In vitro antibacterial activity and major bioactive components of Cinnamomum verum essential oils against cariogenic bacteria,Streptococcus mutans and Streptococcus sobrinus

Objective:To evaluate the antibacterial activity of Cinnamomum verum(C.verum) from32 different essential oils against cariogenic bacteria,Streptococcus mutans(S.mutans)and Streptococcus sobrinus(S.sobrinus).Methods:The antibacterial activities of each essential oil were individually investigated against S.mutans and S.sobrinus.The essential oil of C.verum was selected for further evaluation against S.mutans and S.sobrinus.Gas chromatography mass spectrometry was used to determine the major constituents of C.verum essential oil.In addition,the minimum inhibitory concentration(MIC) and minimum bactericidal concentration of the most effective constituent was investigated.Results:The essential oil from C.verum exhibited the greatest antibacterial activity.Gas chromatography mass spectrometry analysis revealed that the major components of C.verum essential oil were cinnamaldehyde(56.3%),cinnamyl acetate(7.1%) and bphellandrene(6.3%).The MIC of cinnamaldehyde was measured using broth dilution assays.The MIC of cinnamaldehyde was 0.02%(v/v) against both bacterial strains tested.The minimum bactericidal concentration of cinnamaldehyde against S.mutans and S.sobrinus were 0.2% and 0.1%(v/v),respectively.Conclusions:The essential oil of C.verum and its major component cinnamaldehyde possessed considerable in vitro antibacterial activities against cariogenic bacteria,S.mutans and S.sobrinus strains.These results showed that the essential oil of C.verum and its bioactive component,cinnamaldehyde,have potential for application as natural agents for the prevention and treatment of dental caries.

Proteome analysis of alfalfa roots in response to water deficit stress

To evaluate the response of alfalfa to water deficit （WD） stress, WD-induced candidates were investigated through a proteomic approach. Alfalfa seedlings were exposed to WD stress for 12 and 15 days respectively, followed by 3 days re-watering. Water deficit increased H202 content, lipid peroxidation, DPPH （1,1-diphenyl-2-picrylhydrazyl）-radical scavenging activity, and the free proline level in alfalfa roots. Root proteins were extracted and separated by two-dimentional polyacrylamide gel electrophoresis （2-DE）. A total of 49 WD-responsive proteins were identified in alfalfa roots; 25 proteins were reproducibly found to be up-regulated and 24 were down-regulated. Two proteins, namely cytosolic ascorbate peroxidase （APx2） and putative F-box protein were newly detected on 2-DE maps of WD-treated plants. We identified several proteins including agamous-like 65, albumin b-32, inward rectifying potassium channel, and auxin-independent growth promoter. The identified proteins are involved in a variety of cellular functions including calcium signaling, abacisic acid （ABA） biosynthesis, reactive oxygen species （ROS） regulation, transcription/translation, antioxidant/detoxification/stress defense, energy metabolism, signal transduction, and storage. These results indicate the potential candidates were responsible for adaptive response in alfalfa roots.

Regulation of gene expression in chickens by heat stress

High ambient temperatures are a critical challenge in the poultry industry which is a key producer of the animal-based food.To evaluate heat stress levels,various parameters have been used,including growth rates,blood metabolites,and hormones.The most recent advances have explored expression profiling of genes that may play vital roles under stress.A high ambient temperature adversely affects nutrient uptake and is known to modulate the expression of genes encoding for sodium-dependent glucose transporters,glucose transporters,excitatory amino acid transporters,and fatty acidbinding proteins which are responsible for the absorption of macronutrients in the intestine.Various defensive activities are stimulated to protect the cell of different tissues from the heat-generated stress,including expression of early stress response genes coding for heat shock protein(HSP),c-FOS like protein,brain-derived neurotrophic factor(BDNF),and neuronal nitric oxide synthase(nNOS);antioxidant enzyme genes such as superoxide dismutase(SOD),catalase(CAT),and nicotinamide adenine dinucleotide phosphate oxidase(NOX4);and immune-related genes such as cytokines and toll-like receptors(TLRs).The potential role of HSPs in protecting the cell from stress and their presence in several tissues make them suitable markers to be evaluated under heat stress.BDNF and c-FOS genes expressed in the hypothalamus help cells to adapt to an adverse environment.Heat causes damage to the cell by generating reactive oxygen species(ROS).The NOX4 gene is the inducer of ROS under heat stress,which is in turns controlled by antioxidant enzymes such as SOD and CAT.TLRs are responsible for protecting against pathogenic attacks arising from enhanced membrane permeability,and cytokines help in controlling the pathogen and maintaining homeostasis.Thus,the evaluation of nutrient transporters and defense mechanisms using the latest molecular biology tools has made it possible to shed light on the complex cellular mechanism of heat-stressed chickens.As the impacts of heat stress on the above-mentioned aspects are beyond the extent to which the reduced growth performance could be explained,heat stress has more specific effects on the regulation of these genes than previously thought.

Effect of cytokinins on in vitro multiplication of Sophora tonkinensis

Objective:To determine the effects of different cytokinins at various concentrations onin vitro shoot multiplication of an important medicinal plant.Methods:Nodal explants(1.5-2.0 cm)of Sophora tonkinensiswere used.Multiple shoots were induced from nodal explants cultured onthe Murashige and Skoog(MS)medium supplemented with 0.0,0.5,1.0,2.0,4.0,8.0,or 16.0μmol2-isopentyladenine(2iP),N6 benzyladenine,kinetin or thiadiazuron.Results:Among the fourinvestigated cytokinins,2iP showed the best response for shoot multiplication.Maximum shootinduction(75%)was achieved on the MS medium supplemented with 2.0μmol 2iP,with a meannumber of 5.0 shoots per explant.In comparison to other cytokinins tried,2iP showed the highestshoot elongation with a mean shoot length of 4.8 cm.Root initiation was observed within 15 dwithin the transfer of shoots onto the MS basal medium,and the rooting percentage was 100%with a mean number of 5.4 roots per shoot and root length of 6.2 cm over a period of 4 weeks.Thehealthy plants,hardened and transferred to a greenhouse for proper acclimatization,exhibited100%survival.Conclusions:It can be summarized that 2iP is the optimal plant growth regulatorforSophoramultiplication.

Effect of barley straw biochar application on greenhouse gas emissions from upland soil for Chinese cabbage cultivation in short-term laboratory experiments

Chinese cabbage was cultivated in upland soil with the addition of biochar in order to investigate the potential for reduction of greenhouse gas emissions. Barley straw biochar(BSB) was introduced in a Wagner pot(1/5000a) in amounts of 0(BSB0, control), 100(BSB100), 300(BSB300), and 500(BSB500) kg 10a^(-1). After the addition of BSB into the upland soil, carbon dioxide(CO_2) emission increased while methane(CH_4) and nitrous oxide(N_2O) emissions decreased. The highest CO2 flux was measured for the BSB500 sample,(84.6 g m^(-2)) followed by BSB300, BSB100, and BSB0 in decreasing order. Relative to those of control, the total CH_4 flux and N_2O flux for the BSB500 treatment were lower by 31.6% and 26.1%, respectively. The global warming potential(GWP) of the treatment without biochar was 281.4 g CO_2 m-2 and those for treatments with biochar were in the range from 194.1 to 224.9 g CO_2 m^(-2). Therefore, introducing BSB into upland soil to cultivate Chinese cabbages can reduce the global warming potential.

Colonization and degradation of senescent flowers of zucchini squash by Trichoderma harzianum YC459, a biocontrol agent of gray mold, Botrytis cinerea

In commercial greenhouses, senescent flower petals or flowers of vegetables such as tomato, strawberry, hot pepper and zucchini squash were blighted to be removed from fruits within five days after spraying of Trichoderma harzianum YC459 (TORY, JGreen Inc.), a biocontrol agent with good and consistent efficacy as chemical fungicides for the control of gray mold rot caused by B. cinerea. The mechanism for selective colonization of senescent floral tissues by T. harzianum YC459 was elucidated using fresh and senescent (4 days and 14 days after pollination, respectively) floral tissues of zucchini squash (Cucurbita moschata Duchesne) . The spores of T. harzianum YC459 were produced much more on water agar and liquid culture media supplemented with 5% dry powder of senescent floral tissues than with fresh tissues during 15 days incubation. Mycelial growth was also much better in the media with senescent tissues than with fresh tissues. Enzyme activities of carboxymethyl cellulase, amylase and polygalacturonase in the liquid media, which might be involved in the colonization and degradation of tissues by T. harzianum YC459 were compared. The activities of three enzymes were significantly higher in the media with senescent floral tissues than with fresh floral tissues reaching to the maximum during 9 to 12 days of incubation. Especially, the activities of carboxymethyl cellulase and polygalacturonase of T. harzianum YC459 were much higher than those of other Trichoderma species, T. asperellum, T. viride and T. koningii in the liquid media with senescent floral tissues. Based on the results, the selective colonization and degradation of senescent floral tissues, an important habitat for B. cinerea, may be another mechanism for the biocontrol of gray mold rot of vegetables by T. harzianum YC459.

Vegetation of mono-layer landfill cover made of coal bottom ash and soil by compost application

Monolayer barriers called evapotranspiration (ET) covers were developed as alternative final cover systems in waste landfills but high-quality soil remains a limiting factor in these cover systems. Coal bottom ash was evaluated to be a very good alternative to soil in previous tests and a combination of soil (65% wt.wt-1) and coal bottom ash (35% wt.wt-1) was evaluated to be the most feasible materials for ET cover systems. In our pot test, selected manure compost as soil amendment for the composite ET cover system, which was made of soil and bottom ash at ca. 40 Mg.ha-1 application level was very effective to promote vegetation growth of three plants;namely, garden cosmos (Cosmosbipinnatus), Chinese bushclover (Lespedezacuneata), and leafy lespedeza (Lespedeza cyrtobotrya). To evaluate the effect of compost application on plant growth in an ET vegetative cover system, two couples of lysimeters, packed with soil and a mixture of soil and bottom ash, were installed in a pilot landfill cover system in 2007. Manure composts were applied at the rates of 0 and ?40 Mg.ha-11before sowing the five plant species, i.e.indigo-bush (Amorphafruticosa), Japanese mugwort (Artemisia princeps, Arundinella hirta, Lespedezacuneata, and Lespedezacyrtobotrya). Unseeded native plant (green foxtail,Setaria viridis) was dominant in all treatments in the 1st year after installation while the growth of the sown plants significantly improved over the years. Total biomass productivity significantly increased with manure compost application, and more significantly increased in the composite ET cover made of soil and bottom ash treatment compared to the single soil ET cover, mainly due to more improved soil nutrient levels promoting vegetation growth and maintaining the vegetation system. The use of bottom ash as a mixing material in ET cover systems has a strong potential as an alternative to fine-grained soils, and manure compost addition can effectively enhance vegetative propagation in ET cover systems.

The processed C-terminus of AvrRps4 effector suppresses plant immunity via targeting multiple WRKYs

Pathogens generate and secrete effector proteins to the host plant cells during pathogenesis to promote virulence and colonization.If the plant carries resistance(R)proteins that recognize pathogen effectors,effector-triggered immunity(ETI)is activated,resulting in a robust immune response and hypersensitive response(HR).The bipartite effector AvrRps4 from Pseudomonas syringae pv.pisi has been well studied in terms of avirulence function.In planta,AvrRps4 is processed into two parts.The Cterminal fragment of AvrRps4(AvrRps4^(C))induces HR in turnip and is recognized by the paired resistance proteins AtRRS1/AtRPS4 in Arabidopsis.Here,we show that AvrRps4^(C)targets a group of Arabidopsis WRKY,including WRKY46,WRKY53,WRKY54,and WRKY70,to induce its virulence function.Indeed,AvrRps4^(C)suppresses the general binding and transcriptional activities of immune-positive regulator WRKY54 and WRKY54-mediated resistance.AvrRps4^(C)interferes with WRKY54's binding activity to target gene SARD1 in vitro,suggesting WRKY54 is sequestered from the SARD1 promoter by AvrRps4^(C).Through the interaction of Avr Rps4^(C)with four WRKYs,AvrRps4 enhances the formation of homo-/heterotypic complexes of four WRKYs and sequesters them in the cytoplasm,thus inhibiting their function in plant immunity.Together,our results provide a detailed virulence mechanism of AvrRps4 through its C-terminus.

Perfluorooctanoic acid(PFOA) and perfluorooctanesulfonic acid(PFOS) concentrations in the South Korean agricultural environment: A national survey

Research on the occurrence of perfluorochemicals （PFCs） such as perfluorooctanesulfonic acid （PFOS） and perfluorooctanoic acid （PFOA） in the agricultural environment is lacking, in spite of their potential risk via food chain transfer from aquatic and soil-plant systems to animals and/or humans. In the present study, for the first time, soil and water samples collected from 243 different agricultural sites adjacent to waste water treatment plants （WWTPs） belonging to 81 cities and 5 provinces with different levels of industrialization in South Korea were monitored for concentrations of PFOS and PFOA by use of solid phase extraction and liquid chromatography-tandem mass spectroscopy （LC-MS/MS）. Significant mean concentrations of PFOA （0.001-0.007 tJg L-1 water and 〈0.05-1.573 tJg kg-1 soil） and PFOS （0.001-0.22 tJg L-1 water and 〈0.05-0.741 pg kg-1 soil） were found in all samples. Concentrations of PFCs in soils were high, highlighting that soil is an important sink for PFCs in the agricultural environment. Samples from near WWTPs in Gyeongsang Province contained the highest concentrations of PFOS and PFOA, reflecting the concentration of heavy industry in the province. The concentrations of PFCs in agricultural water （most samples 〈0.05 pg L-~） and soils （most samples 〈1 IJg kg-~） from South Korea were less than acceptable guideline values, indicating that South Korea is not a hotspot of PFOS and PFOA contamination and that there is negligible risk to human and ecological health from these chemicals. However, further studies investigating the seasonal variation in PFOA, PFOS and other perfluorochemical concentrations in the agricultural environment are needed.

α1-COP modulates plasmodesmata function through sphingolipid enzyme regulation

Callose,aβ-1,3-glucan plant cell wall polymer,regulates symplasmic channel size at plasmodesmata(PD)and plays a crucial role in a variety of plant processes.However,elucidating the molecular mechanism of PD callose homeostasis is limited.We screened and identified an Arabidopsis mutant plant with excessive callose deposition at PD and found that the mutated gene wasα1-COP,a member of the coat protein I(COPI)coatomer complex.We report that loss of function ofα1-COP elevates the callose accumulation at PD by affecting subcellular protein localization of callose degradation enzyme Pd BG2.This process is linked to the functions of ERH1,an inositol phosphoryl ceramide synthase,and glucosylceramide synthase through physical interactions with theα1-COP protein.Additionally,the loss of function ofα1-COP alters the subcellular localization of ERH1 and GCS proteins,resulting in a reduction of Glc Cers and Glc HCers molecules,which are key sphingolipid(SL)species for lipid raft formation.Our findings suggest thatα1-COP protein,together with SL modifiers controlling lipid raft compositions,regulates the subcellular localization of GPI-anchored PDBG2 proteins,and hence the callose turnover at PD and symplasmic movement of biomolecules.Our findings provide the first key clue to link the COPI-mediated intracellular trafficking pathway to the callose-mediated intercellular signaling pathway through PD.

Acupuncture ameliorates atopic dermatitis by modulating gut barrier function in a gut microbiota-dependent manner in mice

Objective Atopic dermatitis(AD)is a chronic inflammatory skin disease that may be linked to changes in the gut microbiome.Acupuncture has been proven to be effective in reducing AD symptoms without serious adverse events,but its underlying mechanism is not completely understood.The purpose of this study was to investigate whether the potential effect of acupuncture on AD is gut microbiota-dependent.Methods AD-like skin lesions were induced by applying MC903 topically to the cheek of the mouse.Acupuncture was done at the Gok-Ji(LI11)acupoints.AD-like symptoms were assessed by lesion scores,scratching behavior,and histopathological changes;intestinal barrier function was measured by fecal output,serum lipopolysaccharide levels,histopathological changes,and mRNA expression of markers involved in intestinal permeability and inflammation.Gut microbiota was profiled using 16S rRNA gene sequencing from fecal samples.Results Acupuncture effectively improved chronic itch as well as the AD-like skin lesions with epidermal thickening,and also significantly altered gut microbiota structure as revealed byβ-diversity indices and analysis of similarities.These beneficial effects were eliminated by antibiotic depletion of gut microbiota,but were reproduced in gut microbiota-depleted mice that received a fecal microbiota transplant from acupuncture-treated mice.Interestingly,AD mice had intestinal barrier dysfunction as indicated by increased intestinal permeability,atrophy of the mucosal structure(reduced villus height and crypt depth),decreased expression of tight junctions and mucus synthesis genes,and increased expression of inflammatory mediators in the ileum.Acupuncture attenuated these abnormalities,which was gut microbiota-dependent.Conclusion Acupuncture ameliorates AD-like phenotypes in a gut microbiota-dependent manner and some of these positive benefits are explained by modulation of the intestinal barrier,providing new perspective for non-pharmacological strategies for modulating gut microbiota to prevent and treat AD.

Calcium and Calmodulin-Mediated Regulation of Gene Expression in Plants

Sessile plants have developed a very delicate system to sense diverse kinds of endogenous developmental cues and exogenous environmental stimuli by using a simple Ca^2＋ ion. Calmodulin （CAM） is the predominant Ca^2＋ sensor and plays a crucial role in decoding the Ca^2＋ signatures into proper cellular responses in various cellular compartments in eukaryotes. A growing body of evidence points to the importance of Ca^2＋ and CaM in the regulation of the transcriptional process during plant responses to endogenous and exogenous stimuli. Here, we review recent progress in the identification of transcriptional regulators modulated by Ca^2＋ and CaM and in the assessment of their functional significance during plant signal transduction in response to biotic and abiotic stresses and developmental cues.

Overexpression of Arabidopsis YUCCA6 in Potato Results in High-Auxin Developmental Phenotypes and Enhanced Resistance to Water Deficit

Indole-3-acetic acid （IAA）, a major plant auxin, is produced in both tryptophan-dependent and tryptophan-independent pathways. A major pathway in Arabidopsis thaliana generates IAA in two reactions from tryptophan. Step one converts tryptophan to indole-3-pyruvic acid （IPA） by tryptophan aminotransferases followed by a rate-limiting step converting IPA to IAA catalyzed by YUCCA proteins. We identified eight putative StYUC （Solanum tuberosum YUCCA） genes whose deduced amino acid sequences share 50%-70% identity with those of Arabidopsis YUCCA proteins. All include canonical, conserved YUCCA sequences： FATGY motif, FMO signature sequence, and FAD-binding and NADP-binding sequences. In addition, five genes were found with -50% amino acid sequence identity to Arabidopsis trypto-phan aminotransferases. Transgenic potato （Solanum tuberosum cv. Jowon） constitutively overexpressing Arabidopsis AtYUC6 displayed high-auxin phenotypes such as narrow downward-curled leaves, increased height, erect stature, and longevity. Transgenic potato plants overexpressing AtYUC6 showed enhanced drought tolerance based on reduced water loss. The phenotype was correlated with reduced levels of reactive oxygen species in leaves. The results suggest a func-tional YUCCA pathway of auxin biosynthesis in potato that may be exploited to alter plant responses to the environment.

Effect of Different Cultivation Systems on the Accumulation of Nutrients and Phytochemicals in Ligularia fischeri

A hydroponic cultivation system was established to improve the nutraceutical properties of Ligularia fischeri(Ledeb.) Turcz, during which nutrient uptake by the plant from nutrient solution was measured using inductive coupled plasma-atomic emission spectroscopy(ICP-AES).Based on the obtained data, the uptake of macro and micro elements per gram of fresh weight was calculated. The uptake of macro-elements of NH_4^+-N,NO_3^--N, K, S, P, Ca,and Mg were 1,62,4.27, 8.41,1.19, 2.59, 2,79, and 0.84 mg·g^(-1) FW and micro-elements of B, Fe, Mn, Mo, Cu, and Zn were 9.91,22.31,25.73,2.51,2.91, and 5.07 μg·g^(-1) FW. Moreover, the effects of cultivation systems on growth and phytochemical composition of L.fischeri were compared. The greatest biomass was observed in the hydroponic cultivation system with continuous circulation nutrient solution compared to natural soil and Tosilee media based culture systems. The recirculated hydroponic system significantly increased the total phenol contents of the leaf, petiole, and root extracts by 17.6%, 30.60%, and 20.9% more compared to the soil grown. The recirculated hydroponic system treatment significantly increased the total antioxidant capacity of root extracts by 55.9% more compared to the soil treatment. Based on the contents of elements, total phenolic and flavonoid, it was concluded that hydroponic cultivation system is the optimal method to enhance medicinal value.

The Obstacles and Potential Solution Clues of Prime Editing Applications in Tomato

Precision genome editing is highly desired for crop improvement.The recently emerged CRISPR/Cas technology offers great potential applications in precision plant genome engineering.A prime editing(PE)approach combining a reverse transcriptase(RT)with a Cas9 nickase and a“priming”extended guide RNA(gRNA)has shown a high frequency for precise genome modification in mammalian cells and several plant species.Nevertheless,the applications of the PE approach in dicot plants are still limited and inefficient.We designed and tested prime editors for precision editing of a synthetic sequence in a transient assay and for desirable alleles of 10 loci in tomato by stable transformation.Our data obtained by targeted deep sequencing also revealed only low PE efficiencies in both the tobacco and tomato systems.Further assessment of the activities of the PE components uncovered that the fusion of RT to Cas9 and the structure of PE gRNAs(pegRNAs)negatively affected the cleaving activity of the Cas9 nuclease.The self-complementarity between the primer binding sequences(PBSs)and spacer sequence might pose risks to the activity of the Cas9 complex.However,modifying the pegRNA sequences by shortening or introducing mismatches to the PBSs to reduce their melting temperatures did not enhance the PE efficiency at the MADS-box protein(SlMBP21),alcobaca(SlALC),and acetolactate synthase 1(SlALS1)loci.Our data show challenges of the PE approach in tomato,indicating that a further improvement of the PE system for successful applications is demanded,such as the use of improved expression systems for enriching active PE complexes.

Embryonic modulation through thermal manipulation and in ovo feeding to develop heat tolerance in chickens

Healthy chickens are necessary to meet the ever-increasing demand for poultry meat.Birds are subjected to numerous stressful conditions under commercial rearing systems,including variations in the envi-ronmental temperature.However,it is difficult to counter the effects of global warming on the livestock industry.High environmental temperature is a stressful condition that has detrimental effects on growth and production performance,resulting in decreased feed intake,retarded growth,compromised gut health,enhanced oxidative stress,and altered immune responses.Traditional approaches include nutritional modification and housing management to mitigate the harmful effects of hot environments.Currently,broiler chickens are more susceptible to heat stress(HS)than layer chickens because of their high muscle mass and metabolic rate.In this review,we explored the possibility of in ovo manipulation to combat HS in broiler chickens.Given their short lifespan from hatching to market age,embryonic life is thought to be one of the critical periods for achieving these objectives.Chicken embryos can be modulated through either temperature treatment or nourishment to improve thermal tolerance during the rearing phase.We first provided a brief overview of the harmful effects of HS on poultry.An in-depth evaluation was then presented for in ovo feeding and thermal manipulation as emerging strategies to combat the negative effects of HS.Finally,we evaluated a combination of the two methods using the available data.Taken together,these investigations suggest that embryonic manipulation has the po-tential to confer heat resistance in chickens.

HOS15 represses flowering by promoting GIGANTEA degradation in response to low temperature in Arabidopsis

Flowering is the primary stage of the plant developmental transition and is tightly regulated by environmental factors such as light and temperature.However,the mechanisms by which temperature signals are integrated into the photoperiodic flowering pathway are still poorly understood.Here,we demonstrate that HOS15,which is known as a GI transcriptional repressor in the photoperiodic flowering pathway,controls flowering time in response to low ambient temperature.At 16℃,the hos15 mutant exhibits an early flowering phenotype,and HOS15 acts upstream of photoperiodic flowering genes(GI,CO,and FT).GI protein abundance is increased in the hos15 mutant and is insensitive to the proteasome inhibitor MG132.Furthermore,the hos15 mutant has a defect in low ambient temperature-mediated GI degradation,and HOS15 interacts with COP1,an E3 ubiquitin ligase for GI degradation.Phenotypic analyses of the hos15 cop1 double mutant revealed that repression of flowering by HOS15 is dependent on COP1 at 16℃.However,the HOS15-COP1 interaction was attenuated at 16℃,and GI protein abundance was additively increased in the hos15 cop1 double mutant,indicating that HOS15 acts independently of COP1 in GI turnover at low ambient temperature.This study proposes that HOS15 controls GI abundance through multiple modes as an E3 ubiquitin ligase and transcriptional repressor to coordinate appropriate flowering time in response to ambient environmental conditions such as temperature and day length.

Sodium Stress in the Halophyte Thellungiella halophila and Transcriptional Changes in a thsos1-RNA Interference Line

The plasma membrane Na＋/H＋-antiporter salt overly sensitive1 （SOS1） from the halophytic Arabidopsis-relative Thellungiella halophila （ThSOS1） shows conserved sequence and domain structure with the orthologous genes from Arabidopsis thaliana and other plants. When expression of ThSOSt was reduced by RNA interference （RNAi）, pronounced characteristics of salt-sensitivity were observed. We were interested in monitoring altered transcriptional responses between Thellungiella wild type and thsost-4, a representative RNAi line with particular emphasis on root responses to salt stress at 350 mmol/L NaCI, a concentration that is only moderately stressful for mature wild type plants. Transcript profiling revealed several functional categories of genes that were differently affected in wild-type and RNAi plants. Down-regulation of SOS1 resulted in different gene expression even in the absence of stress. The pattern of gene induction in the RNAi plant under salt stress was similar to that of glycophytic Arabidopsis rather than that of wild type Thellungiella. The RNAi plants failed to down-regulate functions that are normally reduced in wild type Thellungiella upon stress and did not up-regulate functions that characterize the Thellungiella salt stress response. Metabolite changes observed in wild type Thellungiella after salt stress were less pronounced or absent in RNAi plants. Transcript and metabolite behavior suggested SOS1 functions including but also extending its established function as a sodium transporter. The down-regulation of ThSOS1 converted the halophyte Thellungiella into a salt-sensitive plant.

Thioredoxin Reductase Type C （NTRC） Orchestrates Enhanced Thermotolerance to Arabidopsis by Its Redox-Dependent Holdase Chaperone Function

Genevestigator analysis has indicated heat shock induction of transcripts for NADPH-thioredoxin reduc-tase, type C （NTRC） in the light. Here we show overexpression of NTRC in Arabidopsis （NTRC°E） resulting in enhanced tolerance to heat shock, whereas NTRC knockout mutant plants （ntrcl） exhibit a temperature sensitive phenotype. To investigate the underlying mechanism of this phenotype, we analyzed the protein＇s biochemical properties and protein structure. NTRC assembles into homopolymeric structures of varying complexity with functions as a disulfide reductase, a foldase chaperone, and as a holdase chaperone. The multiple functions of NTRC are closely correlated with protein structure.. Complexes of higher molecular weight （HMW） showed stronger activity as a holdase chaperone, while low molecular weight （LMW） species exhibited weaker holdase chaperone activity but stronger disulfide reductase and fol-dase chaperone activities. Heat shock converted LMW proteins into HMW complexes. Mutations of the two active site Cys residues of NTRC into Ser （C217/454S-NTRC） led to a complete inactivation of its disulfide reductase and foldase chaperone functions, but conferred only a slight decrease in its holdase chaperone function. The overexpression of the mutated C217/454S-NTRC provided Arabidopsis with a similar degree of thermotolerance compared with that of NTRC°E plants. However, after prolonged incubation under heat shock, NTRC°E plants tolerated the stress to a higher degree than C217/454S-NTRC°E plants. The results suggest that the heat shock-mediated holdase chaperone function of NTRC is responsible for the increased thermotolerance of Arabidopsis and the activity is significantly supported by NADPH.

CRISPR-Mediated Engineering across the Central Dogma in Plant Biology for Basic Research and Crop Improvement

The central dogma(CD)of molecular biology is the transfer of genetic information from DNA to RNA to protein.Major CD processes governing genetic flow include the cell cycle,DNA replication,chromosome packaging,epigenetic changes,transcription,posttranscriptional alterations,translation,and posttranslational modifications.The CD processes are tightly regulated in plants to maintain genetic integrity throughout the life cycle and to pass genetic materials to next generation.Engineering of various CD processes involved in gene regulation will accelerate crop improvement to feed the growing world population.CRISPR technology enables programmable editing of CD processes to alter DNA,RNA,or protein,which would have been impossible in the past.Here,an overview of recent advancements in CRISPR tool development and CRISPR-based CD modulations that expedite basic and applied plant research is provided.Furthermore,CRISPR applications in major thriving areas of research,such as gene discovery(allele mining and cryptic gene activation),introgression(de novo domestication and haploid induction),and application of desired traits beneficial to farmers or consumers(biotic/abiotic stress-resilient crops,plant cell factories,and delayed senescence),are described.Finally,the global regulatory policies,challenges,and prospects for CRISPR-mediated crop improvement are discussed.