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To provide molecular‐scale insight into the structural evolution from tris(methylamino)borane to boron nitride (BN) fiber during the chemical thermal‐treating process, polymeric green fiber is cured in hot synthetic air at 300°C and then treats to 400, 600, 800, and 1000°C in ammonia. The chemical composition and structure of the volatile compounds and residual products are analyzed during the pyrolysis process for the polymeric green fiber. It is demonstrated that oxygen can be used to cure polymeric green fiber rapidly under the premise of ensuring a final fiber content of less than 1 wt% carbon and 2 wt% oxygen while maintaining the fiber tensile strength at 1000°C. The molecular structure evolution during the pyrolysis process for polymeric green fiber after oxygen curing is determined. Specifically, in hot synthetic air, introducing oxygen and releasing methylamine generates a B–O six‐membered ring structure in the polymer in the first stage. Then, the removal of methyl results in the formation of a B–N–O network in hot ammonia. Afterward, nitridation of the B–O six‐membered ring promotes the evolution of the B–N six‐membered ring structure with the release of water and carbon dioxide. Finally, the growth and rearrangement of the BN structure are achieved. [ABSTRACT FROM AUTHOR]

To explore the possible novel microRNA (miRNA) regulatory pathways in Zhengmai 1860, a newly cultivated drought-tolerant wheat (Triticum aestivum L.) cultivar, miRNA transcriptome sequencing of the flag leaves of Zhengmai 1860, drought-sensitive variety Zhoumai 18, and drought-resistant variety Bainong 207 was performed during the grain filling stage. We also observed changes in the chloroplast ultrastructure, phytohormone levels, and antioxidant- and photosynthesis-related physiological indicators in three wheat varieties. The results showed that the flag leaves of the drought-tolerant variety Zhengmai 1860 had higher chlorophyll contents and net photosynthetic rates than those of Zhoumai 18 under drought stress during the grain filling stage; in addition, the chloroplast structure was more complete. However, there was no significant difference between Zhengmai 1860 and Bainong 207. MiRNA transcriptome analysis revealed that the differential expression of the miRNAs and mRNAs exhibited variable specificity. The KEGG pathway enrichment results indicated that most of the genes were enriched in the MAPK signaling pathway, plant hormone signal transduction, photosynthetic antennae protein, and amino acid and carbohydrate metabolism. In the drought-tolerant cultivar Zhengmai 1860, tae-miR408 was targeted to regulate the allene oxide synthase (AOS) gene, inhibit its expression, reduce the AOS content, and decrease the synthesis of jasmonic acid (JA) and abscisic acid (ABA). The results of this study suggest that Zhengmai 1860 could improve the photosynthetic performance of flag leaves by inhibiting the expression of genes involved in the JA pathway through miRNAs under drought conditions. Moreover, multiple miRNAs may target chlorophyll, antioxidant enzymes, phytohormone signal transduction, and other related pathways; thus, it is possible to provide a more theoretical basis for wheat molecular breeding. [ABSTRACT FROM AUTHOR]

Background: Nitrogen use efficiency (NUE) is closely related to crop yield and nitrogen fertilizer application rate. Although NUE is susceptible to environments, quantitative trait nucleotides (QTNs) for NUE in wheat germplasm populations have been rarely reported in genome-wide associated study. Results: In this study, 244 wheat accessions were phenotyped by three NUE-related traits in three environments and genotyped by 203,224 SNPs. All the phenotypes for each trait were used to associate with all the genotypes of these SNP markers for identifying QTNs and QTN-by-environment interactions via 3VmrMLM. Among 279 QTNs and one QTN-by-environment interaction for low nitrogen tolerance, 33 were stably identified, especially, one large QTN (r2 > 10%), qPHR3A.2, was newly identified for plant height ratio in one environment and multi-environment joint analysis. Among 52 genes around qPHR3A.2, four genes (TraesCS3A01G101900, TraesCS3A01G102200, TraesCS3A01G104100, and TraesCS3A01G105400) were found to be differentially expressed in low-nitrogen-tolerant wheat genotypes, while TaCLH2 (TraesCS3A01G101900) was putatively involved in porphyrin metabolism in KEGG enrichment analyses. Conclusions: This study identified valuable candidate gene for low-N-tolerant wheat breeding and provides new insights into the genetic basis of low N tolerance in wheat. [ABSTRACT FROM AUTHOR]

Lack of potassium in soil limits crop yield. Increasing yield and conserving potassium ore requires improving K use efficiency (KUE). Many genes influence KUE in plants, but it is not clear how these genes function in the field. We identified the V-type H+-pyrophosphatase gene EdVP1 from Elymus dahurica. Gene expression analysis showed that EdVP1 was induced by low potassium stress. Protein subcellular localization analysis demonstrated that EdVP1 localized on the plasma membrane. We overexpressed EdVP1 in two wheat varieties and conducted K tolerance experiments across years. Yield per plant, grain number per spike, plant height, and K uptake of four transgenic wheat lines increased significantly compared with WT; results from two consecutive years showed that EdVP1 significantly increased yield and KUE of transgenic wheat. Pot experiments showed that transgenic plants had significantly longer shoots and roots, and higher K accumulation in shoots and roots and H+-PPase activity in shoots than WT under low K. A fluidity assay of potassium ion in EdVP1 transgenic plant roots showed that potassium ion influx and H+ outflow in transgenic plants were higher than WT. Overexpressing EdVP1 significantly improved yield and KUE of transgenic wheat and was related to higher K uptake capacity in root. [ABSTRACT FROM AUTHOR]

Psb28 is a soluble protein in the photosystem II (PSII) complex, but its role in the drought stress response of wheat remains unclear. Here, we functionally characterized the TaPsb28 gene, which positively regulates drought tolerance in wheat. When the full-length 546-bp TaPsb28 cDNA was transferred into Arabidopsis thaliana, it was located in the guard cell chloroplast around the stroma. Overexpression of TaPsb28 conferred drought tolerance, as exhibited by the increases in the survival rate. Transgenic plants maintained lower MDA content and higher chlorophyll content by inducing chlorophyll synthase (ChlG) gene transcription. The content of abscisic acid (ABA) and zeatin increased significantly in wild-type (WT) plants under drought stress, and the transcriptional expression levels of RD22, dihydroflavonol 4-reductase (DFR) and anthocyanin reductase (ANR) genes were induced, thus enhancing the contents of endogenous cyanidin, delphinidin, and proanthocyanidins. However, in transgenic plants, although anthocyanins were further aggregated, the ABA increase was inhibited, zeatin was restored to the control level under drought stress, and stomatal closure was promoted. These findings indicate ABA and zeatin have opposite synergistic effects in the process of drought tolerance caused by TaPsb28 because only after the effect of zeatin is alleviated can ABA better play its role in promoting anthocyanin accumulation and stomatal closure, thus enhancing the drought tolerance of transgenic plants. The results suggest that overexpression of TaPsb28 exerts a positive role in the drought response by influencing the functional metabolism of endogenous hormones. The understanding acquired through the research laid a foundation for further in-depth investigation of the function of TaPsb28 in drought resistance in wheat, especially its relationship with anthocyanidin accumulation. [ABSTRACT FROM AUTHOR]

Summary: Genetically enhancing drought tolerance and nutrient use efficacy enables sustainable and stable wheat production in drought‐prone areas exposed to water shortages and low soil fertility, due to global warming and declining natural resources. In this study, wheat plants, exhibiting improved drought tolerance and N‐use efficacy, were developed by introducing GmTDN1, a gene encoding a DREB‐like transcription factor, into two modern winter wheat varieties, cv Shi4185 and Jimai22. Overexpressing GmTDN1 in wheat resulted in significantly improved drought and low‐N tolerance under drought and N‐deficient conditions in the greenhouse. Field trials conducted at three different locations over a period of 2–3 consecutive years showed that both Shi4185 and Jimai22 GmTDN1 transgenic lines were agronomically superior to wild‐type plants, and produced significantly higher yields under both drought and N‐deficient conditions. No yield penalties were observed in these transgenic lines under normal well irrigation conditions. Overexpressing GmTDN1 enhanced photosynthetic and osmotic adjustment capacity, antioxidant metabolism, and root mass of wheat plants, compared to those of wild‐type plants, by orchestrating the expression of a set of drought stress‐related genes as well as the nitrate transporter, NRT2.5. Furthermore, transgenic wheat with overexpressed NRT2.5 can improve drought tolerance and nitrogen (N) absorption, suggesting that improving N absorption in GmTDN1 transgenic wheat may contribute to drought tolerance. These findings may lead to the development of new methodologies with the capacity to simultaneously improve drought tolerance and N‐use efficacy in cereal crops to ensure sustainable agriculture and global food security. [ABSTRACT FROM AUTHOR]

Objective: Hypertension requires continuous and long‐term care to prevent associated complications. Chronic disease management mode (CDMM) was developed to improve patients' self‐management. We aimed to evaluate quality of care and clinical outcomes of CDMM versus routine care. Methods: 300 patients aged >30 years with primary hypertension were randomly allocated to the CDMM intervention group (n = 162) or the usual care control group (n = 138). CDMM comprised nursing consultations, telephone contact, online WeChat link, health education, and appropriate referrals during hospitalisation and after discharge. QLICD‐HY (V 2.0) scale was used to evaluate the quality of life. Care outcomes were biochemical parameters, body mass index, blood pressure levels, waist circumference, psychological indicators and quality of life assessed on admission (baseline) and one month post‐care for both groups. Data were collected and analysed using SPSS 20.0. Results: After one month, the intervention group had 6 mm Hg (95% CI: −5.12 to −9.08) lower SBP and 0.6 mM/L (95% CI: −0.52 to −0.68) lower LDL than the control group. In terms of improvements in BMI, UmAlb or waist circumference, there were no differences between both groups. The intervention group scored better on psychological indicators than controls (P < 0.05), and scores reflecting social and psychological function in the intervention group were significantly higher than scores at baseline, and higher than scores of controls after one month (P < 0.05). In the control group, there was no statistically significant difference between the scores at baseline and after one month. Conclusions: Under CDMM hypertension care, improvement of blood pressure and LDL was clinically significant. Intervention care further improves social and psychological function among participants with primary hypertension. [ABSTRACT FROM AUTHOR]

Lodging is one of the most important factors that reduce wheat grain yields. To improve lodging resistance, increasing the strength of wheat stems has been an important breeding objective. To assess the rate of genetic improvement of the character, 30 wheat accessions, varying from landraces to cultivars that have been widely grown in Henan Province, China during the last 70 years, were tested for several parameters of lodging resistance in a two-year experiment. Stem strength, morphological and anatomical traits, and chemical composition were measured. The results showed that stem strength, both at anthesis and 25 days thereafter, has increased significantly during this period with average annual genetic gains of 1.07 and 0.87 %, respectively. Compared with older wheat cultivars, stem walls of modern cultivars are thicker, and the lignin content is higher. Grain yield has been significantly increased over the last 70 years, and the results of multiple regression analysis indicated that the genetic improvement of grain yield was associated with the increase in stem strength and the decrease in plant height. [ABSTRACT FROM AUTHOR]

• The influence of various factors on mechanical properties of h -BNNS are systematically investigated via classical MD simulations. • The effect of temperature and the ratio of circular-region radius to nanoindenter radius are greater than other factors. • Failure mechanism of mono-layer h -BNNS starts with discrete point defects, gradually expands and merges to form hole defects, and causes structural fracture. • Fracture mode of multi-layer h -BNNS will translate from the bottom-top failure to the top–bottom failure accompanying with increasing thickness. Hexagonal boron nitride nanosheets (h -BNNS) is one kind of promising 2D materials due to its outstanding mechanical properties especially at elevated temperature. However, the experimentally measured mechanical properties of h -BNNS have great dispersions due to the intricate experimental measurement conditions. In the present study, the classical molecular dynamics simulations are performed to study the effect of various experimental factors on the mechanical properties of h -BNNS based on nanoindentation, including: size, temperature, loading rate of nanoindenter, ratio of circular-region radius to nanoindenter radius, and thickness (the number of layers). Meanwhile, the evolution of microstructure of h -BNNS up to fracture are investigated to elucidate its fracture mechanism during nanoindentation process. The results indicate that the Young's modulus and fracture strength of h -BNNS gradually decreases with the increasing temperature, and the mechanical properties of h -BNNS remain relatively stable when the ratio of circular-region radius to nanoindenter radius and the circular-region radius is bigger than 10 and 18 nm, respectively. Based on the evolutionary process of the microstructure of h -BNNS, the results not only show the failure process of h -BNNS, but also reveal the conversion of the fracture mode in multi-layer h -BNNS, that is, it will be translated from the bottom-top to the top–bottom fracture with increasing thickness. [ABSTRACT FROM AUTHOR]