An efficient CRISPR/Cas9 platform for targeted genome editing in rose(Rosa hybrida)

The clustered regularly interspaced short palindromic repeats(CRISPR)/CRISPR-related nuclease 9(Cas9)system enables precise,simple editing of genes in many animals and plants.However,this system has not been applied to rose(Rosa hybrida)due to the genomic complexity and lack of an efficient transformation technology for this plant.Here,we established a platform for screening single-guide RNAs(sgRNAs)with high editing efficiency for CRISPR/Cas9-mediated gene editing in rose using suspension cells.We used the Arabidopsis thaliana U6-29 promoter,which showed high activity for driving sgRNA expression,to modify the CRISPR/Cas9 system.We used our highly efficient optimized CRISPR/Cas9 system to successfully edit RhEIN2,encoding an indispensable component of the ethylene signaling pathway,resulting in ethylene insensitivity in rose.Our optimized CRISPR/Cas9 system provides a powerful toolbox for functional genomics,molecular breeding,and synthetic biology in rose.

Oblique shock train motion based on schlieren image processing

In this paper,shock train motion in a Mach number 2.7 duct is studied experimentally,and large numbers of schlieren images are obtained by a high-speed camera.An image processing method based on Maximum Correlation Detection(MCD)is proposed to detect shock train motion from the schlieren images,based on which the key structures,e.g.,separation positions and separation shock angles on the top and bottom walls,can be analysed in detail.The oscillations of the shock train are generated by rhombus and ellipse shafts at various excitation frequencies.According to the analysis of MCD results,the distributions of the frequency components of shock train oscillation generated by the two shafts are distinctly different,in which the motion generated by the ellipse shaft is much smoother;shock train motion is mainly characterized by the oscillation of separation position while the separation shock strength is not so sensitive to downstream disturbance;there is a hysteresis loop relation between the downstream pressure and separation position.

An integration method based on a novel combined flow for aerodynamic configuration of strutjet engine

In this paper a novel design method of aerodynamic configuration is proposed to integrate forebody,strut and inlet for strutjet engine,and a model at design point of Mach number6 is generated to investigate the aerodynamic performance by both simulations and experiments.The basic flow field employed by proposed method is a combined flow named IBB,which is combined by Internal Conical Flow A(ICFA),truncated Busemann flow I(BI)for external section,and truncated Busemann flow II(BII)for internal section.The model configuration is generated by streamline tracing method from basic flow field,in which the forebody section is traced from ICFA and BI flows,and the inlet as well as strut section is traced from BII flow.The simulations in Mach number 4,5,and 6 demonstrate uniform starting flow fields with relatively high total pressure recovery,which agree well with experiments in wind tunnel.Additionally,in low Mach number cases,this inlet could start at Mach number 3 while it is unstarted at Mach number 2.7;in high Mach number cases,a uniform flow could still exist in Mach number 6.5 while a relatively strong shock wave boundary layer interaction is found in cowl area of Mach number 7 case,indicating the inlet designed by proposed method works in a relatively wide Mach number range.

Evolution of wall flow structure and measurement of shear stress issuing from supersonic jet with extended shelf

This paper reports an experimental study on the supersonic jet surface flow structure visualization and shear stress field measurement issuing from a rectangular nozzle with extended shelf. The evolution of the near-field surface flow structures with an increased Nozzle Pressure Ratio(NPR) is successfully captured by the surface oil flow, infrared detection technology, and the Shear-Sensitive Liquid Crystal Coating(SSLCC) technique. Results reveal that under smaller NPR, the wall flow structure is similar to that of a jet without the extended shelf i.e., clean jets,and this is caused by insufficient effect on the boundary layer. However, at higher amplitudes of NPR, there exists a significant effect of the boundary layer, as a near triangular separation forms on the trailing edge of the Mach stem due to the adverse pressure gradient, which is visualized for the very first time in this paper. Furthermore, the vector field of shear stress is measured quantitatively by SSLCC technique. Results shows that the magnitude of shear stress heightened with NPR increasing, and the directions of shear stress changes across the shock wave and expansion fans. In addition, surface streamlines measured by SSLCC is significantly consistent with the streamlines visualized using the oil flow technique.