Genetic dissection of yield-related traits in response to drought stress in common bean

Drought stress severely impairs common bean production.For facilitating drought-resistance breeding in common bean,molecular markers were identified in a genome-wide level marker–trait association study.A panel of 210 common bean accessions showed large variation in 11 agronomic traits at the adult stage(plant height,pod number per plant,seed number per pod,seed number per plant,seed yield per plant,pod length,harvest index,pod harvest index,days to maturity,hundred-seed weight,and seed yield)under two water conditions.The coefficient of variation ranged from 6.21% for pod harvest index to51.00% for seed number per plant under well-watered conditions,and from 4.05% for days to maturity to 40.72% for seed number per plant under drought stress.In a genome-wide association study,119quantitative-trait loci were associated with drought resistance,including 41 adjacent to known loci.Among these loci,12 were found to be associated with at least two traits.Three major loci were identified at Pv01 and Pv02.A set of candidate genes were found that encode MYBs,AREBs,WKRYs,and protein kinases.These results reveal promising alleles that control drought resistance,shedding light on the genetic basis of drought resistance and accelerating future efforts for drought resistance improvement in common bean.

Near-Zero Air Pollutant Emission Technologies and Applications for Clean Coal-Fired Power

Coal is the dominant energy source in China,and coal-fired power accounts for about half of coal consumption.However,air pollutant emissions from coal-fired power plants cause severe ecological and environmental problems.This paper focuses on near-zero emission technologies and applications for clean coal-fired power.The long-term operation states of near-zero emission units were evaluated,and synergistic and special mercury(Hg)control technologies were researched.The results show that the principle technical route of near-zero emission,which was applied to 101 of China’s coal-fired units,has good adaptability to coal properties.The emission concentrations of particulate matter(PM),SO2,and NOx were below the emission limits of gas-fired power plants and the compliance rates of the hourly average emission concentrations reaching near-zero emission in long-term operation exceeded 99%.With the application of near-zero emission technologies,the generating costs increased by about 0.01 CNY∙(kW∙h)-1.However,the total emissions of air pollutants decreased by about 90%,resulting in effective improvement of the ambient air quality.Furthermore,while the Hg emission concentrations of the near-zero emission units ranged from 0.51 to 2.89μg∙m^-3,after the modified fly ash(MFA)special Hg removal system was applied,Hg emission concentration reached as low as 0.29μg∙m^-3.The operating cost of this system was only 10%-15%of the cost of mainstream Hg removal technology using activated carbon injection.Based on experimental studies carried out in a 50000 m^3∙h^-1 coal-fired flue gas pollutant control pilot platform,the interaction relationships of multi-pollutant removal were obtained and solutions were developed for emissions reaching different limits.A combined demonstration application for clean coal-fired power,with the new“1123”eco-friendly emission limits of 1,10,20 mg∙m^-3,and 3μg∙m^-3,respectively,for PM,SO2,NOx,and Hg from near-zero emission coal-fired power were put forward and realized,providing engineering and technical support for the national enhanced pollution emission standards.

Molecular cloning and characterization of a gene encoding the proline transporter protein in common bean(Phaseolus vulgaris L.)

As a typical compatible solute, proline is accumulated in plants under environmental stresses. Proline transporter(Pro T) plays an important role in proline distribution between plant organs. Using a candidate gene approach, we cloned a c DNA sequence for Pro T from common bean(Phaseolus vulgaris L.) and designated the gene Pv Pro T. The deduced amino acid sequence of Pv Pro T showed high similarity to Bet/Pro T proteins from other leguminous plants, and the highest similarity was observed with mothbean(Vigna aconitifolia L.) Vu Pro T.Relative quantification of the m RNA level of Pv Pro T using real-time PCR analysis showed that the Pv Pro T transcript level was higher in leaves than in stems and roots of common bean plants subjected to drought and salt stress. Under 20%(w/w) PEG-6000 treatment,drought-resistant plants expressed a higher level of Pv Pro T transcripts than droughtsensitive plants. Although heterologous expression of Pv Pro T in the Escherichia coli mutant mkh13 showed that Pv Pro T exhibited uptake activities for proline and betaine, no betaine content was detected in the common bean. These findings suggest that Pv Pro T plays an important role in the transportation of proline in common bean plants exposed to drought and salt stress.

Editorial: Food Legume Diversity and Legume Research Policies

This special issue is focused on grain legumes,which belong to the Fabaceae family.Legumes are the second largest family of plants in the world after the grasses and are key components of manmade and natural ecosystems[1–3].They provide the environmental service of nitrogen fixation,so essential to soil construction and fertility maintenance,and are thus essential to agricultural systems[4,5].Different species of legumes range from huge trees to shrubs

QTL and candidate genes associated with common bacterial blight resistance in the common bean cultivar Longyundou 5 from China

Common bacterial blight(CBB), caused by Xanthomonas axonopodis pv. phaseoli and Xanthomonas fuscans subsp. fuscans(Xff), is a worldwide disease of common bean(Phaseolus vulgaris L.).Longyundou 5, a Chinese cultivar in the Mesoamerican gene pool of common bean, displays resistance to the Xff strain XSC3-1. To identify the genetic mechanisms behind this resistance,we crossed Long 5 with a susceptible genotype to develop a mapping population of F2 plants.Plant resistance to CBB was identified at 14 and 21 days after inoculation with Xff strain XSC3-1.A major QTL at 14 and 21 days after inoculation was mapped on chromosome Pv10 with LOD scores of 6.41 and 5.35, respectively. This locus was associated with SAP6, a previouslyidentified and much-used dominant marker, but in a 4.2 cM interval between new codominant markers BMp10s174 and BMp10s244. Ten candidate genes were found between markers BMp10s174 and BMp10s244 on chromosome Pv10 and could encode defense response proteins responding to CBB pathogens. Four pairs each of epistatic QTL for CBB resistance were detected at 14 and 21 days after inoculation. Phenotypic variation explained by the epistatic QTL ranged from 7.19% to 12.15% and 7.72% to 8.80% at 14 and 21 days after inoculation, respectively. These results confirmed the importance of epistasis in CBB resistance in common bean. The adjacent markers found may be more efficient for marker assisted selection in common bean breeding for CBB resistance owing to their closer linkage to the target QTL.

The scanning tunneling microscopy and spectroscopy of GaSb_(1-x)Bi_(x) films of a few-nanometer thickness grown by molecular beam epitaxy

The ultrahigh vacuum scanning tunneling microscope(STM)was used to characterize the GaSb_(1-x)Bi_(x) films of a few nanometers thickness grown by the molecular beam epitaxy(MBE)on the GaSb buffer layer of 100 nm with the GaSb(100)substrates.The thickness of the GaSb_(1-x)Bi_(x) layers of the samples are 5 and 10 nm,respectively.For comparison,the GaSb buffer was also characterized and its STM image displays terraces whose surfaces are basically atomically flat and their roughness is generally less than 1 monolayer(ML).The surface of 5 nm GaSb_(1-x)Bi_(x) film reserves the same terraced morphology as the buffer layer.In contrast,the morphology of the 10 nm GaSb_(1-x)Bi_(x) film changes to the mound-like island structures with a height of a few MLs.The result implies the growth mode transition from the two-dimensional mode as displayed by the 5 nm film to the Stranski-Krastinov mode as displayed by the 10 nm film.The statistical analysis with the scanning tunneling spectroscopy(STS)measurements indicates that both the incorporation and the inhomogeneity of Bi atoms increase with the thickness of the GaSb_(1-x)Bi_(x) layer.

Growth Optimization, Strain Compensation and Structure Design of InAs/GaSb Type-II Superlattices for Mid-Infrared Imaging

InAs/GaSb type-II superlattce (T2SL) photodetector structures at the MWIR regime were grown by molecular beam epitaxy. The growth temperature and group-V soaking times were optimized with respect to interface and transport quality. Novel strain compensation schemes with insertion of InSb layers were proposed and tested to be efficient to tune the overall strain between tensile and compressive without degradation of interface and optical quality. The effect of the proposed methods is modeled by analytic functions.? Band structure calculations were also carried out for the proposed T2SL structures to assist optimizing sample designs. Single pixel photodiodes with a low dark current were demonstrated.

High-rate CH_(4)-to-C_(2)H_(6) photoconversion enabled by Au/ZnO porous nanosheets under oxygen-free system

Photocatalytic CH_(4) coupling into high-valued C_(2)H_(6) is highly attractive,whereas the photosynthetic rate,especially under oxygen-free system,is still unsatisfying.Here,we designed the negatively charged metal supported on metal oxide nanosheets to activate the inert C-H bond in CH_(4)and hence accelerate CH_(4) coupling performance.As an example,the synthetic Au/ZnO porous nanosheets exhibit the C_(2)H_(6) photosynthetic rate of 1,121.6μmol g^(-1)_(cat)h^(-1)and the CH_(4) conversion rate of 2,374.6μmol g^(-1)_(cat)h^(-1) under oxygen-free system,2 orders of magnitude higher than those of previously reported photocatalysts.By virtue of several in situ spectroscopic techniques,it is established that the generated Au^(δ-)and O^-species together polarized the C-H bond,while the Au^(δ-)and O^-species jointly stabilized the CH_(3) intermediates,which favored the coupling of CH_(3) intermediate to photosynthesize C_(2)H_(6) instead of overoxidation into CO_(x).Thus,the design of dual active species is beneficial for achieving high-efficient CH_(4)-to-C_(2)H_(6) photoconversion.

普通菜豆抗菜豆象性状的全基因组关联分析

普通菜豆(Phaseolus vulgaris)具有丰富的营养价值,菜豆象(Acanthoscelides obtectus)是危害菜豆的主要害虫,利用抗虫种质资源防治菜豆象是最安全且经济有效的方法。该研究利用改良的室内人工接虫方法,对625份普通菜豆种质资源进行2次菜豆象抗性重复鉴定,筛选出2份抗性稳定且种子受害率均在10%以下的高抗种质。利用种子受害率和蛀孔总数的表型数据,基于3767432个SNP标记进行全基因组关联分析,鉴定出15个与种子受害率相关的显著关联遗传位点,8个与蛀孔总数相关的显著关联位点,解释了4.54%–5.56%的表型变异。在候选位点筛选出包括编码蛋白酶抑制剂、凝集素和过氧化物酶等在内的20个与抗虫防御相关的候选基因。

普通菜豆镰孢菌枯萎病抗性种质资源筛选及全基因组关联分析

普通菜豆镰孢菌枯萎病是严重制约菜豆(Phaseolus vulgaris)产量的主要病害之一。采用下胚轴双孔注射法对601份普通菜豆种质资源进行枯萎病抗性鉴定,共筛选出4份高抗材料。在此基础上,基于分布在全基因组上的3765456个单核苷酸多态性(SNP)标记,进行全基因组关联分析,以P<1×10^(–5)为阈值。结果检测到57个显著关联的SNP位点,分布于1、2、6、8和11号染色体上;共获得8个显著关联区域,其中位于1号染色体上的区域1包含SNP最多(48个),最显著SNP P值为2.18E–07。在8个显著关联区域中,共检测到186个基因,其中157个基因有注释信息,编码过氧化物酶、抗病蛋白、转录因子和蛋白激酶等。结合KEGG富集分析和序列同源性比对,鉴定出9个候选基因可能与抗性相关。

Suggestion on further strengthening ultra-low emission standards for PM emission from coal-fired power plants in China

China has established the largest clean coal-fired power generation system in the world by accomplishing the technological transformation of coal-fired power plants(CFPPs)to achieve ultra-low emission.The potential for further particulate matter(PM)emission reduction to achieve near-zero emission for CFPPs has become a hotspot issue.In this study,PM emission from some ultra-low emission CFPPs adopting advanced air pollutant control technologies in China was reviewed.The results revealed that the average filterable particulate matter(FPM)concentration,measured as the total particulate matter(TPM)according to the current national monitoring standard,was(1.67±0.86)mg/m^(3),which could fully achieve the ultra-low emission standard for key regions(5 mg/m^(3)),but that achieving the near-zero emission standard was difficult(1 mg/m^(3)).However,the condensable particulate matter(CPM),with an average concentration of(1.06±1.28)mg/m^(3),was generally ignored during monitoring,which led to about 38.7%underestimation of the TPM.Even considering both FPM and CPM,the TPM emission from current CFPPs would contribute to less than 5%of atmospheric PM_(2.5) concentrations in the key cities and regions in China.Therefore,further reduction in FPM emission proposed by the near-zero emission plan of CFPPs may have less environmental benefit than emission control of other anthropogenic sources.However,it is suggested that the management of CPM emission should be strengthened,and a national standard for CPM emission monitoring based on the indirect dilution method should be established for CFPPs.Those measurements are helpful for optimal operation of air pollutant control devices and continuously promoting further emission reduction.

In vivo bioorthogonal labeling of rare-earth doped nanoparticles for improved NIR-II tumor imaging by extracellular vesiclemediated targeting

The development of efficient contrast agents for tumor-targeted imaging remains a critical challenge in the clinic.Herein,we proposed a tumor-derived extracellular vesicle(EV)-mediated targeting approach to improve in vivo tumor imaging using ternary downconversion nanoparticles(DCNPs)with strong near infrared II(NIR-II)luminescence at 1,525 nm.The EVs were metabolically engineered with azide group,followed by in vivo labeling of DCNPs through copper-free click chemistry.By taking advantage of the homologous targeting property of tumor derived EVs,remarkable improvement in the tumor accumulation(6.5%injection dose(ID)/g)was achieved in the subcutaneous colorectal cancer model when compared to that of individual DCNPs via passive targeting(1.1%ID/g).Importantly,such bioorthogonal labeling significantly increased NIR-II luminescence signals and prolonged the retention at tumor sites.Our work demonstrates the great potential of EVs-mediated bioorthogonal approach for in vivo labeling of NIR-II optical probes,which provides a robust tool for tumor-specific imaging and targeted therapy.

Engineering Janus gold nanorod–titania heterostructures with enhanced photocatalytic antibacterial activity against multidrugresistant bacterial infection

Photocatalytic antibacterial approach shows great potential in treating multidrug-resistant bacterial infections.However,the bactericidal efficiency heavily depends on the photocatalytic activity of semiconductor materials,which is limited by the fast recombination of photogenerated electron–hole pairs.Janus nano-heterostructures with spatial control growth of TiO_(2)nanoparticles(NPs)at one end of gold nanorods(Au NRs)are designed via surface ligand regulation for photocatalytic sterilization and infected wound healing.The asymmetric nanostructure of Janus gold nanorod-titanium dioxide nanoparticles(Janus AuNR-TiO_(2) NPs)promotes the directional migration of charge carriers and is more conducive to the spatial separation of electron–hole pairs.Moreover,the injection of hot electrons and enhancement of plasmon near-fields from the surface plasmon resonance(SPR)effect further improve the photocatalytic efficiency of Janus AuNR-TiO_(2) NPs.Under simulated sunlight irradiation,large amounts of reactive oxygen species(ROS)are generated for photocatalytic antibacterial activity.Enhanced bactericidal efficiency up to 99.99%against methicillin-resistant Staphylococcus aureus(MRSA)is achieved in vitro.Furthermore,Janus AuNR-TiO_(2) NPs exhibit superior biocompatibility,structural stability,and also remarkably accelerate MRSA-infected wound healing.Taking the above all into consideration,Janus AuNR-TiO_(2) NPs,as an efficient antibacterial photocatalyst,offers a promising strategy for MRSA infectious therapy.

Adult tiger beetles Cicindela gemmata modify their foraging strategy in different hunting contexts

Predator–prey interaction has long been an interesting item in the research of animal behaviors.Given that live prey can damage their predators,predators must trade foraging efficiency for safety while hunting,but the extent of this trade-off is not yet clear.Tiger beetles display diversity in their diets and hunting strategies,and hence,they become an ideal system to address how self-security affects foraging efficiency.We addressed this question in captive adult tiger beetles Cicindela gemmata.By offering several types of arthropod and plant foods,we confirmed that C.gemmata is carnivorous.We found that C.gemmata hunt by either ambushing or chasing their prey,and that they switch between strategies based on differences in the number of prey,the prey status and encounter rate,and the number of predators.Ambushing success increased with the number of prey but decreased with prey encounter rate.Chasing success decreased as prey body size and encounter rate increased.Foraging Cicindela gemmata often gave up an attack when it was nonfatal.This active giving up of hunting may be a consequence of a trade-off between foraging efficiency and self-security.Therefore,it is an adaptive response to the risk of injury when hunting for larger live prey.

Bevacizumab biosimilar LY01008 compared with bevacizumab(Avastin)as first-line treatment for Chinese patients with unresectable,metastatic,or recurrent non-squamous non-small-cell lung cancer:A multicenter,randomized,double-blinded,phase Ⅲ trial

Background:Previous studies have demonstrated the preclinical pharmacological and toxicological consistency,and clinical pharmacokinetic equivalence of bevacizumab biosimilar LY01008 with reference bevacizumab(Avastin).This randomized controlled trial aimed to compare the efficacy and safety of LY01008 with Avastin in first-line treatment of Chinese patients with advanced or recurrent non-squamous non-small cell lung cancer(NSCLC).Methods:StageⅢB-ⅣNSCLC patients with evaluable lesions,good physical status,and adequate organ functions from 67 centers across China were randomized in a ratio of 1:1 to receive LY01008 or Avastin 15 mg/kg intravenously in combination with paclitaxel/carboplatin(combined treatment)for 4-6 cycles,followed by maintenance monotherapy with LY01008 until disease progression,intolerable toxicity,or death.The primary endpoint was objective response rate(ORR)in accordance with Response Evaluation Criteria in Solid Tumors(RECIST)version 1.1 confirmed by independent radiological review committees(IRRC).Secondary endpoints included disease control rate(DCR),duration of response(DoR),progression-free survival(PFS),overall survival(OS),and safety.This study was registered in Clinical Trials.gov(NCT03533127).Results:Between December 15^(th),2017,and May 15^(th),2019,a total of 649 patients were randomized to the LY01008(n=324)or Avastin(n=325)group.As of September 25th,2019 for primary endpoint analysis,589 patients received ORR evaluation,with a median number of combined treatment cycles of 5(range 1-6)andmedian duration of treatment of 3.0(range 0.0-5.1)months.ORRof responseevaluable patients in the LY01008 and Avastin groups were 48.5% and 53.0%,respectively.The stratified ORR ratio was 0.91(90%CI 0.80-1.04,within the prespecified equivalence margin of 0.75-1.33).Up to May 15^(th),2020,with a median follow-up of 13.6(range 0.8-28.4)months,no notable differences in DCR,median DoR,median PFS,median OS,and 1-year OS rate were observed between the LY01008 and Avastin groups.There were no clinically meaningful differences in safety and immunogenicity across treatment groups.Conclusions:LY01008 demonstrated similarity to Avastin in terms of efficacy and safety in Chinese patients with advanced or recurrent non-squamous NSCLC.LY01008 combined with paclitaxel/carboplatin is expected to become a new treatment option for unresectable,metastatic,LY01008 and Avastin groups.There were no clinically meaningful differences in safety and immunogenicity across treatment groups.Conclusions:LY01008 demonstrated similarity to Avastin in terms of efficacy and safety in Chinese patients with advanced or recurrent non-squamous NSCLC.LY01008 combined with paclitaxel/carboplatin is expected to become a new treatment option for unresectable,metastatic,or recurrent non-squamous NSCLC patients in the first-line setting.

Pollutant concentrations and pollution loads in stormwater runoff from different land uses in Chongqing

To investigate the distribution of pollutant concentrations and pollution loads in stormwater runoff in Chongqing,six typical land use types were selected and studied from August 2009 to September 2011.Statistical analysis on the distribution of pollutant concentrations in all water samples shows that pollutant concentrations fluctuate greatly in rainfall-runoff,and the concentrations of the same pollutant also vary greatly in different rainfall events.In addition,it indicates that the event mean concentrations （EMCs） of total suspended solids （TSS） and chemical oxygen demand （COD） from urban traffic roads （UTR） are significantly higher than those from residential roads （RR）,commercial areas （CA）,concrete roofs （CR）,tile roofs （TRoof）,and campus catchment areas （CCA）;and the EMCs of total phosphorus （TP） and NH3-N from UTR and CA are 2.35-5 and 3 times of the class-III standard values specified in the Environmental Quality Standards for Surface Water （GB 3838-2002）.The EMCs of Fe,Pb and Cd are also much higher than the class-III standard values.The analysis of pollution load producing coefficients （PLPC） reveals that the main pollution source of TSS,COD and TP is UTR.The analysis of correlations between rainfall factors and EMCs/PLPC indicates that rainfall duration is correlated with EMCs/PLPC of TSS for TRoof and TP for UTR,while rainfall intensity is correlated with EMCs/PLPC of TP for both CR and CCA.The results of this study provide a reference for better management of non-point source pollution in urban regions.

Suppressing the anomalous rapid oxidation of Ti_3AlC_2 by incorporating TiB_2

The oxidation behavior of Ti_3AlC_2-20 TiB_2 composite was studied at 500℃–900℃ in air. The composite showed a very low oxidation rate and followed a logarithmic oxidation law. The in-situ incorporation of TiB_2 suppressed the anomalous rapid oxidation of the substrate Ti_3AlC_2 occurred near 600℃ by forming a protective B_2O_3 glass layer, and also improved the oxidation resistance of the MAX phase at intermediatetemperature.

In-plane heterostructured Ag_(2)S-In_(2)S_(3) atomic layers enabling boosted CO_(2) photoreduction into CH_(4)

Sluggish separation and migration kinetics of the photogenerated carriers account for the low-efficiency of CO_(2) photoreduction into CH_(4). Design and construction two-dimensional (2D) in-plane heterostructures demonstrate to be an appealing approach to address above obstacles. Herein, we fabricate 2D in-plane heterostructured Ag_(2)S-In_(2)S_(3) atomic layers via an ion-exchange strategy. Photoluminescence spectra, time-resolved photoluminescence spectra, and photoelectrochemical measurements firmly affirm the optimized carrier dynamics of the In_(2)S_(3) atomic layers after the introduction of in-plane heterostructure. In-situ Fourier transform infrared spectroscopy spectra and density functional theory (DFT) calculations disclose the in-plane heterostructure contributes to CO_(2) activation and modulates the adsorption strength of CO* intermediates to facilitate the formation of CHO* intermediates, which are further protonated to CH4. In consequence, the in-plane heterostructure achieves the CH_(4) evolution rate of 20 µmol·g^(−1)·h^(−1), about 16.7 times higher than that of the In2S3 atomic layers. In short, this work proves construction of in-plane heterostructures as a promising method for obtaining high-efficiency CO_(2)-to-CH_(4) photoconversion properties.

PD-1 abrogates the prolonged persistence of CD8+CAR-T cells with 4-1BB co-stimulation

Dear Editor,The central memory differentiation critically dictates CAR-T cell persistence,which is closely associated with the therapeutic effectiveness in the clinic.It is well accepted that 4-1BB costimulation is superior over CD28 to promote the central memory differentiation and persistence of CAR-T cells.1 However,it is also noticed that CAR-T cells with either co-stimulations are comparably differentiated and persisted,2 especially under immunosuppressive conditions.Factors contributing to the discrepancy remain unknown.Mounting evidences show that programmed cell death protein 1(PD-1)directly affects memory differentiation of T cells upon PD-L1 engagement,3 in addition to limiting proliferation.It is unclear whether PD-1 is involved in the diminished difference in memory differentiation and persistence between CAR-T cells with different co-stimulations.Herein,we examined the memory differentiation of CAR-T cells when PD-1 is activated or not,and consequently the persistence and anti-tumor effects.