Stomatal evolution and plant adaptation to future climate.

Global climate change is affecting plant photosynthesis and transpiration processes, as well as increasing weather extremes impacting socio-political and environmental events and decisions for decades to come. One major research challenge in plant biology and ecology is the interaction of photosynthesis with the environment. Stomata control plant gas exchange and their evolution was a crucial innovation that facilitated the earliest land plants to colonize terrestrial environments. Stomata couple homoiohydry, together with cuticles, intercellular gas space, with the endohydric water-conducting system, enabling plants to adapt and diversify across the planet. Plants control stomatal movement in response to environmental change through regulating guard cell turgor mediated by membrane transporters and signaling transduction. However, the origin, evolution, and active control of stomata remain controversial topics. We first review stomatal evolution and diversity, providing fossil and phylogenetic evidence of their origins. We summarize functional evolution of guard cell membrane transporters in the context of climate changes and environmental stresses. Our analyses show that the core signaling elements of stomatal movement are more ancient than stomata, while genes involved in stomatal development co-evolved de novo with the earliest stomata. These results suggest that novel stomatal development-specific genes were acquired during plant evolution, whereas genes regulating stomatal movement, especially cell signaling pathways, were inherited ancestrally and co-opted by dynamic functional differentiation. These two processes reflect the different adaptation strategies during land plant evolution.

Sesquiterpenoids from the roots of Lindera glauca and their cytotoxicity activities.

The chemical investigation of the roots of Lindera glauca guided the isolation and identification of three new sesquiterpenoids, namly glaucatotones J-L (1-3), and one known congener, (1ß,5ß)-1-hydroxyguaia-4(15),11(13)-dieno-12,5-lactone (4). The structures of new compounds were established based on comprehensive spectrographic methods, mainly including 1D & 2D NMR and HRESIMS analyses, and the absolute configurations were further confirmed by the comparison of experimental and calculated electronic circular dichroism (ECD). The cytotoxicity activities of isolates were evaluated, and the results showed that they have moderate cytotoxic activities.

Male vitellogenin regulates gametogenesis through a testis-enriched big protein in Chrysopa pallens.

In insects, vitellogenin (Vg) is generally viewed as a female-specific protein. Its primary function is to supply nutrition to developing embryos. Here, we reported Vg from the male adults of a natural predator, Chrysopa pallens. The male Vg was depleted by RNAi. Mating with Vg-deficient male downregulated female Vg expression, suppressed ovarian development and decreased reproductive output. Whole-organism transcriptome analysis after male Vg knockdown showed no differential expression of the known spermatogenesis-related regulators and seminal fluid protein genes, but a sharp downregulation of an unknown gene, which encodes a testis-enriched big protein (Vcsoo). Separate knockdown of male Vg and Vcsoo disturbed the assembly of spermatid cytoplasmic organelles in males and suppressed the expansion of ovary germarium in mated females. These results demonstrated that C. pallens male Vg signals through the downstream Vcsoo and regulates male and female reproduction.

Molecular evolution and interaction of 14-3-3 proteins with H+-ATPases in plant abiotic stresses.

Environmental stresses severely affect plant growth and crop productivity. Regulated by 14-3-3 proteins (14-3-3s), H+-ATPases (AHAs) are important proton pumps that can induce diverse secondary transport via channels and co-transporters for the abiotic stress response of plants. Many studies demonstrated the roles of 14-3-3s and AHAs in coordinating the processes of plant growth, phytohormone signaling, and stress responses. However, the molecular evolution of 14-3-3s and AHAs has not been summarized in parallel with evolutionary insights across multiple plant species. Here, we comprehensively review the roles of 14-3-3s and AHAs in cell signaling to enhance plant responses to diverse environmental stresses. We analyzed the molecular evolution of key proteins and functional domains that are associated with 14-3-3s and AHAs in plant growth and hormone signaling. The results revealed evolution, duplication, contraction, and expansion of 14-3-3s and AHAs in green plants. We also discussed the stress-specific expression of those 14-3-3and AHA genes in a eudicotyledon (Arabidopsis thaliana), a monocotyledon (Hordeum vulgare), and a moss (Physcomitrium patens) under abiotic stresses. We propose that 14-3-3s and AHAs respond to abiotic stresses through many important targets and signaling components of phytohormones, which could be promising to improve plant tolerance to single or multiple environmental stresses.

Allene oxide synthase 1 contributes to limiting grain arsenic accumulation and seedling detoxification in rice.

Arsenic (As) is a cancerogenic metalloid ubiquitously distributed in the environment, which can be easily accumulated in food crops like rice. Jasmonic acid (JA) and its derivatives play critical roles in plant growth and stress response. However, the role of endogenous JA in As accumulation and detoxification is still poorly understood. In this study, we found that JA biosynthesis enzymes Allene Oxide Synthases, OsAOS1 and OsAOS2, regulate As accumulation and As tolerance in rice. Evolutionary bioinformatic analysis indicated that AOS1 and AOS2 have evolved from streptophyte algae (e.g. the basal lineage Klebsormidium flaccidum) - sister clade of land plants. Compared to other two AOSs, OsAOS1 and OsAOS2 were highly expressed in all examined rice tissues and their transcripts were highly induced by As in root and shoot. Loss-of-function of OsAOS1 (osaos1-1) showed elevated As concentration in grains, which was likely attributed to the increased As translocation from root to shoot when the plants were subjected to arsenate [As(V)] but not arsenite [As (III)]. However, the mutation of OsAOS2 (osaos2-1) showed no such effect. Moreover, osaos1-1 and osaos2-1 increased the sensitivity of rice plants to both As(V) and As(III). Disrupted expression of genes involved in As accumulation and detoxification, such as OsPT4, OsNIP3;2, and OsOASTL-A1, was observed in both osaos1-1 and osaos2-1 mutant lines. In addition, a As(V)-induced significant decrease in Reactive Oxygen Species (ROS) production was observed in the root of osaos1-1 but not in osaos2-1. Taken together, our results indicate OsAOS1 modulates both As allocation and detoxification, which could be partially attributed to the altered gene expression profiling and ROS homeostasis in rice while OsAOS2 is important for As tolerance.

Molecular characterization of TNF-ß and IFN-γ in yellowfin seabream (Acanthopagrus latus, Hottuyn, 1782) and their immune responses to density stress during transport.

The inflammatory cytokines TNF-ß and IFN-γ are important mediators of the vertebrate inflammatory response and coordinators of the immune system in regard to NF-κB signalling pathways. In this study, the TNF-ß and IFN-γ genes of yellowfin seabream, Acanthopagrus latus were identified, and the multiple sequence alignments, evolutionary relationships and gene expressions of the two genes were also determined. AlTNF-ß contained a 762 bp open reading frame (ORF) encoding 253 amino acids, while AlIFN-γ contained a 582 bp ORF encoding 193 amino acids. An amino-acid sequence alignment analysis showed that these proteins have highly conserved transmembrane structural domains among teleosts. Moreover, AlTNF-ß has a close affinity with TNF-ß of yellowfin seabream while AlIFN-γ has a high evolutionary correlation with A. regius and Sparus aurata. In addition, the mRNAs of AlTNF-ß and AlIFN-γ are widely expressed in various tissues. AlTNF-ß is highly expressed in gill and intestinal tissues, and the mRNA levels of AlIFN-γ are higher in spleen, skin, and gill tissues than in other tissues. Under transportation density stress, the mRNA level of AlTNF-ß was significantly elevated in the intestine of the high-density group, while AlTNF-ß transcription in the gills did not vary significantly among the density groups. Furthermore, AlIFN-γ expression was increased in liver, intestinal, and gill tissues under high transportation density. The results of this study show that TNF-ß and IFN-γ expression in yellowfin seabream is greatly affected by density stress. The density of 125 per bag for 4-5 cm fry or 1200 per bag for 1-2 cm fry is most suitable for the transportation of live fish. These results might provide a reference for further studies on the immunomodulatory response process and auxiliary function of immune stress of TNF and IFN genes in fish under density stress.

Spatiotemporal Epidemiology of the Gonorrhea Epidemic in Relation to Neighborhood-level Structural Factors in an Eastern Province of China, 2016-2020.

Context: Gonorrhea, a highly communicable, sexually transmitted infection, remains a major public-health concern globally. In recent years, Zhejiang province, an eastern province, has had the highest incidence of gonorrhea in China. Objective: The study intended to identify the geographic distribution patterns and spaciotemporal clustering characteristics of the disease's incidence in Zhejiang between 2016 and 2020, to understand the spatial epidemiology of gonorrhea and to pinpoint the locations with relatively high risks of gonorrhea, the hotspots, which could be the key areas for disease prevention and control. Design: The research team performed a retrospective, spaciotemporal-clustering analysis of data about newly reported gonorrhea cases from January 2016 to December 2020 in Zhejiang province, using the China Information System for Disease Control and Prevention. Setting: The study took place at the Zhejiang Provincial Institute of Dermatology in Huzhou, China. Outcome Measures: The research team: (1) used the Geographic Information System software-ArcGIS 10.8 software to draw statistical maps; (2) conducted a spatial-pattern clustering analysis at the district or county level; (3) performed an autocorrelation analysis using Getis-Ord (Gi*) statistics to detect spatial patterns and the hotspots of gonorrhea incidence; and (4) used SaTScan9.7 to analyze the space-time clusters. Results: Zhejiang province reported 85 904 gonorrhea cases from 2016 to 2020, with a male to female ratio of 3.81:1. The average annual incidence rate of gonorrhea was 30.50 per 100 000 individuals in the population, ranging from 22.73 cases to 39.65 cases, and the annual incidence showed a significant downward trend over the five years (χ2 = 16.142, P < .001). The northern and central areas had a higher incidence than the southern area did. Autocorrelation analysis showed that the gonorrhea incidence had a significantly clustered distribution (Moran's I from 0.197 to 0.295, Z score from 4.749 to 6.909, P < .001). The high-high cluster areas were mainly in the urban districts of Hangzhou and some counties and districts of Jiaxing. The Gi* statistics further indicated that the hotspots of gonorrhea were mainly in Hangzhou, Jiaxing, and Huzhou. The Kuldorff's scan identified two clusters, mainly composed of 36 counties or districts in northern Zhejiang, such as Hangzhou and Jiaxing, and central Zhejiang, such as Jinhua and Shaoxing. Conclusions: The gonorrhea incidence rates in northern and central Zhejiang from 2016 to 2020 were higher than those in southern Zhejiang. An area of relatively higher risk for gonorrhea existed mainly in the urban districts of Hangzhou and some counties and districts of Jiaxing, Jinhua, and Shaoxing. In the future, the research team plans to focus on strengthening the prevention and control measures against gonorrhea in those areas.

Exploring lemology teaching with "internet plus" flipped classroom pedagogy.

BACKGROUND: To investigate the use of flipped classroom pedagogy based on "Internet plus" in teaching viral hepatitis in the lemology course during the COVID-19 epidemic. METHODS: This study included students from the clinical medicine general practitioner class at Nanjing Medical University's Kangda College, with the observation group consisting of 67 students from the 2020-2021 school year and the control group consisting of 70 students from the 2019-2020 school year. The observation group used "Internet plus" flipped classroom pedagogy, while the control group used conventional offline instruction. The theory course and case analysis ability scores from the two groups were compared and analyzed, and questionnaire surveys were administered to the observation group. RESULT: After the flipped classroom, the observation group had significantly higher theoretical test scores (38.62 ± 4.52) and case analysis ability scores (21.08 ± 3.58) than the control group (37.37 ± 2.43) (t = 2.024, P = 0.045) and (19.16 ± 1.15) (t = 4.254, P < 0.001), respectively. The questionnaire survey in the observation group revealed that the "Internet plus" flipped classroom pedagogy approach can help enhance students' enthusiasm to learn, clinical thinking ability, practical application ability, and learning efficiency, with satisfaction rates of 81.7%, 85.0%, 83.3%, and 78.8%, respectively; 89.4% of students expressed hope that whenever physical classes resumed, the offline courses could be combined with this pedagogy approach. CONCLUSION: The use of the "Internet plus" flipped classroom pedagogy technique for teaching viral hepatitis in a lemology course boosted students' theory learning ability as well as their case analysis ability. The majority of students were pleased with this type of instruction and hoped that whenever physical classes resumed, the offline courses may be integrated with the "Internet plus" flipped classroom pedagogical approach.

Hydrogen peroxide reduces root cadmium uptake but facilitates root-to-shoot cadmium translocation in rice through modulating cadmium transporters.

Cadmium (Cd) contamination in agricultural soils has become a serious worldwide environmental problem threatening crop production and human health. Hydrogen peroxide (H2O2) is a critical second messenger in plant response to Cd exposure. However, its role in Cd accumulation in various organs of plants and the mechanistic basis of this regulation remains to be elucidated. In this study, we used electrophysiological and molecular approaches to understand how H2O2 regulates Cd uptake and translocation in rice plants. Our results showed that the pretreatment of H2O2 significantly reduced Cd uptake by rice roots, which was associated with the downregulation of OsNRAMP1 and OsNRAMP5. On the other hand, H2O2 promoted the root-to-shoot translocation of Cd, which might be attributed to the upregulation of OsHMA2 critical for Cd2+ phloem loading and the downregulation of OsHMA3 involved in the vacuolar compartmentalization of Cd2+, leading to the increased Cd accumulation in rice shoots. Furthermore, such regulatory effects of H2O2 on Cd uptake and translocation were notably amplified by the elevated level of exogenous calcium (Ca). Collectively, our results suggest that H2O2 can inhibit Cd uptake but increase root to shoot translocation through modulating the transcriptional levels of genes encoding Cd transporters, furthermore, application of Ca can amplify this effect. These findings will broaden our understanding of the regulatory mechanisms of Cd transport in rice plants and provide theoretical foundation for breeding rice for low Cd accumulation.

Evaluation of Neisseria gonorrhoeae Isolates Susceptibility to Antibiotics in Zhejiang Province Since 2007.

Objective: This study aimed to assess the drug susceptibility of clinical isolates of Neisseria gonorrhoeae to spectinomycin, ceftriaxone and azithromycin. Moreover, the temporal trends in the minimum inhibitory concentration (MIC) of five antibiotics from Zhejiang, China, are also in the scope of this study. Methods: A total of 1710 gonococcal clinical strains were collected between 2007 and 2021 from health-care institutions in Zhejiang. The MICs of ceftriaxone, azithromycin, spectinomycin, penicillin and ciprofloxacin were assessed by agar dilution method on 1710 Neisseria gonorrhoeae isolates. Count data were expressed as strains and rates, and MICs distribution was elucidated using descriptive statistics. Results: The total resistance rates of gonococci to azithromycin, spectinomycin, penicillin and ciprofloxacin in this study were 19.3%, 0.3%, 75.4% and 99.7%, respectively. Conclusion: The in vitro results showed a high prevalence of resistance to ciprofloxacin and penicillin. Azithromycin resistance rate has exceeded 5%, suggested a high prevalence of resistance. Ceftriaxone and spectinomycin are suggested based on this study for the treatment of Neisseria gonorrhoeae in Zhejiang.

Physiological and transcriptomic evidence of antioxidative system and ion transport in chromium detoxification in germinating seedlings of soybean.

Chromium (Cr) toxicity impairs the productivity of crops and is a major threat to food security worldwide. However, the effect of Cr toxicity on seed germination and transcriptome of germinating seedlings of soybean crop has not been fully explored. In this study, two Cr-tolerant lines (J82, S125) and two Cr-sensitive ones (LD1, RL) were screened out of twenty-one soybean (Glycine max L.) genotypes based on seed germination rate, seed germinative energy, seed germination index, and growth of germinating seedlings under 50 mg L-1 Cr treatment. We found that Cr stress inhibits the growth of soybean seed germinating seedlings due to the Cr-induced overaccumulation of reactive oxygen species (ROS). Significantly different levels of element contents, antioxidant enzyme activities, malondialdehyde content were observed in the four soybean genotypes with contrasting Cr tolerance. Further, a total of 13,777 differentially expressed genes (DEGs) were identified in transcriptomic sequencing and 1298 DEGs in six gene modules were found highly correlated with the physiological traits by weighted correlation network analysis (WGCNA) analysis. The DEGs encoding antioxidant enzymes, transcription factors, and ion transporters are proposed to confer Cr tolerance in soybean germinating seedlings by reducing the uptake and translocation of Cr, decreasing the level of ROS, and keeping the osmotic balance in soybean germinating seedings. In conclusion, our study provided a molecular regulation network on soybean Cr tolerance at seed germinating stage and identified candidate genes for molecular breeding of low Cr accumulation soybean cultivars.

Calcium and L-glutamate present the opposite role in managing arsenic in barley.

Arsenic contamination in agricultural soils has posed tremendous threat to sustainable crop production and human health via food chain. Calcium and Glutamate have been well-documented in metal(loid)s detoxification, but it is poorly understood how they regulate arsenic-induced toxicity to plants. In this study, the effect of glutamate and calcium at high concentration on arsenic toxicity and accumulation in barley seedling was accessed in terms of plant growth, photosynthetic efficacy, arsenic uptake, translocation and accumulation, antioxidant defense, nutrient uptake and the expression of As transporters. Our results have demonstrated that calcium could effectively ameliorate arsenic toxicity to barley seedlings, which is mainly attributed to its beneficial effect on increasing nutrient uptake, reducing the aboveground arsenic accumulation and enhancing antioxidative defense capacity. However, it is unexpected that glutamate considerably exacerbated the arsenic toxicity to barley seedlings. More importantly, for the first time, glutamate was observed to tremendously facilitate the root-to-shoot translocation of arsenic by 41.8- to 60.8-fold, leading to 90% of the total amount of As accumulating in barley shoots. The reason of this phenomenon can be well explained by the glutamate-triggered enormous upregulation of genes involved in arsenic uptake (HvPHT1;1, HvPHR2 and HvNIP3;2), reduction (HvHAC1;1), translocation (HvABCC7, HvNIP1;1 and HvNIP3;3) and intracellular sequestration (HvABCC1). These findings suggest that calcium and glutamate function as the opposite player in managing arsenic, with calcium being an effective alleviator of arsenic stress to ensure the safe production of crops; while glutamate being a highly efficient phytoextraction agent for phytoremediation of arsenate-contaminated soils.

Molecular evidence for adaptive evolution of drought tolerance in wild cereals.

The considerable drought tolerance of wild cereal crop progenitors has diminished during domestication in the pursuit of higher productivity. Regaining this trait in cereal crops is essential for global food security but requires novel genetic insight. Here, we assessed the molecular evidence for natural variation of drought tolerance in wild barley (Hordeum spontaneum), wild emmer wheat (Triticum dicoccoides), and Brachypodium species collected from dry and moist habitats at Evolution Canyon, Israel (ECI). We report that prevailing moist vs dry conditions have differentially shaped the stomatal and photosynthetic traits of these wild cereals in their respective habitats. We present the genomic and transcriptomic evidence accounting for differences, including co-expression gene modules, correlated with physiological traits, and selective sweeps, driven by the xeric site conditions on the African Slope (AS) at ECI. Co-expression gene module 'circadian rhythm' was linked to significant drought-induced delay in flowering time in Brachypodium stacei genotypes. African Slope-specific differentially expressed genes are important in barley drought tolerance, verified by silencing Disease-Related Nonspecific Lipid Transfer 1 (DRN1), Nonphotochemical Quenching 4 (NPQ4), and Brassinosteroid-Responsive Ring-H1 (BRH1). Our results provide new genetic information for the breeding of resilient wheat and barley in a changing global climate with increasingly frequent drought events.

Molecular Evolution of Plant 14-3-3 Proteins and Function of Hv14-3-3A in Stomatal Regulation and Drought Tolerance.

Drought significantly affects stomatal regulation, leading to the reduced growth and productivity of plants. Plant 14-3-3 proteins were reported to participate in drought response by regulating the activities of a wide array of target proteins. However, the molecular evolution, expression pattern and physiological functions of 14-3-3s under drought stress remain unclear. In this study, a comparative genomic analysis and the tissue-specific expression of 14-3-3s revealed the highly conserved and early evolution of 14-3-3s in green plants and duplication and expansion of the 14-3-3s family members in angiosperms. Using barley (Hordeum vulgare) for the functional characterization of 14-3-3 proteins, the transcripts of five members out of six Hv14-3-3s were highly induced by drought in the drought-tolerant line, XZ141. Suppression of the expression of Hv14-3-3A through barley stripe mosaic virus-virus induced gene silencing resulted in significantly increased drought sensitivity and stomatal density as well as significantly reduced net CO2 assimilation (A) and stomatal conductance (gs) in barley. Moreover, we showed the functional interactions between Hv14-3-3s and key proteins in drought and stomatal responses in plants-such as Open Stomata 1 (HvOST1), Slow Anion Channel 1 (HvSLAC1), three Heat Shock Proteins (HvHSP90-1/2/5) and Dehydration-Responsive Element-Binding 3 (HvDREB3). Taken together, we propose that 14-3-3s are highly evolutionarily conserved proteins and that Hv14-3-3s represent a group of the core regulatory components for the rapid stomatal response to drought in barley. This study will provide important evolutionary and molecular evidence for future applications of 14-3-3 proteins in breeding drought-tolerant crops in a changing global climate.

Molecular Regulation and Evolution of Cytokinin Signaling in Plant Abiotic Stresses.

The sustainable production of crops faces increasing challenges from global climate change and human activities, which leads to increasing instances of many abiotic stressors to plants. Among the abiotic stressors, drought, salinity and excessive levels of toxic metals cause reductions in global agricultural productivity and serious health risks for humans. Cytokinins (CKs) are key phytohormones functioning in both normal development and stress responses in plants. Here, we summarize the molecular mechanisms on the biosynthesis, metabolism, transport and signaling transduction pathways of CKs. CKs act as negative regulators of both root system architecture plasticity and root sodium exclusion in response to salt stress. The functions of CKs in mineral-toxicity tolerance and their detoxification in plants are reviewed. Comparative genomic analyses were performed to trace the origin, evolution and diversification of the critical regulatory networks linking CK signaling and abiotic stress. We found that the production of CKs and their derivatives, pathways of signal transduction and drought-response root growth regulation are evolutionarily conserved in land plants. In addition, the mechanisms of CK-mediated sodium exclusion under salt stress are suggested for further investigations. In summary, we propose that the manipulation of CK levels and their signaling pathways is important for plant abiotic stress and is, therefore, a potential strategy for meeting the increasing demand for global food production under changing climatic conditions.

Molecular Regulation and Evolution of Redox Homeostasis in Photosynthetic Machinery.

The recent advances in plant biology have significantly improved our understanding of reactive oxygen species (ROS) as signaling molecules in the redox regulation of complex cellular processes. In plants, free radicals and non-radicals are prevalent intra- and inter-cellular ROS, catalyzing complex metabolic processes such as photosynthesis. Photosynthesis homeostasis is maintained by thiol-based systems and antioxidative enzymes, which belong to some of the evolutionarily conserved protein families. The molecular and biological functions of redox regulation in photosynthesis are usually to balance the electron transport chain, photosystem II, photosystem I, mesophyll and bundle sheath signaling, and photo-protection regulating plant growth and productivity. Here, we review the recent progress of ROS signaling in photosynthesis. We present a comprehensive comparative bioinformatic analysis of redox regulation in evolutionary distinct photosynthetic cells. Gene expression, phylogenies, sequence alignments, and 3D protein structures in representative algal and plant species revealed conserved key features including functional domains catalyzing oxidation and reduction reactions. We then discuss the antioxidant-related ROS signaling and important pathways for achieving homeostasis of photosynthesis. Finally, we highlight the importance of plant responses to stress cues and genetic manipulation of disturbed redox status for balanced and enhanced photosynthetic efficiency and plant productivity.

HvGST4 enhances tolerance to multiple abiotic stresses in barley: Evidence from integrated meta-analysis to functional verification.

Extreme weather events have become more frequent, increasing crop yield fluctuations in many regions and thus the risk to global food security. Breeding crop cultivars with improved tolerance to a combination of abiotic stresses is an effective solution to counter the adverse impact of climate change. The ever-increasing genomic data and analytical tools provide unprecedented opportunities to mine genes with tolerance to multiple abiotic stresses through bioinformatics analysis. We undertook an integrated meta-analysis using 260 transcriptome data of barley related to drought, salt, heat, cold, and waterlogging stresses. A total of 223 shared differentially expressed genes (DEGs) were identified in response to five abiotic stresses, and significantly enriched in 'glutathione metabolism' and 'monoterpenoid biosynthesis' pathways. Using weighted gene co-expression network analysis (WGCNA), we further identified 15 hub genes (e.g., MYB, WRKY, NADH, and GST4) and selected the GST4 gene for functional validation. HvGST4 overexpression in Arabidopsis thaliana enhanced the tolerance to multiple abiotic stresses, likely through increasing the content of glutathione to scavenge reactive oxygen species and alleviate cell membrane peroxidation. Furthermore, we showed that virus-induced gene silencing (VIGS) of HvGST4 in barley leaves exacerbated cell membrane peroxidation under five abiotic stresses, reducing tolerance to multiple abiotic stress. Our study provides a new solution for identifying genes with tolerance to multiple abiotic stresses based on meta-analysis, which could contribute to breeding new varieties adapted genetically to adverse environmental conditions.

Exogenous calcium oxide nanoparticles alleviate cadmium toxicity by reducing Cd uptake and enhancing antioxidative capacity in barley seedlings.

Heavy metal contamination is a serious environmental issue that jeopardize global food production and safety, while cadmium (Cd) is a most widely distributed heavy metal in the earth's crust and highly toxic to organisms. The available strategies of fighting against heavy metal contamination are not commonly used due to their ineffectiveness and time- or cost-consuming. Recently, nanotechnology-based ameliorative strategies have emerged as a potential alternative to physic-chemical techniques. In the current study, we used two barley genotypes, LJZ (Cd sensitive) and Pu-9 (Cd tolerant), to study the effects of exogenous calcium oxide nanoparticles (CaO NPs) in alleviating Cd stress. Cd exposure to barley plants led to significant reduction in morph-physiological, nutrient contents, photosynthetic rate, and large accumulation of Cd in plant tissues. However, CaO NPs application significantly increased plant biomass, activities of anti-oxidative enzymes (i.e., ascorbate peroxidase, catalase, superoxide dismutase, and glutathione reductase) and the content of non-enzymatic antioxidants (ascorbate and glutathione) accompanied by great reduction of malondialdehyde (MDA) and hydrogen peroxide contents under Cd stress. Furthermore, CaO NPs increased the expression levels of genes associated with anti-oxidative enzymes. The alleviation of Cd stress by CaO NPs is more obvious in Pu-9 than LJZ. It may be suggested that CaO NPs can be used as a potential chemical to alleviate Cd uptake and toxicity of the crops planted in the Cd-contaminated soil.