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1.
An Arabidopsis deletion mutant was fortuitously identified from the alpha population of T-DNA insertional mutants generated
at the University of Wisconsin Arabidopsis Knockout Facility. Segregation and reciprocal crosses indicated that the mutant
was a gametophytic pollen sterile mutant. Pollen carrying the mutation has the unusual phenotype that it is viable, but cannot
germinate. Thus, the mutant was named pollen germination defective mutant 1 (pgd1), based on the pollen phenotype. Flanking sequences of the T-DNA insertion in the pgd1 mutant were identified by thermal asymmetric interlaced (TAIL) PCR. Sequencing of bands from TAIL PCR revealed that the T-DNA
was linked to the gene XLG1, At2g23460, at its downstream end, while directly upstream of the T-DNA was a region between At2g22830 and At2g22840, which
was 65 genes upstream of XLG1. Southern blotting and genomic PCR confirmed that the 65 genes plus part of XLG1 were deleted in the pgd1 mutant. A 9,177 bp genomic sequence containing the XLG1 gene and upstream and downstream intergenic regions could not rescue the pgd1 pollen phenotype. One or more genes from the deleted region were presumably responsible for the pollen germination defect
observed in the pgd1 mutant. Because relatively few mutations have been identified that affect pollen germination independent of any effect on
pollen viability, this mutant line provides a new tool for identification of genes specifically involved in this phase of
the reproductive cycle. 相似文献
2.
Background
Differentiating Dictyostelium discoideum amoebae respond upon cAMP-stimulation with an increase in the cytosolic free Ca2+ concentration ([Ca2+]i) that is composed of liberation of stored Ca2+ and extracellular Ca2+-influx. In this study we investigated whether intracellular cAMP is involved in the control of [Ca2+]i. 相似文献3.
Agnieszka Katarzyna Banaś Weronika Krzeszowiec Jerzy Dobrucki Halina Gabryś 《Acta Physiologiae Plantarum》2010,32(4):773-779
A dynamic cytoskeleton able to recognize and respond to both abiotic and biotic stimuli is necessary for the proper functioning
of a living cell. The cytoskeleton is involved in cell growth and division, maintenance of cell shape, cytoplasmic streaming,
and organelle movements. Numerous studies have focused on the relationships between sugar metabolism, sugar signaling, and
the cytoskeleton in yeast and animal cells. Data on such connections in plants are scarce. In the present study we investigated
the effects of exogenously delivered sugars on the plant actin cytoskeleton. Detached Arabidopsis thaliana leaves were incubated with sugars for 2 days and the cytoskeleton was visualized using fluorescent-labeled phalloidin. Glucose
and sucrose did not influence the pattern of the actin cytoskeleton. In contrast, mannose caused the disappearance of filamentous
structures and generated actin foci. The symptoms started to be visible after 24 h of the exposure to mannose. The effect
did not occur in Nicotiana tabacum mesophyll cells. This insensitivity was probably due to the presence of phosphomannose isomerase in tobacco cells. Mannose
is commonly used as a selection marker for the transformation of plants lacking the enzymes responsible for the metabolism
of mannose-6-phosphate. Exposure to this hexose has been linked with DNA fragmentation and a release of cytochrome c from mitochondria. Both responses are treated as features of programmed cell death. However, in our experiments no DNA laddering
was observed in mannose-treated Arabidopsis leaves. 相似文献
4.
A new deletion allele of the APETALA1 (AP1) gene encoding a type II MADS-box protein with the key role in the initiation of flowering and development of perianth organs has been identified in A. thaliana. The deletion of seven amino acids in the conserved region of the K domain in the ap1-20 mutant considerably delayed flowering and led to a less pronounced abnormality in the corolla development compared to the weak ap1-3 and intermediate ap1-6 alleles. At the same time, a considerable stamen reduction has been revealed in ap1-20 as distinct from ap1-3 and ap1-6 alleles. These data indicate that the K domain of AP1 can be crucial for the initiation of flowering and expression regulation of B-class genes controlling stamen development. 相似文献
5.
Arabidopsis ACT2 represents an ancient class of vegetative plant actins and is strongly and constitutively expressed in almost all Arabidopsis sporophyte vegetative tissues. Using the beta glucuronidase report system, the studies showed that ACT2 5′ regulatory region was significantly more active than CaMV 35S promoter in Arabidopsis seedlings and gametophyte vegetative tissues of Physcomitrella patens. Its activity was also observed in rice and maize seedlings. Thus, the ACT2 5′ regulatory region could potentially serve as a strong regulator to express a transgene in divergent plant species. ACT2 5′ regulatory region contained 15 conserved sequence elements, an ancient intron in its 5′ un-translated region (5′ UTR),
and a purine-rich stretch followed by a pyrimidine-rich stretch (PuPy). Mutagenesis and deletion analysis illustrated that
some of the conserved sequence elements and the region containing PuPy sequences played regulatory roles in Arabidopsis. Interestingly, mutation of the conserved elements did not lead a dramatic change in the activity of ACT2 5′ regulatory region. The ancient intron in ACT2 5′ UTR was required for its strong expression in both Arabidopsis and P. patens, but did not fully function as a canonical intron. Thus, it was likely that some of the conserved sequence elements and gene
structures had been preserved in ACT2 5′ regulatory region over the course of land plant evolution partly due to their functional importance. The studies provided
additional evidences that identification of evolutionarily conserved features in non-coding region might be used as an efficient
strategy to predict gene regulatory elements. 相似文献
6.
G. A. Pozhvanov A. E. Gobova M. P. Bankin K. Vissenberg S. S. Medvedev 《Russian Journal of Plant Physiology》2016,63(5):587-596
Gravitropism, the directed plant growth with respect to the gravity vector, is regulated by auxin and its polar transport system, several secondary messengers, and by the cytoskeleton. Recently we have shown that the actin cytoskeleton in the root transition zone of Arabidopsis thaliana (L.) Heynh was rearranged after gravistimulation (rotation by 90°): the fraction of axially aligned microfilaments decreased and the fraction of oblique and transversally-oriented microfilaments increased. In the present research we have studied the effect of ethylene and inhibitors of its synthesis on actin cytoskeleton rearrangement during the gravitropic response. Application of the ethylene releasing substance ethephon to A. thaliana seedlings led to the disassembly of actin microfilaments as well as their broad angle distribution in cells of the root transition zone. This actin rearrangement was escaped by treatment with the ethylene synthesis inhibitor aminoethoxyvinylglycine (AVG). Another negative regulator of ethylene, salicylic acid, was shown to disturb actin microfilament rearrangement as well. We conclude that ethylene is essential for the process of actin cytoskeleton rearrangement in root cortex cells during the gravitropic bending response. 相似文献
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8.
We isolated several mutants of Arabidopsis thaliana (L.) Heynh. that accumulated less anthocyanin in the plant tissues, but had seeds with a brown color similar to the wild-type.
These mutants were allelic with the anthocyaninless1 (anl1) mutant that has been mapped at 15.0 cM of chromosome 5. We performed fine mapping of the anl1 locus and determined that ANL1 is located between the nga106 marker and a marker corresponding to the MKP11 clone. About 70 genes are located between these
two markers, including three UDP-glucose:flavonoid-3-O-glucosyltransferase-like genes and a glutathione transferase gene (TT19). A mutant of one of the glucosyltransferase genes (At5g17050) was unable to complement the anl1 phenotype, showing that the ANL1 gene encodes UDP-glucose:flavonoid-3-O-glucosyltransferase. ANL1 was expressed in all tissues examined, including rosette leaves, stems, flower buds and roots. ANL1 was not regulated by TTG1. 相似文献
9.
Sonja Vorwerk Celine Schiff Marjorie Santamaria Serry Koh Marc Nishimura John Vogel Chris Somerville Shauna Somerville 《BMC plant biology》2007,7(1):35
Background
The hypersensitive necrosis response (HR) of resistant plants to avirulent pathogens is a form of programmed cell death in which the plant sacrifices a few cells under attack, restricting pathogen growth into adjacent healthy tissues. In spite of the importance of this defense response, relatively little is known about the plant components that execute the cell death program or about its regulation in response to pathogen attack. 相似文献10.
Aminoacyl-tRNA synthetases (aaRSs) decipher the genetic code, covalently linking amino acids to cognate tRNAs, thus preparing substrates for the process of translation. Although aaRSs funtion primarily in translation and are localized in cytosol, mitochondria and chloroplasts there are many reports on their additional functions and subcellular destinations beyond translation. However, data on plant aaRSs are scarce. Initial analysis of amino acid sequence of Arabidopsis thaliana seryl-tRNA synthetase (SerRS) suggested that protein contains putative nuclear localization signals. GFP-localization experiments in transiently transformed epidermal onion cells and Arabidopsis protoplasts gave ambiguous results because in some cells SerRS appeared to be dually localized to both cytosol and nucleus. However, data obtained on transgenic lines expressing SerRS-TAP and GFP-SerRS revealed exclusive cytosolic location of SerRS. Subcellular distribution of SerRS did not change during stress. Cytosolic Arabidopsis SerRS was expressed and purified. The enzyme efficiently aminoacylated eukaryotic and bacterial tRNAsSer, that are structurally very different. Given the fact that the same behavior was previously shown for monocot maize SerRS, it seems that plant SerRSs exhibit unusually broad tRNASer specificity, unlike SerRSs from other organisms. Possible functional implications of this unique characteristic of plant SerRSs are discussed. 相似文献
11.
Jakub Nowosad Alfred Stach Idalia Kasprzyk Elżbieta Weryszko-Chmielewska Krystyna Piotrowska-Weryszko Małgorzata Puc Łukasz Grewling Anna Pędziszewska Agnieszka Uruska Dorota Myszkowska Kazimiera Chłopek Barbara Majkowska-Wojciechowska 《Aerobiologia》2016,32(3):453-468
The aim of the study was to create and evaluate models for predicting high levels of daily pollen concentration of Corylus, Alnus, and Betula using a spatiotemporal correlation of pollen count. For each taxon, a high pollen count level was established according to the first allergy symptoms during exposure. The dataset was divided into a training set and a test set, using a stratified random split. For each taxon and city, the model was built using a random forest method. Corylus models performed poorly. However, the study revealed the possibility of predicting with substantial accuracy the occurrence of days with high pollen concentrations of Alnus and Betula using past pollen count data from monitoring sites. These results can be used for building (1) simpler models, which require data only from aerobiological monitoring sites, and (2) combined meteorological and aerobiological models for predicting high levels of pollen concentration. 相似文献
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14.
The ability of the CRE recombinase to catalyze excision of a DNA fragment flanked by directly repeated lox sites has been exploited to modify gene expression and proved to function well in particular case studies. However, very
often variability in CRE expression and differences in efficiency of CRE-mediated recombination are observed. Here, various approaches were investigated
to reproducibly obtain optimal CRE activity. CRE recombination was analyzed either by transforming the CRE T-DNA into plants
containing a lox-flanked fragment or by transforming a T-DNA harboring a lox-flanked fragment into plants producing the CRE recombinase. Although somatic CRE-mediated excision of a lox-flanked fragment was obtained in all transformants, a variable amount of germline-transmitted deletions was found among different
independent transformants, irrespective of the orientation of transformation. Also, the efficiency of CRE-mediated excision
correlated well with the CRE mRNA level. In addition, CRE-mediated fragment excision was compared after floral dip and after root tissue transformation
when transforming in a CRE-expressing background. Importantly, less CRE activity was needed to excise the lox-flanked fragment from the transferred T-DNA after root tissue transformation than after floral dip transformation. We hypothesize
that this is correlated with the lower T-DNA copy number inserted during root transformation as compared to floral dip transformation.
Gordana Marjanac and Annelies De Paepe contributed equally to this work. 相似文献
15.
An Arabidopsis thaliana pectin methylesterase that was not predicted to contain any signaling sequence was produced in E. coli and purified using a His tag added at its N-terminus. The enzyme demethylesterified Citrus pectin with a Km of 0.86 mg/ml. The enzyme did not require salt for activity and was found to be relatively temperature-sensitive. The precipitation of enzyme-treated pectin by CaCl2 suggested that the enzyme had a blockwise mode of pectin demethylesterification. A purified kiwi (Actinidia chinensis) pectin methylesterase inhibitor had no effect on the activity of the enzyme whereas it strongly inhibited a flax pectin methylesterase. A model of the protein structure revealed that an extra amino acid sequence in this particular Arabidopsis pectin methylesterase could form a ss-strand outside the core structure, which might be preventing the inhibitor from binding the protein. 相似文献
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17.
Michela Landoni Alessandra De Francesco Massimo Galbiati Chiara Tonelli 《Plant molecular biology》2010,74(3):235-247
Calmodulin (CAM) is an ubiquitous calcium binding protein whose function is to translate the signals, perceived as calcium
concentration variations, into the appropriate cellular responses. In Arabidopsis
thaliana there are 4 CAM isoforms which are highly similar, encoded by 7 genes, and one possible explanation proposed for the evolutionary
conservation of the CAM gene family is that the different genes have acquired different functions so that they play possibly overlapping but non-identical
roles. Here we report the characterization of the Arabidopsis mutant cam2-2, identified among the lines of the gene-trapping collection EXOTIC because of a distorted segregation of kanamycin resistance.
Phenotypic analysis showed that in normal growth conditions cam2-2 plants were indistinguishable from the wild type while genetic analysis showed a reduced transmission of the cam2-2 allele through the male gametophyte and in vitro pollen germination revealed a reduced level of germination in comparison
with the wild type. These results provide genetic evidence of the involvement of a CAM gene in pollen germination and support the theory of functional diversification of the CAM gene family. 相似文献
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19.
K. B. McIntosh J. L. Hulm L. W. Young P. C. Bonham-Smith 《Plant Molecular Biology Reporter》2004,22(1):53-61
Stable transformation ofArabidopsis thaliana is a lengthy process that involves up to 3 mo of plant growth and seed selection. We have developed a rapid, 3-wk transient
assay system to test the functionality ofcis-regulatory regions controlling expression of a reporter gene in plants before undertaking stable transformation. Two-week-oldArabidopsis seedlings were vacuum-infiltrated withAgrobacterium tumefaciens cultures carrying various upstream regulatory regions controllinguidA (β-glucuronidase [GUS]) expression. Seedlings were fixed and stained for GUS activity 3–5 d following infiltration. Regulatory
regions tested in this system include the cauliflower mosaic virus (CaMV)35S promoter, the upstream regulatory region of ribosomal protein geneL23A-1, and a temperature-inducible regulatory region (HSP101B) also fromArabidopsis. The percentage of seedlings positive for GUS activity varied depending on the construct used, with the CaMV35S promoter producing the highest number of GUS-positive seedlings. Temperature induction treatments elicited increased GUS
expression in seedlings transformed with theHSP101B regulatory region. Regardless of construct, GUS expression levels were higher in seedlings collected 5 d followingAgrobacterium infiltration than those collected 3–4 d postinfiltration. 相似文献