The OsBZR1-OsSPX1/2 module fine-tunes the growth-immunity trade-off in adaptation to phosphate availability in rice

The growth-promoting hormones brassinosteroids(BRs)and their key signaling component BZR1 play a vital role in balancing normal growth and defense reactions.Here,we discovered that BRs and OsBZR1 up-regulated sakuranetin accumulation and conferred basal defense against Magnaporthe oryzae infection under normal conditions.Resource shortages,including phosphate(Pi)deficiency,potentially disrupt this growth-defense balance.OsSPX1 and OsSPX2 have been reported to sense Pi concentration and interact with the Pi signal mediator OsPHR2,thus regulating Pi starvation responses.In this study,we discovered that OsSPX1/2 interacts with OsBZR1 in both Pi-sufficient and Pi-deficient conditions,inhibit-ing BR-responsive genes.When Pi is sufficient,OsSPX1/2 is captured by OsPHR2,enabling most of OsBzR1 to promote plant growth and maintain basal resistance.In response to Pi starvation,more OsSPX1/2 is released from OsPHR2 to inhibit OsBZR1 activity,resulting in slower growth.Collectively,our study reveals that the OsBZR1-SPX1/2 module balances the plant growth-immunity trade-off in responsetoPiavailability.He Y.,Zhao Y.,Hu J.,Wang L.,Li L.,Zhang X.,Zhou Z.,Chen L.,Wang H.,Wang J.,and Hong G.(2024).The OsBZR1-OsSPX1/2 module fine-tunes the growth-immunity trade-off in adaptation to phosphate availability in esponse to Pi availability.

WRKY33 negatively regulates anthocyanin biosynthesis and cooperates with PHR1 to mediate acclimation to phosphate starvation

Anthocyanin accumulation is acknowledged as a phenotypic indicator of phosphate(Pi)starvation.However,negative regulators of this process and their molecular mechanisms remain largely unexplored.In this study,we demonstrate that WRKY33 acts as a negative regulator of phosphorus-status-dependent anthocyanin biosynthesis.WRKY33 regulates the expression of the gene encoding dihydroflavonol 4-reductase(DFR),a rate-limiting enzyme in anthocyanin production,both directly and indirectly.WRKY33 binds directly to the DFR promoter to repress its expression and also interferes with the MBW complex through interacting with PAP1 to indirectly influence DFR transcriptional activation.Under�Pi conditions,PHR1 interacts with WRKY33,and the protein level of WRKY33 decreases;the repression of DFR expression by WRKY33 is thus attenuated,leading to anthocyanin accumulation in Arabidopsis.Further genetic and biochemical assays suggest that PHR1 is also involved in regulating factors that affect WRKY33 protein turnover.Taken together,ourfindings reveal that Pi starvation represses WRKY33,a repressor of anthocyanin biosynthesis,tofinely tune anthocyanin biosynthesis.This‘‘double-negative logic’’regulation of phosphorus-status-dependent anthocyanin biosynthesis is required for the mainte-nance of plant metabolic homeostasis during acclimation to Pi starvation.

刺激响应自毁聚乙醛酸乙酯的合成改性和应用研究现状

由于武器装备、信息安全等领域对自毁器件的重大需求,对外界环境能产生响应的自毁型聚合物受到了人们的重点关注。所谓自毁聚合物(SIPs)是指在特定外界环境刺激下,聚合物产生程序化的解聚反应,以熔化、液化、蒸发等方式使其自毁并消失。聚乙醛酸乙酯是近年来可自毁聚合物的研究热点之一,其具有多刺激响应、固态下快速解聚、降解产物无毒害等显著优势,在智能封装、传感器、药物控释等领域具有明确的应用前景。文中系统综述了聚乙醛酸乙酯的自毁机理、合成方法、改性策略及应用发展等内容,对聚乙醛酸乙酯的国内外研究现状进行了梳理,并对这一热点新兴领域未来发展的机遇与挑战进行了展望。

Effects of Reynolds number and Schmidt number on variable density mixing in shock bubble interaction

Effects of Reynolds(Re)number and Schmidt(Sc)number on the flow structures and variable density mixing are numerically investigated through the canonical shock cylindrical bubble interaction.By determining the viscosity and diffusivity within a wide range,the controlling parameters,total vortex circulation,and compression rate,are conservative under a broad range of Re and Sc numbers(Re≈10^(3)-10^(5)and Sc≈0.1-5)in the same shock Mach(Ma)number condition(Ma=2.4).As for the Re number effect,the circulation of secondary baroclinic vorticity(SBV),induced by the main vortex centripetal acceleration,is observed to be higher in high Re number and vice versa.Based on the vorticity transport equation decomposition,a growth-inhibition vorticity dynamics balance mechanism is revealed:the vorticity viscous term grows synchronously with baroclinic production to inhibit SBV production in low Re number.By contrast,the viscous term terminates the baroclinic term with a time lag in high Re number,leading to the SBV production.Since the SBV reflects the local stretching enhancement based on the advection-diffusion equation,mixing is influenced by the Sc number in a different behavior if different Re numbers are considered.The time-averaged variable density mixing rate emerges a scaling law with Sc number asχ^(∗)=β·Sc^(−α),where the coefficientβ∼Re−0.2 and the scaling exponentα∼Re−0.385.The understanding of Re number and Sc number effect on variable density mixing provides an opportunity for mixing enhancement from the perspective of designing the viscosity and diffusivity of the fluid mixture.

An Approach to Obtain the Correct Shock Speed for Euler Equations with Stiff Detonation

Incorrect propagation speed of discontinuities may occur by straightforward application of standard dissipative schemes for problems that contain stiff source terms for underresolved grids even for time steps within the CFL condition.By examining the dissipative discretized counterpart of the Euler equations for a detonation problem that consists of a single reaction,detailed analysis on the spurious wave pattern is presented employing the fractional stepmethod,which utilizes the Strang splitting.With the help of physical arguments,a threshold values method(TVM),which can be extended to more complicated stiff problems,is developed to eliminate the wrong shock speed phenomena.Several single reaction detonations as well as multispecies and multi-reaction detonation test cases with strong stiffness are examined to illustrate the performance of the TVM approach.