian Rhythm ◽  
Comparative Analysis ◽  
Low Temperature ◽  
Transgenic Plants ◽  
Cold Stress ◽  
Stress Tolerance ◽  
Low Temperatures ◽  
Wild Type

Abstract In this study the artificial microRNAs (amiRNAs) technology targeting HOS1 gene was tested for its applicability for the improvement of cold stress tolerance in Landsberg-0 (Ler-0) ecotype of Arabidopsis thaliana. The chosen approach was designed to suppress AtHOS1 gene expression through the overexpression of amiRNA-HOS1. The effect of AtHOS1-amiRNA overexpression to transgenic plants’ response to cold stress was determined by Real Time PCR. The expression levels of amiRNA and its target, AtHOS1 gene, were observed in 3-week old seedlings of T3 generation and in wild-type plants after 6h, 12h, 24h, 48h and 96h of their exposure to cold stress (4ºC). Comparative analysis revealed that AtHOS1-amiRNA negatively regulated AtHOS1 in transgenic plants upon plants lengthen exposure (for 48h and 96h) to low temperature (Pearson’s correlation coefficient of -0.407; P < 0.05). Even though prolonged cold stress caused extended up regulation of AtHOS1 in wild type plants, in transgenic plants AtHOS1-amiRNA suppression disturbed expected AtHOS1 circadian rhythm by preventing further AtHOS1 up regulation. Moreover, transgenic plants showed AtHOS1 down regulation 96h after the cold stress onset, due to sufficient overexpression of AtHOS1-amiRNA, which allowed cold signaling amplification in transgenic plants. As a result of that, cold-acclimated transformed plants displayed 17% higher freezing tolerance (-1°C to -8°C) in comparison to wild type plants, demonstrating the success of chosen approach in improving Arabidopsis tolerance to low temperatures, at least in Ler-0 ecotype.

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 Overexpression of the pitaya phosphoethanolamine N-methyltransferase gene (HpPEAMT) enhanced simulated drought stress in tobacco

2021 ◽  
Author(s):  
Ai-Hua Wang ◽  
Lan Yang ◽  
Xin-Zhuan Yao ◽  
Xiao-Peng Wen
Keyword(s):  
Drought Stress ◽  
Stress Response ◽  
Transgenic Plants ◽  
Drought Tolerance ◽  
Transgenic Tobacco ◽  
Sequence Similarity ◽  
Amino Acid Sequence Similarity ◽  
Transgenic Tobacco Plants ◽  
Wild Type ◽  
Tobacco Plants

AbstractPhosphoethanolamine N-methyltransferase (PEAMTase) catalyzes the methylation of phosphoethanolamine to produce phosphocholine and plays an important role in the abiotic stress response. Although the PEAMT genes has been isolated from many species other than pitaya, its role in the drought stress response has not yet been fully elucidated. In the present study, we isolated a 1485 bp cDNA fragment of HpPEAMT from pitaya (Hylocereus polyrhizus). Phylogenetic analysis showed that, during its evolution, HpPEAMT has shown a high degree of amino acid sequence similarity with the orthologous genes in Chenopodiaceae species. To further investigate the function of HpPEAMT, we generated transgenic tobacco plants overexpressing HpPEAMT, and the transgenic plants accumulated significantly more glycine betaine (GB) than did the wild type (WT). Drought tolerance trials indicated that, compared with those of the wild-type (WT) plants, the roots of the transgenic plants showed higher drought tolerance ability and exhibited improved drought tolerance. Further analysis revealed that overexpression of HpPEAM in Nicotiana tabacum resulted in upregulation of transcript levels of GB biosynthesis-related genes (NiBADH, NiCMO and NiSDC) in the leaves. Furthermore, compared with the wild-type plants, the transgenic tobacco plants displayed a significantly lower malondialdehyde (MDA) accumulation and higher activities of the superoxide dismutase (SOD) and peroxidase (POD) antioxidant enzymes under drought stress. Taken together, our results suggested that HpPEAMT enhanced the drought tolerance of transgenic tobacco.

scholarly journals First genome edited poinsettias: targeted mutagenesis of flavonoid 3′-hydroxylase using CRISPR/Cas9 results in a colour shift

2021 ◽  
Author(s):  
Daria Nitarska ◽  
Robert Boehm ◽  
Thomas Debener ◽  
Rares Calin Lucaciu ◽  
Heidi Halbwirth
Keyword(s):  
Transgenic Plants ◽  
Genome Editing ◽  
Ornamental Plants ◽  
Targeted Mutagenesis ◽  
Cloning And Expression ◽  
Euphorbia Pulcherrima ◽  
Loss Of Function ◽  
Wild Type ◽  
Promising Tool ◽  
Reddish Orange

AbstractThe CRISPR/Cas9 system is a remarkably promising tool for targeted gene mutagenesis, and becoming ever more popular for modification of ornamental plants. In this study we performed the knockout of flavonoid 3′-hydroxylase (F3′H) with application of CRISPR/Cas9 in the red flowering poinsettia (Euphorbia pulcherrima) cultivar ‘Christmas Eve’, in order to obtain plants with orange bract colour, which accumulate prevalently pelargonidin. F3′H is an enzyme that is necessary for formation of cyanidin type anthocyanins, which are responsible for the red colour of poinsettia bracts. Even though F3′H was not completely inactivated, the bract colour of transgenic plants changed from vivid red (RHS 45B) to vivid reddish orange (RHS 33A), and cyanidin levels decreased significantly compared with the wild type. In the genetically modified plants, an increased ratio of pelargonidin to cyanidin was observed. By cloning and expression of mutated proteins, the lack of F3′H activity was confirmed. This confirms that a loss of function mutation in the poinsettia F3′H gene is sufficient for obtaining poinsettia with orange bract colour. This is the first report of successful use of CRISPR/Cas9 for genome editing in poinsettia.

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