bluuebunny/crossref_metadata_2025_split huggingface dataset:
Adaptation to high salinity in poplar involves changes in xylem anatomy and auxin physiology
Authors: JUNGHANS U. , POLLE A. , DÜCHTING P. , WEILER E. , KUHLMAN B. , GRUBER F. , TEICHMANN T. 
Published: May 2006

ABSTRACTTo investigate the physiological basis of salt adaptation in poplar, we compared the effect of salt stress on wood anatomy and auxin physiology of the salt‐resistant Populus euphratica and salt‐sensitive Populus × canescens. Both poplar species showed decreases in vessel lumina associated with increases in wall strength in response to salt, however, in P. euphratica at three‐fold higher salt concentrations than in P. × canescens. The predicted hydraulic conductivity of the wood formed under salt stress decreased in P. × canescens, while in P. euphratica, no significant effects of salt on conductivity and transpiration were observed. The concentration of free indole‐3‐acetic acid (IAA) decreased under salt stress in the xylem of both poplar species, but to a larger extent in P. × canescens than in P. euphratica. Only salt‐treated P. euphratica exhibited an increase in IAA‐conjugates in the xylem. Genes homologous to the auxin‐amidohydrolase ILL3 were isolated from the xylems of P. euphratica and P. × canescens. For functional analysis, the auxin‐amidohydrolase from P. × canescens was overexpressed in Arabidopsis. Transgenic Arabidopsis plants were more resistant to salt stress than the wild‐type plants. Increased sensitivity of the transgenic Arabidopsis to IAA‐Leu showed that the encoded hydrolase used IAA‐Leu as a substrate. These results suggest that poplar can use IAA‐amidoconjugates in the stem as a source of auxin to balance the effects of salt stress on auxin physiology.
13CO2 pulse‐labelling of photoassimilates reveals carbon allocation within and between tree rings
Authors: KAGAWA AKIRA , SUGIMOTO ATSUKO , MAXIMOV TROFIM C. 
Published: May 2006

ABSTRACTPost‐photosynthetic fractionation processes during translocation, storage and remobilization of photoassimilate are closely related to intra‐annual δ13C of tree rings, and understanding how these processes affect tree‐ring δ13C is therefore indispensable for improving the quality of climate reconstruction. Our first objective was to study the relationship between translocation path and phloem grain. We pulse‐labelled a branch of Larix gmelinii (Rupr.) Rupr. and later analysed the δ13C distribution in the stem. A 13C spiral translocation path closely related to the spiral grain was observed. Our second objective was to study the use of remobilized storage material for earlywood formation in spring, which is a suspected cause of the autocorrelation (correlation of ring parameters to the climate in the previous year) observed in (isotope) dendroclimatology. We pulse‐labelled whole trees to study how spring, summer and autumn photoassimilate is later used for both earlywood and latewood formation. Analysis of intra‐annual δ13C of the tree rings formed after the labelling revealed that earlywood contained photoassimilate from the previous summer and autumn as well as from the current spring. Latewood was mainly composed of photoassimilate from the current year’s summer/autumn, although it also relied on stored material in some cases. These results emphasize the need for separating earlywood and latewood for climate reconstruction work with narrow boreal tree rings.
Desiccation of the resurrection plant Craterostigma plantagineum induces dynamic changes in protein phosphorylation
Authors: RÖHRIG HORST , SCHMIDT JÜRGEN , COLBY THOMAS , BRÄUTIGAM ANNE , HUFNAGEL PETER , BARTELS DOROTHEA 
Published: May 2006

ABSTRACTReversible phosphorylation of proteins is an important mechanism by which organisms regulate their reactions to external stimuli. To investigate the involvement of phosphorylation during acquisition of desiccation tolerance, we have analysed dehydration‐induced protein phosphorylation in the desiccation tolerant resurrection plant Craterostigma plantagineum. Several dehydration‐induced proteins were shown to be transiently phosphorylated during a dehydration and rehydration (RH) cycle. Two abundantly expressed phosphoproteins are the dehydration‐ and abscisic acid (ABA)‐responsive protein CDeT11‐24 and the group 2 late embryogenesis abundant (LEA) protein CDeT6‐19. Although both proteins accumulate in leaves and roots with similar kinetics in response to dehydration, their phosphorylation patterns differ. Several phosphorylation sites were identified on the CDeT11‐24 protein using liquid chromatography‐tandem mass spectrometry (LC‐MS/MS). The coincidence of phosphorylation sites with predicted coiled‐coil regions leads to the hypothesis that CDeT11‐24 phosphorylations influence the stability of coiled‐coil interactions with itself and possibly other proteins.
Resedimentation of cold pumiceous ignimbrite into water: facies transformations simulated in flume experiments
Authors: ALLEN S. R. , FREUNDT A. 
Published: May 2006

AbstractDeposits and transport processes resulting from the resedimentation of cold, unconsolidated ignimbrite into water were simulated by flume experiments. The ignimbrite sample used was poorly sorted (σ = 2·4–3), fine ash‐rich (< 63 μm, 17–30 wt%) and included both dense lithic clasts (> 2000 kg m−3) and pumice (500 to ca 1300 kg m−3). As a result of the binding forces of the ash matrix, the experiments involved resedimentation from a steep front onto the floor (with or without an initial ramp) of the water‐filled tank under both still and wave‐generated conditions. Larger discrete collapse events were induced by oversteepening the sample front and by undercutting from wave action. The mass of the collapse and proportion of pore–space water strongly influenced the style of resedimentation and the deposits. Initial collapse events were from the top of the steep front and fell onto the floor. The largest, densest clasts were deposited as a lithic lag in a proximal sediment wedge or rolled down to a break‐in‐slope. Fine ash was transported in dilute turbidity currents, and coarse unsaturated pumice clasts floated off. Moderate collapse events generated high‐density turbidity currents, trapping pumice in the flow, causing them to saturate. These low‐density pumice clasts were easily remobilized by wave activity and passing currents and accumulated on the gentle slope at the bottom of the resedimented deposit. Large collapse events slumped, producing poorly sorted mounds similar in texture to the original starting material. As the matrix of the ignimbrite sample became saturated with water, moderate and large collapse events generated debrisflows and slurries that deposited massive, poorly sorted deposits. Furthermore, once more gentle slopes were established between the sample and deposit, small cascading grainflows deposited lithic clasts on the upper slopes and levees of pumice at the terminus of low‐relief, ash channels. The experiments show that, excluding large collapse events and debrisflows, resedimenting ignimbrite in water is effective at segregating low‐density pumice clasts from dense lithic clasts and fine ash. Experiments using fine‐ash poor ignimbrite and well‐sorted quartz sand for comparison formed an inherently unstable initial steep front that immediately collapsed by continuous grain avalanches. The grainflow deposits had textures similar to the fines‐poor starting material.
A mutation in the GTP hydrolysis site of Arabidopsis dynamin‐related protein 1E confers enhanced cell death in response to powdery mildew infection
Authors: Tang Dingzhong , Ade Jules , Frye Catherine A. , Innes Roger W. 
Published: May 2006

SummaryWe screened for mutants of Arabidopsis thaliana that displayed enhanced disease resistance to the powdery mildew pathogen Erysiphe cichoracearum and identified the edr3 mutant, which formed large gray lesions upon infection with E. cichoracearum and supported very little sporulation. The edr3‐mediated disease resistance and cell death phenotypes were dependent on salicylic acid signaling, but independent of ethylene and jasmonic acid signaling. In addition, edr3 plants displayed enhanced susceptibility to the necrotrophic fungal pathogen Botrytis cinerea, but showed normal responses to virulent and avirulent strains of Pseudomonas syringae pv. tomato. The EDR3 gene was isolated by positional cloning and found to encode Arabidopsis dynamin‐related protein 1E (DRP1E). The edr3 mutation caused an amino acid substitution in the GTPase domain of DRP1E (proline 77 to leucine) that is predicted to block GTP hydrolysis, but not GTP binding. A T‐DNA insertion allele in DRP1E did not cause powdery mildew‐induced lesions, suggesting that this phenotype is caused by DRP1E being locked in the GTP‐bound state, rather than by a loss of DRP1E activity. Analysis of DRP1E–green fluorescent protein fusion proteins revealed that DRP1E is at least partially localized to mitochondria. These observations suggest a mechanistic link between salicylic acid signaling, mitochondria and programmed cell death in plants.
Development of Arabidopsis whole‐genome microarrays and their application to the discovery of binding sites for the TGA2 transcription factor in salicylic acid‐treated plants
Authors: Thibaud‐Nissen Françoise , Wu Hank , Richmond Todd , Redman Julia C. , Johnson Christopher , Green Roland , Arias Jonathan , Town Christopher D. 
Published: May 2006

SummaryWe have developed two long‐oligonucleotide microarrays for the analysis of genome features in Arabidopsis thaliana, in particular for the high‐throughput identification of transcription factor‐binding sites. The first platform contains 190 000 probes representing the 2‐kb regions upstream of all annotated genes at a density of seven probes per promoter. The second platform is divided into three chips, each of over 390 000 features, and represents the entire Arabidopsis genome at a density of one probe per 90 bases.Protein–DNA complexes resulting from the formaldehyde fixation of leaves of plants 2 h after exposure to 1 mm salicylic acid (SA) were immunoprecipitated using antibodies against the TGA2 transcription factor. After reversal of the cross‐links and amplification, the resulting ChIP sample was hybridized to both platforms. High signal ratios of the ChIP sample versus raw chromatin for clusters of neighboring probes provided evidence for 51 putative binding sites for TGA2, including the only previously confirmed site in the promoter of PR‐1 (At2g14610). Enrichment of several regions was confirmed by quantitative real‐time PCR. Motif search revealed that the palindromic octamer TGACGTCA was found in 55% of the enriched regions. Interestingly, 15 of the putative binding sites for TGA2 lie outside the presumptive promoter regions. The effect of the 2‐h SA treatment on gene expression was measured using Affymetrix ATH1 arrays, and SA‐induced genes were found to be significantly over‐represented among genes neighboring putative TGA2‐binding sites.
The diallelic locus encoding the minor histocompatibility antigen HA‐1 is evolutionarily conserved
Authors: Wieles B. , Pool J. , Wilke M. , Weber M. , Kolb H.‐J. , Bontrop R. E. , Goulmy E. 
Published: May 2006

AbstractThe polymorphic minor histocompatibility antigen HA‐1 induces powerful T‐cell alloreactivities with important consequences for graft‐vs‐tumor activity and development of graft‐vs‐host disease in patients after human leukocyte antigen‐matched stem‐cell transplantation (SCT). In view of possible translational animal studies, we analyzed the evolutionary conservation of the diallelic HA‐1 locus in four mammalian species. Our results show that rodents do not encode the HA‐1H allele, neither show polymorphism in this position on the HA‐1 gene. Contrariwise, the HA‐1H allele is present in non‐human primate species and dogs. Interestingly, both the HA‐1H T‐cell epitope and its non‐immunogenic counterpart HA‐1R are present in the latter species. Thus, the HA‐1 allelic polymorphism is conserved in evolution in primates and dogs.
Distribution of killer cell immunoglobulin‐like receptors genotypes in the Lebanese population
Authors: Mahfouz R. , Rayes R. , Mahfoud Z. , Bazarbachi A. , Zaatari G. 
Published: May 2006

AbstractThis study represents the first report on the distribution of 16 Killer cell Immunoglobulin‐like Receptors (KIR) genes in 120 unrelated healthy Lebanese individuals. We observed that 2DL2 frequency (61%) comes second highest after South Asians (64%) and 2DL5 frequency (58.3%) is the second highest reported so far after the South Asians (74%). Interestingly, a large number of AA1 genotype individuals with no loci for activating KIR and three completely new BB profiles not previously reported were found in our population with a group A : group B haplotypes ratio of 1.3:1. The frequency of the KIR loci suggests that the Lebanese population shares common general features with the Caucasoid populations studied before, but still has its own unique decreased or increased frequencies of several loci.
Detailed gene and allele content analysis of three homozygous KIR haplotypes
Authors: Murdoch S. , Seoud M. , Kircheisen R. , Mazhar B. , Slim R. 
Published: May 2006

AbstractThe killer immunoglobulin‐like receptors are a highly polymorphic family of receptors encoded by 15 genes clustered on 19q13.4. Because of the complexity of the genetic analysis of the KIR cluster, much of the data regarding KIR sequences and alleles has been generated by cDNA typing and partial sequencing. Here we report the genomic sequencing of the KIR genes in individuals with three different haplotypes homozygous by descent. We provide a detailed analysis of their haplotypes and identify new alleles for KIR3DL3 and KIR2DL1. The primers we describe will be a valuable tool for studying the involvement of the KIR genes in various human diseases.
Development and application of a new codominant PCR marker for detecting 1BL·1RS wheat–rye chromosome translocations
Authors: Chai J. F. , Zhou R. H. , Jia J. Z. , Liu X. 
Published: May 2006

AbstractThe 1BL·1RS translocation has been widely used in wheat breeding programmes throughout the world. Unfortunately, this translocation has frequently resulted in unsatisfactory grain processing quality. Two primer combinations derived from the published sequence of a ω‐secalin gene on 1RS gave polymerase chain reaction (PCR) fragments 0.4 and 1.1 kb in size. Both fragments can be used to quickly detect 1BL·1RS translocations. By combining the PCR assay resulting in the 1.1‐kb fragment from 1RS and a PCR assay resulting in a 0.6‐kb fragment from the Glu‐B3 gene on 1BS, plants homozygous for the 1BL 1RS could clearly be distinguished from the heterozygous ones. This codominant marker was successfully applied to genotype a segregating F2 population and a local cultivar collection.
Natural occurrence of autopolyploidy within the allotetraploid‐cultivated peanut
Authors: Branch W. D. , Hanna W. W. 
Published: May 2006

AbstractThe cultivated peanut is classified as an allotetraploid species. During the past several years, abnormal plants with coarse stems, thick leaves and an occasional single seed per pod have been found within different cultivars and advanced breeding lines. The spontaneous natural occurrence of these plants has been very rare, and frequently they do not produce any pods or seed. However, over a 3‐year period (2001–2003), four individual plant selections with one mature seed per plant were found and saved. In 2003, another similar plant was also found that had the same plant characteristics, except for a single branch that had normal leaves with typical two‐seeded pods. A greenhouse study was conducted during the winter of 2003–2004. The four coarse stem individual plant selections from the previous years were planted along with the check cultivar ‘Georgia Green’ and the sectorial plant found in 2003. S1 seed from both the one‐seeded pods as well as normal two‐seeded pods were planted from the sectorial plant. Relative DNA content was measured by flow cytometry on all plants. Results from the test showed that the coarse stem, thick leaf plants with poor fruit set were autooctoploids and had about twice the DNA content when compared with the normal sectorial branch and the allotetraploid peanut cultigen.
Modified full‐sib selection and best linear unbiased prediction of progeny performance in a European F2 maize population
Authors: Flachenecker C. , Frisch M. , Muminovic J. , Falke K. C. , Melchinger A. E. 
Published: May 2006

AbstractFour cycles of modified recurrent full‐sib (FS) selection were conducted in an intermated F2 population of European flint maize. The objectives of our study were to monitor trends across selection cycles in the estimates of population mean, inbreeding coefficients and variance components, and to investigate the usefulness of best linear unbiased prediction (BLUP) of progeny performance under the recurrent FS selection scheme applied. We used a selection rate of 25% for a selection index, based on grain yield and dry matter content. A pseudo‐factorial mating scheme was used for recombination. In this scheme, the selected FS families were divided into an upper‐ranking group of parents mated to the lower‐ranking group. Variance components were estimated with restricted maximum likelihood (REML). Average grain yield increased 1.2 t/ha per cycle, average grain moisture decreased 20.1 g/kg per cycle, and the selection index relative to the F2 check entries decreased 0.3% per cycle. For a more precise calculation of selection response, the four cycles should be tested together in multi‐environmental trials. We observed a significant decrease in additive variance in the selection index, suggesting smaller future selection response. Predictions of FS family performance in Cn + 1 based on mean performance of parental FS families in Cn were of equal precision as those based on the mean additive genetic BLUP of their parents, and corresponding correlations were of moderate size for grain moisture and selection index.
Factors affecting oat haploid production following oat × maize hybridization
Authors: Sidhu P. K. , Howes N. K. , Aung T. , Zwer P. K. , Davies P. A. 
Published: May 2006

AbstractDoubled haploids (DHs) are becoming increasingly important in crop breeding programmes but methods for producing oat DHs remain inefficient. In this study haploid and DH oat plants were produced using the oat × maize hybridization method. Factors influencing the rate of caryopsis and haploid embryo production including genotype, post‐pollination plant growth regulator application and temperature were investigated. The four growth regulators tested showed significant differences in their capacity to induce caryopsis formation with dicamba producing the highest numbers of caryopses, followed by picloram, 2,4‐dichlorophenoxyacetic acid (2,4‐D) and gibberellic acid (GA3). No significant differences were observed between these growth regulators for their effect on embryo production. The concentration of dicamba was also important and was found to influence caryopsis but not embryo production, with 50 and 100 mg/l dicamba producing significantly more caryopses than 25 or 5 mg/l. Temperature had a significant impact on both caryopsis and embryo production with the magnitude and direction of response depending on genotype. Rates of haploid embryo production observed were between 0.8% and 6.7% of the pollinated florets. The proportion of haploids, which survived and were successfully doubled with colchicine following transfer to soil was between 72% and 81%.
Evaluation of genetic diversity in jute (Corchorus species) using STMS, ISSR and RAPD markers
Authors: Roy A. , Bandyopadhyay A. , Mahapatra A. K. , Ghosh S. K. , Singh N. K. , Bansal K. C. , Koundal K. R. , Mohapatra T. 
Published: May 2006

AbstractJute is an important fibre crop that has dominated the packaging sector for over one and a half centuries in India. For sustenance of the trade in the face of tough competition from synthetics, there is an urgent need to redesign the ongoing breeding strategy to improve both the yield and quality of jute fibre. It is therefore, essential to understand the pattern of diversity in this important commercial crop species. In the present study, genetic diversity analysis of 20 exotic germplasm lines and 20 commercial varieties of the two cultivated species (Corchorus olitorius and C. capsularis) and two wild relatives of jute (C. aestuans and C. trilocularis) was carried out using sequence tagged microsatellite site (STMS), inter simple sequence repeat (ISSR) and random amplified polymorphic DNA (RAPD) markers. The first set of six STMS markers developed from the genomic sequence of C. olitorius was not fully transferable to the related species C. capsularis. The level of intraspecific polymorphism revealed by these markers was very low. The four ISSR and 22 RAPD primers employed in the study revealed 98.44% and 100% polymorphism, respectively, across all the species, while the level of polymorphism was significantly low within a species. The commercial varieties, particularly those of C. capsularis, had an extremely narrow genetic base that demands immediate effort for diversification. The germplasm accessions in both the cultivated species showed considerably higher levels of diversity and thus should be used in broadening the base of the varieties. All the accessions of C. olitorius together with the wild species C. aestuans clustered separately from those of C. capsularis and C. trilocularis, suggesting a polyphyletic origin of the two cultivated species.
No DNA loss in autotetraploids of Arabidopsis thaliana
Authors: Ozkan H. , Tuna M. , Galbraith D. W. 
Published: May 2006

AbstractTo address the issue of genome evolution in autopolyploids and particularly to investigate whether rapid sequence elimination also occurs in autopolyploids as in allopolyploids, amplified fragment length polymorphism (AFLP) fingerprinting was employed to examine a large number of genomic loci in F1 hybrids between two different autotetraploids of Arabidopsis thaliana accessions, namely Ler and Col. Using this approach, perfect additivity in the F1 hybrids was found between the newly‐formed autopolyploids when compared with their parental lines. Using flow cytometry, the study was extended in a quantitative manner, in which the nuclear DNA contents in one autotetraploid A. thaliana accession Ler, was determined. The increase in genome size of the autotetraploid line was additive. Taken together, no evidence was found for genome size reduction due to autopolyploidization of A. thaliana. The results indicating that there was no DNA loss in autotetraploid A. thaliana suggest that a different type of genome evolution may occur in autopolyploids during the initial stages of their formation when compared with allopolyploids.