Comparative Analysis of the Genomes of Three Field Isolates of the Rice Blast Fungus <i>Magnaporthe oryzae</i>from Southern China

Rice blast caused by Magnaporthe oryzae (M. oryzae) is one of the most destructive diseases, which causes significant rice yield losses and affects global food security. To better understand genetic variations among different isolates of M. oryzae in the nature field, we re-sequenced and analyzed the genomes of three field isolates, QJ08-2006, QJ10-10, and QJ10-3001, which showed distinct pathogenicity on Xin-Yin-Zhan, an elite variety in South China. Genome annotation indicated that these three isolates assemblies have similar genome sizes with 38.4 Mb, 38.3 Mb, and 38.4 Mb, respectively. The QJ08-2006 assembly has 2082 contigs with an N50 of 127.4 kb, the QJ10-10 assembly has 2239 contigs with an N50 of 105.13 kb, the QJ10-3001 assembly has 2025 contigs with an N50 of 133.16 kb. A total of 10,432 genes including 1408 putative secreted protein genes were identified from the annotated isolate QJ08-2006 genome, 10,418 genes including 1410 putative secreted protein genes were identified in QJ10-10, and 10,401 genes including 1420 putative secreted protein genes were identified in QJ10-3001. There are as many as 11,076 identical genes in these three isolates and contained only a few unique genes among three isolates, of which 277 unique genes in QJ08-2006 and 264 unique genes in QJ10-10, and 213 unique genes in QJ10-3001. Most of the predicted secreted protein genes had been identified, and the three re-sequenced strains contained 371, 369, and 387 small Indel, respectively. Avr genes were analyzed in several sequenced Magnaporthe strains, the results revealed that Avr-Pi9 and Avr-Piz-t were present in all the sequenced isolates. The isolates QJ08-2006 contained AvrPib, QJ10-10, and QJ10-3001 had an insertion of a Pot3 element in the promoter of the AvrPib gene. Our results showed that, the rapid dominancy of virulence mutant isolates via clonal propagation displayed in the field after the release of the elite variety Xin-Yin-Zhan.

Differential Detection and Analysis of Pathotypes and Differentiation against Xanthomonas oryzae pv. oryzae in Southern China

Pathogenic isolates were collected from different rice-cropping regions in southern China to dissect the pathogenic disintegration and variation of Xanthornonas oryzae pv. oryzae （Xoo）. Two sets of rice-Xoo differential hosts, including Chinese system with such five euhivars as IR26, Java14, Nangeng15, Tetep and Jingang 30 and international system with a series of nearisogenic lines （NILs） including IRBB5, IRBB13, IRBB3, IRBB14, IRBB2 and IR24 carrying different known resistance genes,were used to detect pathogenic disintegration for the reaction between host and pathogen with leaf-clippingmethod at the rice booting stage. The results showed the type of the pathogen were divided intosix pathotypes, i.e. , Ⅰ, Ⅱ, Ⅲ, Ⅳ, Ⅴ and Ⅸ based on the Chinese differential system, and seven pathogenicraces including RI, R2, R3, R4, R5, R8 and R10 based on the international differential system. The pathogenicity frequency of Xoo pathotypes V and IV and pathogenic races R8 and R5 were 27.40% , 19.30% and 44.67% , 15.34%, which were considered to be the prevailing races in southern China. Pathogenic rates of pathotypes Ⅳ, Ⅴ, Ⅸ and races R8, R5 against 500 varieties derived from southernChina were 96.40% , 95.00% , 50.40% , 62.00% , and 42.60%, respectively. Among which pathotype Ⅸ was the most virulent pathotype. The pathotype Ⅴ became preponderant pathotype and the new pathotype Ⅸ grew up quickly.

Highly efficient subnanometer Ru-based catalyst for ammonia synthesis via an associative mechanism

The industrial manufacture of ammonia(NH_(3))using Fe-based catalyst works under rigorous conditions.For the goal of carbon-neutrality,it is highly desired to develop advanced catalyst for NH_(3)synthesis at mild conditions to reduce energy consumption and CO_(2)emissions.However,the main challenge of NH_(3)synthesis at mild conditions lies in the dissociation of steady N≡N triple bond.In this work,we report the design of subnanometer Ru clusters(0.8 nm)anchored on the hollow N-doped carbon spheres catalyst(Ru-SNCs),which effectively promotes the NH_(3)synthesis at mild conditions via an associative route.The NH_(3)synthesis rate over Ru-SNCs(0.49%(mass)Ru)reaches up to 11.7 mmol NH_(3)·(g cat)^(-1)·h^(-1) at 400℃ and 3 MPa,which is superior to that of 8.3 mmol NH_(3)·(g cat)^(-1)·h^(-1) over Ru nanoparticle catalyst(1.20%(mass)Ru).Various characterizations show that the N_(2)H_(4)species are the main intermediates for NH_(3)synthesis on Ru-SNCs catalyst.It demonstrates that Ru-SNCs catalyst can follow an associative route for N_(2)activation,which circumvents the direct dissociation of N_(2)and results in highly efficient NH_(3)synthesis at mild conditions.

Spectral polarization-encoding of broadband laser pulses by optical rotatory dispersion and its applications in spectral manipulation

We propose a kind of spectral polarization-encoding(SPE)for broadband light pulses,which is realized by inducing optical rotatory dispersion(ORD),and decoded by compensating ORD.Combining with polarization-sensitive devices,SPE can not only work to control polarization-dependent transmission for central wavelength or bandwidth-tunable filtering,but also can be used for broadband regenerative or multi-pass amplification with a polarization-dependent gain medium to improve output bandwidth.SPE is entirely passive thus very simple to be designed and aligned.By using an ORD crystal with a good transmission beyond 3-μm mid-infrared region,e.g.,Ag Ga S_(2),SPE promises to be applied for the wavelength tuning lasers in mid-infrared region,where the tunning devices are rather under developed compared with those in visible and near-infrared region.

Resistance Analysis on Major Resistant Genes of Rice Bacterial Blight in Different Donors and Genetic Background

The different donors of eight rice bacterial blight( BB) major resistant( MR) genes,Xa3,Xa4,xa5,Xa7,Xa10,Xa11,Xa14 and Xa23,were inoculated with two Chinese Xoo strains,strain IV and strain V,respectively. The strain IV was a predominant pathotype in south China,while the strain V was a severe virulentstrain. Two susceptible sterile lines and two susceptible inbred rice were employed to study the effect of geneticbackground on expression of resistance to BB for Xa4,xa5,Xa7 and Xa23. The application value of twodominant resistant genes Xa7 and Xa23 on hybrid rice was also evaluated. The results indicated that the resistance inheritance behaviors of most of the MR genes to the Xoo strains were similar and only a few genes show contradictory reaction in different donors,which suggests that the genetic background would produce an effect on the resistant expression of some R genes. Four resistant donors,IRBB4,IRBB5,IRBB7 and CBB23,were crossed with four susceptible cultivars,WufengA,JitianA,Jingang30 and IR24,respectively,using the resistant donors as male parent. The analysis of F1 populations revealed that the recessive resistance gene xa5 and dominant resistance gene Xa23 conformed to recessive and dominant expression model,respectively,while the other two dominant resistance genes,Xa4 and Xa7,conformed to dominant expression model only in some of F1 populations but not for others. In conclusion,expression of resistance for xa5 and Xa23 was independent of genetic background,while Xa4 and Xa7 show specific behaviors of resistance related to the receptor background. This study also suggests that Xa7 is not suitable for application in hybrid rice,for the F1 generation of its cross with two male sterile lines were highly susceptible,and Xa23( CBB23) had important value in improving BB resistance of hybridrice,as the F1 generations from its cross with 4 susceptible parents,including sterile lines and inbred rice,were all show highly resistant.

Development of Specific DNA Markers for Detecting the Rice Blast Resistance Gene Alleles Pi2/9/z-t

Specific molecular markers for detecting the alleles of Pi2/Pi9/Piz-t,designated as Pi2 SNP,Pi9 SNP and Pizt-PA,respectively,have been successfully developed through sequence comparison method.These three specific markers can distinctly distinguish target genes from others mapped on Pi2/9 locus,which facilitates the molecular marker-assistant selection and the development of pyramiding cultivars combined with other allele R genes.Additionally,101 main cultivars and breeding parents collected from different rice-planting areas have been diagnosed with these three specific markers,and the results showed that only 2 out of the 101 cultivars carried Piz-t,but neither Pi2 nor Pi9 band had been detected.It indicates that most of the main cultivars and breeding parents in China do not carry Pi2/Pi9/Piz-t.These results provide important information for the application of Pi2/Pi9/Piz-t in the blast resistance breeding programs.

Neuron stem cell NLRP6 sustains hippocampal neurogenesis to resist stress-induced depression

Neurogenesis decline in hippocampal dentate gyrus(DG)participates in stress-induced depressive-like behaviors,but the underlying mechanism remains poorly understood.Here,we observed low-expression of NOD-like receptor family pyrin domain containing 6(NLRP6)in hippocampus of stress-stimulated mice,being consistent with high corticosterone level.NLRP6 was found to be abundantly expressed in neural stem cells(NSCs)of DG.Both Nlrp6 knockout(Nlrp6^(-/-))and NSCconditional Nlrp6 knockout(Nlrp6CKO)mice were susceptible to stress,being more likely to develop depressive-like behaviors.Interestingly,NLRP6 was required for NSC proliferation in sustaining hippocampal neurogenesis and reinforcing stress resilience during growing up.Nlrp6 deficiency promoted esophageal cancer-related gene 4(ECRG4)expression and caused mitochondrial dysfunction.Corticosterone as a stress factor significantly down-regulated NLRP6 expression,damaged mitochondrial function and suppressed cell proliferation in NSCs,which were blocked by Nlrp6 overexpression.ECRG4 knockdown reversed corticosterone-induced NSC mitochondrial function and cell proliferation disorders.Pioglitazone,a well-known clinical drug,up-regulated NLRP6 expression to inhibit ECRG4 expression in its protection against corticosterone-induced NSC mitochondrial dysfunction and proliferation restriction.In conclusion,this study demonstrates that NLRP6 is essential to maintain mitochondrial homeostasis and proliferation in NSCs,and identifies NLRP6 as a promising therapeutic target for hippocampal neurogenesis decline linked to depression.

Review and Prospect of Single-Shot Ultrafast Optical Imaging by Active Detection

In the recent decade,single-shot ultrafast optical imaging by active detection,called single-shot active ultrafast optical imaging(SS-AUOI)here,has made great progress,e.g.,with a temporal resolution of 50 fs and a frame rate beyond 10 trillion frames per second.Now,it has become indispensable for charactering the nonrepeatable and difficult-to-reproduce events and revealing the underlying physical,chemical,and biological mechanisms.On the basis of this delightful status,we would like to make a review of SS-AUOI.On the basis of a brief introduction of SS-AUOI,our review starts with discussing its characteristics and then focuses on the survey and prospect of SS-AUOI technology.

一心创业,一路坚持:青年创业者创业韧性影响因素的扎根研究

近年来,国家不断部署深入推进"大众创业、万众创新",重点支持高校毕业生等青年群体就业创业。然而,创业是一项高风险活动,我国青年创业平均成功率仅有约2%。创业韧性有助于青年创业者在创业过程中应对各种困难和挑战,从而获取创业成功。尽管如此,"青年创业者的创业韧性如何产生,受哪些因素影响,其形成机理是什么"这一问题还少有考察。本研究以我国青年创业的主力军大学生创业者为研究对象,运用扎根理论方法 ,通过对30个青年创业大学生的深度访谈,构建出"重大事件激活—动机形成—动态能力形成"的理论模型,包括重大事件等13个子范畴以及创业期望的形成等7个主范畴,并运用事件系统理论、自我差异理论、社会转型理论和场理论分析形成此模式的深层次原因。在此基础上探讨促使其增强创业韧性行为的外部干预措施,研究结论对发展创新创业教育的理论和实践都有一定的促进作用。

Forty-five terawatt vortex ultrashort laser pulses from a chirped-pulse amplification system

We report on a vortex laser chirped-pulse amplification(CPA)system that delivers pulses with a peak power of 45 TW.A focused intensity exceeding 1019 W/cm2 has been demonstrated for the first time by the vortex amplification scheme.Compared with other schemes of strong-field vortex generation with high energy flux but narrowband vortex-converting elements at the end of the laser,an important advantage of our scheme is that we can use a broadband but size-limited q-plate to realize broadband mode-converting in the front end of the CPA system,and achieve high-power amplification with a series of amplifiers.This method is low cost and can be easily implemented in an existing laser system.The results have verified the feasibility to obtain terawatt and even petawatt vortex laser amplification by a CPA system,which has important potential applications in strong-field laser physics,for example,generation of vortex particle beams with orbital angular momentum,fast ignition for inertial confinement fusion and simulation of the extreme astrophysical environment.

Effect of pore-size distribution on Ru/ZSM-5 catalyst for enhanced N2 activation to ammonia via dissociative mechanism

In the present study,a series of Ru/ZSM-5 catalysts with different pore-size distributions were prepared and investigated for NH3 synthesis.Our studies indicate that Ru/ZSM-5-Mic with micropore structure exhibits superior NH3 synthesis rate,which is much higher than those of Ru/ZSM-5-Mac(with macroporous structure)and Ru/ZSM-5-Mes(with mesoporous structure)catalysts.A series of TPD experiments demonstrate that pore-size distributions play an important role in N2 adsorption and activation over Ru/ZSM-5.Moreover,the addition of La significantly promotes the NH3 synthesis performance over Ru/ZSM-5-Mic.Additionally,in situ DRIFTS studies indicate that the main intermediate species over Ru/ZSM-5-Mic are-NH2,and most of the surface hydrogen species desorb following the H2O-formation pathway.

High spatial-resolution biological tissue imaging in the second near-infrared region via optical parametric amplification pumped by an ultrafast vortex pulse [Invited]

Applying an ultrafast vortex laser as the pump,optical parametric amplification can be used for spiral phase-contrast imaging with high gain,wide spatial bandwidth,and high imaging contrast.Our experiments show that this design has realized the 1064 nm spiral phase-contrast idler imaging of biological tissues(frog egg cells and onion epidermis)with a spatial resolution at several microns level and a superior imaging contrast to both the traditional bright-or dark-field imaging under a weak illumination of 7 nW/cm^(2).This work provides a powerful way for biological tissue imaging in the second near-infrared region.

Boosting Efficient Ammonia Synthesis over Atomically Dispersed Co-Based Catalyst via the Modulation of Geometric and Electronic Structures

Ammonia(NH_(3))synthesis at mild conditions is of great significance,while the significant bottleneck of this process is the activation of N_(2) to realize the desired NH_(3) synthesis performance,which requires deep insight and rational design of active sites at the atomic level.Here,were synthesized atomically dispersed Co-based catalysts with different Co-N coordination numbers(CNs)to explore the coordination-sensitive NH_(3) synthesis reaction for the first time.Our studies showed that Co-based catalysts increased the NH_(3) synthesis rate gradually with a decrease in CN.The Co-N_(2) catalyst exhibited the highest NH_(3) synthesis rate of 85.3 mmol gCo^(−1) h^(−1) at 300℃ and 1 MPa,which outperformed most of the previously reported Co-based catalysts.Various characterizations and theoretical calculations demonstrated that atomically dispersed Co catalyst with low CN could generate more unoccupied Co 3d charges and tetrahedral cobalt(Ⅱ)sites.The unoccupied Co 3d charge,in turn,promoted the electron donation from the Co active center to the antibonding π-orbital(π*)of N_(2) and expedites N_(2) hydrogenation.Furthermore,the Co-N_(2) catalyst with more tetrahedral cobalt(II)sites could effectively facilitate the desorption of N-containing intermediate species(such as*NH_(3) and*N_(2)H_(4))to obtain a high NH_(3) synthesis rate.

Single-shot terahertz polarization detection based on terahertz time-domain spectroscopy

This paper presents a novel design for single-shot terahertz polarization detection based on terahertz time-domain spectroscopy(THz-TDS).Its validity has been confirmed by comparing its detection results with those of the THz common-path spectral interferometer through two separate measurements for the orthogonal components.Our results also show that its detection signal-to-noise ratios(SNRs)are obviously superior to those of the 45°optical bias THz-TDS by electro-optical sampling due to its operation on common-path spectral interference rather than the polarization-sensitive intensity modulation.The setup works without need of any optical scan,which does not only save time,but also efficiently avoids the disturbances from the fluctuations of the system and environment.Its single-shot mode allows it to work well for the applications with poor or no repeatability.

Carbon nanotube films with ultrahigh thermal-shock and thermalshock-fatigue resistance characterized by ultra-fast ascending shock testing

The exploration of material failure behavior not only involves defining its limits and underlying mechanisms but also entails devising strategies for improvement and protection in extreme conditions.We've pioneered an advanced multi-scale,high-speed ascending thermal shock testing platform capable of inducing unprecedented heat shocks at rates surpassing 105℃/s.Through meticulous examination of the thermal shock responses of carbon nanotube(CNT)films,we've achieved remarkable breakthroughs.By employing an innovative macro-scale synchronous tightening and relaxing approach,we've attained a critical temperature differential in CNT films that exceeds an exceptional 2500℃—surpassing any previously reported metric for highperformance,thermal-shock-resistant materials.Notably,these samples have demonstrated exceptional resilience,retaining virtually unchanged strength even after enduring 10,000 thermal shock cycles at temperatures exceeding 1000℃.Furthermore,our research has revealed a novel thermal shock/fatigue failure mechanism that fundamentally diverges from conventional theories centered on thermal stress.