A predicted NEDD8 conjugating enzyme gene identified as a Capsicum candidate Rf gene using bulk segregant RNA sequencing

Cytoplasmic male sterility(CMS)is an important tool for producing F1 hybrids,which can exhibit heterosis.The companion system,restorer-of-fertility(Rf),is poorly understood at the molecular level and would be valuable in producing restorer lines for hybrid seed production.The identity of the Rf gene in Capsicum(pepper)is currently unclear.In this study,using bulked segregant RNA sequencing(BSR-seq),a strong candidate Rf gene,Capana06g002866,which is annotated as a NEDD8 conjugating enzyme E2,was identified.Capana06g002866 has an ORF of 555 bp in length encoding 184 amino acids;it can be cloned from F1 plants from the hybridization of the CMS line 8A and restorer line R1 but is not found in CMS line 8A.With qRT-PCR validation,Capana06g002866 was found to be upregulated in restorer accessions compared to sterile accessions.The relative expression in flower buds increased with the developmental stage in F1 plants,while the expression was very low in all flower bud stages of the CMS lines.These results provide new insights into the Rf gene in pepper and will be useful for other crops utilizing the CMS system.

Enhancing {1012} twin boundary migration capability in Ti-Al solid solution alloys with increasing Al content

1.Introduction Titanium(Ti)and its alloys have been widely used in the aerospace,biomedical and chemical industries due to their high specific strength,low Young’s modulus,superior biocompatibility and strong corrosion resistance[1–5].While Ti alloys have high strength,they usually present relatively poor ductility and formability at room temperature[5].Therefore,their deformation behaviors and corresponding mechanisms have been the focus of attention in order to obtain better formability and mechanical properties.Forα-Ti and its alloys with hexagonal close-packed(HCP)structure,the most common slip system is prismatic a slip at room temperature[6–9].Pyramidal c+a slip can coordinate c-axis strain,but it is general difficult to activate c+a slip in polycrystalline Ti alloys[6,9]although reducing grain size can increase the propensity of c+a slip[9].Due to the limited slip systems for accommodating c-axis strain,deformation twinning plays an important role to coordinate strain along the c-axis of the HCP structure during plastic deformation.

Phase transformation and structural evolution in a Ti-5at.%Al alloy induced by cold-rolling

The phase transformation,deformation mechanism and their correlation in a cold-rolled Ti-5 at.%Al alloy were investigated.Two types of phase transformations from a hexagonal close-packed(HCP)structure to a face-centered cubic(FCC)structure were observed:the basal-type(B-type)with an orientation relation-ship of<1210HCP//<110FCC and{0001}HCP//{111}FCC,and the prismatic-type(P-type)with an orientation-relationship of<1210HCP//<110FCC and 1010HCP//110FCC.The two types of transformations both accommodate the strain along the<c>axis of the HCP matrix.With the proceeding of deformation,different deformation mechanisms were activated in the FCC and the HCP structures,respectively,which led to a faster grain refinement rate in the FCC structure than in the HCP matrix.Deformation twins with zero macroscopic strain were prevalent in the FCC domains produced by the B-type transformation,while deformation twins with macroscopic strain were normally observed in the FCC domains produced by the P-type transformation.This is in accordance with the lattice mismatches produced during phase transformation.The easy occurrence of deformation twinning in the FCC structure contributed significantly to the grain refinement process.In addition,the interaction between neighboring FCC domains produced by the two types of phase transformations also accelerated the grain refinement process.

Structural characterization of the{1122}twin boundary and the corresponding stress accommodation mechanisms in pure titanium

{11-22}compression twin plays an important role in accommodating deformation along the c axis of HCP metals.However,the studies on the interface structure of{11-22}twin boundary(TB),especially the twin tip,and the corresponding local stress release mechanism are still limited.This work studied the interface characters of{11-22}TB of a deformed pure titanium by transmission electron microscope.The{11-22}TB presented serrated character,consisting of coherent twin boundary(CTB)and(0002)_(T)//(11-2-2)_(M) or(11-2-2)_(T)//(0002)_(M) steps,and the twin tip was fully composed of the basal-pyramidal(BPy)and pyramidal-basal(PyB)steps.The twin tip presents asymmetric morphology and the step height at the twin tip is much larger than that away from the twin tip.Two types of local stress accommodation mechanisms were observed:zonal dislocation emission and hexagonal close packed structure to facecentered cubic structure transformation.The zonal dislocation was produced by the dissociation of the1/3<11-2-3>dislocation that was nucleated at the twin tip and the phase transformation was introduced by emission of Shockley partial dislocations from the{11-22}twin boundary.

Simple and rapid conversion of silicon carbide to nanodiamonds at ambient pressure

Nanodiamonds(NDs)were prepared under ambient pressure by sublimation decomposition of silicon carbide in an intermediate frequency furnace for only 8 min.The synthesis proceeded in the temperature range of 2600-2800℃ without any catalyst or highly active gas components(such as H2,alkane,and halogen).The conversion began at 2600℃ and produced NDs with particle sizes in the range of 1-5 nm with a uniform particle shape and excellent dispersion.The linear reaction kinetics allowed for rapid transformation to any depth with reasonable control of the temperature.The linear rate constant(K_(l))for the reaction at 2800℃ was 37.5 mm/h,which is 31.2 times that of the reaction at 2600℃.The Si C sublimation decomposition produced carbon atoms that filled the Si C lattice vacancies or were combined with the suspended carbon chain bonds to form sp3 carbon,while the diffusion of amorphous carbon atoms promoted nucleation and growth of diamond.High-resolution transmission electron microscopy analysis indicated that the NDs were separated from the Si C matrix by break-off due to propagation of the reaction front.This Si C sublimation decomposition method is considered simple,fast,environmentally friendly and promising for industrial-scale production.