2,329 research outputs found
Development of ESTs from chickpea roots and their use in diversity analysis of the Cicer genus
BACKGROUND: Chickpea is a major crop in many drier regions of the world where it is an important protein-rich food and an increasingly valuable traded commodity. The wild annual Cicer species are known to possess unique sources of resistance to pests and diseases, and tolerance to environmental stresses. However, there has been limited utilization of these wild species by chickpea breeding programs due to interspecific crossing barriers and deleterious linkage drag. Molecular genetic diversity analysis may help predict which accessions are most likely to produce fertile progeny when crossed with chickpea cultivars. While, trait-markers may provide an effective tool for breaking linkage drag. Although SSR markers are the assay of choice for marker-assisted selection of specific traits in conventional breeding populations, they may not provide reliable estimates of interspecific diversity, and may lose selective power in backcross programs based on interspecific introgressions. Thus, we have pursued the development of gene-based markers to resolve these problems and to provide candidate gene markers for QTL mapping of important agronomic traits. RESULTS: An EST library was constructed after subtractive suppressive hybridization (SSH) of root tissue from two very closely related chickpea genotypes (Cicer arietinum). A total of 106 EST-based markers were designed from 477 sequences with functional annotations and these were tested on C. arietinum. Forty-four EST markers were polymorphic when screened across nine Cicer species (including the cultigen). Parsimony and PCoA analysis of the resultant EST-marker dataset indicated that most accessions cluster in accordance with the previously defined classification of primary (C. arietinum, C. echinospermum and C. reticulatum), secondary (C. pinnatifidum, C. bijugum and C. judaicum), and tertiary (C. yamashitae, C. chrossanicum and C. cuneatum) gene-pools. A large proportion of EST alleles (45%) were only present in one or two of the accessions tested whilst the others were represented in up to twelve of the accessions tested. CONCLUSION: Gene-based markers have proven to be effective tools for diversity analysis in Cicer and EST diversity analysis may be useful in identifying promising candidates for interspecific hybridization programs. The EST markers generated in this study have detected high levels of polymorphism amongst both common and rare alleles. This suggests that they would be useful for allele-mining of germplasm collections for identification of candidate accessions in the search for new sources of resistance to pests / diseases, and tolerance to abiotic stresses
The New Political Economy of EU State Aid Policy
Despite its importance and singularity, the EUâs state aid policy has attracted less scholarly attention than other elements of EU competition policy. Introducing the themes addressed by the special issue, this article briefly reviews the development of EU policy and highlights why the control of state aid matters. The Commissionâs response to the current economic crisis notably in banking and the car industry is a key concern, but the interests of the special issue go far beyond. They include: the role of the European Commission in the development of EU policy, the politics of state aid, and a clash between models of capitalism. The special issue also examines the impact of EU policy. It investigates how EU state aid decisions affect not only industrial policy at the national level (and therefore at the EU level), but the welfare state and territorial relations within federal member states, the external implications of EU action and the strategies pursued by the Commission to limit any potential disadvantage to European firms, and the conflict between the EUâs expanding legal order and national
NEXUS/Physics: An interdisciplinary repurposing of physics for biologists
In response to increasing calls for the reform of the undergraduate science
curriculum for life science majors and pre-medical students (Bio2010,
Scientific Foundations for Future Physicians, Vision & Change), an
interdisciplinary team has created NEXUS/Physics: a repurposing of an
introductory physics curriculum for the life sciences. The curriculum interacts
strongly and supportively with introductory biology and chemistry courses taken
by life sciences students, with the goal of helping students build general,
multi-discipline scientific competencies. In order to do this, our two-semester
NEXUS/Physics course sequence is positioned as a second year course so students
will have had some exposure to basic concepts in biology and chemistry.
NEXUS/Physics stresses interdisciplinary examples and the content differs
markedly from traditional introductory physics to facilitate this. It extends
the discussion of energy to include interatomic potentials and chemical
reactions, the discussion of thermodynamics to include enthalpy and Gibbs free
energy, and includes a serious discussion of random vs. coherent motion
including diffusion. The development of instructional materials is coordinated
with careful education research. Both the new content and the results of the
research are described in a series of papers for which this paper serves as an
overview and context.Comment: 12 page
A legume genomics resource: The Chickpea Root Expressed Sequence Tag Database
Chickpea, a lesser-studied grain legume, is being investigated due to its taxonomic proximity with the model legume genome Medicago truncatula and its ability to endure and grow in relatively low soil water contents making it a model legume crop for the study of agronomic response to drought stress. Public databases currently contain very few sequences from chickpea associated with expression in root tissues. However, root traits are likely to be one of the most important components of drought tolerance in chickpea. Thus, we have generated a set of over 2800 chickpea expressed sequence tags (ESTs) from a library constructed after subtractive suppressive hybridization (SSH) of root tissue from two closely related chickpea genotypes possessing different sources of drought avoidance and tolerance (ICC4958 and Annigeri respectively). This database provides researchers in legume genomics with a major new resource for data mining associated with root traits and drought tolerance. This report describes the development and utilization of the database and provides the tools we have developed to facilitate the bioinformatics pipeline used for analysis of the ESTs in this database. We also discuss applications that have already been achieved using this resourc
LaF3 insulators for MIS structures
Thin films of Laf3 deposited on Si or GaAs substrates have been observed to form blocking contacts with very high capacitances. This results in comparativelyâhysteresisâfree and sharpCâV (capacitanceâvoltage) characteristics for MIS structures. Such structures have been used to study the interface states of GaAs with increased resolution and to construct improved photocapacitive infrared detectors
Resolving the Azimuthal Ambiguity in Vector Magnetogram Data with the Divergence-Free Condition: Application to Discrete Data
We investigate how the divergence-free property of magnetic fields can be
exploited to resolve the azimuthal ambiguity present in solar vector
magnetogram data, by using line-of-sight and horizontal heliographic derivative
information as approximated from discrete measurements. Using synthetic data we
test several methods that each make different assumptions about how the
divergence-free property can be used to resolve the ambiguity. We find that the
most robust algorithm involves the minimisation of the absolute value of the
divergence summed over the entire field of view. Away from disk centre this
method requires the sign and magnitude of the line-of-sight derivatives of all
three components of the magnetic field vector.Comment: Solar Physics, in press, 20 pages, 11 figure
A legume genomics resource: The Chickpea Root Expressed Sequence Tag Database
Chickpea, a lesser-studied grain legume, is being investigated due to
its taxonomic proximity with the model legume genome Medicago
truncatula and its ability to endure and grow in relatively low soil
water contents making it a model legume crop for the study of agronomic
response to drought stress. Public databases currently contain very few
sequences from chickpea associated with expression in root tissues.
However, root traits are likely to be one of the most important
components of drought tolerance in chickpea. Thus, we have generated a
set of over 2800 chickpea expressed sequence tags (ESTs) from a library
constructed after subtractive suppressive hybridization (SSH) of root
tissue from two closely related chickpea genotypes possessing different
sources of drought avoidance and tolerance (ICC4958 and Annigeri
respectively). This database provides researchers in legume genomics
with a major new resource for data mining associated with root traits
and drought tolerance. This report describes the development and
utilization of the database and provides the tools we have developed to
facilitate the bioinformatics pipeline used for analysis of the ESTs in
this database. We also discuss applications that have already been
achieved using this resource
Isolation and characterization of microsatellite markers from Musa balbisiana
This is the first report of targeted development of B genome microsatellite markers in Musa. A total of 44 sequences with microsatellites were isolated from an enriched library of Musa balbisiana cv. 'Tani' (BB genome). Of these, 25 were polymorphic when screened on 14 diverse diploid and triploid Musa accessions. The number of alleles detected by each marker ranged between one and seven. All 25 microsatellite markers generated amplification products in all species and genome complements. These new microsatellite markers fill an important gap for diversity assessment and linkage mapping studies in plantain (AAB) and cooking banana (ABB
Analysis of genomic sequences from peanut ( Arachis hypogaea )
Peanut is an important legume crop across the world. However, in
contrast to most legume crops, groundnut lacks taxonomic proximity to
any major model genome. A relatively large number of genomic sequences
were generated from groundnut as part of a microsatellite marker
development project. In the current study, a total of 1312 sequences
were analyzed of which 448 contained microsatellite motifs. All
sequences (GenBank Accessions: BZ999351-CC000573) were analyzed after
clustering for possible similarity with publicly available sequences
from Arabidopsis, Lotus, soybean and Medicago. At least 39% of the
sequences analyzed had significant BLAST similarities with sequences
from the four databases searched, of which nearly half (47%) found
significant similarity with Lotus japonicus sequences. Over one
quarter (26.7%) of sequences found similarity with Arabidopsis thaliana
, while the remainder aligned with publicly available sequences from
the legumes soybean and Medicago truncatula . At least 17% of
microsatellite containing sequences could be assigned an identity. The
codon usage pattern for Arachis hypogaea most closely resembles that
of L. japonicus reflecting the similarly high sequence similarity
observed in BLAST searches at the protein level. The implications of
these findings for the taxonomy, and comparative genomics of groundnut
and its legume family relatives are discussed
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