Showing papers on "Arabidopsis published in 1986"

A highly repeated DNA sequence in Arabidopsis thaliana

Abstract: Three members of a family of highly repeated DNA sequences from Arabidopsis thaliana have been cloned and characterized. The repeat unit has an average length of 180 bp and is tandemly repeated in arrays longer than 50 kb. This family represents more than one percent of the Arabidopsis genome. Sequence comparisons with tandemly repeated DNA sequences from other Cruciferae species show several regions of homology and a similar length of the repeat unit. Homologies are also found to highly repeated sequences from other plant species. When the sequence CCGG occurs in the repeated DNA, the inner cytosine is generally methylated.

Transformation of Arabidopsis thaliana with Agrobacterium tumefaciens

Abstract: Transformed Arabidopsis thaliana plants have been produced by a modified leaf disk transformation-regeneration method Leaf pieces from sterilely grown plants were precultured for 2 days and inoculated with an Agrobacterium tumefaciens strain containing an avirulent Ti (tumor-inducing) plasmid with a chimeric gene encoding hygromycin resistance After cocultivation for 2 days, the leaf pieces were placed on a medium that selects for hygromycin resistance Shoots regenerated within 3 months and were excised, rooted, and transferred to soil Transformation was confirmed by opine production, hygromycin resistance, and DNA blot hybridization of both primary transformants and progeny This process for producing transgenic Arabidopsis plants should enhance the usefulness of the species for experimental biology

Molecular cloning and DNA sequence of the Arabidopsis thaliana alcohol dehydrogenase gene.

Abstract: Arabidopsis thaliana provides an excellent experimental plant system for molecular genetics because of its remarkably small genome size, near absence of dispersed middle repetitive DNA, and short life cycle. We have cloned and determined the nucleotide sequence of a single-copy gene from A. thaliana likely to be the gene encoding alcohol dehydrogenase (ADH; alcohol:NAD+ oxidoreductase, EC 1.1.1.1). The gene was isolated from a random recombinant library by cross-hybridization with a maize Adh1 gene probe. The DNA sequence contains an open reading frame capable of encoding a polypeptide the same length as maize ADH1 and ADH2 (379 amino acids) and having approximately equal to 80% homology with both maize enzymes. This open reading frame is interrupted by six introns whose positions are conserved with six of the nine intron positions present in both maize genes. The 5' and 3' untranslated regions are, respectively, 58 and 204 base pairs long. Sequences important for eukaryotic gene expression such as the TATA box, polyadenylylation signal, and intron splicesite sequences are found in the expected locations. The gene hybridizes to a specific anaerobically induced RNA in Arabidopsis whose appearance correlates with the anaerobic induction of Arabidopsis ADH protein.

Structure and expression of three light-harvesting chlorophyll a/b-binding protein genes in Arabidopsis thaliana

Abstract: The genome of Arabidopsis thaliana is exceedingly small, in part because it lacks the large middle repetitive DNA component characteristic of other plants. In this paper we have characterized a member of the low copy DNA component: the gene family for the light-harvesting chlorophyll a/b-protein. This gene family is unusual in that it contains far fewer members than the 7-16 coding sequences for this protein found in other plants. We used cross-hybridization with a Lemna gene encoding a light-harvesting chlorophyll a/b-protein to isolate 3 genes from Arabidopsis, all of which are clustered on an 11-kb genomic clone. Southern blot analysis suggests that there is a fourth related gene in Arabidopsis. Sequence analysis of the three genes demonstrates that within the translated region the nucleic acid sequence homology is 96%, the deduced amino acid sequence of the mature proteins is identical for the three genes, and two of the genes have a high degree of sequence homology in both their 5' and 3' immediate flanking regions. The genes have regulatory sequences typical of eukaryotic genes upstream of the translation start sites. However, not all of these genes are equally expressed in plants grown under normal light-dark conditions.

Analysis of storage proteins in normal and aborted seeds from embryo-lethal mutants of Arabidopsis thaliana.

Abstract: The major storage proteins isolated from wild-type seeds of Arabidopsis thaliana (L.) Heynh., strain “Columbia”, were studied by sucrose gradient centrifugation and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Both the hypocotyl and cotyledons of mature embryos contained abundant 12 S (cruciferin) and 2 S (arabin) proteins that appeared similar in size and subunit composition to the cruciferin (12 S) and napin (1.7 S) seed-storage proteins of Brassica napus. The 12 S protein from Arabidopsis was resolved by SDS-PAGE into two groups of subunits with approximate relative molecular weights of 22–23 kDa (kilodalton) and 30–34 kDa. These polypeptides accumulated late in embryo development, disappeared early in germination, and were not detected in other vegetative or reproductive tissues. Accumulation of the 12 S proteins in aborted seeds from nine embryo-lethal mutants with different patterns of abnormal development was studied to determine the extent of cellular differentiation in arrested embryos from each mutant line. Abundant 12 S proteins were found in arrested embryos from two mutants with late lethal phases, but not in seven other mutants with lethal phases ranging from the globular to the cotyledon stages of embryo development. These results indicate that the accumulation of seed-storage proteins in wild-type embryos of Arabidopsis is closely tied to morphogenetic changes that occur during embryo development. Embryo-lethal mutants may therefore be useful in future studies on the developmental regulation of storage-protein synthesis.

Regeneration of Arabidopsis callus in vitro

Abstract: This paper reports on an easy and reproducible method of regenerating Arabidopsis plants from callus culture. A combination of 6-benzylaminopurine (BAP) and α-naphthalene acetic acid (NAA) in a Murashige and Skoog's (MS) based medium gives a high percentage of shoot formation in several genotypes.

Organic solvents inhibit the mutagenicity of promutagens dimethylnitrosamine and methylbutylnitrosamine in a higher plant Arabidopsis thuliana

Abstract: The organic solvents dimethylsulphoxide (DMSO), acetone, ethanol and dimethylformamide inhibited the mutagenic activity of the promutagens dimethylnitrosamine and methylbutylnitrosamine in a higher plant Arabidopsis thaliana. In contrast, the direct-acting mutagens N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) and N-methyl-N-nitrosourea (MNU) were not affected by the organic solvents (with the exception of DMSO). The effect of DMSO on MNNG- and MNU-mutagenesis is explained by its effect on the pH of the mutagenic solution. The results support the assumption that the activation of promutagenic nitrosamines in A. thaliana proceeds by the same, or similar, mechanisms to that in 'animal' activation.

Gametophytic Gene Expression in Embryo-lethal Mutants of Arabidopsis thaliana

Abstract: The genetic control of embryo development in higher plants has been approached in part through the isolation and characterization of embryo-lethal mutants (Meinke 1986). The most extensive studies have dealt with defective kernel mutants of corn (Sheridan and Neuffer 1982), embryo-lethal mutants of Arabidopsis (Muller 1963; Meinke 1985), and variant cell lines of carrot unable to complete somatic embryogenesis in vitro (Breton and Sung 1982). Arabidopsis thaliana (Cruciferae) has been used as a model plant system for various studies in developmental and molecular genetics because it produces many seeds per plant and has a short generation time, low chromosome number, well-characterized mutants (Redei 1975), an established linkage map (Koornneef et al. 1983), and an unusually small genome with little repetitive DNA (Leutwiler et al. 1984). Recessive embryolethal mutants of Arabidopsis isolated following EMS seed mutagenesis have been shown previously to differ with respect to the stage of developmental arrest, the color of arrested embryos and aborted seeds, the percentage and distribution of aborted seeds in heterozygous siliques, the extent of abnormal embryo development, the response of mutant embryos in culture, the development of homozygous mutant plants, the formation of protein and lipid bodies, and the accumulation of seed storage proteins (Meinke and Sussex 1979a,b; Meinke 1982, 1985; Meinke et al. 1985; Marsden and Meinke 1985).

Jasmonate-responsive AP2-domain transcription factors in Arabidopsis

Abstract: Jasmonic acid (JA) is a plant signaling molecule that plays a key role in defense against certain pathogens and insects. JA does so by inducing the expression of a battery of genes encoding defense-related proteins and enzymes involved in biosynthesis of protective secondary metabolites. Little is known about the mechanisms whereby JA signaling results in gene expression. In Catharanthus roseus, JA-responsive expression of alkaloid biosynthesis genes is regulated by AP2-domain transcription factors. Therefore, we focused our attention on this family of transcription factors in our efforts to identify JA-responsive transcription factors in Arabidopsis thaliana. The Arabidopsis genome encodes 126 proteins with a single DNA-binding domain of AP2-domain–like structure. Expression profiling of this gene family resulted in the identification of fourteen members called ORA genes, which show increased expression in response to JA within 4 hours in Arabidopsis seedlings. Several ORA genes were also induced by salicylic acid (SA) or ethylene, however this response was not as fast as for JA. JAresponsive ORA gene expression depends on COI1, a central component of the JA signal transduction pathway. Induction of JA-responsive ORA gene expression was not affected by a mutation in the SA pathway component NPR1. The expression of several ORA genes was induced synergistically by JA in combination with ethylene. This ORA gene subset showed reduced JA responsiveness in Arabidopsis mutants affected in ethylene signal transduction, suggesting that the encoded ORA proteins may play key roles in the integration of both signals to activate JAand ethylene-dependent responses.