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Abstract Nitrogen is widely used in various laboratories as a suppressive gas and a protective gas. Once nitrogen leaks and accumulates in a such confined space, it will bring serious threats to the experimental staff. Especially in underground tunnels or underground laboratories where there is no natural wind, the threat is more intense. In this work, the ventilation design factors and potential leakage factors are identified by taking the leakage and diffusion of a large liquid nitrogen tank in China Jinping Underground Laboratory (CJPL) as an example. Based on computational fluid dynamics (CFD) research, the effects of fresh air inlet position, fresh air velocity, exhaust outlet position, leakage hole position, leakage hole size, and leaked nitrogen mass flow rate on nitrogen diffusion behavior in specific environments are discussed in detail from the perspectives of nitrogen concentration field and nitrogen diffusion characteristics. The influencing factors are parameterized, and the Latin hypercube sampling (LHS) is used to uniformly sample within the specified range of each factor to obtain samples that can represent the whole sample space. The nitrogen concentration is measured by numerical value, and the nitrogen diffusion characteristics are measured by category. The GA-BP-ANN numerical regression and classification regression models for nitrogen concentration prediction and nitrogen diffusion characteristics prediction are established. By using various rating indicators to evaluate the performance of the trained model, it is found that models have high accuracy and recognition rate, indicating that it is effective in predicting and determining the concentration value and diffusion characteristics of nitrogen according to ventilation factors and potential leakage factors. The research results can provide a theoretical reference for the parametric design of the ventilation system.

The transition of light fixture from fluorescent light to light-emitting diodes (LEDs) in growth chambers prompts a reevaluation of current practices in plant biotechnology. Agrobacterium-mediated transformation is crucial for genetic engineering and genome editing in soybean (Glycine max). The critical co-cultivation step of soybean transformation occurs under light condition. Current protocols for co-cultivation in soybean transformation lack a standard for light intensity. In the present study, the objective is to investigate the effect of light intensity during co-cultivation on soybean transformation efficiency. Five light intensities were implemented during five days of co-cultivation: 50, 100, 150, 190 μmol∙m-2∙s-1 of white LEDs in addition to 100 μmol∙m-2∙s-1 of fluorescent light. After co-cultivation, all the explants underwent shoot induction and elongation with selection pressure, rooting and acclimation under uniform condition. The experiment was conducted with two selectable markers, hppdPf-4Pa and bar, separately, investigating whether the potential light effects vary due to the marker-associated pathways. The positive PCR analysis of rooted in vitro plants suggested successful transformation events achieved under both selectable markers across all light treatments ranging from 2.4% to 6.9%. Increasing LED light intensity during co-cultivation resulted in different transformation efficiencies between the two selectable markers. Results indicated that increasing the light intensity during co-cultivation led to a linear increase in transformation efficiency when shoot regeneration was under 4-Hydroxyphenylpyruvate dioxygenase (HPPD) inhibitor selection. No difference in transformation efficiency was detected among the treatments under glufosinate selection. Furthermore, when selection occurred with HPPD inhibitor, variation of transformation efficiency was also observed between fluorescent light and white LED at 100 μmol∙m-2∙s-1. The results highlight the significance and potential applications of investigating the impact of light on transformation efficiency.

Phosphate (Pi) stress is an important environmental factor that limits plant growth and development. Of various posttranslational modifications (PTMs), protein phosphorylation and succinylation are the two most important PTMs that regulate multiple biological processes in response to Pi stress. However, these PTMs have been investigated individually but their interactions with proteins in response to Pi stress remain poorly understood. In this study, to elucidate the underlying mechanisms of protein phosphorylation and succinylation in response to Pi stress, we performed a global analysis of the barley root phosphorylome and succinylome in Pi starvation and recovery stages, respectively. A total of 3,634 and 884 unique phosphorylated and succinylated proteins, respectively, corresponding to 11,538 and 2,840 phospho- and succinyl-sites, were identified; of these, 275 proteins were found to be simultaneously phosphorylated and succinylated. Gene Set Enrichment Analysis was performed with a Kyoto Encyclopedia of Genes and Genomes pathway database revealing pathways that significantly enriched in the phosphorylome and succinylome. Such pathways, were dynamically regulated by Pi starvation and recovery treatments, and could be partitioned into distinct metabolic processes. In particular, phosphorylated proteins related to purine, the mitogen-activated protein kinase (MAPK) signaling pathway, pyrimidine, and ATP-binding cassette (ABC) transporters were upregulated in both Pi deprivation and recovery stages. Succinylated proteins, significantly upregulated by both Pi starvation and recovery, were enriched in nitrogen metabolism and phenylpropanoid biosynthesis. Meanwhile, succinylated proteins that were significantly downregulated by both Pi starvation and recovery were enriched in lysine degradation and tryptophan metabolism. This highlighted the importance of these metabolic pathways in regulating Pi homeostasis. Furthermore, protein–protein interaction network analyses showed that the response of central metabolic pathways to Pi starvation and recovery was significantly modulated by phosphorylation or succinylation, both individually and together. In addition, we discovered relevant proteins involved in MAPK signaling and phenylpropanoid biosynthetic pathways existing in interactions between phosphorylated and succinylated proteins in response to Pi recovery. The current study not only provides a comprehensive analysis of phosphorylated and succinylated proteins in plant responses to Pi starvation and recovery, but also reveals detailed interactions between phosphorylated and succinylated proteins in barley roots.

Melatonin (N-acetyl-5-methoxytryptamine) plays an important role in plant growth and development, and in the response to various abiotic stresses. However, its role in the responses of barley to low phosphorus (LP) stress remains largely unknown. In the present study, we investigated the root phenotypes and metabolic patterns of LP-tolerant (GN121) and LP-sensitive (GN42) barley genotypes under normal P, LP, and LP with exogenous melatonin (30 μM) conditions. We found that melatonin improved barley tolerance to LP mainly by increasing root length. Untargeted metabolomic analysis showed that metabolites such as carboxylic acids and derivatives, fatty acyls, organooxygen compounds, benzene and substituted derivatives were involved in the LP stress response of barley roots, while melatonin mainly regulated indoles and derivatives, organooxygen compounds, and glycerophospholipids to alleviate LP stress. Interestingly, exogenous melatonin showed different metabolic patterns in different genotypes of barley in response to LP stress. In GN42, exogenous melatonin mainly promotes hormone-mediated root growth and increases antioxidant capacity to cope with LP damage, while in GN121, it mainly promotes the P remobilization to supplement phosphate in roots. Our study revealed the protective mechanisms of exogenous MT in alleviating LP stress of different genotypes of barley, which can be used in the production of phosphorus-deficient crops.

Halogeton glomeratus is a succulent annual herbaceous halophyte belonging to the Chenopodiaceae family, has attracted wide attention as a promising candidate for phytoremediation and as an oilseed crop and noodle-improver. More importantly, H. glomeratus has important medicinal value in traditional Chinese medicine. However, there are few comprehensive studies on the nutrients, particularly secondary metabolites. Here, we adopted untargeted metabolomics to compare the differences in metabolites of different tissues (root, stem, leaf, and seed) and identify the compounds related to pharmacological effects and response to abiotic stress in H. glomeratus. A total of 2,152 metabolites were identified, and the metabolic profiles of root, stem, leaf, and seed samples were clearly separated. More than 50% of the metabolites showed significant differences among root, stem, leaf, and seed. The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis of differential metabolites suggested an extensive alteration in the metabolome among the different organs. Furthermore, the identified metabolites related to pharmacological effects and response to abiotic stress included flavones, flavonols, flavandiols, glucosinolates, isoquinolines, pyridines, indoles, amino acids, lipids, carbohydrates, and ATP-binding cassette transporters. These metabolites have application in treating human cardiovascular diseases, cancers, diabetes, and heart disease, induce sleeping and have nutritive value. In plants, they are related to osmotic adjustment, alleviating cell damage, adjusting membrane lipid action and avoiding toxins. To the best of our knowledge, this is the first metabolomics-based report to overview the metabolite compounds in H. glomeratus and provide a reference for future development and utilization of H. glomeratus.

Phosphorus (P) deficiency is a major threat to the crop production, and for understanding the response mechanism of plant roots, P stress may facilitate the development of crops with increased tolerance. Phosphorylation plays a critical role in the regulation of proteins for plant responses to biotic and abiotic stress; however, its functions in P starvation/resupply are largely unknown for barley (Hordeum vulgare) growth. Here, we performed a global review of phosphorylation in barley roots treated by P starvation/resupply. We identified 7,710 phosphorylation sites on 3,373 proteins, of which 76 types of conserved motifs were extracted from 10,428 phosphorylated peptides. Most phosphorylated proteins were located in the nucleus (36%) and chloroplast (32%). Compared with the control, 186 and 131 phosphorylated proteins under P starvation condition and 156 and 111 phosphorylated proteins under P resupply condition showed significant differences at 6 and 48 h, respectively. These proteins mainly participated in carbohydrate metabolism, phytohormones, signal transduction, cell wall stress, and oxidases stress. Moreover, the pathways of the ribosome, RNA binding, protein transport, and metal binding were significantly enriched under P starvation, and only two pathways of ribosome and RNA binding were greatly enriched under Pi resupply according to the protein–protein interaction analysis. The results suggested that the phosphorylation proteins might play important roles in the metabolic processes of barley roots in response to Pi deficiency/resupply. The data not only provide unique access to phosphorylation reprogramming of plant roots under deficiency/resupply but also demonstrate the close cooperation between these phosphorylation proteins and key metabolic functions.

Barley (Hordeum vulgare L.)—a major cereal crop—has low Pi demand, which is a distinct advantage for studying the tolerance mechanisms of phosphorus deficiency. We surveyed dynamic protein succinylation events in barley roots in response to and recovery from Pi starvation by firstly evaluating the impact of Pi starvation in a Pi-tolerant (GN121) and Pi-sensitive (GN42) barley genotype exposed to long-term low Pi (40 d) followed by a high-Pi recovery for 10 d. An integrated proteomics approach involving label-free, immune-affinity enrichment, and high-resolution LC-MS/MS spectrometric analysis was then used to quantify succinylome and proteome in GN121 roots under short-term Pi starvation (6, 48 h) and Pi recovery (6, 48 h). We identified 2,840 succinylation sites (Ksuc) across 884 proteins; of which, 11 representative Ksuc motifs had the preferred amino acid residue (lysine). Furthermore, there were 81 differentially abundant succinylated proteins (DFASPs) from 119 succinylated sites, 83 DFASPs from 110 succinylated sites, 93 DFASPs from 139 succinylated sites, and 91 DFASPs from 123 succinylated sites during Pi starvation for 6 and 48 h and during Pi recovery for 6 and 48 h, respectively. Pi starvation enriched ribosome pathways, glycolysis, and RNA degradation. Pi recovery enriched the TCA cycle, glycolysis, and oxidative phosphorylation. Importantly, many of the DFASPs identified during Pi starvation were significantly overexpressed during Pi recovery. These results suggest that barley roots can regulate specific Ksuc site changes in response to Pi stress as well as specific metabolic processes. Resolving the metabolic pathways of succinylated protein regulation characteristics will improve phosphate acquisition and utilization efficiency in crops.

In this paper, an improved multi-source thermal model is used to analyze the transverse momentum spectra in pp collisions at high energies, ranging from sNN = 62.4 GeV to 7 TeV. Via a detailed comparison between the model results and experimental data at RHIC and LHC energies, the thermodynamic properties of particle production are decided. It is shown that the excitation factors of emission sources depend linearly on lnsNN in the framework. Based on the variation regularity of the source excitation factors, transverse momentum spectra are predicted in pp collisions at higher energies; potential future pp colliders operating at sNN = 33 and 100 TeV.

A lack of phosphorus (P) in plants can severely constrain growth and development. Barley, one of the earliest domesticated crops, is extensively planted in poor soil around the world. To date, the molecular mechanisms of enduring low phosphorus, at the transcriptional level, in barley are still unclear. In the present study, two different barley genotypes (GN121 and GN42)—with contrasting phosphorus efficiency—were used to reveal adaptations to low phosphorus stress, at three time points, at the morphological, physiological, biochemical, and transcriptome level. GN121 growth was less affected by phosphorus starvation and recovery than that of GN42. The biomass and inorganic phosphorus concentration of GN121 and GN42 declined under the low phosphorus-induced stress and increased after recovery with normal phosphorus. However, the range of these parameters was higher in GN42 than in GN121. Subsequently, a more complete genome annotation was obtained by correcting with the data sequenced on Illumina HiSeq X 10 and PacBio RSII SMRT platform. A total of 6,182 and 5,270 differentially expressed genes (DEGs) were identified in GN121 and GN42, respectively. The majority of these DEGs were involved in phosphorus metabolism such as phospholipid degradation, hydrolysis of phosphoric enzymes, sucrose synthesis, phosphorylation/dephosphorylation and post-transcriptional regulation; expression of these genes was significantly different between GN121 and GN42. Specifically, six and seven DEGs were annotated as phosphorus transporters in roots and leaves, respectively. Furthermore, a putative model was constructed relying on key metabolic pathways related to phosphorus to illustrate the higher phosphorus efficiency of GN121 compared to GN42 under low phosphorus conditions. Results from this study provide a multi-transcriptome database and candidate genes for further study on phosphorus use efficiency (PUE).