Unrevealed structural requirements for auxin-like molecules by theoretical and experimental evidences.

An computational-biostatistical approach, supported by ab initio optimizations of auxin-like molecules, was used to find biologically meaningful relationships between quantum chemical variables and fresh bioassay's data. It is proven that the auxin-like recognition requires different molecular assembling states. We suggest that the carboxyl group is not the determining factor in explaining the biological auxin-like conduct.

Coulomb and overlap self-similarities: a comparative selectivity analysis of structure-function relationships for auxin-like molecules.

Auxins are defined mainly by a set of physiological actions, but the structure-effect relationship still is based on chemical intuition. Currently a well-defined auxin molecular structure is not available. The existence of different auxin binding proteins and mechanisms of auxin action, the wide diversity of the auxin molecules, and the pleiotropic effects of auxin imply a completely different mechanism as described for the animal hormone concept.

Nuclear DNA content variation among Central European Koeleria taxa.

Background And Aims: Polyploidization plays an important role in the evolution of many plant genera, including Koeleria. The knowledge of ploidy, chromosome number and genome size may enable correct taxonomic treatment when other features are insufficient as in Koeleria. Therefore, these characteristics and their variability were determined for populations of six central European Koeleria taxa.

Distribution of tight DNA-protein complexes along the barley chromosome 1H, as revealed by microsatellite marker analysis.

The distribution of DNA complexes with proteins resistant to routine deproteinisation procedures (tightly bound proteins, TBP) was studied on the barley chromosome 1H by means of microsatellite analysis. The polypeptide spectrum of the barley shoot TBP was similar to that formerly described for other organisms. In order to reveal developmental changes in the distribution of the TBP, DNA was extracted from dry grains, coleoptiles, root tips, and young and old leaves.

SNP2CAPS: a SNP and INDEL analysis tool for CAPS marker development.

With the influx of various SNP genotyping assays in recent years, there has been a need for an assay that is robust, yet cost effective, and could be performed using standard gel-based procedures. In this context, CAPS markers have been shown to meet these criteria. However, converting SNPs to CAPS markers can be a difficult process if done manually.

Snipping polymorphisms from large EST collections in barley (Hordeum vulgare L.).

The public EST (expressed sequence tag) databases represent an enormous but heterogeneous repository of sequences, including many from a broad selection of plant species and a wide range of distinct varieties. The significant redundancy within large EST collections makes them an attractive resource for rapid pre-selection of candidate sequence polymorphisms. Here we present a strategy that allows rapid identification of candidate SNPs in barley (Hordeum vulgare L.

Production of cysteine for bacterial and plant biotechnology: application of cysteine feedback-insensitive isoforms of serine acetyltransferase.

The first step of cysteine biosynthesis in bacteria and plants consists in the formation of O-acetylserine catalyzed by serine acetyltransferase (SAT). SAT is highly sensitive to feedback inhibition by cysteine as part of the regulatory circuit of cysteine biosynthesis und thus hampers over-expression and fermentation of cysteine in biotechnological production processes. Since plants contain multiple SAT isoforms with different cysteine feedback sensitivity, this resource was exploited to demonstrate the suitability of plant SATs for the production of cysteine in both bacteria and plants.

Construction and analysis of a microsatellite-based database of European wheat varieties.

A database of 502 recent European wheat varieties, mainly of winter type, was constructed using 19 wheat microsatellites and one secalin-specific marker. All datapoints were generated in at least two laboratories using different techniques for fragment analysis. An overall level of >99.

Comparative analysis of polymorphism and chromosomal location of tomato microsatellite markers isolated from different sources.

Previously isolated tomato ( Lycopersicon esculentum) microsatellite markers were mainly clustered in the centromeric heterochromatin and not located in euchromatic regions. To achieve a more-uniform distribution of microsatellite markers for genome mapping purposes, a set of tomato microsatellite markers containing dinucleotide simple sequence repeats were developed by screening genomic libraries enriched for single-copy sequences, and screening the tomato EST database. The tomato microsatellites isolated in these ways were characterized by combinations of different types of repeated motifs and they were polymorphic in a set of L.

Molecular and biochemical analysis of the enzymes of cysteine biosynthesis in the plant Arabidopsis thaliana.

Among the amino acids produced by plants cysteine plays a special role as a mediator between assimilatory sulfate reduction and provision of reduced sulfur for cell metabolism. Part of this characteristic feature is the presence of cysteine synthesis in plastids, mitochondria and cytosol. Plants are the major source of reduced sulfur for human and animal nutrition.

Use of biomolecular interaction analysis to elucidate the regulatory mechanism of the cysteine synthase complex from Arabidopsis thaliana.

Real time biomolecular interaction analysis based on surface plasmon resonance has been proven useful for studying protein-protein interaction but has not been extended so far to investigate enzyme-enzyme interactions, especially as pertaining to regulation of metabolic activity. We have applied BIAcore technology to study the regulation of enzyme-enzyme interaction during mitochondrial cysteine biosynthesis in Arabidopsis thaliana. The association of the two enzyme subunits in the hetero-oligomeric cysteine synthase complex was investigated with respect to the reaction intermediate and putative effector O-acetylserine.

Construction of a YAC library from barley cultivar Franka and identification of YAC-derived markers linked to the Rh2 gene conferring resistance to scald (Rhynchosporium secalis).

The Rh2 resistance gene of barley (Hordeum vulgare) confers resistance against the scald pathogen (Rhynchosporium secalis). A high-resolution genetic map of the Rh2 region on chromosome I (7H) was established by the use of molecular markers. Tightly linked markers from this region were used to screen existing and a newly constructed yeast artificial chromosome (YAC) library of barley cv.

Genomic and functional characterization of the oas gene family encoding O-acetylserine (thiol) lyases, enzymes catalyzing the final step in cysteine biosynthesis in Arabidopsis thaliana.

The final step of cysteine biosynthesis in plants is catalyzed by O-acetylserine (thiol) lyase (OAS-TL), which occurs as several isoforms found in the cytosol, the plastids and the mitochondria. Genomic DNA blot hybridization and isolation of genomic clones indicate single copy genes (oasA1, oasA2, oasB and oasC) that encode the activities of OAS-TL A, B and C found in separate subcellular compartments in the model plant Arabidopsis thaliana. Sequence analysis reveals that the newly discovered oasA2 gene represents a pseudogene that is still transcribed, but is not functionally translated.

Sequence analysis and gene identification in a set of mapped RFLP markers in barley (Hordeum vulgare).

The "Igri/Franka" (I/F) map ranks among the most comprehensive genetic linkage maps of barley (Hordeum vulgare), containing a large number of markers derived from cDNA and genomic PstI clones. Fourty-three cDNA clones and 259 genomic clones were at least partially sequenced and compared with the major data bases of protein and nucleic acid sequences. Of the cDNA clones, 53% show significant similarity to known sequences in protein data bases.

Long tomato microsatellites are predominantly associated with centromeric regions.

Microsatellites as genetic markers are used in many crop plants. Major criteria for their usability as molecular markers include that they are highly polymorphic and evenly spread throughout a genome. In tomato, it has been reported that long arrays of tetranucleotide microsatellites containing the motif GATA are highly clustered around the centromeres of all chromosomes.

Map-based cloning of chloronerva, a gene involved in iron uptake of higher plants encoding nicotianamine synthase.

The uptake of iron in plants is a highly regulated process that is induced on iron starvation. In tomato, the mutant chloronerva exhibits constitutive expression of iron uptake responses and intercostal chlorosis. Biochemically, chloronerva is an auxotroph for nicotianamine, a key polyamine in plant iron uptake metabolism.

RAPDs and noncoding chloroplast DNA reveal a single origin of the cultivated Allium fistulosum from A. altaicum (Alliaceae).

The origin of the crop species Allium fistulosum (bunching onion) and its relation to its wild relative A. altaicum were surveyed with a restriction fragment length polymorphism (RFLP) analysis of five noncoding cpDNA regions and with a random amplified polymorhic DNA (RAPD) analysis of nuclear DNA. Sixteen accessions of A.

Sequencing of cDNA clones from the genetic map of tomato (Lycopersicon esculentum).

The dense RFLP linkage map of tomato (Lycopersicon esculentum) contains >300 anonymous cDNA clones. Of those clones, 272 were partially or completely sequenced. The sequences were compared at the DNA and protein level to known genes in databases.

Genetic mapping of a wide spectrum nematode resistance gene (Hero) against Globodera rostochiensis in tomato.

The Hero gene confers resistance to a wide spectrum of pathotypes of the potato cyst nematode Globodera rostochiensis. This gene has been introgressed from the wild tomato species Lycopersicon pimpinellifolium into the cultivated tomato. We have used RFLP and RAPD analysis for the targeted search of the L.

Direct isolation of cDNA sequences from specific chromosomal regions of the tomato genome by the differential display technique.

The differential display technique was originally developed for the isolation of differentially expressed genes from eukaryotic tissues. We have adapted this technique for the isolation of cDNA markers from specific regions of the tomato genome. For this purpose, differential display was performed on RNA extracted from leaf tissue of nearly isogenic lines for the Tm-2a gene of tomato.

Infraspecific differentiation of garlic (Allium sativum L.) by isozyme and RAPD markers.

Garlic (Allium sativum L.) is a sterile species of considerable variability with respect to morphological and physiological features. The crop presumably originated in West to Middle Asia from its progenitor A.

Pulsed-field gel analysis of 5S and satellite DNA in barley.

Pulsed-field gel electrophoresis was used to study the variability of clustered tandemly repeated sequences in barley. Twelve spring barley cultivars were investigated with a heterologous 5S DNA probe and the 118 base pair barley satellite DNA probe HVT01. On a per fragment basis, the 5S probe was 5 times and the barley satellite probe 6.