Several fungal pathogens cause root rot of common bean,among which Fusarium spp.are the most common pathogens causing Fusarium root rot(FRR)worldwide.FRR has been becoming an increasingly severe disease of common bean...Several fungal pathogens cause root rot of common bean,among which Fusarium spp.are the most common pathogens causing Fusarium root rot(FRR)worldwide.FRR has been becoming an increasingly severe disease of common bean in China,but the species of Fusarium spp.have remained unclear.Thus,this study was performed to identify the pathogen causing common bean root rot in Liangcheng County,Inner Mongolia,China.Nineteen Fusarium-like isolates were obtained after pathogen isolation and purification.The pathogenicity test indicated that eight isolates caused severe disease symptoms on common bean,while 11 other isolates were not pathogenic.The eight pathogenic isolates,FCL1–FCL8,were identified as Fusarium cuneirostrum by morphological characterization and phylogenetic analysis using partial sequences of EF-1α,ITS,28S,and IGS regions.Host range test showed that the representative F.cuneirostrum isolate FCL3 was also pathogenic to mung bean,while not pathogenic to adzuki bean,chickpea,cowpea,faba bean,pea,and soybean.Moreover,50 common bean and 50 mung bean cultivars were screened for resistance to FRR,and seven highly resistant or resistant cultivars of common bean were identified,while no resistant cultivars of mung bean were screened.This study revealed that F.cuneirostrum was one of common bean FRR pathogens in Inner Mongolia and it could induce mung bean root rot as well.To our knowledge,this is the first report of F.cuneirostrum causing FRR of common bean in China.展开更多
The small brown planthopper(SBPH), Laodelphax striatellus Fallén(Homoptera: Delphacidae), is a serious pest of rice(Oryza sativa L.) in China. To understand the mechanisms of rice resistance to SBPH, defense resp...The small brown planthopper(SBPH), Laodelphax striatellus Fallén(Homoptera: Delphacidae), is a serious pest of rice(Oryza sativa L.) in China. To understand the mechanisms of rice resistance to SBPH, defense response genes and related defense enzymes were examined in resistant and susceptible rice varieties in response to SBPH infestation. The salicylic acid(SA) synthesis-related genes phenylalanine ammonia-lyase(PAL), NPR1, EDS1 and PAD4 were induced rapidly and to a much higher level in the resistant variety Kasalath than in the susceptible cultivar Wuyujing 3 in response to SBPH infestation. The expression level of PAL in the Kasalath rice at 12 h post-infestation(hpi) increased 7.52-fold compared with the un-infested control, and the expression level in Kasalath was 49.63, 87.18, 57.36 and 75.06 times greater than that in Wuyujing 3 at 24, 36, 48 and 72 hpi, respectively. However, the transcriptional levels of the jasmonic acid(JA) synthesis-related genes LOX and AOS2 in resistant Kasalath were significantly lower than in susceptible Wuyujing 3 at 24, 36, 48 and 72 hpi. The activities of the defense enzymes PAL, peroxidase(POD), and polyphenol oxidase(PPO) increased remarkably in Kasalath in response to SBPH infestation, and were closely correlated with the PAL gene transcript level. Our results indicated that the SA signaling pathway was activated in the resistant Kasalath rice variety in response to SBPH infestation and that the gene PAL played a considerable role in the resistance to SBPH.展开更多
Powdery mildew, caused by Erysiphe pisi D.C., is a major constraint to pea production worldwide. The pea cultivar Xucai 1 has shown high resistance to E. pisi under greenhouse and field conditions. The objectives of t...Powdery mildew, caused by Erysiphe pisi D.C., is a major constraint to pea production worldwide. The pea cultivar Xucai 1 has shown high resistance to E. pisi under greenhouse and field conditions. The objectives of this study were to identify and characterize genes conferring resistance to powdery mildew in Xucai 1. Three crosses, Qizhen 76 × Xucai 1,Bawan 6 × Xucai 1, and Xucai 1 × Bawan 6, were made to generate populations for genetic analysis. The resistance to E. pisi and segregation ratios in the F_1, F_2, and F_(2:3)populations suggested a single recessive gene conferring the resistance of Xucai 1. Bulked segregant analysis was used to map the resistance gene using two F2 populations. The resistance gene was close to markers AD60 and c5 DNAmet on linkage group VI with genetic distances of9.9 c M and 15.4 c M in the Xucai 1 × Bawan 6 F_2 population and 8.7 c M and 8.1 c M in the Qizhen 76 × Xucai 1 F_2 population, respectively, suggesting that the resistance gene was an er1 allele. This hypothesis was confirmed by comparison of the c DNA sequences of the Ps MLO1 gene between the parents and the Ps MLO1 wild type. Three distinct types of transcripts in Xucai 1, characterized by a 129-bp deletion and 155- and 220-bp insertions,were detected, consistent with the structure of the er1-2 allele. We concluded that resistance in Xucai 1 was conferred by er1-2 and that its linked markers will be useful in pea breeding programs.展开更多
Background: Male germline stem cells(MGSCs) are a subpopulation of germ cells in the testis tissue. MGSCs are capable of differentiation into spermatozoa and thus are perfect targets for genomic manipulation to genera...Background: Male germline stem cells(MGSCs) are a subpopulation of germ cells in the testis tissue. MGSCs are capable of differentiation into spermatozoa and thus are perfect targets for genomic manipulation to generate transgenic animals.Method: The present study was to optimize a protocol of production of transgenic mice through transduction of MGSCs in vivo using lentiviral-based vectors. The recombinant lentiviral vectors with either EF-1 or CMV promoter to drive the expression of enhanced green fluorescent protein(e GFP) transgene were injected into seminiferous tubules or inter-tubular space of 7-day-old and 28-day-old mouse testes. At 5 or 6 wk post-surgery, these pre-founders were mated with wild-type C57BL/6J female mice(1.5 to 2.0-month-old).Results: Sixty-seven percent of F1 generation and 55.56 % of F2 offspring were positive for eG FP transgene under the control of EF-1 promoter via PCR analysis. The transgenic pups were generated in an injection site-and age-independent manner. The expression of transgene was displayed in the progeny derived from lentiviral vector containing CMV promoter to drive transgene, but it was silenced or undetectable in the offspring derived from lentiviral vector with transgene under EF-1 promoter. The methylation level of g DNA in the promoter region of transgene was much higher in the samples derived lentiviral vectors with EF-1 promoter than that with CMV promoter,suggesting e GFP transgene was suppressed by DNA methylation in vivo.Conclusion: This research reported here an effective strategy for generation of transgenic mice through transduction of MGSCs in vivo using lentivirus vectors with specific promoters, and the transgenic offspring were obtained in an injection site-and age-independent manner. This protocol could be applied to other animal species, leading to advancement of animal transgenesis in agricultural and biomedical fields.展开更多
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...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.展开更多
Phytophthora sojae infection severely impairs soybean production. We previously identified a dirigent protein, Gm DRR1(Glycine max Disease Resistant Response 1), that increases soybean resistance to P.sojae. However, ...Phytophthora sojae infection severely impairs soybean production. We previously identified a dirigent protein, Gm DRR1(Glycine max Disease Resistant Response 1), that increases soybean resistance to P.sojae. However, the molecular basis of Gm DRR1 function remained largely uncharacterized. In the present study, analysis of Gm DRR1-RNAi, Gm DRR1-overexpressing, and CRISPR/Cas9-derived Gmdrr1 mutant lines revealed that Gm DRR1 expression significantly restricted P. sojae growth. Combining coimmunoprecipitation with liquid chromatography–tandem mass spectrometry revealed a Gm DRR1-interacting protein, Gm DRR2, which is homologous to Gm DRR1. An E-coniferyl alcohol coupling assay indicated that Gm DRR1 promotes the synthesis of(+)-pinoresinol, which helps to protect plants from P. sojae. The Gm NAC1(Glyma.05 G025500) transcription factor bound to the Gm DRR1 promoter both in vitro and in vivo to upregulate Gm DRR1 expression. Soybean resistance to P. sojae was increased by overexpression of Gm NAC1. Our findings suggest a novel signaling pathway involving a NAC transcription factor that mediates soybean resistance to P. sojae. Specifically, Gm NAC1 directly induces Gm DRR1 expression to increase resistance of soybean plants to P. sojae.展开更多
Powdery mildew, caused by Erysiphe pisi D.C., is an important disease of pea(Pisum sativum L.).The use of cultivars carrying powdery mildew resistance alleles at the er1 locus is the most effective and economical mean...Powdery mildew, caused by Erysiphe pisi D.C., is an important disease of pea(Pisum sativum L.).The use of cultivars carrying powdery mildew resistance alleles at the er1 locus is the most effective and economical means of controlling this disease. The objectives of this study were to screen Chinese elite pea cultivars for resistance to E. pisi and to identify the responsible gene at the er1 locus. Among the 37 pea cultivars tested, three(Yunwan 8, Yunwan 21, and Yunwan 23) were immune to E. pisi infection in phenotypic evaluations. The full-length cD NA sequences of the er1 candidate gene, PsM LO1, from the three resistant cultivars and control plants were analyzed. Comparison of the cD NA sequences of 10 clones revealed differences among the powdery mildew-resistant cultivars, susceptible controls, and wild-type cultivar Sprinter. The observed resistance in Yunwan 8 plants resulted from a point mutation(C → G) at position 680 of PsM LO1 that introduced a stop codon, leading to premature termination of protein synthesis. The responsible resistance allele was identified as er1–1. Powdery mildew resistance in Yunwan 21 and Yunwan 23 plants was caused by identical insertions or deletions in PsM LO1. Three distinct PsM LO1 transcripts were observed in Yunwan 21 and Yunwan 23 plants. These transcripts were characterized by a129-bp deletion and 155- and 220-bp insertions, respectively. The responsible resistance allele was identified as er1–2. We have characterized two important er1 alleles in three E. pisi-resistant pea cultivars bred in Yunnan Province, China. These cultivars represent important genetic resources for the breeding of powdery mildew-resistant pea cultivars.展开更多
Polyploidization plays a crucial role in the evolution of angiosperm species.Almost all newly formed polyploids encounter genetic or epigenetic instabilities.However,the molecular mechanisms contributing to genomic in...Polyploidization plays a crucial role in the evolution of angiosperm species.Almost all newly formed polyploids encounter genetic or epigenetic instabilities.However,the molecular mechanisms contributing to genomic instability in synthetic polyploids have not been clearly elucidated.Here,we performed a comprehensive transcriptomic and methylomic analysis of natural and synthetic polyploid rapeseeds(Brassica napus).Our results showed that the CHG methylation levels of synthetic rapeseed in different genomic contexts(genes,transposon regions,and repeat regions)were signi fi cantly lower than those of natural rapeseed.The total number and length of CHG-DMRs between natural and synthetic polyploids were much greater than those of CG-DMRs and CHH-DMRs,and the genes overlapping with these CHG-DMRs were signi fi cantly enriched in DNA damage repair and nucleotide metabolism pathways.These results indicated that CHG methylation may be more sensitive than CG and CHH methylation in regulating the stability of the polyploid genome of B.napus.In addition,many genes involved in DNA damage repair,nucleotide metabolism,and cell cycle control were significantly differentially expressed between natural and synthetic rapeseeds.Our results highlight that the genes related to DNA repair and nucleotide metabolism display differential CHG methylation patterns between natural and synthetic polyploids and reveal the potential connection between the genomic instability of polyploid plants with DNA methylation defects and dysregulation of the DNA repair system.In addition,it was found that the maintenance of CHG methylation in B.napus might be partially regulated by MET1.Our study provides novel insights into the establishment and evolution of polyploid plants and offers a potentialidea for improving the genomic stability of newly formed Brassica polyploids.展开更多
SIZ1 is a small ubiquitin-related modifier(SUMO) E3 ligase that mediates post-translational SUMO modification of target proteins and thereby regulates developmental processes and hormonal and environmental stress resp...SIZ1 is a small ubiquitin-related modifier(SUMO) E3 ligase that mediates post-translational SUMO modification of target proteins and thereby regulates developmental processes and hormonal and environmental stress responses in Arabidopsis. However,the role of SUMO E3 ligases in crop plants is largely unknown. Here, we identified and characterized two Glycine max(soybean) SUMO E3 ligases, GmSIZ1a and GmSIZ1b. Expression of GmSIZ1a and GmSIZ1b was induced in response to salicylic acid(SA), heat, and dehydration treatment, but not in response to cold, abscisic acid(ABA), and Na Cl treatment. Although GmSIZ1a was expressed at higher levels than GmSIZ1b, both genes encoded proteins with SUMO E3 ligase activity in vivo.Heterologous expression of GmSIZ1a or GmSIZ1b rescued the mutant phenotype of Arabidopsis siz1-2, including dwarfism, constitutively activated expression of pathogen-related genes, and ABA-sensitive seed germination.Simultaneous downregulation of GmSIZ1a and GmSIZ1b(GmSIZ1a/b) using RNA interference(RNAi)-mediated gene silencing decreased heat shock-induced SUMO conjugation in soybean. Moreover, GmSIZ1 RNAi plants exhibited reduced plant height and leaf size. However,unlike Arabidopsis siz1-2 mutant plants, flowering time and SA levels were not significantly altered in GmSIZ1 RNAi plants. Taken together, our results indicate that GmSIZ1a and GmSIZ1b mediate SUMO modification and positively regulate vegetative growth in soybean.展开更多
Cascaded optical field enhancement(CFE)can be realized in some specially designed multiscale plasmonic nanostructures,in which the generation of extremely strong fields at nanoscale volume is crucial for many applicat...Cascaded optical field enhancement(CFE)can be realized in some specially designed multiscale plasmonic nanostructures,in which the generation of extremely strong fields at nanoscale volume is crucial for many applications,for example,surface-enhanced Raman spectroscopy(SERS).In this paper,we propose a strategy for realizing a high-quality plasmonic nanoparticle-in-cavity(PIC)nanoantenna array,in which strong coupling between a nanoparticle(NP)dark mode with a high-order nanocavity bright mode can produce strong Fano resonance at the target wavelength.The Fano resonance can effectively boost the CFE in a PIC.A cost-effective and reliable nanofabrication method is developed using room temperature nanoimprinting lithography to manufacture high-quality PIC arrays.This technique guarantees the generation of only one gold NP at the bottom of each nanocavity,which is crucial for the generation of the expected CFE.To demonstrate the performance and application of the PIC array,the PIC array is employed as an active SERS substrate for detecting 4-aminothiophenol molecules.An experimental SERS enhancement factor of 2×10^(7) is obtained,which verifies the field enhancement and the potential of this device.展开更多
Kerr frequency combs have been attracting significant interest due to their rich physics and broad applications in metrology,microwave photonics,and telecommunications.In this review,we first introduce the fundamental...Kerr frequency combs have been attracting significant interest due to their rich physics and broad applications in metrology,microwave photonics,and telecommunications.In this review,we first introduce the fundamental physics,master equations,simulation methods,and dynamic process of Kerr frequency combs.We then analyze the most promising material platform for realizing Kerr frequency combs—silicon nitride on insulator(SNOI)in comparison with other material platforms.Moreover,we discuss the fabrication methods,process optimization as well as tuning and measurement schemes of SNOI-based Kerr frequency combs.Furthermore,we highlight several emerging applications of Kerr frequency combs in metrology,including spectroscopy,ranging,and timing.Finally,we summarize this review and envision the future development of chip-scale Kerr frequency combs from the viewpoint of theory,material platforms,and tuning methods.展开更多
Multistep plasmonic nanostructures can induce the deep modulation ofelectromagnetic-field interactions on the nanoscale for positioning hotspots,and this generation of enhanced fields is important in many optical appl...Multistep plasmonic nanostructures can induce the deep modulation ofelectromagnetic-field interactions on the nanoscale for positioning hotspots,and this generation of enhanced fields is important in many optical applications.In this article, a new strategy is proposed for fabricating a plasmonic double-stacked nanocone （DSC） nanostructure. In the DSC structure, a tunable plasmonichybrid mode proceeds from the strong coupling of the plasmonic resonance ofa fundamental cavity mode with a localized surface plasmon gap mode. In thenanostructure, the far-field response is deeply modulated and the hottest spotscan be effectively positioned on the top surface of the DSC nanostructure. Acontrollable and cost-effective mask-reconfiguration technique for manufacturingthe multiscale nanostructure is developed, which guarantees the generation ofthe introduced crucial stage on the DSC nanostructure. To evaluate the features ofthe plasmonic resonance, the DSC nanostructure is used as a surface-enhancedRaman scattering （SERS） substrate for detecting 4-mercaptopyridine moleculesunder specific excitation conditions. Its good performance, with an averagemeasured SERS enhancement factor as high as 108,展开更多
基金supported by the China Agriculture Research System of MOF and MARA(CARS-08)the Scientific Innovation Program of the Chinese Academy of Agricultural Sciences。
文摘Several fungal pathogens cause root rot of common bean,among which Fusarium spp.are the most common pathogens causing Fusarium root rot(FRR)worldwide.FRR has been becoming an increasingly severe disease of common bean in China,but the species of Fusarium spp.have remained unclear.Thus,this study was performed to identify the pathogen causing common bean root rot in Liangcheng County,Inner Mongolia,China.Nineteen Fusarium-like isolates were obtained after pathogen isolation and purification.The pathogenicity test indicated that eight isolates caused severe disease symptoms on common bean,while 11 other isolates were not pathogenic.The eight pathogenic isolates,FCL1–FCL8,were identified as Fusarium cuneirostrum by morphological characterization and phylogenetic analysis using partial sequences of EF-1α,ITS,28S,and IGS regions.Host range test showed that the representative F.cuneirostrum isolate FCL3 was also pathogenic to mung bean,while not pathogenic to adzuki bean,chickpea,cowpea,faba bean,pea,and soybean.Moreover,50 common bean and 50 mung bean cultivars were screened for resistance to FRR,and seven highly resistant or resistant cultivars of common bean were identified,while no resistant cultivars of mung bean were screened.This study revealed that F.cuneirostrum was one of common bean FRR pathogens in Inner Mongolia and it could induce mung bean root rot as well.To our knowledge,this is the first report of F.cuneirostrum causing FRR of common bean in China.
基金sponsored by the National Nature Science Foundation of China (30971746)the Major Project for Breeding Genetically Modified Organisms (2009ZX08009-046B)
文摘The small brown planthopper(SBPH), Laodelphax striatellus Fallén(Homoptera: Delphacidae), is a serious pest of rice(Oryza sativa L.) in China. To understand the mechanisms of rice resistance to SBPH, defense response genes and related defense enzymes were examined in resistant and susceptible rice varieties in response to SBPH infestation. The salicylic acid(SA) synthesis-related genes phenylalanine ammonia-lyase(PAL), NPR1, EDS1 and PAD4 were induced rapidly and to a much higher level in the resistant variety Kasalath than in the susceptible cultivar Wuyujing 3 in response to SBPH infestation. The expression level of PAL in the Kasalath rice at 12 h post-infestation(hpi) increased 7.52-fold compared with the un-infested control, and the expression level in Kasalath was 49.63, 87.18, 57.36 and 75.06 times greater than that in Wuyujing 3 at 24, 36, 48 and 72 hpi, respectively. However, the transcriptional levels of the jasmonic acid(JA) synthesis-related genes LOX and AOS2 in resistant Kasalath were significantly lower than in susceptible Wuyujing 3 at 24, 36, 48 and 72 hpi. The activities of the defense enzymes PAL, peroxidase(POD), and polyphenol oxidase(PPO) increased remarkably in Kasalath in response to SBPH infestation, and were closely correlated with the PAL gene transcript level. Our results indicated that the SA signaling pathway was activated in the resistant Kasalath rice variety in response to SBPH infestation and that the gene PAL played a considerable role in the resistance to SBPH.
基金supported by the Modern Agro-industry Technology Research System(CARS-09)the Crop Germplasm Conservation and Utilization Program(2014NWB030-14)from the Ministry of Agriculture of Chinathe Scientific Innovation Program of Chinese Academy of Agricultural Sciences
文摘Powdery mildew, caused by Erysiphe pisi D.C., is a major constraint to pea production worldwide. The pea cultivar Xucai 1 has shown high resistance to E. pisi under greenhouse and field conditions. The objectives of this study were to identify and characterize genes conferring resistance to powdery mildew in Xucai 1. Three crosses, Qizhen 76 × Xucai 1,Bawan 6 × Xucai 1, and Xucai 1 × Bawan 6, were made to generate populations for genetic analysis. The resistance to E. pisi and segregation ratios in the F_1, F_2, and F_(2:3)populations suggested a single recessive gene conferring the resistance of Xucai 1. Bulked segregant analysis was used to map the resistance gene using two F2 populations. The resistance gene was close to markers AD60 and c5 DNAmet on linkage group VI with genetic distances of9.9 c M and 15.4 c M in the Xucai 1 × Bawan 6 F_2 population and 8.7 c M and 8.1 c M in the Qizhen 76 × Xucai 1 F_2 population, respectively, suggesting that the resistance gene was an er1 allele. This hypothesis was confirmed by comparison of the c DNA sequences of the Ps MLO1 gene between the parents and the Ps MLO1 wild type. Three distinct types of transcripts in Xucai 1, characterized by a 129-bp deletion and 155- and 220-bp insertions,were detected, consistent with the structure of the er1-2 allele. We concluded that resistance in Xucai 1 was conferred by er1-2 and that its linked markers will be useful in pea breeding programs.
基金supported in part by National Basic Research Program of China (973 program 2013CB943103)+2 种基金the National Natural Science Foundation of China (Grant No. 31072029, No.31272439, No. C170104 and No. 31230048)Ph.D. Programs Foundation of Ministry of Education of China (Grant No.20130204110017) for W. Zeng and W Dongthe scholarship from China Scholarship Council (CSC)
文摘Background: Male germline stem cells(MGSCs) are a subpopulation of germ cells in the testis tissue. MGSCs are capable of differentiation into spermatozoa and thus are perfect targets for genomic manipulation to generate transgenic animals.Method: The present study was to optimize a protocol of production of transgenic mice through transduction of MGSCs in vivo using lentiviral-based vectors. The recombinant lentiviral vectors with either EF-1 or CMV promoter to drive the expression of enhanced green fluorescent protein(e GFP) transgene were injected into seminiferous tubules or inter-tubular space of 7-day-old and 28-day-old mouse testes. At 5 or 6 wk post-surgery, these pre-founders were mated with wild-type C57BL/6J female mice(1.5 to 2.0-month-old).Results: Sixty-seven percent of F1 generation and 55.56 % of F2 offspring were positive for eG FP transgene under the control of EF-1 promoter via PCR analysis. The transgenic pups were generated in an injection site-and age-independent manner. The expression of transgene was displayed in the progeny derived from lentiviral vector containing CMV promoter to drive transgene, but it was silenced or undetectable in the offspring derived from lentiviral vector with transgene under EF-1 promoter. The methylation level of g DNA in the promoter region of transgene was much higher in the samples derived lentiviral vectors with EF-1 promoter than that with CMV promoter,suggesting e GFP transgene was suppressed by DNA methylation in vivo.Conclusion: This research reported here an effective strategy for generation of transgenic mice through transduction of MGSCs in vivo using lentivirus vectors with specific promoters, and the transgenic offspring were obtained in an injection site-and age-independent manner. This protocol could be applied to other animal species, leading to advancement of animal transgenesis in agricultural and biomedical fields.
基金supported by the National Natural Science Foundation of China (31471559)the China Agriculture Research System (CARS-09)+2 种基金the National Key Technology R&D Program of China (2013BAD01B03-18a)the Evans Allen Fund of the U.S. Department of Agriculturethe Agricultural Science and Technology Innovation Program (ASTIP) of the Chinese Academy of Agricultural Sciences
文摘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.
基金supported by the National Natural Science Foundation of China(U20A2027,32070274,32072014)the Heilongjiang Postdoctoral Science Foundation(LBH-Q16014)。
文摘Phytophthora sojae infection severely impairs soybean production. We previously identified a dirigent protein, Gm DRR1(Glycine max Disease Resistant Response 1), that increases soybean resistance to P.sojae. However, the molecular basis of Gm DRR1 function remained largely uncharacterized. In the present study, analysis of Gm DRR1-RNAi, Gm DRR1-overexpressing, and CRISPR/Cas9-derived Gmdrr1 mutant lines revealed that Gm DRR1 expression significantly restricted P. sojae growth. Combining coimmunoprecipitation with liquid chromatography–tandem mass spectrometry revealed a Gm DRR1-interacting protein, Gm DRR2, which is homologous to Gm DRR1. An E-coniferyl alcohol coupling assay indicated that Gm DRR1 promotes the synthesis of(+)-pinoresinol, which helps to protect plants from P. sojae. The Gm NAC1(Glyma.05 G025500) transcription factor bound to the Gm DRR1 promoter both in vitro and in vivo to upregulate Gm DRR1 expression. Soybean resistance to P. sojae was increased by overexpression of Gm NAC1. Our findings suggest a novel signaling pathway involving a NAC transcription factor that mediates soybean resistance to P. sojae. Specifically, Gm NAC1 directly induces Gm DRR1 expression to increase resistance of soybean plants to P. sojae.
基金supported by the China Agriculture Research System (CARS-09)the Agricultural Science and Technology Program for Innovation Team on Identification and Excavation of Elite Crop Germplasm from Chinese Academy of Agricultural Sciences (CAAS)+1 种基金the Special Fund for Agro-scientific Research in the Public Interest (1610092015002-01) from the Institute of Crop Science, CAASthe Fund (2013BB010) from Science and Technology Department of Yunnan Province
文摘Powdery mildew, caused by Erysiphe pisi D.C., is an important disease of pea(Pisum sativum L.).The use of cultivars carrying powdery mildew resistance alleles at the er1 locus is the most effective and economical means of controlling this disease. The objectives of this study were to screen Chinese elite pea cultivars for resistance to E. pisi and to identify the responsible gene at the er1 locus. Among the 37 pea cultivars tested, three(Yunwan 8, Yunwan 21, and Yunwan 23) were immune to E. pisi infection in phenotypic evaluations. The full-length cD NA sequences of the er1 candidate gene, PsM LO1, from the three resistant cultivars and control plants were analyzed. Comparison of the cD NA sequences of 10 clones revealed differences among the powdery mildew-resistant cultivars, susceptible controls, and wild-type cultivar Sprinter. The observed resistance in Yunwan 8 plants resulted from a point mutation(C → G) at position 680 of PsM LO1 that introduced a stop codon, leading to premature termination of protein synthesis. The responsible resistance allele was identified as er1–1. Powdery mildew resistance in Yunwan 21 and Yunwan 23 plants was caused by identical insertions or deletions in PsM LO1. Three distinct PsM LO1 transcripts were observed in Yunwan 21 and Yunwan 23 plants. These transcripts were characterized by a129-bp deletion and 155- and 220-bp insertions, respectively. The responsible resistance allele was identified as er1–2. We have characterized two important er1 alleles in three E. pisi-resistant pea cultivars bred in Yunnan Province, China. These cultivars represent important genetic resources for the breeding of powdery mildew-resistant pea cultivars.
基金This work was supported by grants from the National Key Research and Developme nt Program(2016YFD0101300)Major Science and Technology Program in Sichuan Province(2018NZDZX0003)Chengdu Applied Technology Research and Development Program(2018030502).
文摘Polyploidization plays a crucial role in the evolution of angiosperm species.Almost all newly formed polyploids encounter genetic or epigenetic instabilities.However,the molecular mechanisms contributing to genomic instability in synthetic polyploids have not been clearly elucidated.Here,we performed a comprehensive transcriptomic and methylomic analysis of natural and synthetic polyploid rapeseeds(Brassica napus).Our results showed that the CHG methylation levels of synthetic rapeseed in different genomic contexts(genes,transposon regions,and repeat regions)were signi fi cantly lower than those of natural rapeseed.The total number and length of CHG-DMRs between natural and synthetic polyploids were much greater than those of CG-DMRs and CHH-DMRs,and the genes overlapping with these CHG-DMRs were signi fi cantly enriched in DNA damage repair and nucleotide metabolism pathways.These results indicated that CHG methylation may be more sensitive than CG and CHH methylation in regulating the stability of the polyploid genome of B.napus.In addition,many genes involved in DNA damage repair,nucleotide metabolism,and cell cycle control were significantly differentially expressed between natural and synthetic rapeseeds.Our results highlight that the genes related to DNA repair and nucleotide metabolism display differential CHG methylation patterns between natural and synthetic polyploids and reveal the potential connection between the genomic instability of polyploid plants with DNA methylation defects and dysregulation of the DNA repair system.In addition,it was found that the maintenance of CHG methylation in B.napus might be partially regulated by MET1.Our study provides novel insights into the establishment and evolution of polyploid plants and offers a potentialidea for improving the genomic stability of newly formed Brassica polyploids.
基金supported by grants from the National Natural Science Foundation of China (31471363 for J.B.J.)the Ministry of Science and Technology of the People’s Republic of China (2012CB114302 for J.B.J.)+1 种基金the National Transgenic Major Program (2009ZX08009-087B for J.B.J.and 2009ZX08009-132B for X.L.)the Chinese Academy of Sciences (XDA08010105 for J.B.J.)
文摘SIZ1 is a small ubiquitin-related modifier(SUMO) E3 ligase that mediates post-translational SUMO modification of target proteins and thereby regulates developmental processes and hormonal and environmental stress responses in Arabidopsis. However,the role of SUMO E3 ligases in crop plants is largely unknown. Here, we identified and characterized two Glycine max(soybean) SUMO E3 ligases, GmSIZ1a and GmSIZ1b. Expression of GmSIZ1a and GmSIZ1b was induced in response to salicylic acid(SA), heat, and dehydration treatment, but not in response to cold, abscisic acid(ABA), and Na Cl treatment. Although GmSIZ1a was expressed at higher levels than GmSIZ1b, both genes encoded proteins with SUMO E3 ligase activity in vivo.Heterologous expression of GmSIZ1a or GmSIZ1b rescued the mutant phenotype of Arabidopsis siz1-2, including dwarfism, constitutively activated expression of pathogen-related genes, and ABA-sensitive seed germination.Simultaneous downregulation of GmSIZ1a and GmSIZ1b(GmSIZ1a/b) using RNA interference(RNAi)-mediated gene silencing decreased heat shock-induced SUMO conjugation in soybean. Moreover, GmSIZ1 RNAi plants exhibited reduced plant height and leaf size. However,unlike Arabidopsis siz1-2 mutant plants, flowering time and SA levels were not significantly altered in GmSIZ1 RNAi plants. Taken together, our results indicate that GmSIZ1a and GmSIZ1b mediate SUMO modification and positively regulate vegetative growth in soybean.
基金We acknowledge the support by the National Natural Science Foundation of China(Projects No.11474180,and No.61227014)the Ministry of Science and Technology of China(Project No.2011BAK15B03).
文摘Cascaded optical field enhancement(CFE)can be realized in some specially designed multiscale plasmonic nanostructures,in which the generation of extremely strong fields at nanoscale volume is crucial for many applications,for example,surface-enhanced Raman spectroscopy(SERS).In this paper,we propose a strategy for realizing a high-quality plasmonic nanoparticle-in-cavity(PIC)nanoantenna array,in which strong coupling between a nanoparticle(NP)dark mode with a high-order nanocavity bright mode can produce strong Fano resonance at the target wavelength.The Fano resonance can effectively boost the CFE in a PIC.A cost-effective and reliable nanofabrication method is developed using room temperature nanoimprinting lithography to manufacture high-quality PIC arrays.This technique guarantees the generation of only one gold NP at the bottom of each nanocavity,which is crucial for the generation of the expected CFE.To demonstrate the performance and application of the PIC array,the PIC array is employed as an active SERS substrate for detecting 4-aminothiophenol molecules.An experimental SERS enhancement factor of 2×10^(7) is obtained,which verifies the field enhancement and the potential of this device.
基金the National Key Research and Development Program of China(2021YFA1401000,2021YFB2801600,and 2017YFF0206104)National Natural Science Foundation of China(62075114 and 62175121)the Beijing Natural Science Foundation(4212050)。
文摘Kerr frequency combs have been attracting significant interest due to their rich physics and broad applications in metrology,microwave photonics,and telecommunications.In this review,we first introduce the fundamental physics,master equations,simulation methods,and dynamic process of Kerr frequency combs.We then analyze the most promising material platform for realizing Kerr frequency combs—silicon nitride on insulator(SNOI)in comparison with other material platforms.Moreover,we discuss the fabrication methods,process optimization as well as tuning and measurement schemes of SNOI-based Kerr frequency combs.Furthermore,we highlight several emerging applications of Kerr frequency combs in metrology,including spectroscopy,ranging,and timing.Finally,we summarize this review and envision the future development of chip-scale Kerr frequency combs from the viewpoint of theory,material platforms,and tuning methods.
文摘Multistep plasmonic nanostructures can induce the deep modulation ofelectromagnetic-field interactions on the nanoscale for positioning hotspots,and this generation of enhanced fields is important in many optical applications.In this article, a new strategy is proposed for fabricating a plasmonic double-stacked nanocone （DSC） nanostructure. In the DSC structure, a tunable plasmonichybrid mode proceeds from the strong coupling of the plasmonic resonance ofa fundamental cavity mode with a localized surface plasmon gap mode. In thenanostructure, the far-field response is deeply modulated and the hottest spotscan be effectively positioned on the top surface of the DSC nanostructure. Acontrollable and cost-effective mask-reconfiguration technique for manufacturingthe multiscale nanostructure is developed, which guarantees the generation ofthe introduced crucial stage on the DSC nanostructure. To evaluate the features ofthe plasmonic resonance, the DSC nanostructure is used as a surface-enhancedRaman scattering （SERS） substrate for detecting 4-mercaptopyridine moleculesunder specific excitation conditions. Its good performance, with an averagemeasured SERS enhancement factor as high as 108,
