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Genetic diversity plays an essential role in plant breeding and utilization. Pepper is an important vegetable and spice crop worldwide. The genetic diversity of 1 904 accessions of pepper conserved at the National Mid-term Genebank for Vegetables, Beijing, China was analyzed based on 29 simple sequence repeat (SSR) markers, which were evenly distributed over 12 pepper chromosomes. The pepper accessions were divided into two groups in a genetic structure analysis, and the two groups showed obvious differences in fruit type and geographical distribution. We finally selected 248 accessions capturing 75.6% of the SSR alleles as the core collection for further research. Insights into the genetic structure of pepper provide the basis for population-level gene mining and genetic improvement.

Background Colletotrichum species are the causal agents of anthracnose, a major disease affecting the yield and quality of pepper (Capsicum spp.). Colletotrichum scovillei is widespread in China, has strong pathogenicity and drug resistance, and causes anthracnose disease in pepper fruits that severely reduces production. Previously, an anti-anthracnose locus AnRGO5 was mapped to the P5 chromosome on the basis of analyses of fruit at the green mature stage. The aim of this study was to narrow down the interval of this locus and identify the gene responsible for conferring resistance. Results On the basis of results of re-sequencing of Capsicum chinense ‘PBC932’ and C. annuum ‘77013’, we developed Kompetitive allele-specific PCR (KASPar) markers and insertion–deletion (InDel) markers linked to AnRGO5 at the green mature fruit stage and used them to construct a genetic linkage map (42 markers, 24.4 cM in length). Using data obtained in phenotypic and genotypic analyses of BC4S1, BC4S2, and BC4S3 populations, AnRGO5 was located between the markers P5in-2266-404 and P5in-2268-978 within a physical distance of 164 kb. This region contained five genes, including CA05g17730. CA05g17730 encodes ‘R1C-3-like’ putative late blight resistance protein homologs. The transcript level of CA05g17730 differed between ‘PBC932’ and ‘77013’. The structure of the CA05g17730 gene also differed between ‘PBC932’ and ‘77013’. Conclusions We narrowed down the QTL interval to a region containing five genes. These results will be useful for further research on the mechanisms of resistance to anthracnose, and for marker assisted selection for anthracnose-resistant capsicum lines.

Foodborne protein hydrolysates exhibit biological activity that may be therapeutic in a number of human disease settings. Hemp peptides (HP) generated by controlled hydrolysis of hemp proteins have a number of health benefits and are of pharmaceutical value. In the present study, we produce small molecular weight HP from hemp seed and investigate its anticancer properties in Hep3B human liver cancer cells. We demonstrate that HP treatment increased apoptosis, reduced cell viability, and reduced cell migration in Hep3B human liver cancer cells without affecting the normal liver cell line L02. We correlate these phenotypes with increased cellular ROS levels, upregulation of cleaved caspase 3 and Bad, and downregulation of antiapoptotic Bcl‐2. HP treatment led to increased Akt and GSK‐3β phosphorylation, with subsequent downregulation of β‐catenin, suggesting β‐catenin signaling modulation as a critical mechanism by which HP exhibits anticancer properties. Our findings suggest HP are of potential therapeutic interest for liver cancer treatment., Anti‐cancer property of new hemp protein hydrolysates on human liver cancers

A novel strong candidate gene CA00g82510 for the male fertility restoration locus CaRf032 in Capsicum annuum was identified by genome re-sequencing and recombination analysis. A single dominant locus (CaRf032) for fertility restoration of cytoplasmic male sterility was identified in the strong restorer inbred line IVF2014032 of chili pepper (Capsicum annuum L.). CaRf032 was localized within an 8.81-Mb candidate intervals on chromosome 6 using bulked segregant analysis based on high-throughput sequencing data. Subsequently, the candidate interval was genetically mapped and defined to a 249.41-kb region using an F2 population of 441 individuals generated by crossing the male-sterile line 77013A and the restorer line IVF2014032. To fine map CaRf032, eight newly developed KASP markers were used to genotype 23 recombinants screened from a larger F2 population of 2877 individuals. The CaRf032 locus was localized to a 148.05-kb region between the KASP markers S1402 and S1354, which was predicted to contain 22 open reading frames (ORFs). One ORF with an incomplete sequence was predicted to contain a PPR motif, and its physical position overlapped with the Rf candidate gene CaPPR6_46. The PPR ORF sequence before the gap showed 100% identity with the CA00g82510 locus of the CM334 reference genome. CA00g82510 encodes a protein of 583 amino acids, containing 14 PPR motifs, and shows significantly differential expression between the flower buds of the maintainer line 77013 and the restorer line IVF2014032. These results indicated that CA00g82510 is a strong candidate gene for CaRf032. Five KASP markers, which detected single-nucleotide polymorphisms in CA00g82510 of 77013 and IVF2014032, co-segregated with CaRf032 and showed 64.4% successful genotyping of 38 maintainer and 63 restorer lines.

Fruit set and development are affected by many phytohormones, including gibberellin. Little is known regarding molecular mechanism underlying gibberellin mediated fruit set and development especially in Capsicum. Three gibberellin receptors, CaGID1b.1, CaGID1b.2 and CaGID1c, and a DELLA protein, CaGAI, have been identified in Capsicum annuum L. During the fruit development, the expression level of CaGID1c was low, and the expression fold change is mild. However, CaGID1b.1 and CaGID1b.2 were relatively higher and more acute, which indicates that CaGID1b.1 and CaGID1b.2 may play an important role in fruit pericarp, placenta and seed. Ectopic expressions of CaGID1b.1, CaGID1b.2 and CaGID1c in Arabidopsis double mutant gid1a gid1c increased plant height, among which CaGID1b.2 had the most significant effect; CaGAI reduced plant height in double mutant rga-24/gai-t6 , having a similar function to AtGID1 and AtGAI in stem elongation. Yeast two-hybrid (Y2H) and bimolecular fluorescence complementation (BiFC) assays indicated that CaGID1b.1 and CaGID1b.2 interact with CaGAI in a GA-dependent manner, while CaGID1c interacts with CaGAI in a GA-independent manner. Our study reveals the key elements during gibberellin signaling in Capsicum and supports the critical importance of gibberellin for Capsicum fruit set and development.

The Zn-22 wt.%Al was processed using five different selected routes including thermal, thermo-mechanical and severe plastic deformation (SPD) techniques in order to produce ultrafine grained (UFG) microstructure for achieving room temperature (RT) and high strain rate (HSR) superplasticity, and to compare the same set of the results. After all routes, the microstructural evolutions and RT uniaxial tensile tests at different strain rates ranging from 1 × 10-3 to 1 × 100 s-1 were investigated. The smallest grain size was achieved to be 300 nm after the thermo-mechanical process including conventional hot and cold rolling steps. However, the lamellar microstructure of the alloy was not completely eliminated during that process. On the other hand, equal-channel angular pressing (ECAP) as one of the SPD techniques decreased the grain size down to 400 nm with a lamellar-free microstructure. The maximum elongation value was achieved to be 330% with the sample tested at 1 × 10-3 s-1 after a thermo-mechanical process including conventional hot and cold rolling, and an aging stage between these rolling steps. It was found that lamellar-free microstructure causes higher superplastic elongation even if it has higher grain size compared to the sample having partially lamellar structure. © 2015 Elsevier B.V.

Continuous cropping of American ginseng (Panax quinquefolius L.) is often associated with the scarcity or unavailability of soil nutrients and an imbalance of rhizosphere microbiota, resulting in low yield and poor plant quality. Inoculation with arbuscular mycorrhizal fungi (AMF) improves plant growth and production by facilitating nutrient acquisition and by modifying the abundance and diversity of rhizosphere microorganisms. In the present study, we investigated the mechanisms by which continuous cropping of American ginseng caused growth inhibition and how AMF biofertilizer application relieved these cropping obstacles. The results showed that: 1) continuous cropping of American ginseng significantly decreased the emergence rate, shoot and root dry weight, rhizosphere soil pH, the contents of ammonium, available phosphorus (P), and available potassium (K) in the rhizosphere, while increasing the root rot disease index and the soil content of nitrate; 2) continuous cropping of American ginseng decreased the diversity of bacteria, while increasing the diversity of fungi, and increased the relative abundances of Acidobacteria and Ascomycota, while decreasing the relative abundances of Actinobacteria, Firmicutes and Zygomycota; 3) in contrast, the application of AMF biofertilizer relieved the negative effects of continuous cropping American ginseng; 4) significant positive correlations were found between Pseudarthrobacter, Streptomyces and the content of ammonium, between Bacillus and the content of available K, and between Mortierella elongata and the content of available P, suggesting that the increase of rhizosphere plant-beneficial bacteria and fungi promoted the contents of available nutrients in the rhizosphere; 5) application of AMF biofertilizer significantly decreased the abundances of soil-borne pathogenic fungi Fusarium oxysporum, F. solani and the deleterious bacteria Candidatus Solibacter. In summary, our results suggest that AMF biofertilizer application improved the continuous cropping of American ginseng growth by increasing the AMF inoculation rate, by recruiting rhizosphere beneficial bacteria and fungi that promote plant-uptake of nitrogen (N) and P, and by suppressing soil-borne pathogens. Therefore, AMF biofertilizer is a probiotic agent that prevents microbial imbalances and nutrient deficiencies during continuous cropping of American ginseng.

Quasi-single phase (dilute) Zn-0.3Al alloy was subjected to severe plastic deformation via equal-channel angular extrusion/pressing (ECAE/P), and the effects of ECAP on its room temperature (RT) and high strain rate (HSR) superplasticity and deformation mechanism were investigated. Multi-pass ECAP may refine the coarse-grained microstructure into the fine grained (FG) one. The grain size of Zn-matrix phase decreased down to 2.0m after ECAP. Many spherical Al-rich precipitates decomposed and homogeneously distributed inside the matrix phase. They are ultrafine grained (UFG) ?-particles with the grain sizes ranging from 50nm to ~200nm. This special microstructure having FG and UFG micro-constituents brought about an improvement in RT superplasticity even at HSRs. While multi-pass ECAP decreased flow stress of the alloy, its elongation to failure increased substantially depending on the initial strain rates. The maximum elongation was 1000% at a low strain rate of 10-4s-1, and 350% elongation was achieved at a high strain rate of 10-2s-1. Grain boundary sliding (GBS) was found to be the main deformation mechanism in region-II as the optimum superplastic region. © 2015 Elsevier B.V..

Multi-pass equal-channel angular extrusion/pressing (ECAE/P) was applied to the eutectic Zn-5Al alloy to achieve high strain-rate (HSR) superplasticity in that alloy at room temperature (RT) by producing ultra-fine- grained (UFG) microstructure. ECAE processing transformed the coarse-grained lamellar/spherical microstructure into a unique bimodal structure having equiaxed Zn-rich eta-phase with a mean grain size of 540 nm and spherical Al-rich a-phase with an average grain size of 110 nm. The alpha-phase particles accumulated mainly along the eta-phase boundaries. This unique microstructure brought about an extraordinary improvement in HSR superplasticity of the alloy even at RT. While the strength values decreased after ECAE, the elongation to failure increased substantially. The maximum elongation was 520% at the strain rate of 10(-3) s(-1), still high elongation of about 400% was achieved at a high strain rate of 10(-2) s(-1). This extraordinary improvement in HSR superplasticity of Zn-5Al alloy was attributed to the morphologically unique bimodal microstructure in UFG regime formed after ECAE. The grain boundary sliding (GBS) was found to be the main deformation mechanism for this alloy in superplastic regime. (C) 2014 Elsevier B.V. All rights reserved.

For Fe–22Mn–0.6C (wt%) twinning-induced plasticity (TWIP) steel with grain sizes of 35 and 170 μm, both the ultimate tensile strength and uniform elongation decrease with increasing the tensile strain rates (from 10 −4 to 10 0 s −1 ). The density of twin boundary (DTB) is presumed to be the major factor influencing mechanical properties. Accordingly, a parameter 2/( t + s ) ( t and s represent the thickness and spacing of deformation twins), also the inverse of the mean free path for dislocation slip, is proposed to characterize the planar-oriented twinned structure in infinite grain size ( D » t ≈ s ). It also evaluates the effect of DTB on the work hardening ability and ductility of the TWIP steel.