Neurotoxic lesions of the anterior claustrum influence cued fear memory in rats.

Background: The claustrum (CLA), a subcortical area between the insular cortex and striatum, innervates almost all cortical regions of the mammalian brain. There is growing evidence that CLA participates in many brain functions, including memory, cognition, and stress response. It is proposed that dysfunction or malfunction of the CLA might be the pathology of some brain diseases, including stress-induced depression and anxiety. However, the role of the CLA in fear memory and anxiety disorders remains largely understudied. Methods: We evaluated the influences of neurotoxic lesions of the CLA using auditory-cued fear memory and anxiety-like behaviors in rats. Results: We found that lesions of anterior CLA (aCLA) but not posterior CLA (pCLA) before fear conditioning attenuated fear retrieval, facilitated extinction, and reduced freezing levels during the extinction retention test. Post-learning lesions of aCLA but not pCLA facilitated fear extinction and attenuated freezing behavior during the extinction retention test. Lesions of aCLA or pCLA did not affect anxiety-like behaviors evaluated by the open field test and elevated plus-maze test. Conclusion: These data suggested that aCLA but not pCLA was involved in fear memory and extinction. Future studies are needed to further investigate the anatomical and functional connections of aCLA subareas that are involved in fear conditioning, which will deepen our understanding of CLA functions.

Activation of trace amine-associated receptor 1 ameliorates PTSD-like symptoms.

Trace amine-associated receptor 1 (TAAR1) negatively modulates monoaminergic transmission in the mammalian brain and participates in many psychiatric disorders. Preclinical evidence indicate that selective TAAR1 agonists have anxiolytic effects and anti-stress properties. Post-traumatic stress disorder (PTSD) is an anxiety disorder triggered by experiencing or witnessing traumatic stressors. However, it remains unknown whether TAAR1 is involved in PTSD. Here, we investigated the role of TAAR1 in two PTSD animal models, including single prolonged stress (SPS)-induced impairment of fear extinction and stress-enhanced fear learning (SEFL). SPS decreased TAAR1 mRNA levels in the prefrontal cortex and ventral tegmental area. Acute treatment of the TAAR1 partial agonist RO5263397 attenuated SPS-induced anxiety-like behavior evaluated by the elevated-plus maze test. Compared to non-stressed animals, rats that experienced SPS showed higher freezing levels in the extinction retention test, indicating an impairment of fear extinction retention after SPS exposure. Acute and chronic treatment of RO5263397 ameliorated SPS-induced impairment of fear extinction retention. In the SEFL model, compared to the No-shock group, rats that experienced severe foot shock before fear conditioning showed higher freezing levels during the tests, indicating enhanced fear learning after stress exposure. Chronic treatment of RO5263397 partially attenuated the SEFL. Moreover, chronic treatment with the selective TAAR1 full agonist RO5166017 completely prevented the SEFL. Taken together, these data showed that pharmacological activation of TAAR1 could ameliorate PTSD-like symptoms. The present study thus provides the first evidence that TAAR1 might participate in the development of PTSD, and TAAR1 agonists could be potential pharmacological treatments for this disorder.

Integrative gene duplication and genome-wide analysis as an approach to facilitate wheat reverse genetics: An example in the TaCIPK family.

INTRODUCTION: Reverse genetic studies conducted in the plant with a complex or polyploidy genome enriched with large gene families (like wheat) often meet challenges in identifying the key candidate genes related to important traits and prioritizing the genes for functional experiments. OBJECTIVE: To overcome the above-mentioned challenges of reverse genetics, this work aims to establish an efficient multi-species strategy for genome-wide gene identification and prioritization of the key candidate genes. METHODS: We established the integrative gene duplication and genome-wide analysis (iGG analysis) as a strategy for pinpointing key candidate genes deserving functional research. The iGG captures the evolution, and the expansion/contraction of large gene families across phylogeny-related species and integrates spatial-temporal expression information for gene function inference. Transgenic approaches were also employed to functional validation. RESULTS: As a proof-of-concept for the iGG analysis, we took the wheat calcineurin B-like protein-interacting protein kinases (CIPKs) family as an example. We identified CIPKs from seven monocot species, established the orthologous relationship of CIPKs between rice and wheat, and characterized Triticeae-specific CIPK duplicates (e.g., CIPK4 and CIPK17). Integrated with our analysis of CBLs and CBL-CIPK interaction, we revealed that divergent expressions of TaCBLs and TaCIPKs could play an important role in keeping the stoichiometric balance of CBL-CIPK. Furthermore, we validated the function of TaCIPK17-A2 in the regulation of drought tolerance by using transgenic approaches. Overexpression of TaCIPK17 enhanced antioxidant capacity and improved drought tolerance in wheat. CONCLUSION: The iGG analysis leverages evolutionary and comparative genomics of crops with large genomes to rapidly highlight the duplicated genes potentially associated with speciation, domestication and/or particular traits that deserve reverse-genetic functional studies. Through the identification of Triticeae-specific TaCIPK17 duplicates and functional validation, we demonstrated the effectiveness of the iGG analysis and provided a new target gene for improving drought tolerance in wheat.

Comparison of antibody persistency through one year between one-dose and two-dose regimens of Ad5-nCoV vaccine for COVID-19.

This post-hoc analysis compared the receptor-binding domain (RBD)-specific and pseudovirus neutralizing antibodies against the wild-type SARS-CoV-2 strain elicited by one or two doses (56-d interval) of Ad5-nCoV vaccine regimen (NCT04341389 and NCT04566770). Both trials had low-dose and high-dose groups. Propensity score matching was used to adjust the baseline between one- and two-dose regimens. To predict the decrease in antibody titers 1 y after vaccination, half-lives of RBD-binding antibodies and pseudovirus neutralizing antibodies were computed. We obtained 34 and 29 pairs of participants in the low- and high-dose groups based on the propensity score matching. The two-dose regimen of Ad5-nCoV increased the peaking level of neutralizing antibodies compared to the one-dose regimen at day 28, but the responses of the neutralizing antibodies were not consistent with those of the RBD antibodies. Half-lives of the RBD-binding antibodies in the two-dose Ad5-nCoV regimen (202-209 days) were longer than those in the one-dose regimen (136-137 d); half-lives of the pseudovirus neutralizing antibody in the one-dose Ad5-nCoV regimen (177 d) were longer than those in the two-dose regimen (116-131 d). The predicted positive rates of RBD-binding antibodies in the one-dose regimen (34.1%-38.3%) would be lower than those in the two-dose Ad5-nCoV regimen (67.0%-84.0%), while the positive rates of pseudovirus neutralizing antibodies in the one-dose regimen (65.4%-66.7%) would be higher than those in the two-dose regimen (48.3%-58.0%). The two-dose Ad5-nCoV regimen with a 56-d interval had no effect on the persistence of neutralizing antibodies but slowed decay trend of RBD-binding antibodies.

Environmental Impact Assessment for the Use of an Orally Aerosolized Adenovirus Type-5 Vector-Based COVID-19 Vaccine in Randomized Clinical Trials.

BACKGROUND: An orally aerosolized adenovirus type-5 vector-based coronavirus disease 2019 (COVID-19) vaccine (Ad5-nCoV) has recently been authorized for boosting immunization in China. Our study aims to assess the environmental impact of the use of aerosolized Ad5-nCoV. METHODS: We collected air samples from rooms, swabs from the desks on which the vaccine nebulizer was set, mask samples from participants, and blood samples of nurses who administered the inoculation in the clinical trials. The viral load of adenovirus type-5 vector in the samples and the antibody levels against the wild-type severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) strain in serum were detected. RESULTS: Only one (4.00%) air sample collected before initiation of vaccination was positive and most air samples collected during and after vaccination were positive (97.96%, 100%, respectively). All nurses in trial A showed at least 4-fold increase of the neutralizing antibody against SARS-CoV-2 after initiation of the study. In trial B, the proportion of positive mask samples was 72.97% at 30 minutes after vaccination, 8.11% at day 1, and 0% at days 3, 5, and 7. CONCLUSIONS: Vaccination with the orally aerosolized Ad5-nCoV could result in some spillage of the vaccine vector viral particles in the environment and cause human exposure. Clinical Trials Registration. NCT04840992 and NCT05303584.

Antibody persistence and safety after heterologous boosting with orally aerosolised Ad5-nCoV in individuals primed with two-dose CoronaVac previously: 12-month analyses of a randomized controlled trial.

Antibody persistence and safety up to 12 months of heterologous orally administered adenovirus type-5 vector-based COVID-19 vaccine (Ad5-nCoV) in individuals who were primed with two-dose inactivated SARS-CoV-2 vaccine (CoronaVac) previously, has not been reported yet. This randomized, open-label, single-centre trial included Chinese adults who have received two-dose CoronaVac randomized to low-dose or high-dose aerosolised Ad5-nCoV group, or CoronaVac group. In this report, we mainly evaluated the geometric mean titres (GMTs) of neutralizing antibodies (NAbs) against live wild-type SARS-CoV-2 virus and omicron BA.4/5 pseudovirus at 12 months after the booster dose and the incidence of serious adverse events (SAEs) till month 12. Of 419 participants, all were included in the safety analysis and 120 (28.64%) were included in the immunogenicity analysis. Serum NAb GMT against live wild-type SARS-CoV-2 was 204.36 (95% CI 152.91, 273.14) in the low-dose group and 171.38 (95% CI 121.27, 242.19) in the high-dose group at month 12, significantly higher than the GMT in the CoronaVac group (8.00 [95% CI 4.22, 15.17], p < 0.0001). Serum NAb GMT against omicron BA.4/5 pseudovirus was 40.97 (95% CI 30.15, 55.67) in the low-dose group and 35.08 (95% CI 26.31, 46.77) in the high-dose group at month 12, whereas the GMT in the CoronaVac group was below the lower limit of detection. No vaccine-related SAEs were observed. Orally administered aerosolised Ad5-nCoV following two-dose CoronaVac priming has a good safety profile and is persistently more immunogenic than three-dose CoronaVac within 12 months after the booster dose.Trial registration: ClinicalTrials.gov identifier: NCT05043259..

Impact of vaccination on kinetics of neutralizing antibodies against SARS-CoV-2 by serum live neutralization test based on a prospective cohort.

How much the vaccine contributes to the induction and development of neutralizing antibodies (NAbs) of breakthrough cases relative to those unvaccinated-infected cases is not fully understood. We conducted a prospective cohort study and collected serum samples from 576 individuals who were diagnosed with SARS-CoV-2 Delta strain infection, including 245 breakthrough cases and 331 unvaccinated-infected cases. NAbs were analysed by live virus microneutralization test and transformation of NAb titre. NAbs titres against SARS-CoV-2 ancestral and Delta variant in breakthrough cases were 7.8-fold and 4.0-fold higher than in unvaccinated-infected cases, respectively. NAbs titres in breakthrough cases peaked at the second week after onset/infection. However, the NAbs titres in the unvaccinated-infected cases reached their highest levels during the third week. Compared to those with higher levels of NAbs, those with lower levels of NAbs had no difference in viral clearance duration time (P>0.05), did exhibit higher viral load at the beginning of infection/maximum viral load of infection. NAb levels were statistically higher in the moderate cases than in the mild cases (P<0.0001). Notably, in breakthrough cases, NAb levels were highest longer than 4 months after vaccination (Delta strain: 53,118.2 U/mL), and lowest in breakthrough cases shorter than 1 month (Delta strain: 7551.2 U/mL). Cross-neutralization against the ancestral strain and the current circulating isolate (Omicron BA.5) was significantly lower than against the Delta variant in both breakthrough cases and unvaccinated-infected cases. Our study demonstrated that vaccination could induce immune responses more rapidly and greater which could be effective in controlling SARS-CoV-2.

Functional characterization of BdCIPK31 in plant response to potassium deficiency stress.

Potassium (K) is one of the most essential macronutrients for plants. However, K+ is deficient in some cultivated soils. Hence, improving the efficiencies of K+ uptake and utilization is important for agricultural production. Ca2+ signaling pathways play an important role in regulation of K+ acquisition. In the present study, BdCIPK31, a Calcineurin B-like protein interacting protein kinase (CIPK) from Brachypodium distachyon, was found to be a potential positive regulator in plant response to low K+ stress. The expression of BdCIPK31 was responsive to K+-deficiency, and overexpression of BdCIPK31 conferred enhanced tolerance to low K+ stress in transgenic tobaccos. Furthermore, BdCIPK31 was demonstrated to promote the K+ uptake in root, and could maintain normal root growth under K+-deficiency conditions. Additionally, BdCIPK31 functioned in scavenging excess reactive oxygen species (ROS), reduced oxidative damage caused by low K+ stress. Collectively, our study indicates that BdCIPK31 is a vital regulatory component in K+-acquisition system in plants.

A novel conductive nanocomposite-based biosensor for ultrasensitive detection of microRNA-21 in serum, using methylene blue as mediator.

MicroRNA-21 (miRNA-21) is a common biomarker with high expression in breast tumors. Therefore, sensitive detection of miRNA-21 is of great significance for clinical breast tumor diagnosis. A TH/rGO/CMK-3/AuNPs nanocomposite is composed of thionine (TH), reduced graphene oxide (rGO), ordered mesoporous carbon (CMK-3), and gold nanoparticles (AuNPs), which help to increase the specific surface area of a glassy carbon electrode (GCE) and to amplify the DPV signal. Meanwhile, methylene blue (MB) was combined with the capture probe guanine and absorbed by the composite material to mediate the differential pulse voltammetry (DPV) of the obtained miRNA biosensor. The current response decreased with increasing miRNA-21 concentration under optimal conditions. The biosensor responds to miRNA-21 in the 0.1fM-1 pM concentration range, and the detection limit (LOD) was 0.046 fM. Moreover, human serum samples were effectively detected utilizing the miRNA-21 biosensor with satisfactory results.

Safety and immunogenicity of heterologous boost immunization with an adenovirus type-5-vectored and protein-subunit-based COVID-19 vaccine (Convidecia/ZF2001): A randomized, observer-blinded, placebo-controlled trial.

BACKGROUND: Heterologous boost vaccination has been proposed as an option to elicit stronger and broader, or longer-lasting immunity. We assessed the safety and immunogenicity of heterologous immunization with a recombinant adenovirus type-5-vectored Coronavirus Disease 2019 (COVID-19) vaccine (Convidecia, hereafter referred to as CV) and a protein-subunit-based COVID-19 vaccine (ZF2001, hereafter referred to as ZF). METHODS AND FINDINGS: We conducted a randomized, observer-blinded, placebo-controlled trial, in which healthy adults aged 18 years or older, who have received 1 dose of Convidecia, with no history of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) infection, were recruited in Jiangsu, China. Sixty participants were randomly assigned (2:1) to receive either 1 dose of ZF2001 or placebo control (trivalent inactivated influenza vaccine (TIV)) administered at 28 days after priming, and received the third injection with ZF2001 at 5 months, referred to as CV/ZF/ZF (D0-D28-M5) and CV/ZF (D0-M5) regimen, respectively. Sixty participants were randomly assigned (2:1) to receive either 1 dose of ZF2001 or TIV administered at 56 days after priming, and received the third injection with ZF2001 at 6 months, referred to as CV/ZF/ZF (D0-D56-M6) and CV/ZF (D0-M6) regimen, respectively. Participants and investigators were masked to the vaccine received but not to the boosting interval. Primary endpoints were the geometric mean titer (GMT) of neutralizing antibodies against wild-type SARS-CoV-2 and 7-day solicited adverse reactions. The primary analysis was done in the intention-to-treat population. Between April 7, 2021 and May 6, 2021, 120 eligible participants were randomly assigned to receive ZF2001/ZF2001 (n = 40) or TIV/ZF2001 (n = 20) 28 days and 5 months post priming, and receive ZF2001/ZF2001 (n = 40) or TIV/ZF2001 (n = 20) 56 days and 6 months post priming. Of them, 7 participants did not receive the third injection with ZF2001. A total of 26 participants (21.7%) reported solicited adverse reactions within 7 days post boost vaccinations, and all the reported adverse reactions were mild, with 13 (32.5%) in CV/ZF/ZF (D0-D28-M5) regimen, 7 (35.0%) in CV/ZF (D0- M5) regimen, 4 (10.0%) in CV/ZF/ZF (D0-D56-M6) regimen, and 2 (10.0%) in CV/ZF (D0-M6) regimen, respectively. At 14 days post first boost, GMTs of neutralizing antibodies in recipients receiving ZF2001 at 28 days and 56 days post priming were 18.7 (95% CI 13.7 to 25.5) and 25.9 (17.0 to 39.3), respectively, with geometric mean ratios of 2.0 (1.2 to 3.5) and 3.4 (1.8 to 6.4) compared to TIV. GMTs at 14 days after second boost of neutralizing antibodies increased to 107.2 (73.7 to 155.8) in CV/ZF/ZF (D0-D28-M5) regimen and 141.2 (83.4 to 238.8) in CV/ZF/ZF (D0-D56-M6) regimen. Two-dose schedules of CV/ZF (D0-M5) and CV/ZF (D0-M6) induced antibody levels comparable with that elicited by 3-dose schedules, with GMTs of 90.5 (45.6, 179.8) and 94.1 (44.0, 200.9), respectively. Study limitations include the absence of vaccine effectiveness in a real-world setting and current lack of immune persistence data. CONCLUSIONS: Heterologous boosting with ZF2001 following primary vaccination with Convidecia is more immunogenic than a single dose of Convidecia and is not associated with safety concerns. These results support flexibility in cooperating viral vectored and recombinant protein vaccines. TRIAL REGISTRATION: Study on Heterologous Prime-boost of Recombinant COVID-19 Vaccine (Ad5 Vector) and RBD-based Protein Subunit Vaccine; ClinicalTrial.gov NCT04833101.

Electrochemical aptasensor based on electrodeposited poly(3,4-ethylenedioxythiophene)-graphene oxide coupled with Au@Pt nanocrystals for the detection of 17ß-estradiol.

An electrochemical aptasensor is reported for the sensitive and specific monitoring of 17ß-estradiol (E2) based on the modification of electrodeposited poly(3,4-ethylenedioxythiophene) (PEDOT)-graphene oxide (GO) coupled with Au@Pt nanocrystals (Au@Pt). With excellent conductivity, chemical stability and active sites, the PEDOT-GO nanocomposite film was firstly in situ polymerized on the glassy carbon electrode by cyclic voltammetry. Subsequently, one-step synthesized Au@Pt were decorated on the conductive polymer, providing a platform for immobilizing the aptamer and enhancing the detecting sensitivity. With the addition of E2, since the interfacial electron transfer process was retarded by the E2-aptamer complex, the differential pulse voltammetry signal decreased gradually. Under optimum conditions, the calibration curve of E2 exhibited a linear range between 0.1 pM and 1 nM, with a low detection limit (S/N = 3) of 0.08 pM. The developed aptasensor showed admiring selectivity, stability, and reproducibility. It was tested in human serum, lake water and tap water samples after low-cost and simple pretreatment. Consequently, the developed platform could provide a new design thought for ultrasensitive detection of E2 in clinical and environmental samples.

TaASR1-D confers abiotic stress resistance by affecting ROS accumulation and ABA signalling in transgenic wheat.

Cultivating new crop cultivars with multiple abiotic stress tolerances is important for crop production. The abscisic acid-stress-ripening (ASR) protein has been shown to confer abiotic stress tolerance in plants. However, the mechanisms of ASR function under stress condition remain largely unclear. In this study, we characterized all ASR family members in common wheat and constitutively overexpressed TaASR1-D in a commercial hexaploid wheat cultivar Zhengmai 9023. The transgenic wheat plants exhibited increased tolerance to multiple abiotic stresses and increased grain yields under salt stress condition. Overexpression of TaASR1-D conferred enhanced antioxidant capacity and ABA sensitivity in transgenic wheat plants. Further, RNA in situ hybridization results showed that TaASR1-D had higher expression levels in the vascular tissues of leaves and the parenchyma cells around the vascular tissues of roots and stems. Yeast one-hybrid and electrophoretic mobility shift assays revealed that TaASR1-D could directly bind the specific cis-elements in the promoters of TaNCED1 and TaGPx1-D. In conclusion, our findings suggest that TaASR1-D can be used to breed new wheat cultivars with increased multiple abiotic stress tolerances, and TaASR1-D enhances abiotic stress tolerances by reinforcing antioxidant capacity and ABA signalling.

Genome-wide identification and expression profiling of trihelix gene family under abiotic stresses in wheat.

BACKGROUND: The trihelix gene family is a plant-specific transcription factor family that plays important roles in plant growth, development, and responses to abiotic stresses. However, to date, no systemic characterization of the trihelix genes has yet been conducted in wheat and its close relatives. RESULTS: We identified a total of 94 trihelix genes in wheat, as well as 22 trihelix genes in Triticum urartu, 29 in Aegilops tauschii, and 31 in Brachypodium distachyon. We analyzed the chromosomal locations and orthology relations of the identified trihelix genes, and no trihelix gene was found to be located on chromosome 7A, 7B, or 7D of wheat, thereby reflecting the uneven distributions of wheat trihelix genes. Phylogenetic analysis indicated that the 186 identified trihelix proteins in wheat, rice, B. distachyon, and Arabidopsis were clustered into five major clades. The trihelix genes belonging to the same clades usually shared similar motif compositions and exon/intron structural patterns. Five pairs of tandem duplication genes and three pairs of segmental duplication genes were identified in the wheat trihelix gene family, thereby validating the supposition that more intrachromosomal gene duplication events occur in the genome of wheat than in that of other grass species. The tissue-specific expression and differential expression profiling of the identified genes under cold and drought stresses were analyzed by using RNA-seq data. qRT-PCR was also used to confirm the expression profiles of ten selected wheat trihelix genes under multiple abiotic stresses, and we found that these genes mainly responded to salt and cold stresses. CONCLUSIONS: In this study, we identified trihelix genes in wheat and its close relatives and found that gene duplication events are the main driving force for trihelix gene evolution in wheat. Our expression profiling analysis demonstrated that wheat trihelix genes responded to multiple abiotic stresses, especially salt and cold stresses. The results of our study built a basis for further investigation of the functions of wheat trihelix genes and provided candidate genes for stress-resistant wheat breeding programs.

Identification of Potential Genes Responsible for Thermotolerance in Wheat under High Temperature Stress.

Wheat, a major worldwide staple food crop, is relatively sensitive to a changing environment, including high temperature. The comprehensive mechanism of heat stress response at the molecular level and exploitation of candidate tolerant genes are far from enough. Using transcriptome data, we analyzed the gene expression profiles of wheat under heat stress. A total of 1705 and 17 commonly differential expressed genes (DEGs) were identified in wheat grain and flag leaf, respectively, through transcriptome analysis. Gene Ontology (GO) and pathway enrichment were also applied to illustrate the functions and metabolic pathways of DEGs involved in thermotolerance of wheat grain and flag leaf. Furthermore, our data suggest that there may be a more complex molecular mechanism or tighter regulatory network in flag leaf than in grain under heat stress over time, as less commonly DEGs, more discrete expression profiles of genes (principle component analysis) and less similar pathway response were observed in flag leaf. In addition, we found that transcriptional regulation of zeatin, brassinosteroid and flavonoid biosynthesis pathways may play an important role in wheat's heat tolerance. The expression changes of some genes were validated using quantitative real-time polymerase chain reaction and three potential genes involved in the flavonoid biosynthesis process were identified.

Expression of TaGF14b, a 14-3-3 adaptor protein gene from wheat, enhances drought and salt tolerance in transgenic tobacco.

MAIN CONCLUSION: TaGF14b enhances tolerance to multiple stresses through ABA signaling pathway by altering physiological and biochemical processes, including ROS-scavenging system, stomatal closure, compatible osmolytes, and stress-related gene expressions in tobaccos. The 14-3-3 proteins are involved in plant growth, development, and in responding to abiotic stresses. However, the precise functions of 14-3-3s in responding to drought and salt stresses remained unclear, especially in wheat. In this study, a 14-3-3 gene from wheat, designated TaGF14b, was cloned and characterized. TaGF14b was upregulated by polyethylene glycol 6000, sodium chloride, hydrogen peroxide, and abscisic acid (ABA) treatments. Ectopic expression of TaGF14b in tobacco conferred enhanced tolerance to drought and salt stresses. Transgenic tobaccos had longer root, better growth status, and higher relative water content, survival rate, photosynthetic rate, and water use efficiency than control plants under drought and salt stresses. The contribution of TaGF14b to drought and salt tolerance relies on the regulations of ABA biosynthesis and ABA signaling, as well as stomatal closure and stress-related gene expressions. Moreover, TaGF14b expression could significantly enhance the reactive oxygen species (ROS) scavenging system to ameliorate oxidative damage to cells. In addition, TaGF14b increased tolerance to osmotic stress evoked by drought and salinity through modifying water conservation and compatible osmolytes in plants. In conclusion, TaGF14b enhances tolerance to multiple abiotic stresses through the ABA signaling pathway in transgenic tobaccos by altering physiological and biochemical processes.

TaSnRK2.9, a Sucrose Non-fermenting 1-Related Protein Kinase Gene, Positively Regulates Plant Response to Drought and Salt Stress in Transgenic Tobacco.

Sucrose non-fermenting 1-related protein kinase 2 (SnRK2) family members play crucial roles in plant abiotic stress response. However, the precise mechanism underlying the function of SnRKs has not been thoroughly elucidated in plants. In this research, a novel SnRK2 gene, TaSnRK2.9 was cloned and characterized from common wheat. The expression of TaSnRK2.9 was upregulated by polyethylene glycol (PEG), NaCl, H2O2, abscisic acid (ABA), methyl jasmonate (MeJA), and ethrel treatments. TaSnRK2.9 was mainly expressed in wheat young root, stamen, pistil, and lemma. Overexpressing TaSnRK2.9 in transgenic tobacco enhanced plants' tolerance to drought and salt stresses both in young seedlings and mature plants with improved survival rate, seed germination rate, and root length. Physiological analyses suggest that TaSnRK2.9 improved antioxidant system such as superoxide dismutase (SOD), catalase (CAT), peroxidase (POD), and glutathione (GSH) to reduce the H2O2 content under drought or salt stress. Additionally, TaSnRK2.9 overexpression plants had elevated ABA content, implying that the function of TaSnRK2.9 may be ABA-dependent. Moreover, TaSnRK2.9 increased the expression of some ROS-related, ABA-related, and stress-response genes under osmotic or salt treatment. TaSnRK2.9 could interact with NtABF2 in yeast two-hybrid assay, and increased the expression of NtABF2 under mannitol or NaCl treatment in transgenic tobacco plants. In conclusion, overexpression of TaSnRK2.9 in tobacco conferred plants tolerance to drought and salt stresses through enhanced ROS scavenging ability, ABA-dependent signal transduction, and specific SnRK-ABF interaction.

BdCIPK31, a Calcineurin B-Like Protein-Interacting Protein Kinase, Regulates Plant Response to Drought and Salt Stress.

Calcineurin B-like protein interacting protein kinases (CIPKs) are vital elements in plant abiotic stress signaling pathways. However, the functional mechanism of CIPKs has not been understood clearly, especially in Brachypodium distachyon, a new monocot model plant. In this study, BdCIPK31, a CIPK gene from B. distachyon was characterized. BdCIPK31 was downregulated by polyethylene glycol, NaCl, H2O2, and abscisic acid (ABA) treatments. Transgenic tobacco plants overexpressing BdCIPK31 presented improved drought and salt tolerance, and displayed hypersensitive response to exogenous ABA. Further investigations revealed that BdCIPK31 functioned positively in ABA-mediated stomatal closure, and transgenic tobacco exhibited reduced water loss under dehydration conditions compared with the controls. BdCIPK31 also affected Na+/K+ homeostasis and root K+ loss, which contributed to maintain intracellular ion homeostasis under salt conditions. Moreover, the reactive oxygen species scavenging system and osmolyte accumulation were enhanced by BdCIPK31 overexpression, which were conducive for alleviating oxidative and osmotic damages. Additionally, overexpression of BdCIPK31 could elevate several stress-associated gene expressions under stress conditions. In conclusion, BdCIPK31 functions positively to drought and salt stress through ABA signaling pathway. Overexpressing BdCIPK31 functions in stomatal closure, ion homeostasis, ROS scavenging, osmolyte biosynthesis, and transcriptional regulation of stress-related genes.

Identification of the ASR gene family from Brachypodium distachyon and functional characterization of BdASR1 in response to drought stress.

KEY MESSAGE: A genome-wide investigation identified five B. distachyon ASR genes. BdASR1 may be a transcription factor that confers drought resistance by activating antioxidant systems involving ROS-scavenging enzymes and non-enzymatic antioxidants. Abscisic acid-, stress-, and ripening-induced (ASR) proteins belong to a family of plant-specific, small, and hydrophilic proteins with important roles in responses to abiotic stresses. Although several ASR genes involved in drought tolerance have been characterized in various plant species, the mechanisms regulating ASR activities are still uncharacterized. Additionally, no research on Brachypodium distachyon ASR proteins have been completed. In this study, five B. distachyon BdASR genes were identified through genome-wide analyses. Phylogenetic analyses revealed that BdASR genes originated from tandem and whole genome duplications. Expression analyses revealed the BdASR genes responded to various abiotic stresses, including cold, drought, and salinity, as well as signaling molecules such as abscisic acid, ethylene, and H2O2. BdASR1, which localizes to the nucleus and is transcriptionally active, was functionally characterized. BdASR1 overexpression considerably enhanced drought tolerance in transgenic tobacco plants, which was accompanied by increased superoxide dismutase, catalase, and peroxidase activities, as well as an increased abundance of antioxidants such as ascorbate, tocopherols, and glutathione. BdASR1 may function as a transcription factor that provides drought stress resistance by inducing the production of reactive oxygen species-scavenging enzymes and non-enzymatic antioxidants.

TaCIPK29, a CBL-interacting protein kinase gene from wheat, confers salt stress tolerance in transgenic tobacco.

Calcineurin B-like protein-interacting protein kinases (CIPKs) have been found to be responsive to abiotic stress. However, their precise functions and the related molecular mechanisms in abiotic stress tolerance are not completely understood, especially in wheat. In the present study, TaCIPK29 was identified as a new member of CIPK gene family in wheat. TaCIPK29 transcript increased after NaCl, cold, methyl viologen (MV), abscisic acid (ABA) and ethylene treatments. Over-expression of TaCIPK29 in tobacco resulted in increased salt tolerance, which was demonstrated by higher germination rates, longer root lengths and better growth status of transgenic tobacco plants compared to controls when both were treated with salt stress. Physiological measurements indicated that transgenic tobacco seedlings retained high K(+)/Na(+) ratios and Ca(2+) content by up-regulating some transporter genes expression and also possessed lower H2O2 levels and reduced membrane injury by increasing the expression and activities of catalase (CAT) and peroxidase (POD) under salt stress. Moreover, transgenic lines conferred tolerance to oxidative stress by increasing the activity and expression of CAT. Finally, TaCIPK29 was located throughout cells and it preferentially interacted with TaCBL2, TaCBL3, NtCBL2, NtCBL3 and NtCAT1. Taken together, our results showed that TaCIPK29 functions as a positive factor under salt stress and is involved in regulating cations and reactive oxygen species (ROS) homeostasis.

Ectopic expression of wheat TaCIPK14, encoding a calcineurin B-like protein-interacting protein kinase, confers salinity and cold tolerance in tobacco.

Calcineurin B-like protein-interacting protein kinases (CIPKs) are components of Ca(2+) signaling in responses to abiotic stresses. In this work, the full-length cDNA of a novel CIPK gene (TaCIPK14) was isolated from wheat and was found to have significant sequence similarity to OsCIPK14/15. Subcellular localization assay revealed the presence of TaCIPK14 throughout the cell. qRT-PCR analysis showed that TaCIPK14 was upregulated under cold conditions or when treated with salt, PEG or exogenous stresses related signaling molecules including ABA, ethylene and H2 O2 . Transgenic tobaccos overexpressing TaCIPK14 exhibited higher contents of chlorophyll and sugar, higher catalase activity, while decreased amounts of H2 O2 and malondialdehyde, and lesser ion leakage under cold and salt stresses. In addition, overexpression also increased seed germination rate, root elongation and decreased Na(+) content in the transgenic lines under salt stress. Higher expression of stress-related genes was observed in lines overexpressing TaCIPK14 compared to controls under stress conditions. In summary, these results suggested that TaCIPK14 is an abiotic stress-responsive gene in plants.