Discovery and genome-guided mapping of REN12 from Vitis amurensis, conferring strong, rapid resistance to grapevine powdery mildew

Powdery mildew resistance genes restrict infection attempts at different stages of pathogenesis.Here,a strong and rapid powdery mildew resistance phenotype was discovered from Vitis amurensis‘PI 588631’that rapidly stopped over 97%of Erysiphe necator conidia,before or immediately after emergence of a secondary hypha from appressoria.This resistance was effective across multiple years of vineyard evaluation on leaves,stems,rachises,and fruit and against a diverse array of E.necator laboratory isolates.Using core genome rhAmpSeq markers,resistance mapped to a single dominant locus(here named REN12)on chromosome 13 near 22.8–27.0 Mb,irrespective of tissue type,explaining up to 86.9%of the phenotypic variation observed on leaves.Shotgun sequencing of recombinant vines using skim-seq technology enabled the locus to be further resolved to a 780 kb region,from 25.15 to 25.93 Mb.RNASeq analysis indicated the allele-specific expression of four resistance genes(NLRs)from the resistant parent.REN12 is one of the strongest powdery mildew resistance loci in grapevine yet documented,and the rhAmpSeq sequences presented here can be directly used for marker-assisted selection or converted to other genotyping platforms.While no virulent isolates were identified among the genetically diverse isolates and wild populations of E.necator tested here,NLR loci like REN12 are often race-specific.Thus,stacking of multiple resistance genes and minimal use of fungicides should enhance the durability of resistance and could enable a 90%reduction in fungicides in low-rainfall climates where few other pathogens attack the foliage or fruit.

Factors affecting genomic selection revealed by empirical evidence in maize

Genomic selection(GS) as a promising molecular breeding strategy has been widely implemented and evaluated for plant breeding, because it has remarkable superiority in enhancing genetic gain, reducing breeding time and expenditure, and accelerating the breeding process. In this study the factors affecting prediction accuracy(rMG) in GS were evaluated systematically, using six agronomic traits(plant height, ear height, ear length, ear diameter,grain yield per plant and hundred-kernel weight) evaluated in one natural and two biparental populations. The factors examined included marker density, population size, heritability,statistical model, population relationships and the ratio of population size between the training and testing sets, the last being revealed by resampling individuals in different proportions from a population. Prediction accuracy continuously increased as marker density and population size increased and was positively correlated with heritability; rMGshowed a slight gain when the training set increased to three times as large as the testing set. Low predictive performance between unrelated populations could be attributed to different allele frequencies, and predictive ability and prediction accuracy could be improved by including more related lines in the training population. Among the seven statistical models examined, including ridge regression best linear unbiased prediction(RR-BLUP), genomic BLUP(GBLUP), Bayes A, Bayes B, Bayes C, Bayesian least absolute shrinkage and selection operator(Bayesian LASSO), and reproducing kernel Hilbert space(RKHS), the RKHS and additive-dominance model(Add + Dom model) showed credible ability for capturing non-additive effects, particularly for complex traits with low heritability. Empirical evidence generated in this study for GS-relevant factors will help plant breeders to develop GS-assisted breeding strategies for more efficient development of varieties.

Zea mays(L.) P1 locus for cob glume color identified as a post-domestication selection target with an effect on temperate maize genomes

Artificial selection during domestication and post-domestication improvement results in loss of genetic diversity near target loci. However, the genetic locus associated with cob glume color and the nature of the genomic pattern surrounding it was elusive and the selection effect in that region was not clear. An association mapping panel consisting of 283 diverse modern temperate maize elite lines was genotyped by a chip containing over 55,000 evenly distributed SNPs. Ten-fold resequencing at the target region on 40 of the panel lines and 47 tropical lines was also undertaken. A genome-wide association study(GWAS) for cob glume color confirmed the P1 locus, which is located on the short arm of chromosome 1, with a-log10 P value for surrounding SNPs higher than the Bonferroni threshold(α/n, α < 0.001) when a mixed linear model(MLM) was implemented. A total of 26 markers were identified in a 0.78 Mb region surrounding the P1 locus, including 0.73 Mb and 0.05 Mb upstream and downstream of the P1 gene, respectively. A clear linkage disequilibrium(LD) block was found and LD decayed very rapidly with increasing physical distance surrounding the P1 locus. The estimates of π and Tajima's D were significantly(P < 0.001) lower at both ends compared to the locus. Upon comparison of temperate and tropical lines at much finer resolution by resequencing(180-fold finer than chip SNPs), a more structured LD block pattern was found among the 40 resequenced temperate lines. All evidence indicates that the P1 locus in temperate maize has not undergone neutral evolution but has been subjected to artificial selection during post-domestication selection or improvement. The information and analytical results generated in this study provide insights as to how breeding efforts have affected genome evolution in crop plants.

New Dopamine Derivative from Lycium Barbarum

A new dopamine derivative, lyciumide A, was isolated from the fruits of Lycium barbarum. Its structure was elucidated as p-methoxy-cis-cinnamoyl dopamine by spectral methods.

Diacylated Triterpenoid Saponin from Silene szechuensis

A new triterpenoid saponin, named silenoside, with sugar chains esterified by two different acyl groups was isolated from Silene szechuensis. Its structure was elucidated by chemical and spectral methods.

Diels-Alder Reaction of Hedychenone and Maleic Anhydride

Diels-Alder reaction of hedychenone 1 and maleic anhydride 2 gave several products 4 similar to 7, whose structures were identified by spectral methods. Effect of temperature on the reaction was disscussed.

Anti-tumor Activity of Derivatives of Protopanaxadiol Prepared with Acid Anhydrides

[Objectives]This paper aimed to prepare derivatives of protopanaxadiol from Panax notoginseng(Burk.)FH Chen with acid anhydrides and study their anti-tumor activity.[Methods]The 3-hydroxyl group of protopanaxadiol was subjected to structural modification and reacted with acid anhydrides to prepare derivatives,in order to improve the anti-tumor activity of protopanaxadiol.None of the five compounds designed and synthesized had been reported in the literature,and they were novel compounds.The anti-tumor activity of the derivatives was studies using MTS method.Taking cisplatin and paclitaxel as positive control drugs,the bioactivity of the compounds 1-5 on anti-tumor cell lines(HL-60 cells,SMMC-7721 cells,A-549 cells,MCF-7 cells and SW480 cells)in vitro was screened.[Results]The compound 5 showed inhibitory effect on HL-60 cells,SMMC-7721 cells and A-549 cells.[Conclusions]The acid anhydride esterification method is simple to operate and easy to control.This study has reference value for the structural modification and anti-tumor activity research of protopanaxadiol from P.notoginseng(Burk.)FH Chen.

Recent Progress in Structural Modification and Activities on Panax notoginseng Saponins

This paper reviews recent progress in the structural modification and activities on Panax notoginseng saponins(PNS).PNS can not only improve the function of cardio-cerebral system,central nervous system and immune system,but also reveal anticancer,anti-aging and anti-oxidation activities.In order to solve the problem of low bioavailability and poor absorbability of PNS in vivo,usually,the researchers modified the structure of PNS with three methods:glycoside cleavage(including acid hydrolysis,sulfation,etc.),biotransformation method(including enzyme hydrolysis,microbial transformation)and combinatorial chemical method.It was found that the structural modification sites of PNS were single,mainly aimed at C-3,C-6 and C-20,which provided a new perspective for the structural modification of PNS.Therefore,structural modification on PNS with high yield and ready availability are significant in the discovery of new active ingredients and industrialization.Derivatives of PNS are applied to research of structure-activity relationship,which is beneficial to the development of new medicines.

可同时增强驱动应力和应变的近红外光驱动液晶弹性体

液晶弹性体(LCEs)在先进软执行器和机器人的应用中引起了广泛关注.具有高驱动应力和驱动应变的新兴LCEs始终是实际应用的理想选择.然而,一个常识是,LCEs特定机械性能的改善必须以牺牲其他性能为代价.在本工作中,通过简单的硫醇-丙烯酸酯反应制备了LCE,随后进行光引发的自由基聚合.通过调节侧链液晶(LC)基元的含量,调控了液晶网络的交联密度,优化了LCE的驱动.侧链LC基元的引入降低了驱动温度并且提高了驱动应变,而丙烯酸酯官能化的MXene纳米片交联了LCE基体,确保了高驱动应力和光热转化.因此,本工作通过引入侧链基元和MXene纳米片作为交联剂,同时增强了LCE的驱动应力和驱动应变,克服了LCE致动器以往高温或有害紫外光驱动、物理掺杂引起的分子扰动等局限性,大大提高了整体驱动性能(驱动应力为0.773 MPa,驱动应变为45%),实现了近红外光下的可逆变形(54%).该策略可能为优化LCE执行器的性能提供一条新途径.

Meta‐analysis and candidate gene mining of low‐phosphorus tolerance in maize

Plants with tolerance to low-phosphorus （P） can grow better under Iow-P conditions, and understanding of genetic mechanisms of Iow-P tolerance can not only facilitate identifying relevant genes but also help to develop Iow-P tolerant cultivars. QTL meta-analysis was conducted after a comprehensive review of the reports on O, TL mapping for Iow-P tolerance-related traits in maize. Meta-analysis pro- duced 23 consensus QTL （cQTL）, 17 of which located in similar chromosome regions to those previously reported to influence root traits. Meanwhile, candidate gene mining yielded 215 genes, 22 of which located in the cQTL regions. These 22 genes are homologous to 14 functionally characterized genes that were found to participate in plant Iow-P tolerance, including genes encoding miR399s, Pi transporters and purple acid phosphatases. Four cQTL loci （cQTL2-L cQTLS-3, cQTL6-2, and cQTL10-2） may play important roles for low-P tolerance because each contains more original QTL and has better consistency across previous reports.

Identification and functional characterization of the AGO1 ortholog in maize

Eukaryotic Argonaute proteins play primary roles in mi RNA and si RNA pathways that are essential for numerous developmental and biological processes. However, the functional roles of the four Zm AGO1 genes have not yet been characterized in maize（Zea mays L.）. In the present study, Zm AGO1 a was identified from four putative Zm AGO1 genes for further characterization. Complementation of the Arabidopsis ago1-27 mutant with Zm AGO1 a indicated that constitutive overexpression of Zm AGO1 a could restore the smaller rosette, serrated leaves, later flowering and maturation, lower seed set, and darker green leaves at late stages of the mutant to the wild-type phenotype. The expression profiles of Zm AGO1 a under five different abiotic stresses indicated that Zm AGO1 a shares expression patterns similar to those of Argonaute genes in rice, Arabidopsis, and wheat.Further, variation in Zm AGO1 a alleles among diverse maize germplasm that resulted in several amino acid changes revealed genetic diversity at this locus. The present data suggest that Zm AGO1 a might be an important AGO1 ortholog in maize. The results presented provide further insight into the function of ZmAGO1a.

Catalytic depolymerization/degradation of alkali lignin by dual-component catalysts in supercritical ethanol

Depolymerization of lignin is an important step to obtain lignin monomer for the synthesis of functional bio-polymers.In this paper,catalytic degradation/depolymerization of an alkali lignin was investigated in a supercritical ethanol system.The process conditions were optimized in terms of lignin monomer yield,and the liquid products and solid residue were characterized.Results show that the conversion rate of the alkali lignin was improved in both the Ni7Au3 catalyzed and Nickel-catalyzed systems with supercritical ethanol as the solvent.The maximum lignin conversion rate was 69.57%and 68%respectively for the Ni7Au3 and Nickel-based catalysis systems.Gas chromatography/mass spectroscopy(GC/MS)analysis indicated that the catalytic depolymerization products of alkali lignin were mainly monomeric phenolic compounds such as 2-methoxyphenol.The highest yield of 2-methoxyphenol(84.72%)was achieved with Ni7Au3 as the catalyst.

Facet-dependent Cu2O nanocrystals in manipulating alignment of liquid crystals and photomechanical behaviors

Manipulating the alignment of liquid crystals (LCs) is a hot and fundamental issue for their applications in block copolymers, photonics, actuators, biosensors, and liquid-crystal displays. Here, the surface characteristic of Cu2O nanocrystals was well controlled to manipulate the orientation of the LCs. The mechanism of the orientation of the LCs induced by Cu2O nanocrystals was elucidated based on the interaction between the LCs and Cu2O nanocrystals. To comprehensively prove our assumption, different types of LCs (nematic, cholesteric, and smectic) as well as the same type of LCs with different polarities were selected in our system. Moreover, the photomechanical behaviors of the LC polymer composites demonstrated that the alignment of LCs can be effectively manipulated using Cu2O nanocrystals. [Figure not available: see fulltext.] © 2016, Tsinghua University Press and Springer-Verlag Berlin Heidelberg.