Phase Relations in TiAl+Nb System

The microstructures and phases of ternary TiAl+Nb alloys containing 50-60 at.-%Al, 0-21 at.-%Nb have been studied using transmission electron microscopy (TEM) and X-ray powder diffraction. The phases present in the alloys and their distribution were found to be a sensitive function of composition. The phase relations between γ-TiAl and γ1 (a new ordered ternary intermetallic compound based on γ-TiAl) were determined. Essentially single γ phase was determined for alloys with relativety low Nb content (≤10 at.-%Nb). the γ1 phase was determined to exist in the composition range containing higher Nb contents (15-21 at.-%Nb). Between γ and γ1 phases, with intermediate Nb contents there is a transitional phase γ1 (a superstructure of γ-TiAl). As for the influence of Al concentration on the phase relations. the γ1 phase was inclined to form in the alloys with relatively high Al contents. The ordering transformation of γ, to γ1 is a continuous ordering process and the transition may be second order.

OsADR3 increases drought stress tolerance by inducing antioxidant defense mechanisms and regulating OsGPX1 in rice(Oryza sativa L.)

The C (Cys) 2H (His) 2-type transcription factor is one of the most important transcription factors in plants and plays a regulatory role in the physiological responses of rice to abiotic stresses.A novel rice C2H2-type zinc finger protein,abscisic acid (ABA)-drought-reactive oxygen species (ROS) 3 (OsADR3),was found to confer drought stress tolerance by enhancing antioxidant defense and regulating Os GPX1.Overexpression of OsADR3 in rice increased tolerance to drought stress by increasing ROS scavenging ability and ABA sensitivity.In contrast,CRISPR/Cas9-mediated knockout of osadr3 increased the sensitivity of rice to drought and oxidative stress.An exogenous ROS-scavenging reagent restored the droughtstress tolerance of osadr3-CRISPR plants.Global transcriptome analysis suggested that OsADR3 increased the expression of Os GPX1 under drought stress.Electrophoretic mobility shift,yeast one-hybrid,and dualluciferase reporter assays revealed that OsADR3 modified the expression of Os GPX1 by directly binding to its promoter.Knockdown of Os GPX1 repressed ROS scavenging ability under drought stress in OsADR3-overexpression plants.These findings suggest that OsADR3 plays a positive regulatory role in droughtstress tolerance by inducing antioxidant defense and associated with the ABA signaling pathway in rice.

Elite sd1 alleles in japonica rice and their breeding applications in northeast China

The Green Revolution gene sd1 has been used extensively in modern rice breeding,especially in indica cultivars.However,elite sd1 alleles and related germplasm resources used for japonica rice breeding have not been identified,and extensive efforts are needed for japonica rice breeding to obtain new dwarfing sources.Data from MBKbase-Rice revealed seven sd1 haplotypes in indica and four in japonica rice.Two new sd1 alleles were identified in indica rice.In 295 japonica accessions from northeast Asia,except for the weak functional allele SD1-EQ,sd1-r was the major allele,reducing plant height in comparison with SD1-EQ.Japonica germplasm resources carrying reported sd1 alleles were identified by genotype searching and further verified by literature search,genealogical analysis,and d Caps markers.Pedigrees and geographic distribution showed that sd1-r is an excellent allele widely used in northern China and Tohoku in Japan,and sd1-j is commonly used in east China and Kyushu in Japan.Dongnong-and Xiushui-series cultivars carrying sd1-r and sd1-j,respectively,are essential branches of the backbone parents of Chinese japonica rice,Akihikari and Ce21,with the largest number of descendants and derived generations.In semi-dwarf japonica rice breeding,sd1-d was introgressed into Daohuaxiang 2(DHX2).Dwarf and semi-dwarf lines carrying sd1-d were selected and designated as 1279 and 1280,respectively,after withstanding typhoon-induced strong winds and heavy rains in 2020,and are anticipated to become useful intermediate materials for future genetic research and breeding.This work will facilitate the introduction,parental selection,and marker-assisted breeding,and provide a material basis for the next step in identifying favorable genes that selected together with the sd1 alleles in japonica backbone parents.

Cryptobiosis-inspired assembly of “AND” logic gate platform for potential tumor-specific drug delivery

Developing tumor-specific drug delivery systems with minimized off-target cargo leakage remains an enduring challenge.In this study,inspired from the natural cryptobiosis explored by certain organisms and stimuli-responsive polyphenol-metal coordination chemistry,doxorubicin(DOX)-conjugated gelatin nanoparticles with protective shells formed by complex of tannic acid and FeⅢ(DG@TA-FeⅢNPs)were successfully developed as an"AND"logic gate platform for tumor-targeted DOX delivery.Moreover,benefiting from the well-reported photothermal conversion ability of TA-FeⅢcomplex,a synergistic tumor inhibition effect was confirmed by treating 4 T1 tumor-beaing mice with DG@TA-FeⅢNPs and localized near-infrared(NIR)laser irradiation.As a proof of concept study,this work present a simple strategy for developing"AND"logic gate platforms by coating enzyme-degradable drug conjugates with detachable polyphenol-metal shells.

Enhanced N2O emission rate in field soil undergoing conventional intensive fertilization is attributed to the shifts of denitrifying guilds

The emission of greenhouse gas N2O in agricultural soil is modulated by N fertilization that could be converted to N2O by denitrifiers under anaerobic condition. Nevertheless, the effect of denitrifiers on N2O emission has not been thoroughly elucidated. In this study, we explored the denitrifying gas kinetics,nitrate content, transcribed denitrifying functional genes(narG, nirS, nirK, and nosZ), and the active bacteria during anaerobic incubation of soils with conventional intensive N fertilization(CNS) and reduced N fertilization(RNS), both sampled from a vegetable greenhouse experimental site. The CNS sample showed significantly higher N2O emission rates relative to the RNS sample. However, the difference in N2O emission between the soils was neither because of the cumulative nitrate content nor the quantity of denitrifying gene transcripts. The distinct fertilization regimes shaped the significantly different bacterial communities in these soils. The absolute abundance of bacteria that produce N2O but lack the nosZ gene for N2O reduction(for example, the dominant Kaistobacter) was higher in CNS than in RNS. Meanwhile, the abundance of two operational taxonomy units(OTUs), namely Rhodanobacter,belonging to the most abundant genus in denitrifying guilds, was strongly enriched in CNS and showed significant positive correlation with N2O/(N2O +N2). The predominance of these bacterial OTUs in the CNS denitrifying guild strongly suggested that high N2O emission from the soil with long-term conventional intensive fertilization might be primarily attributed to the reshaping of distinct denitrifying guilds in their bacterial communities.