ALBERT

Description: Background: Soybean cyst nematode (SCN) is the most economically devastating pathogen of soybean. Two resistance loci, Rhg1 and Rhg4 primarily contribute resistance to SCN race 3 in soybean. Peking and PI 88788 are the two major sources of SCN resistance with Peking requiring both Rhg1 and Rhg4 alleles and PI 88788 only the Rhg1 allele. Although simple sequence repeat (SSR) markers have been reported for both loci, they are linked markers and limited to be applied in breeding programs due to accuracy, throughput and cost of detection methods. The objectives of this study were to develop robust functional marker assays for high-throughput selection of SCN resistance and to differentiate the sources of resistance. Results: Based on the genomic DNA sequences of 27 soybean lines with known SCN phenotypes, we have developed Kompetitive Allele Specific PCR (KASP) assays for two Single nucleotide polymorphisms (SNPs) from Glyma08g11490 for the selection of the Rhg4 resistance allele. Moreover, the genomic DNA of Glyma18g02590 at the Rhg1 locus from 11 soybean lines and cDNA of Forrest, Essex, Williams 82 and PI 88788 were fully sequenced. Pairwise sequence alignment revealed seven SNPs/insertion/deletions (InDels), five in the 6th exon and two in the last exon. Using the same 27 soybean lines, we identified one SNP that can be used to select the Rhg1 resistance allele and another SNP that can be employed to differentiate Peking and PI 88788-type resistance. These SNP markers have been validated and a strong correlation was observed between the SNP genotypes and reactions to SCN race 3 using a panel of 153 soybean lines, as well as a bi-parental population, F5–derived recombinant inbred lines (RILs) from G00-3213 x LG04-6000. Conclusions: Three functional SNP markers (two for Rhg1 locus and one for Rhg4 locus) were identified that could provide genotype information for the selection of SCN resistance and differentiate Peking from PI 88788 source for most germplasm lines. The robust KASP SNP marker assays were developed. In most contexts, use of one or two of these markers is sufficient for high-throughput marker-assisted selection of plants that will exhibit SCN resistance.

Description: Shennongjia Rhinopithecus roxellana (SNJ R. roxellana ) is the smallest geographical population of R .  roxellana . The phylogenetic relationships among its genera and species and the biogeographic processes leading to their current distribution are largely unclear. To address these issues, we resequenced and obtained a new, complete mitochondrial genome of SNJ R. roxellana by next-generation sequencing and standard Sanger sequencing. We analyzed the gene composition, constructed a phylogenetic tree, inferred the divergence ages based on complete mitochondrial genome sequences, and analyzed the genetic divergence of 13 functional mtDNA genes. The phylogenetic tree and divergence ages showed that R. avunculus (the Tonkin snub-nosed monkey) was the first to diverge from the Rhinopithecus genus ca. 2.47 million years ago (Ma) . Rhinopithecus bieti and Rhinopithecus strykeri formed sister groups, and the second divergence from the Rhinopithecus genus occurred ca. 1.90 Ma. R. roxellana and R. brelichi diverged from the Rhinopithecus genus third, ca. 1.57 Ma. SNJ R. roxellana was the last to diverge within R. roxellana species in 0.08 Ma, and the most recent common ancestor of R. roxellana is 0.10 Ma. The analyses on gene composition showed SNJ R. roxellana was the newest geographic population of R. roxellana . The work will help to develop a more accurate protection policy for SNJ R. roxellana and facilitate further research on selection and adaptation of R. roxellana . The analyses on phylogenetic tree and divergence time showed that SNJ Rhinopithecus roxellana had the least structure and the more recent divergence times of R. roxellana , which indicated more unfavorable environmental factors made SNJ R. roxellana into a newest rapid evolutionary geographic population of R. roxellana .

Description: Establishing the accurate mathematical and simulation model of transformer is the basis of the power system steady state and transient state analysis, but the nonlinear of the transformer main magnetic circuit makes it difficult to accurate analysis of the transformer and its system. Jiles-Atherton hysteresis model as one of the classical model of ferromagnetic materials, is a physical basis of phenomenological model. It enables the mathematical description of hysteresis curves using five parameters that depend on the magnetic material characteristics. This paper introduces a modified Jiles-Atherton static hysteresis model, and the inverse model was deducted. And then this paper identifies of a hysteresis model parameters using the differential evolution algorithm, and the calculated results are well agreed with the date.

Description: This paper studies the effect of high-strength steel fiber reinforced concrete (SFRC) on the axial compression behavior of rectangular-sectional SFRC-filled steel tube columns. The purpose is to improve the integrated bearing capacity of these composite columns. Nine rectangular-sectional SFRC-filled steel tube columns and one normal concrete-filled steel tube column were designed and tested under axial loading to failure. The compressive strength of concrete, the volume fraction of steel fiber, the type of internal longitudinal stiffener and the spacing of circular holes in perfobond rib were considered as the main parameters. The failure modes, axial load-deformation curves, energy dissipation capacity, axial bearing capacity, and ductility index are presented. The results identified that steel fiber delayed the local buckling of steel tube and increased the ductility and energy dissipation capacity of the columns when the volume fraction of steel fiber was not less than 0.8%. The longitudinal internal stiffening ribs and their type changed the failure modes of the local buckling of steel tube, and perfobond ribs increased the ductility and energy dissipation capacity to some degree. The compressive strength of SFRC failed to change the failure modes, but had a significant impact on the energy dissipation capacity, bearing capacity, and ductility. The predictive formulas for the bearing capacity and ductility index of rectangular-sectional SFRC-filled steel tube columns are proposed to be used in engineering practice.

Description: The soybean GmSNAP18 gene underlies two types of resistance to soybean cyst nematode Nature Communications, Published online: 27 March 2017; doi:10.1038/ncomms14822 Peking-type and PI 88788-type soybeans are both used as sources of resistance against soybean cyst nematode. Here the authors show that in contrast to PI 88788-type resistance, where GmSNAP18 acts in combination with two neighbouring genes, in Peking-type resistance GmSNAP18 acts with GmSHMT08 to confer resistance.

Description: In this paper, a theoretical study of N-polar GaN/Al x Ga 1 -x N/GaN heterostructures is conducted systematically. The dependence of two-dimensional hole gas (2DHG, at the bottom Al x Ga 1 -x N/GaN interface) and electron gas (2DEG, at the upper GaN/Al x Ga 1 -x N interface) sheet densities on variables, such as GaN top layer thickness, Al x Ga 1 -x N back barrier thickness, and Al content, is investigated. The effect of n-type doping in Al x Ga 1 -x N and δ-doping concentrations in the GaN buffer on 2DHG and 2DEG sheet densities is also presented. For the unintentionally doped structure, the 2DHG-induced electric field E 2 DHG provides the only driving force in the 2DEG formation. Thus, in order to get high dense of 2DEG in such heterostructure, 2DEG and 2DHG shall coexist through proper Al x Ga 1 -x N back barrier design. While for intentionally doped structure (with the n-type doped Al x Ga 1 -x N back barrier layer or δ-doped GaN buffer layer), ionized donor-induced electric field E donor is another driving force for 2DEG. The obtained insight offers indications for the structure design of the N-polar GaN/Al x Ga 1 -x N/GaN high electron mobility transistors.