Genetic basis of high aroma and stress toleranee in the oolong tea cultivar genome

Tea plants(Camellia sinensis)are commercially cultivated in>60 countries,and their fresh leaves are processed into tea,which is the most widely consumed beverage in the world.Although several chromosome-level tea plant genomes have been published,they collapsed the two haplotypes and ignored a large number of allelic variations that may underlie important biological functions in this species.Here,we present a phased chromosome-scale assembly for an elite oolong tea cultivar,"Huangdan",that is well known for its high levels of aroma.Based on the two sets of haplotype genome data,we identi fi ed numerous genetic variations and a substantial proportion of allelic imbalance related to important traits,including aroma-and stress-related alleles.Comparative genomics revealed extensive structural variations as well as expansion of some gene families,such as terpene synthases(TPSs),that likely contribute to the high-aroma characteristics of the backbone parent,underlying the molecular basis for the biosynthesis of aroma-related chemicals in oolong tea.Our results uncovered the genetic basis of special features of this oolong tea cultivar,providing fundamental genomic resources to study evolution and domestication for the economically important tea crop.

Throughput Maximization for Multi-UAV Enabled Millimeter Wave WPCN: Joint Time and Power Allocation

In this paper,we investigate the effective deployment of millimeter wave(mmWave)in unmanned aerial vehicle(UAV)-enabled wireless powered communication network(WPCN).In particular,a novel framework for optimizing the performance of such UAV-enabled WPCN in terms of system throughput is proposed.In the considered model,multiple UAVs monitor in the air along the scheduled flight trajectory and transmit monitoring data to micro base stations(mBSs)with the harvested energy via mmWave.In this case,we propose an algorithm for jointly optimizing transmit power and energy transfer time.To solve the non-convex optimization problem with tightly coupled variables,we decouple the problem into more tractable subproblems.By leveraging successive convex approximation(SCA)and block coordinate descent techniques,the optimal solution is obtained by designing a two-stage joint iteration optimization algorithm.Simulation results show that the proposed algorithm with joint transmit power and energy transfer time optimization achieves significant performance gains over Q-learning method and other benchmark schemes.

Identification of PAL genes related to anthocyanin synthesis in tea plants and its correlation with anthocyanin content

The phenylalanine ammonia-lyase(PAL)gene family in tea plants(Camellia sinensis L.)encodes the enzyme that catalyzes the first reaction of the phenylpropane metabolic pathway.The present study aimed to characterize the PAL genes in tea plants,and get better insights on the CsPALs in anthocyanins accumulation.Seven CsPAL genes were identified and characterized in tea plants by bioinformatics analysis.Systematic analysis of CsPALs was conducted for its phylogenetic relationship,gene structure,chromosomal location,and protein conserved motifs based on tea plant genome.The cis-elements of CsPALs were responsive to light,abiotic stress,hormone,and MYB-binding site.Furthermore,tissuespecific expression analysis showed that CsPAL4 was expressed preferentially in young leaves and buds.Correlation analysis was performed in purple-leaf tea with anthocyanin components,and it was suggested that CsPAL4 was closely related with different anthocyanin accumulated,especially with cyanidin 3-O-galactoside,cyanidin 3-O-glucoside,and delphinidin 3-O-glucoside.Additionally,the putative upstream regulation factors CsMYBs(CsMYB59,CsARR1,CsSRM1,CsMYB101,and CsMYB52)and CsbHLHs(CsbHLH104,CsbHLH3,CsbIM1,CsTCP14,and CsPIF4)could bind to the promoter of CsPALs,thereby activating its transcription.This study provides a theoretical basis for further research to elucidate the functions of the CsPAL genes.

Chromatin accessibility and translational Iandscapes of tea plants under chilling stress

Plants have evolved regulatory mechanisms at multiple levels to regulate gene expression in order to improve their cold adaptability.However,limited information is available regarding the stress response at the chromatin and translational levels.Here,we characterize the chromatin accessibility,transcriptional,and translational landscapes of tea plants in vivo under chilling stress for the first time.Chilling stress signi ficantly affected both the transcription and translation levels as well as the translation efficiency of tea plants.A total of 3010 genes that underwent rapid and independent translation under chilling stress were observed,and they were signi ficantly enriched in the photosynthesis-antenna protein and phenylpropanoid biosynthesis pathways.A set of genes that were signi ficantly responsive to cold at the transcription and translation levels,including four(+)-neomenthol dehydrogenases(MNDs)and two(E)-nerolidol synthases(NESs)arranged in tandem on the chromosomes,were also found.We detected potential upstream open reading frames(uORFs)on 3082 genes and found that tea plants may inhibit the overall expression of genes by enhancing the translation of uORFs under chilling stress.In addition,we identi fied distal transposase hypersensitive sites(THSs)and proximal THSs and constructed a transcriptional regulatory network for tea plants under chilling stress.We also identi fied 13 high-con fidence transcription factors(TFs)that may play a crucial role in cold regulation.These results provide valuable information regarding the potential transcriptional regulatory network in plants and help to clarify how plants exhibit flexible responses to chilling stress.

High-energy-density plasma in femtosecond-laser-irradiated nanowire-array targets for nuclear reactions

In this work,the high-energy-density plasmas(HEDP)evolved from joule-class-femtosecond-laser-irradiated nanowire-array(NWA)targets were numerically and experimentally studied.The results of particle-in-cell simulations indicate that ions accelerated in the sheath field around the surfaces of the nanowires are eventually confined in a plasma,contributing most to the high energy densities.The protons emitted from the front surfaces of the NWA targets provide rich information about the interactions that occur.We give the electron and ion energy densities for broad target parameter ranges.The ion energy densities from NWA targets were found to be an order of magnitude higher than those from planar targets,and the volume of the HEDP was several-fold greater.At optimal target parameters,8%of the laser energy can be converted to confined protons,and this results in ion energy densities at the GJ/cm^(3) level.In the experiments,the measured energy of the emitted protons reached 4 MeV,and the changes in energy with the NWA’s parameters were found to fit the simulation results well.Experimental measurements of neutrons from 2H(d,n)3He fusion with a yield of(24±18)×10^(6)/J from deuterated polyethylene NWA targets also confirmed these results.

Development of new technology for coal gasification purification and research on the formation mechanism of pollutants

Coal-fired power generation is the main source of CO_(2)emission in China.To solve the problems of declined efficiency and increased costs caused by CO_(2)capture in coal-fired power systems,an integrated gasification fuel cell(IGFC)power generation technology was developed.The interaction mechanisms among coal gasification and purification,fuel cell and other components were further studied for IGFCs.Towards the direction of coal gasification and purification,we studied gasification reaction characteristics of ultrafine coal particles,ash melting characteristics and their effects on coal gasification reactions,the formation mechanism of pollutants.We further develop an elevated temperature/pressure swing adsorption rig for simultaneous H_(2)S and CO_(2)removals.The results show the validity of the Miura-Maki model to describe the gasification of Shenhua bituminous coal with a good fit between the predicted DTG curves and experimental data.The designed 8–6–1 cycle procedure can effectively remove CO_(2)and H_(2)S simultaneously with removal rate over 99.9%.In addition,transition metal oxides used as mercury removal adsorbents in coal gasified syngas were shown with great potential.The techniques presented in this paper can improve the gasification efficiency and reduce the formation of pollutants in IGFCs.

Evolutionary genomics of structural variation in the tea plant,Camellia sinensis

Structural variants(SVs)are a type of genetic variation that contribute substantially to phenotypic diversity and evolution.Further study of SVs will help us understand the influence of SVs associated with tea quality and stress resistance and provide new insight into tea plant breeding improvement and genetic research.However,SVs have not been thoroughly discovered in the tea plant genomes.Herein,we constructed a large-scale SV map across a population of 107 resequenced genomes,including both ancient and cultivated tea plants.A total of 44,240 highconfident SVs were identified,including 34,124 DEL(deletions),4,448 DUP(duplications),2,503 INV(inversions),544 INS(insertions)and 2,621 TRA(translocations).In total,12,400 protein-coding genes were overlapped with SVs,of which 49.5%were expressed in all five tea tissues.SVbased analysis of phylogenetic relationships and population structure in tea plants showed a consistent evolutionary history with the SNP-based results.We also identified SVs subject to artificial selection and found that genes under domestication were enriched in metabolic pathways involving theanine and purine alkaloids,biosynthesis of monoterpenoid,phenylpropanoid,fatty acid,and isoflavonoid,contributing to traits of agronomic interest in tea plants.In addition,a total of 27 terpene synthase(TPS)family genes were selected during domestication.These results indicate that these SVs could provide extensive genomic information for tea quality improvement.

Low-temperature environments for quantum computation and quantum simulation

This review summarizes the requirement of low temperature conditions in existing experimental approaches to quantum computation and quantum simulation.

The influence of different heating rates on mortality of Tribolium castaneum(Herbst)(Coleoptera: Tenebrionidae)

In order to elucidate the ability of stored product insects to resist high temperature at varying temperature conditions,the influence of different heating rates on the mortality of all life stages of Tribolium castaneum(Herbst)(Coleoptera:Tenebrionidae)was investigated.After acclimation from 28 to 42,44 and 46℃ at different heating rates(0,1.25,2.50,5.00,and 10.00℃/h),eggs,larvae,pupae,and adults of T.castaneum were exposed at 50℃ for 0(as a control),10,15,20,25 and 30 min,respectively.The corrected mortality of T.castaneum was determined after 24 h.The results showed that different exposure times and heating rates had significant effects on the mortality of T.castaneum.The mortality of all life stages of T.castaneum with the same acclimation experience increased significantly with the increasing exposure time,and acclimation improved the heat tolerance of T.castaneum.The mortalities exposed at 50℃ for 30 min of T.castaneum eggs(acclimated to 46℃ at 5.00℃/h),larvae(acclimated to 44℃ at 2.50℃/h),pupae(acclimated to 46℃ at 5.00℃/h),and adults(acclimated to 46℃ at 2.50℃/h)were 62.50%,54.44%,58.89%and 53.33%,respectively,significantly lower than that of corresponding life stages of T.castaneum acclimated at 1.25 and 10.00℃/h.The present results are in favor of developing an effective heat treatment protocol for pest control.

A comprehensive diagnostic system of ultra-thin liquid sheet targets

To meet the demands of laser-ion acceleration at a high repetition rate,we have developed a comprehensive diagnostic system for real-time and in situ monitoring of liquid sheet targets(LSTs).The spatially resolved rapid characterizations of an LST’s thickness,flatness,tilt angle and position are fulfilled by different subsystems with high accuracy.With the help of the diagnostic system,we reveal the dependence of thickness distribution on collision parameters and report the 238-nm liquid sheet generated by the collision of two liquid jets.Control methods for the flatness and tilt angle of LSTs have also been provided,which are essential for applications of laser-driven ion acceleration and others.

Synchronous post-acceleration of laser-driven protons in helical coil targets by controlling the current dispersion

Post-acceleration of protons in helical coil targets driven by intense,ultrashort laser pulses can enhance ion energy by utilizing the transient current from the targets’self-discharge.The acceleration length of protons can exceed a few millimeters,and the acceleration gradient is of the order of GeV/m.How to ensure the synchronization between the accelerating electric field and the protons is a crucial problem for efficient post-acceleration.In this paper,we study how the electric field mismatch induced by current dispersion affects the synchronous acceleration of protons.We propose a scheme using a two-stage helical coil to control the current dispersion.With optimized parameters,the energy gain of protons is increased by four times.Proton energy is expected to reach 45 MeV using a hundreds-of-terawatts laser,or more than 100 MeV using a petawatt laser,by controlling the current dispersion.

Characteristic volatile components and transcriptional regulation of seven major tea cultivars(Camellia sinensis)in China

The volatiles in the young shoots of tea cultivars are the important material basis for the formation of tea aroma,but the cultivar-specific aroma and its molecular regulation are still lacking in research.In this study,the characteristic volatiles of seven tea cultivars in China were detected,and the results showed that the green tea cultivars'Fuding Dabaicha'(FDDB),'Longjing43'(LJ43),'Shuchazao'(SCZ),and'Baihaozao'(BHZ)were rich in(E)-3-hexenol,phenylethyl alcohol,phenylacetaldehyde,andβ-ionone.For oolong tea cultivars,the characteristic volatiles of'Tieguanyin'(TGY)were heptanal and eugenol,while the contents of(E)-β-ocimene,geraniol,and methyl salicylate were significantly increased in'Jinxuan'(JX).In addition,'Fujian Shuixian'(FJSX)has the highest content of esters,mainly jasmonolactone and dihydrojasmonolactone.Transcriptomic analysis showed that the different tea cultivars were significantly enriched in different levels of gene transcription in the three pathways related to aroma biosynthesis.Potential regulatory modules and genes of several characteristic volatiles were identified by WGCNA,among which CsbHLH(CsTGY12G0001520)may regulate the expression of CsTPS(CsTGY05G0001285)to directly affect the accumulation ofβ-caryophyllene in young shoots,while CsMYB(CsTGY01G0001203,CsTGY04G0001918,CsTGY06G0002545)may affect the synthesis of(Z)-3-hexenol and(E)-3-hexen-1-ol acetate by regulating the CsADH(CsTGY09G0001879).In addition,the transcription factors bHLH,WRKY,ERF,and MYB may be involved in the biosynthesis of linalool by regulating the expression of CsLIS/NES(CsTGY08G0001704,CsTGY08G0000359)genes individually or through interaction.These results revealed the characteristic volatiles and their key regulatory genes of seven tea cultivars,which will provide a theoretical basis for breeding and suitability research of tea cultivars.

红蓝光调控茉莉开花的转录组分析

茉莉花是多年生常绿灌木植物,因其香气芬芳怡人,常被作为天然香料的原材料。本研究通过红光和蓝光分别处理茉莉植株,以白光模拟日光作为对照,观察茉莉植株开花早晚情况,结果表明,红光处理可促使茉莉花提前开花且增加花蕾数量,而蓝光延迟茉莉开花但花蕾数量减少,且各组之间花蕾数量差异显著。采用Illumina Hiseq/Miseq 2000高通量测序技术对红光组、蓝光组及白光组的顶芽部分进行转录组测序,共得到2 452 457条单基因簇(Unigene),其中1 760 723个Unigenes注释到GO、COG、KEGG、KOG、NR、Pfam、Swiss-Prot、NOG数据库。差异表达基因分析显示,对照组vs红光组共获得894个DEGs,对照组vs蓝光组共获得2 690个DEGs,红光组vs蓝光组共获得3 828个DEGs,共有的DEGs有72个。KEGG富集分析显示对照组vs红光组与对照组vs蓝光组共有的显著富集通路包括次生代谢物生物合成、苯丙素生物合成、吲哚生物碱生物合成、光合作用、植物激素信号传导和植物-病原体相互作用等,并从中筛选出24条差异表达基因,采用荧光定量PCR技术检测其表达水平,进行相关性分析,结果表明与转录组数据显著相关。通过对转录组数据进一步分析,发掘出大量调控开花相关的激素(IAA、ETH、GA、CTK、ABA、SA、JA)信号转导基因、开花途径相关调控基因(PHY、CRY1、FPA、AGL和SOC1)以及转录因子(bHLH、MYB、WKRY)家族基因,有助于阐明不同光质调控茉莉开花的差异表达机理。

Electrooxidation-Induced C(sp^(3))-H/C(sp^(2))-H Radical-Radical Cross-Coupling between Xanthanes and Electron-Rich Arenes

The arylation of C(sp^(3))-H bonds has been a priority research topic in organic synthesis.Minsici reactions have been the powerful methods for C(sp^(3))-C(sp^(2))bonds formation.Despite its mature development,the scopes of arenes are usually suitable for elec-tron-deficient heterocyclic compounds,rather than electron-rich arenes.Herein,we report an electrooxidation-induced alkylation of electron-rich arenes with H_(2) evolution under exogenous oxidant-free conditions,avoiding the utilization of metal catalysts.This pro-tocol is well performed with various electron-rich aniline derivatives and nitrogen-containing heterocyclic compounds.We anticipate that this electro-oxidative C(sp^(3))-H arylation represents an important expansion for the classic arenes alkylation,thereby proving an attractive strategy for the developments of radical cross-coupling chemistry.

Precise electro-reduction of alkyl halides for radical defluorinative alkylation

Reported here is a precise electro-reduction strategy for radical defluorinative alkylation towards the synthesis of gem-difluoroalkenes from α-trifluoromethylstyrenes. According to the redox-potential difference of the radical precursors, direct or indirect electrolysis is respectively adopted to realize the precise reduction. An easy-to-handle, catalyst-and metal-free condition is developed for the reduction of alkyl radical precursors that are generally easier to be reduced than α-trifluoromethylstyrenes,while a novel electro-Ni-catalytic system is established for the electro-reduction of alkyl bromides or chlorides towards the electrochemical synthesis of gem-difluoroalkenes. The merit of this protocol is exhibited by its mild conditions, wide substrate scope, and scalable preparation. Mechanistic studies and DFT calculations proved that the coordination of α-trifluoromethylstyrenes to Ni-catalyst prevents the direct reduction of the alkene and, in turn, promotes the activation of alkyl bromide through halogen atom transfer mechanism.

Fabrication of large-area uniform carbon nanotube foams as near-critical-density targets for laser–plasma experiments

Carbon nanotube foams(CNFs)have been successfully used as near-critical-density targets in the laser-driven acceleration of high-energy ions and electrons.Here we report the recent advances in the fabrication technique of such targets.With the further developed floating catalyst chemical vapor deposition(FCCVD)method,large-area(>25 cm^(2))and highly uniform CNFs are successfully deposited on nanometer-thin metal or plastic foils as double-layer targets.The density and thickness of the CNF can be controlled in the range of 1−13 mg/cm^(3)and 10−200µm,respectively,by varying the synthesis parameters.The dependence of the target properties on the synthesis parameters and the details of the target characterization methods are presented for the first time.

Laser-induced damage thresholds of ultrathin targets and their constraint on laser contrast in laser-driven ion acceleration experiments

Single-shot laser-induced damage threshold(LIDT)measurements of multi-type free-standing ultrathin foils were performed in a vacuum environment for 800 nm laser pulses with durationsτranging from 50 fs to 200 ps.The results show that the laser damage threshold fluences(DTFs)of the ultrathin foils are significantly lower than those of corresponding bulk materials.Wide band gap dielectric targets such as SiN and formvar have larger DTFs than semiconductive and conductive targets by 1–3 orders of magnitude depending on the pulse duration.The damage mechanisms for different types of targets are studied.Based on the measurement,the constrain of the LIDTs on the laser contrast is discussed.

Dynamic ordering transitions in charged solid

The phenomenon of group motion is common in nature,ranging from the schools of fish,birds and insects,to avalanches,landslides and sand drift.If we treat objects as collectively moving particles,such phenomena can be studied from a physical point of view,and the research on many-body systems has proved that marvelous effects can arise from the simplest individuals.The motion of numerous individuals presents different dynamic phases related to the ordering of the system.However,it is usually difficult to study the dynamic ordering and its transitions through experiments.Electron bubble states formed in a two-dimensional electron gas,as a type of electron solids,can be driven by an external electric field and provide a platform to study the dynamic collective behaviors.Here,we demonstrate that the noise spectrum is a powerful method to investigate the dynamics of bubble states.We observed not only the phenomena of dynamically ordered and disordered structures,but also unexpected alternations between them.Our results show that a dissipative system can convert between chaotic structures and ordered structures when tuning global parameters,which is concealed in conventional transport measurements of resistance or conductance.Moreover,charging the objects to study the electrical noise spectrum in collective motions can be an additional approach to revealing dynamic ordering transitions.