Novel SSR Markers from BAC-End Sequences, DArT Arrays and a Comprehensive Genetic Map with 1,291 Marker Loci for Chickpea (Cicer arietinum L.)

Chickpea (Cicer arietinum L.) is the third most important cool season food legume, cultivated in arid and semi-arid regions of the world. The goal of this study was to develop novel molecular markers such as microsatellite or simple sequence repeat (SSR) markers from bacterial artificial chromosome (BAC)-end sequences (BESs) and diversity arrays technology (DArT) markers, and to construct a high-density genetic map based on recombinant inbred line (RIL) population ICC 4958 (C. arietinum)×PI 489777 (C. reticulatum). A BAC-library comprising 55,680 clones was constructed and 46,270 BESs were generated. Mining of these BESs provided 6,845 SSRs, and primer pairs were designed for 1,344 SSRs. In parallel, DArT arrays with ca. 15,000 clones were developed, and 5,397 clones were found polymorphic among 94 genotypes tested. Screening of newly developed BES-SSR markers and DArT arrays on the parental genotypes of the RIL mapping population showed polymorphism with 253 BES-SSR markers and 675 DArT markers. Segregation data obtained for these polymorphic markers and 494 markers data compiled from published reports or collaborators were used for constructing the genetic map. As a result, a comprehensive genetic map comprising 1,291 markers on eight linkage groups (LGs) spanning a total of 845.56 cM distance was developed (http://cmap.icrisat.ac.in/cmap/sm/cp/thudi/). The number of markers per linkage group ranged from 68 (LG 8) to 218 (LG 3) with an average inter-marker distance of 0.65 cM. While the developed resource of molecular markers will be useful for genetic diversity, genetic mapping and molecular breeding applications, the comprehensive genetic map with integrated BES-SSR markers will facilitate its anchoring to the physical map (under construction) to accelerate map-based cloning of genes in chickpea and comparative genome evolution studies in legumes

Single Nucleotide Polymorphism–based Genetic Diversity in the Reference Set of Peanut (Arachis spp.) by Developing and Applying Cost-Effective Kompetitive Allele Specific Polymerase Chain Reaction Genotyping Assays

Kompetitive allele-specific polymerase chain reaction (KASP) assays have emerged as cost-effective marker assays especially for molecular breeding applications. Therefore, a set of 96 informative single nucleotide polymorphisms (SNPs) was used to develop KASP assays in groundnut or peanut (Arachis spp.). Developed assays were designated as groundnut KASP assay markers (GKAMs) and screened on 94 genotypes (validation set) that included parental lines of 27 mapping populations, seven synthetic autotetraploid and amphidiploid lines, and 19 wild species accessions. As a result, 90 GKAMs could be validated and 73 GKAMs showed polymorphism in the validation set. Validated GKAMs were screened on 280 diverse genotypes of the reference set for estimating diversity features and elucidating genetic relationships. Cluster analysis of marker allelic data grouped accessions according to their genome type, subspecies, and botanical variety. The subspecies Arachis hypogaea L. subsp. fastigiata Waldron and A. hypogaea subsp. hypogaea formed distinct cluster; however, some overlaps were found indicating their frequent intercrossing during the course of evolution. The wild species, having diploid genomes, were grouped into a single cluster. The average polymorphism information content value for polymorphic GKAMs was 0.32 in the validation set and 0.31 in the reference set. These validated and highly informative GKAMs may be useful for genetics and breeding applications in Arachis species

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Not AvailableBarnyard millet (Echinochloa spp.) is one of the most underresearched crops with respect to characterization of genetic resources and genetic enhancement. A total of 95 germplasm lines representing global collection were evaluated in two rainy seasons at Almora, Uttarakhand, India for qualitative and quantitative traits and the data were subjected to multivariate analysis. High variation was observed for days to maturity, five-ear grain weight, and yield components. The first three principal component axes explained 73% of the total multivariate variation. Three major groups were detected by projection of the accessions on the first two principal components. The separation of accessions was based mainly on trait morphology. Almost all Indian and origin-unknown accessions grouped together to form an Echinochloa frumentacea group. Japanese accessions grouped together except for a few outliers to form an Echinochloa esculenta group. The third group contained accessions from Russia, Japan, Cameroon, and Egypt. They formed a separate group on the scatterplot and represented accessions with lower values for all traits except basal tiller number. The interrelationships between the traits indicated that accessions with tall plants, long and broad leaves, longer inflorescences, and greater numbers of racemes should be given priority as donors or parents in varietal development initiatives. Cluster analysis identified two main clusters based on agro-morphological characters.Not Availabl

Dielectric/ferroelectric properties of ferroelectric ceramic dispersed poly (vinylidene fluoride) with enhanced beta-phase formation

Free standing and flexible ferroelectric ceramic-polymer composites (PVDF + Phi wt% of BNBT (0.94Na(0)(.)(5)Bi(0)(.)(5)TiO(3)-0.06BaTiO(3))) with 0-3 connectivity were synthesized by solution-casting technique. Composite nature and homogeneous distribution of ceramic filler particles in PVDF were confirmed with x-ray diffraction and scanning electron microscopic analysis. The intensity ratio of beta-phase with respect to alpha-phase i.e., I-20(.2)./I-18.4. (obtained from XRD analysis) and the fraction of electro-active beta phase i.e., F(beta)% (obtained from FTIR analysis) are enhanced with increase in filler concentrations and peaked for 35 wt% of the ceramic filler. An enhancement of the % of crystallinity (calculated from XRD analysis) has been observed with increase in the filler concentrations. The increase of the fraction of beta-phase has been explained on the basis of ion (negatively charged surface ion of the ferroelectric ceramic filler) -dipole (-CH2 dipole of the polymer matrix) interactions, as evidenced from FTIR and UV-VIS absorbance spectra. Relative dielectric permittivity (dielectric constant) and ferroelectric polarization were found to be highest for the composite with 35 we% of ferroelectric ceramic filler. Percolation theory has been successfully employed to explain the observed trend in the dielectric properties with the compositional variation. Significant enhancement in the electro active beta-phase has been correlated with the improved dielectric and ferroelectric properties of the composite

Suppression of RNA silencing by Flock house virus B2 protein is mediated through its interaction with the PAZ domain of Dicer

RNA silencing is a conserved pathway that functions as an antiviral mechanism. The majority of viruses encode silencing suppressors that interfere with siRNA- and miRNA-guided silencing pathways. The insect flock house virus B2 protein (FHVB2) functions as an RNAi silencing suppressor that inhibits siRNA biogenesis. Here, we describe the generation of a GFP silent sensor line (Sf21) and a GFP sensor line expressing FHVB2 to study RNAi suppression mechanisms. Overexpression of FHVB2 resulted in suppression of GFP-RNAi and resumption of GFP expression. Protein fractionation studies with FHVB2-transfected cells showed that FHVB2 associates with a high-molecular-weight complex of Dicer and dsRNA/siRNAs. Yeast two-hybrid and pulldown assays revealed an interaction between FHVB2 and Drosophila Dicer proteins that appeared to involve PAZ domains. To map the FHVB2 domains interacting with Dicer, we used a 17-residue C-terminal deletion mutant. RNAi suppression was reversed in cells transfected with the FHVB2 mutant as revealed by loss of GFP. Additional yeast two-hybrid and in vitro pulldown assays confirmed that the C-terminal region of FHVB2 was involved in the interaction with the PAZ domains of Dicers. These results thus reveal a novel interaction between FHVB2 and Dicer that leads to suppression of siRNA biogenesis.-Singh, G., Popli, S., Hari, Y., Malhotra, P., Mukherjee, S., Bhatnagar, R. K. Suppression of RNA silencing by Flock house virus B2 protein is mediated through its interaction with the PAZ domain of Dicer

Impedance spectroscopic study on microwave sintered (1-x) Na0.5Bi0.5TiO3-x BaTiO3 ceramics

Complex impedance spectroscopic technique has been implemented to study the detailed electrical transport properties of Lead free ferroelectric ceramic solid solutions of (1 - x) Na0.5Bi0.5TiO3-x BaTiO3 (NBT-BT) (0.00 <= x <= 0.10). The NBT-BT ceramics have been synthesized by sol-gel auto combustion method and sintered via microwave sintering technique. Room temperature X-ray diffraction patterns confirmed the formation of the single phase materials with perovskite structure. The surface morphology of the samples has been studied using field emission scanning electron microscopic (FESEM) technique. The FESEM micrographs confirm that the grain size decreases with increasing BaTiO3 (BT) concentration. Complex impedance, complex electric modulus formalism, and frequency dependent ac conductivity analysis have been used to study the relaxation and conduction mechanism in these materials. The presence of grain- and grain boundary contribution to impedance spectra in NBT-BT ceramics were analyzed using complex impedance plot in association with complex modulus plot. The grain- and grain boundary contributions were discerned in NBT-BT ceramic through least-squares fitting of the experimental data with a suitable equivalent circuit model. Complex impedance and complex electric modulus spectroscopic analysis indicate that the dielectric relaxation in these materials are of non-Debye type. A negative temperature coefficient of resistance (NTCR) behavior of our NBT-BT ceramics was seen from the temperature dependent conductivity studies. We have obtained similar activation energies from the conduction and relaxation process