[Objective] The aim was to study the cDNA cloning of SMAT gene from Chimonanthus praecox and its expression. [Method] A novel cDNA was cloned by PT-PCR using the total RNA as template, and amplified to the desirable s...[Objective] The aim was to study the cDNA cloning of SMAT gene from Chimonanthus praecox and its expression. [Method] A novel cDNA was cloned by PT-PCR using the total RNA as template, and amplified to the desirable size. The RT-PCR products were reclaimed and transformed into E. coli DH 5o together with the PMD18-T vector after ligating by T-A cloning. Identified by colony PCR and EcoRI and Notl digestion, the recombinant plasmid with target gene was screened out and conducted the sequence analysis. [Result] Results of the sequence analysis showed that the ORF fragment of the SAMT cDNA was successfully cloned from Chimonanthus praecox gene, with the length of 1 196 bp and encoding 380 amino acids fragment which shared 99.2% homology to that of previously reported SAMT cDNA from Chimonanthus praecox （ABU88887）. The SAMT cDNA fragment was sub-cloned into the prokaryotic expression vector PGEX1-4T-1, and the obtained re- combinant plasmid was named PGSAMT. After inducting by 0.01mol/L IPTG, the re- sult of the SDS-PAGE analysis showed that the molecular weight of the fusion ex- pression SAMT protein was about 66 kDa, which was close to the predicted fusion protein derived from the 26 kDa GST band and 42.3 kDa SAMT gene of Chimo- nanthus praecox encoded protein. [Conclusion] This study successfully cloned and expressed the SAMT gene of Chimonanthus praecox.展开更多
To provide physically based wind modelling for wind erosion research at regional scale, a 3D computational fluid dynamics (CFD) wind model was developed. The model was programmed in C language based on the Navier-Stok...To provide physically based wind modelling for wind erosion research at regional scale, a 3D computational fluid dynamics (CFD) wind model was developed. The model was programmed in C language based on the Navier-Stokes equations, and it is freely available as open source. Integrated with the spatial analysis and modelling tool (SAMT), the wind model has convenient input preparation and powerful output visualization. To validate the wind model, a series of experiments was con- ducted in a wind tunnel. A blocking inflow experiment was designed to test the performance of the model on simulation of basic fluid processes. A round obstacle experiment was designed to check if the model could simulate the influences of the obstacle on wind field. Results show that measured and simulated wind fields have high correlations, and the wind model can simulate both the basic processes of the wind and the influences of the obstacle on the wind field. These results show the high reliability of the wind model. A digital elevation model (DEM) of an area (3800 m long and 1700 m wide) in the Xilingele grassland in Inner Mongolia (autonomous region, China) was applied to the model, and a 3D wind field has been successfully generated. The clear imple- mentation of the model and the adequate validation by wind tunnel experiments laid a solid foundation for the prediction and assessment of wind erosion at regional scale.展开更多
Aphids represent a major threat to crops.Hundreds of different viruses are aphid-borne.Upon aphid attack,plants release volatile organic compounds(VOCs)as airborne alarm signals to turn on the airborne defense(AD)of n...Aphids represent a major threat to crops.Hundreds of different viruses are aphid-borne.Upon aphid attack,plants release volatile organic compounds(VOCs)as airborne alarm signals to turn on the airborne defense(AD)of neighboring plants,thereby repelling aphids as well as reducing aphid fitness and virus transmission.This phenomenon provides a critical community-wide plant protection to fend off aphids,but the underlying molecular basis remains undetermined for a long time.In a recent article,Gong et al.established the NAC2-SAMT1 module as the core component regulating the emission of methyl-salicylate(MeSA),a major component of VOCs in aphid-attacked plants.Furthermore,they showed that SABP2 protein is critical for the perception of volatile MeSA signal by converting MeSA to Salicylic Acid(SA),which is the cue to elicit AD against aphids at the community level.Moreover,they showed that multiple viruses use a conserved glycine residue in the ATP-dependent helicase domain in viral proteins to shuttle NAC2 from the nucleus to the cytoplasm for degradation,leading to the attenuation of MeSA emission and AD.These findings illuminate the functional roles of key regulators in the complex MeSA-mediated airborne defense process and a counter-defense mechanism used by viruses,which has profound significance in advancing the knowledge of plant-pathogen interactions as well as providing potential targets for gene editing-based crop breeding.展开更多
文摘[Objective] The aim was to study the cDNA cloning of SMAT gene from Chimonanthus praecox and its expression. [Method] A novel cDNA was cloned by PT-PCR using the total RNA as template, and amplified to the desirable size. The RT-PCR products were reclaimed and transformed into E. coli DH 5o together with the PMD18-T vector after ligating by T-A cloning. Identified by colony PCR and EcoRI and Notl digestion, the recombinant plasmid with target gene was screened out and conducted the sequence analysis. [Result] Results of the sequence analysis showed that the ORF fragment of the SAMT cDNA was successfully cloned from Chimonanthus praecox gene, with the length of 1 196 bp and encoding 380 amino acids fragment which shared 99.2% homology to that of previously reported SAMT cDNA from Chimonanthus praecox （ABU88887）. The SAMT cDNA fragment was sub-cloned into the prokaryotic expression vector PGEX1-4T-1, and the obtained re- combinant plasmid was named PGSAMT. After inducting by 0.01mol/L IPTG, the re- sult of the SDS-PAGE analysis showed that the molecular weight of the fusion ex- pression SAMT protein was about 66 kDa, which was close to the predicted fusion protein derived from the 26 kDa GST band and 42.3 kDa SAMT gene of Chimo- nanthus praecox encoded protein. [Conclusion] This study successfully cloned and expressed the SAMT gene of Chimonanthus praecox.
基金the Sino-German research project MAGIM (Matter fluxes in Grasslands of Inner Mongolia as influenced by stocking rate) funded by DFG (German Research Foundation, Research Unit 536)
文摘To provide physically based wind modelling for wind erosion research at regional scale, a 3D computational fluid dynamics (CFD) wind model was developed. The model was programmed in C language based on the Navier-Stokes equations, and it is freely available as open source. Integrated with the spatial analysis and modelling tool (SAMT), the wind model has convenient input preparation and powerful output visualization. To validate the wind model, a series of experiments was con- ducted in a wind tunnel. A blocking inflow experiment was designed to test the performance of the model on simulation of basic fluid processes. A round obstacle experiment was designed to check if the model could simulate the influences of the obstacle on wind field. Results show that measured and simulated wind fields have high correlations, and the wind model can simulate both the basic processes of the wind and the influences of the obstacle on the wind field. These results show the high reliability of the wind model. A digital elevation model (DEM) of an area (3800 m long and 1700 m wide) in the Xilingele grassland in Inner Mongolia (autonomous region, China) was applied to the model, and a 3D wind field has been successfully generated. The clear imple- mentation of the model and the adequate validation by wind tunnel experiments laid a solid foundation for the prediction and assessment of wind erosion at regional scale.
基金supported by the US National Science Foundation(MCB-1906060 and MCB-2145967 to Y.W.)。
文摘Aphids represent a major threat to crops.Hundreds of different viruses are aphid-borne.Upon aphid attack,plants release volatile organic compounds(VOCs)as airborne alarm signals to turn on the airborne defense(AD)of neighboring plants,thereby repelling aphids as well as reducing aphid fitness and virus transmission.This phenomenon provides a critical community-wide plant protection to fend off aphids,but the underlying molecular basis remains undetermined for a long time.In a recent article,Gong et al.established the NAC2-SAMT1 module as the core component regulating the emission of methyl-salicylate(MeSA),a major component of VOCs in aphid-attacked plants.Furthermore,they showed that SABP2 protein is critical for the perception of volatile MeSA signal by converting MeSA to Salicylic Acid(SA),which is the cue to elicit AD against aphids at the community level.Moreover,they showed that multiple viruses use a conserved glycine residue in the ATP-dependent helicase domain in viral proteins to shuttle NAC2 from the nucleus to the cytoplasm for degradation,leading to the attenuation of MeSA emission and AD.These findings illuminate the functional roles of key regulators in the complex MeSA-mediated airborne defense process and a counter-defense mechanism used by viruses,which has profound significance in advancing the knowledge of plant-pathogen interactions as well as providing potential targets for gene editing-based crop breeding.
