Integrated metabolomics and proteomics analyses reveal the molecular mechanism underlying the yellow leaf phenotype of Camellia sinensis

The tea plant cultivar‘Zhonghuang 2'(ZH2)possesses albino-induced yellow leaves that contain low levels of catechins but high contents of amino acids.However,the molecular mechanism underlying the yellow leaf phenotype of ZH2 has not been elucidated clearly.In the current research,the yellow shoots(ZH2-Y)and naturally converted green shoots(ZH2-G)of ZH2 were studied using metabolic and proteomic profiling for a better understanding of the mechanism underlying phenotype formation.In total,107 differentially changed metabolites(DCMs)were identified from the GC-MS-based metabolomics,and 189 differentially accumulated proteins(DAPs)were identified from the tandem mass tag(TMT)-based quantitative proteomics.Subsequently,integrated analysis revealed that‘porphyrin and chlorophyll metabolism',‘carbon fixation in photosynthetic organisms',and‘phenylpropanoid biosynthesis'pathways were commonly enriched for DAPs and DCMs.We further found that the inhibition of chlorophyll biosynthesis,the deficiency of photosynthetic proteins and the imbalance of the ROS-scavenging system were the crucial reasons responsible for the chlorosis,chloroplast abnormality and photooxidative damage of ZH2 leaves.Altogether,our research combines metabolomics and proteomics approaches to uncover the molecular mechanism leading to the yellow leaf phenotype of tea plants.

Determination of the constant m_(i) in the Hoek-Brown criterion of rock based on drilling parameters

The constant m_(i) in the Hoek-Brown(H-B) criterion is a fundamental parameter required for determining the compressive strength of rock. In this paper, drilling parameters provide a new basis for determining the constant mi. An analytical relationship between the drilling parameters and constant miis established in consideration of the contact response between the drilling bit and the cut rock in the crushed zone.New models are developed to predict the triaxial compressive strength(TCS), internal friction angle φand cohesion c of rock. Drilling tests are carried out on 6 rock types to study the correlation between φ and m_(i). A comparison between the predicted values of rock mechanical properties and the measured values from the laboratory is performed to verify the accuracy of the proposed model(yielding an error less than 10%). The TCSs and constant m_(i) values of fifteen rocks are cited to validate the accuracy of the proposed model. The result shows that the proposed model predicts the TCS and constant m_(i) within a maximum error of 20%. The method can be conveniently applied to the rock mechanical properties.

ABI5 promotes heat stress-induced chlorophyll degradation by modulating the stability of MYB44 in cucumber

The yellowing of leaves caused by the decomposition of chlorophyll(Chl)is a characteristic event during senescence,which can be induced by various environmental stresses.However,the molecular mechanisms of high temperature-induced Chl degradation in horticultural plants remain poorly understood.Here,we found that heat stress induced Chl degradation and the expression of ABI5 and MYB44 in cucumber.Silencing of ABI5 compromised heat stress-induced Chl degradation,and the transcription of pheophytinase(PPH)and pheophorbide a oxygenase(PAO),two key genes in Chl catabolic pathway,but silencing of MYB44 exhibited the opposite results.Furthermore,ABI5 interacted with MYB44 in vitro and in vivo.ABI5 positively regulated heat stress-induced Chl degradation through two pathways.ABI5 directly bound to PPH and PAO promoters to promote their expression,leading to accelerating Chl degradation.On the other hand,the interaction between ABI5 and MYB44 reduced the binding of MYB44 to PPH and PAO promoters and led to the ubiquitination-depended protein degradation of MYB44,thereby alleviating the transcription inhibitory effect of MYB44 on PPH and PAO.Taken together,our findings propose a new regulatory network for ABI5 in regulating heat stress-induced Chl degradation.

The key cyclic electron flow protein PGR5 associates with cytochrome b_(6)f, and its function is partially influenced by the LHCⅡ state transition

In plants and algae,PGR5-dependent cyclic electron flow(CEF)is an important regulator of acclimation to fluctuating environments,but how PGR5 participates in CEF is unclear.In this work,we analyzed two PGR5s in cucumber(Cucumis sativus L.)under different conditions and found that CsPGR5a played the dominant role in PGR5-dependent CEF.The results of yeast two-hybrid,biomolecular fluorescence complementation(BiFC),blue native PAGE,and coimmunoprecipitation(CoIP)assays showed that PGR5a interacted with PetC,Lhcb3,and PsaH.Furthermore,the intensity of the interactions was dynamic during state transitions,and the abundance of PGR5 attached to cyt b_(6)f decreased during the transition from state 1 to state 2,which revealed that the function of PGR5a is related to the state transition.We proposed that PGR5 is a small mobile protein that functions when attached to protein complexes.

Ordered mesoporous materials for water pollution treatment:Adsorption and catalysis

To meet the growing emission of water contaminants,the development of new materials that enhance the efficiency of the water treatment system is urgent.Ordered mesoporous materials provide opportunities in environmental processing applications due to their exceptionally high surface areas,large pore sizes,and enough pore volumes.These properties might enhance the performance of materials concerning adsorption/catalysis capability,durability,and stability.In this review,we enumerate the ordered mesoporous materials as adsorbents/catalysts and their modifications in water pollution treatment from the past decade,including heavy metals(Hg^(2+),Pb^(2+),Cd^(2+),Cr^(6+),etc.),toxic anions(nitrate,phosphate,fluoride,etc.),and organic contaminants(organic dyes,antibiotics,etc.).These contributions demonstrate a deep understanding of the synergistic effect between the incorporated framework and homogeneous active centers.Besides,the challenges and perspectives of the future developments of ordered mesoporous materials in wastewater treatment are proposed.This work provides a theoretical basis and complete summary for the application of ordered mesoporous materials in the removal of contaminants from aqueous solutions.

In-situ construction of abundant active centers on hierarchically porous carbon electrode toward high-performance phosphate electrosorption: Synergistic effect of electric field and capture sites

Phosphate removal is crucial for eutrophication control and water quality improvement.Electro-assisted adsorption,an eco-friendly elec-trosorption process,exhibited a promising potential for wastewater treatment.However,there are few works focused on phosphate electro-sorption,and reported electrodes cannot attach satisfactory removal capacities and rates.Herein,electro-assisted adsorption of phosphate via in-situ construction of La active centers on hierarchically porous carbon(LaPC)has been originally demonstrated.The resulted LaPC composite not only possessed a hierarchically porous structure with uniformly dispersed La active sites,but also provided good conductivity for interfacial electron transfer.The LaPC electrode achieved an ultrahigh phosphate electrosorption capability of 462.01 mg g^(-1) at 1 V,outperforming most existing electrodes.The superior phosphate removal performance originates from abundant active centers formed by the coupling of electricfield and capture sites.Besides,the stability and selectivity toward phosphate capture were maintained well even under comprehensive conditions.Moreover,a series of kinetics and isotherms models were employed to validate the electrosorption process.This work demonstrates a deep understanding and promotes a new level of phosphate electrosorption.

Effect of layered joints on rockburst in deep tunnels

The existence of joints in the surrounding rock mass has a considerable efect on tunnel rockbursts.Herein,we studied the efect of layered joints with diferent inclination angles and spacings on rockburst in deep tunnels and investigated the failure area,deformation process of the surrounding rock mass,stress change inside the surrounding rock mass,velocity of the failed rock,and the kinetic energy of the failure.The failure type of the surrounding rock mass can thus be determined.The results showed that the intensity of rockburst increases as rock quality designation(RQD)decreases,while the deformation rate of the surrounding rock mass frst increases and then decreases.The deformation rate exhibits a turning point between RQD=50 and 70,below which the deformation rate of the surrounding rock mass gradually decreases,ultimately ceasing to be a rockburst.Rockburst always occurs perpendicular to the direction of the joint.Whenσ_(x)=σ_(y),as the joint inclination angle changes from 45°to 90°,the intensity of a rockburst frst decreases(from 45°to 60°),and then increases(from 60°to 90°).When combined with the evolution law of stress and strain energy,the rockburst process can be divided into four stages.

Experimental investigation on the anisotropy of friction property for dry and water-saturated rock

Friction properties of rock are closely connected with the anisotropy.The anisotropy of rock friction can provide a valuable assessment for geotechnical and geological engineering.In this study,the rotary friction tests were conducted to analyze the water effect on the friction property and the friction anisotropy of the four types of rock.The drilling response model(DD-model)was employed to characterize the rotary friction behavior of the rocks.The parameters of this model include the three types of friction parameters:1/ς,μ,and f,where 1/ςandμare constant,and f is a variable.A quantitative method is proposed for assessing the anisotropy of rock friction.The results of the rotary friction tests indicate that the relation between torque force and thrust force conforms to the DD-model.The changes of two friction constants 1/ςandμfrom dry state to water-saturated state suggest that the water effect on the friction strength of the rocks exhibits significant anisotropy.The friction strength determined by the friction variable f increases first,then decreases,and finally stabilizes with the increasing of depth.AIf is an anisotropy index calculated by the proposed method.The percentage difference of the average value of AIf between water-saturated and dry states shows the degree of the water effect on the friction anisotropy of the rocks,mudstone(MU)>granite(GR)>fine sandstone(FS)>argillaceous siltstone(AS).The quantitative model is hopefully constructed for characterizing the relation between the anisotropic friction strength of rock and the moisture state in future.

Investigation of solution chemistry to enable efficient lithium recovery from low-concentration lithium-containing wastewater

In the production of lithium-ion batteries(LIBs)and recycling of spent LIBs,a large amount of low-concentration lithium-containing wastewater(LCW)is generated.The recovery of Li from this medium has attracted significant global attention from both the environmental and economic perspectives.To achieve effective Li recycling,the features of impurity removal and the interactions among different ions must be understood.However,it is generally dificult to ensure highly efficient removal of impurity ions while retaining Li in the solution for further recovery.In this study,the removal of typical impurity ions from LCW and the interactions between these species were systematically investigated from the thermodynamic and kinetics aspects.It was found that the main impurities(e.g.,Fe^+,AIP^+,Ca^2+,and Mg^2+)could be efficiently removed with high Li recovery by control-ling the ionic strength of the solution.The mechanisms of Fe^3+,Al^+,Ca^2+,and Mg^2+removal were investigated to identify the controlling steps and reaction kinetics.It was found that the precipitates are formed by a zero-order reaction,and the activation energies tend to be low with a sequence of fast chemical reactions that reach equilibrium very quickly.Moreover,this study focused on Li loss during removal of the impurities,and the corresponding removal rates of Fe^+,Al^+,Ca^2+,and Mg^2+were found to be 99.8%,99.5%,99%,and 99.7%,respectively.Conse-quently,high-purity LisPO4 was obtained via one-step precipitation.Thus,this research demonstrates a potential route for the effective recovery of Li from low-concentra-tion LCW and for the appropriate treatment of acidic LCW.

Viscoelastic solution of optimal reserved deformation for deep soft rock tunnels with large deformation

In the construction process of soft rock tunnels,determining a reasonable amount of reserved deformation is important to ensure the tunnel stability.This article presents the viscoelastic solution of reserved deformation for deep soft rock tunnels considering the support effects.Based on the analytical solution of the Burgers model,the expression of surrounding rock displacement was derived by considering reserved deformation and optimal reserved deformation.Subsequently,based on numerical simulation experiments,the variation laws and errors of the numerical and analytical solutions of the expressions of reserved deformation and surrounding rock displacement were analyzed.To gain a better understanding of the factors that affect reserved deformation,the factors influencing the expression of optimal reserved deformation were analyzed.The errors in the numerical simulation and analytical solution results were within 10%.This study could provide a theoretical basis for determining the amount of reserved deformation and analyzing the variation law of surrounding rock affected by the amount of reserved deformation.

含锂矿物机械化学强化提锂工艺

采用机械化学活化方法,在机械活化过程中用K2SO4为活化添加剂,强化锂云母中惰性Li-O配位结构活化转型,通过温和稀酸浸出高效分离锂,考察了活化过程添加剂用量、球磨时间和球料比及浸出条件如酸浓度、液固比、搅拌速度、温度和时间等对锂回收率的影响,确定了最佳工艺条件,讨论了反应过程机理。结果表明,机械化学活化强化破坏云母片层结构中的Si-O-K结构,降低了Si-O配位结构对Li-O配位结构的牵制力,导致Li-O键强减弱,反应活性增加。在最优条件下(精矿与K2SO4质量比5:1、球磨机转速500 r/min、球料质量比20:1、球磨时间3 h、硫酸浓度15vol%、液固比4 L/g、反应温度80℃、浸出搅拌速率200 r/min),锂浸出率可达99.1%。

Nitrate transporter NRT1.1 and anion channel SLAH3 form a functional unit to regulate nitrate-dependent alleviation of ammonium toxicity

Ammonium(NH_(4)^(+))and nitrate(NO_(3)^(-))are major inorganic nitrogen(N)sources for plants.When serving as the sole or dominant N supply,NH_(4)^(+)often causes root inhibition and shoot chlorosis in plants,known as ammonium toxicity.NO_(3)^(-) usually causes no toxicity and can mitigate ammonium toxicity even at low concentrations,referred to as nitrate-dependent alleviation of ammonium toxicity.Our previous studies indicated a NO_(3)^(-) efflux channel SLAH3 is involved in this process.However,whether additional components contribute to NO_(3)^(-)-mediated NH_(4)^(+)detoxification is unknown.Previously,mutations in NO_(3)^(-) transporter NRT1.1 were shown to cause enhanced resistance to high concentrations of NH_(4)^(+).Whereas,in this study,we found when the high-NH_(4)^(+) medium was supplemented with low concentrations of NO_(3)^(-),nrt1.1 mutant plants showed hyper-sensitive phenotype instead.Furthermore,mutation in NRT1.1 caused enhanced medium acidification under high-NH_(4)^(+)/Iow-NO_(3)^(-) condition,suggesting NRT1.1 regulates ammonium toxicity by facilitating H+uptake.Moreover,NRT1.1 was shown to interact with SLAH3 to form a transporter-channel complex.Interestingly,SLAH3 appeared to affect NO_(3)^(-) influx while NRT1.1 influenced NO_(3)^(-) efflux,suggesting NRT1.1 and SLAH3 regulate each other at protein and/or gene expression levels.Our study thus revealed NRT1.1 and SLAH3 form a functional unit to regulate nitrate-dependent alleviation of ammonium toxicity through regulating NO_(3)^(-) transport and balancing rhizosphere acidification.