ABSTRACT
Fibrinogen, a biomarker of thrombosis and inflammation, is related to a high risk for cardiovascular diseases. However, studies on the prognostic value of blood fibrinogen concentrations for heart failure (HF) patients are few and controversial. We performed a retrospective analysis among acute or deteriorating chronic HF patients admitted to a hospital in Sichuan, China, between 2016 and 2019, integrating electronic health care records and external outcome data (N = 1532). During 6 months of follow-up, 579 HF patients were readmitted within 6 months, and 46 of them died. Surprisingly, we found an inverted U-shaped association of blood fibrinogen levels with risk of readmission within 6 months but not with risk of death within 6 months. It was found that HF patients had the highest risk for readmission within 6 months after reaching the turning point for blood fibrinogen (2.4 g/L). In HF patients with low fibrinogen levels < 2.4 g/L, elevated fibrinogen concentrations were still significantly associated with a higher risk for readmission within 6 months [OR = 2.3, 95% CI (1.2, 4.6); P = 0.014] after controlling for relevant covariates. There was no significant association between blood fibrinogen and readmission within 6 months [(OR = 1.0, 95% CI (0.9, 1.1); P = 0.675] in HF patients with high fibrinogen (> 2.4 g/L). The effect difference for the two subgroups was significant (P = 0.014). However, we did not observe any association between blood fibrinogen and death within 6 months stratified by the turning point, and the effect difference for the stratification was not significant (P = 0.380). We observed an inverted U-shaped association between blood fibrinogen and rehospitalization risk in HF patients for the first time. Additionally, our results did not support that elevated blood fibrinogen was related to increased death risk after discharge.
Subject(s)
Fibrinogen , Heart Failure , Patient Readmission , Humans , Fibrinogen/metabolism , Fibrinogen/analysis , Heart Failure/blood , Heart Failure/mortality , Female , Male , Aged , Middle Aged , Retrospective Studies , Biomarkers/blood , China/epidemiology , Risk Factors , Prognosis , Aged, 80 and overABSTRACT
BACKGROUND: Hypertrophic cardiomyopathy (HCM) is an inherited heart disease that can lead to sudden cardiac death. Impact of genetic testing for the prognosis and treatment of patients with HCM needs to be improved. We conducted a systematic review and meta-analysis to investigate the characteristics and outcomes associated with sarcomere genotypes in index patients with HCM. METHODS: A systematic search was conducted in Medline, Embase, and Cochrane Library up to Dec 31, 2023. Data on clinical characteristics, morphological and imaging features, outcomes and interventions were collected from published studies and pooled using a random-effects meta-analysis. RESULTS: A total of 30 studies with 10,825 HCM index patients were included in the pooled analyses. The frequency of sarcomere genes in HCM patients was 41%. Sarcomere mutations were more frequent in women (p < 0.00001), and were associated with lower body mass index (26.1 ± 4.7 versus 27.5 ± 4.3; p = 0.003) and left ventricular ejection fraction (65.7% ± 10.1% vs. 67.1% ± 8.6%; p = 0.03), less apical hypertrophy (6.5% vs. 20.1%; p < 0.0001) and left ventricular outflow tract obstruction (29.1% vs. 33.2%; p = 0.03), greater left atrial volume index (43.6 ± 21.1 ml/m2 vs. 37.3 ± 13.0 ml/m2; p = 0.02). Higher risks of ventricular tachycardia (23.4% vs. 14.1%; p < 0.0001), syncope (18.3% vs. 10.9%; p = 0.01) and heart failure (17.3% vs. 14.6%; p = 0.002) were also associated with sarcomere mutations. CONCLUSIONS: Sarcomere mutations are more frequent in women, and are associated with worse clinical characteristics and poor outcomes.
Subject(s)
Cardiomyopathy, Hypertrophic , Mutation , Sarcomeres , Humans , Sarcomeres/genetics , Cardiomyopathy, Hypertrophic/genetics , Cardiomyopathy, Hypertrophic/diagnosisABSTRACT
Nitrogen (N) is one of the essential nutrients for the growth and development of crops. The adequate application of N not only increases the yield of crops but also improves the quality of agricultural products, but the excessive application of N can cause many adverse effects on ecology and the environment. In this study, genome-wide association analysis (GWAS) was performed under low- and high-N conditions based on 788,396 SNPs and phenotypic traits relevant to N uptake and utilization (N content and N accumulation). A total of 75 QTLs were obtained using GWAS, which contained 811 genes. Of 811 genes, 281 genes showed different haplotypes, and 40 genes had significant phenotypic differences among different haplotypes. Of these 40 genes, 5 differentially expressed genes (Os01g0159250, Os02g0618200, Os02g0618400, Os02g0630300, and Os06g0619000) were finally identified as the more valuable candidate genes based on the transcriptome data sequenced from Longjing31 (low-N-tolerant variety) and Songjing 10 (low-N-sensitive variety) under low- and high-N treatments. These new findings enrich the genetic resources for N uptake and utilization in rice, as well as lay a theoretical foundation for improving the efficiency of N uptake and utilization in rice.
Subject(s)
Oryza , Seedlings , Seedlings/genetics , Chromosome Mapping , Oryza/genetics , Genome-Wide Association Study , Nitrogen , Crops, Agricultural/geneticsABSTRACT
Low-temperature chilling is a major abiotic stress leading to reduced rice yield and is a significant environmental threat to food security. Low-temperature chilling studies have focused on physiological changes or coding genes. However, the competitive endogenous RNA mechanism in rice at low temperatures has not been reported. Therefore, in this study, antioxidant physiological indices were combined with whole-transcriptome data through weighted correlation network analysis, which found that the gene modules had the highest correlation with the key antioxidant enzymes superoxide dismutase and peroxidase. The hub genes of the superoxide dismutase-related module included the UDP-glucosyltransferase family protein, sesquiterpene synthase and indole-3-glycerophosphatase gene. The hub genes of the peroxidase-related module included the WRKY transcription factor, abscisic acid signal transduction pathway-related gene plasma membrane hydrogen-ATPase and receptor-like kinase. Therefore, we selected the modular hub genes and significantly enriched the metabolic pathway genes to construct the key competitive endogenous RNA networks, resulting in three competitive endogenous RNA networks of seven long non-coding RNAs regulating three co-expressed messenger RNAs via four microRNAs. Finally, the negative regulatory function of the WRKY transcription factor OsWRKY61 was determined via subcellular localization and validation of the physiological indices in the mutant.
Subject(s)
MicroRNAs , Oryza , RNA, Long Noncoding , Oryza/metabolism , RNA, Long Noncoding/genetics , RNA, Long Noncoding/metabolism , Antioxidants , Gene Expression Profiling , MicroRNAs/genetics , MicroRNAs/metabolism , Gene Regulatory Networks , Transcription Factors/genetics , Transcription Factors/metabolism , Peroxidases/genetics , Superoxide Dismutase/geneticsABSTRACT
Salinity stress is one of the major abiotic stresses affecting crop growth and production. Rice is an important food crop in the world, but also a salt-sensitive crop, and the rice seedling stage is the most sensitive to salt stress, which directly affects the final yield formation. In this study, two RIL populations derived from the crosses of CD (salt-sensitive)/WD (salt-tolerant) and KY131 (salt-sensitive)/XBJZ (salt-tolerant) were used as experimental materials, and the score of salinity toxicity (SST), the relative shoot length (RSL), the relative shoot fresh weight (RSFW), and the relative shoot dry weight (RSDW) were used for evaluating the degree of tolerance under salt stress in different lines. The genetic linkage map containing 978 and 527 bin markers were constructed in two RIL populations. A total of 14 QTLs were detected on chromosomes 1, 2, 3, 4, 7, 9, 10, 11, and 12. Among them, qSST12-1, qSST12-2, and qRSL12 were co-localized in a 140-kb overlap interval on chromosome 12, which containing 16 candidate genes. Furthermore, transcriptome sequencing and qRT-PCR were analyzed in CD and WD under normal and 120 mM NaCl stress. LOC_Os12g29330, LOC_Os12g29350, LOC_Os12g29390, and LOC_Os12g29400 were significantly induced by salt stress in both CD and WD. Sequence analysis showed that LOC_Os12g29400 in the salt-sensitive parents CD and KY131 was consistent with the reference sequence (Nipponbare), whereas the salt-tolerant parents WD and XBJZ differed significantly from the reference sequence both in the promoter and exon regions. The salt-tolerant phenotype was identified by using two T3 homozygous mutant plants of LOC_Os12g29400; the results showed that the score of salinity toxicity (SST) of the mutant plants (CR-3 and CR-5) was significantly lower than that of the wild type, and the seedling survival rate (SSR) was significantly higher than that of the wild type, which indicated that LOC_Os12g29400 could negatively regulate the salinity tolerance of rice at the seedling stage. The results lay a foundation for the analysis of the molecular mechanism of rice salinity tolerance and the cultivation of new rice varieties.
Subject(s)
Oryza , Salt Tolerance , Salt Tolerance/genetics , Oryza/genetics , Seedlings/genetics , Transcriptome , Salinity , Sequence AnalysisABSTRACT
Improving rice yield is one of the most important food issues internationally. It is an undeniable goal of rice breeding, and the effective panicle number (EPN) is a key factor determining rice yield. Increasing the EPN in rice is a major way to increase rice yield. Currently, the main quantitative trait locus (QTL) for EPN in rice is limited, and there is also limited research on the gene for EPN in rice. Therefore, the excavation and analysis of major genes related to EPN in rice is of great significance for molecular breeding and yield improvement. This study used japonica rice varieties Dongfu 114 and Longyang 11 to construct an F5 population consisting of 309 individual plants. Two extreme phenotypic pools were constructed by identifying the EPN of the population, and QTL-seq analysis was performed to obtain three main effective QTL intervals for EPN. This analysis also helped to screen out 34 candidate genes. Then, EPN time expression pattern analysis was performed on these 34 genes to screen out six candidate genes with higher expression levels. Using a 3K database to perform haplotype analysis on these six genes, we selected haplotypes with significant differences in EPN. Finally, five candidate genes related to EPN were obtained.
Subject(s)
Oryza , Chromosome Mapping , Oryza/genetics , Phenotype , Plant Breeding , Quantitative Trait LociABSTRACT
Grain length (GL) is one of the crucial determinants of rice yield and quality. However, there is still a shortage of knowledge on the major genes controlling the inheritance of GL in japonica rice, which severely limits the improvement of japonica rice yields. Here, we systemically measured the GL of 667 F2 and 1570 BC3F3 individuals derived from two cultivated rice cultivars, Pin20 and Songjing15, in order to identify the major genomic regions associated with GL. A novel major QTL, qGL9.1, was mapped on chromosome 9, which is associated with the GL, using whole-genome re-sequencing with bulked segregant analysis. Local QTL linkage analysis with F2 and fine mapping with the recombinant plant revealed a 93-kb core region on qGL9.1 encoding 15 protein-coding genes. Only the expression level of LOC_Os09g26970 was significantly different between the two parents at different stages of grain development. Moreover, haplotype analysis revealed that the alleles of Pin20 contribute to the optimal GL (9.36 mm) and GL/W (3.31), suggesting that Pin20 is a cultivated species carrying the optimal GL variation of LOC_Os09g26970. Furthermore, a functional-type mutation (16398989-bp, G>A) located on an exon of LOC_Os09g26970 could be used as a molecular marker to distinguish between long and short grains. Our experiments identified LOC_Os09g26970 as a novel gene associated with GL in japonica rice. This result is expected to further the exploration of the genetic mechanism of rice GL and improve GL in rice japonica varieties by marker-assisted selection.
Subject(s)
Oryza , Quantitative Trait Loci , Humans , Chromosome Mapping , Oryza/genetics , Genes, Plant , Edible Grain/genetics , Genetic Association StudiesABSTRACT
MAIN CONCLUSION: Through QTL-seq, QTL mapping and RNA-seq, six candidate genes of qLTG9 can be used as targets for cold tolerance functional characterization, and six KASP markers can be used for marker-assisted breeding to improve the germination ability of japonica rice at low temperature. The development of direct-seeded rice at high latitudes and altitudes depends on the seed germination ability of rice under a low-temperature environment. However, the lack of regulatory genes for low-temperature germination has severely limited the application of genetics in improving the breeds. Here, we used cultivars DN430 and DF104 with significantly different low-temperature germination (LTG) and 460 F2:3 progeny derived from them to identify LTG regulators by combining QTL-sequencing, linkage mapping, and RNA-sequencing. The QTL-sequencing mapped qLTG9 within a physical interval of 3.4 Mb. In addition, we used 10 Kompetitive allele-specific PCR (KASP) markers provided by the two parents, and qLTG9 was optimized from 3.4 Mb to a physical interval of 397.9 kb and accounted for 20.4% of the phenotypic variation. RNA-sequencing identified qLTG9 as eight candidate genes with significantly different expression within the 397.9 kb interval, six of which possessed SNPs on the promoter and coding regions. Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) completely validated the results of these six genes in RNA-sequencing. Subsequently, six non-synonymous SNPs were designed using variants in the coding region of these six candidates. Genotypic analysis of these SNPs in 60 individuals with extreme phenotypes indicated these SNPs determined the differences in cold tolerance between parents. The six candidate genes of qLTG9 and the six KASP markers could be used together for marker-assisted breeding to improve LTG.
Subject(s)
Oryza , Oryza/genetics , Germination/genetics , Quantitative Trait Loci/genetics , Alleles , Temperature , Plant Breeding , Chromosome Mapping , Polymerase Chain ReactionABSTRACT
Background: Salinity tolerance plays a vital role in rice cultivation because the strength of salinity tolerance at the seedling stage directly affects seedling survival and final crop yield in saline soils. Here, we combined a genome-wide association study (GWAS) and linkage mapping to analyze the candidate intervals for salinity tolerance in Japonica rice at the seedling stage. Results: We used the Na+ concentration in shoots (SNC), K+ concentration in shoots (SKC), Na+/K+ ratio in shoots (SNK), and seedling survival rate (SSR) as indices to assess the salinity tolerance at the seedling stage in rice. The GWAS identified the lead SNP (Chr12_20864157), associated with an SNK, which the linkage mapping detected as being in qSK12. A 195-kb region on chromosome 12 was selected based on the overlapping regions in the GWAS and the linkage mapping. Based on haplotype analysis, qRT-PCR, and sequence analysis, we obtained LOC_Os12g34450 as a candidate gene. Conclusion: Based on these results, LOC_Os12g34450 was identified as a candidate gene contributing to salinity tolerance in Japonica rice. This study provides valuable guidance for plant breeders to improve the response of Japonica rice to salt stress.
ABSTRACT
Nitrogen-based nutrients are the main factors affecting rice growth and development. As the nitrogen (N) application rate increased, the nitrogen use efficiency (NUE) of rice decreased. Therefore, it is important to understand the molecular mechanism of rice plant morphological, physiological, and yield formation under low N conditions to improve NUE. In this study, changes in the rice morphological, physiological, and yield-related traits under low N (13.33 ppm) and control N (40.00 ppm) conditions were performed. These results show that, compared with control N conditions, photosynthesis and growth were inhibited and the carbon (C)/N and photosynthetic nitrogen use efficiency (PNUE) were enhanced under low N conditions. To understand the post-translational modification mechanism underlying the rice response to low N conditions, comparative phosphoproteomic analysis was performed, and differentially modified proteins (DMPs) were further characterized. Compared with control N conditions, a total of 258 DMPs were identified under low N conditions. The modification of proteins involved in chloroplast development, chlorophyll synthesis, photosynthesis, carbon metabolism, phytohormones, and morphology-related proteins were differentially altered, which was an important reason for changes in rice morphological, physiological, and yield-related traits. Additionally, inconsistent changes in level of transcription and protein modification, indicates that the study of phosphoproteomics under low N conditions is also important for us to better understand the adaptation mechanism of rice to low N stress. These results provide insights into global changes in the response of rice to low N stress and may facilitate the development of rice cultivars with high NUE by regulating the phosphorylation level of carbon metabolism and rice morphology-related proteins.
Subject(s)
Oryza , Oryza/metabolism , Nitrogen/metabolism , Photosynthesis , Acclimatization , Carbon/metabolismABSTRACT
KEY MESSAGE: LOC_Os07g07690 on qCTB7 is associated with cold tolerance at the booting stage in rice, and analysis of transgenic plants demonstrated that qCTB7 influenced cold tolerance by altering the morphology and cytoarchitecture of anthers and pollen. Cold tolerance at the booting stage (CTB) in rice can significantly affect yield in high-latitude regions. Although several CTB genes have been isolated, their ability to induce cold tolerance is insufficient to ensure adequate rice yields in cold regions at high latitudes. Here, we identified the PHD-finger domain-containing protein gene qCTB7 using QTL-seq and linkage analysis through systematic measurement of CTB differences and the spike fertility of the Longjing31 and Longdao3 cultivars, resulting in the derivation of 1570 F2 progeny under cold stress. We then characterized the function of qCTB7 in rice. It was found that overexpression of qCTB7 promoted CTB and the same yield as Longdao3 under normal growing conditions while the phenotype of qctb7 knockout showed anther and pollen failure under cold stress. When subjected to cold stress, the germination of qctb7 pollen on the stigma was reduced, resulting in lower spike fertility. These findings indicate that qCTB7 regulates the appearance, morphology, and cytoarchitecture of the anthers and pollen. Three SNPs in the promoter region and coding region of qCTB7 were identified as recognition signals for CTB in rice and could assist breeding efforts to improve cold tolerance for rice production in high latitudes.
Subject(s)
Oryza , Oryza/genetics , Plant Breeding , Cold-Shock Response , Fertility/genetics , Open Reading FramesABSTRACT
Nitrogen is an important nutrient for plant growth and essential metabolic processes. Roots integrally obtain nutrients from soil and are closely related to the growth and development of plants. In this study, the morphological analysis of rice root tissues collected at different time points under low-nitrogen and normal nitrogen conditions demonstrated that, compared with normal nitrogen treatment, the root growth and nitrogen use efficiency (NUE) of rice under low-nitrogen treatment were significantly improved. To better understand the molecular mechanisms of the rice root system's response to low-nitrogen conditions, a comprehensive transcriptome analysis of rice seedling roots under low-nitrogen and control conditions was conducted in this study. As a result, 3171 differentially expressed genes (DEGs) were identified. Rice seedling roots enhance NUE and promote root development by regulating the genes related to nitrogen absorption and utilization, carbon metabolism, root growth and development, and phytohormones, thereby adapting to low-nitrogen conditions. A total of 25,377 genes were divided into 14 modules using weighted gene co-expression network analysis (WGCNA). Two modules were significantly associated with nitrogen absorption and utilization. A total of 8 core genes and 43 co-expression candidates related to nitrogen absorption and utilization were obtained in these two modules. Further studies on these genes will contribute to the understanding of low-nitrogen adaptation and nitrogen utilization mechanisms in rice.
Subject(s)
Oryza , Transcriptome , Oryza/metabolism , Gene Expression Profiling , Seedlings/genetics , Seedlings/metabolism , Nitrogen/metabolism , Plant Roots/metabolism , Gene Expression Regulation, PlantABSTRACT
BACKGROUND: Digitalis has been widely utilized for heart failure therapy and several studies have demonstrated an association of digitalis and adverse outcome events in patients receiving implantable cardioverter defibrillators (ICDs) or cardiac resynchronization therapy defibrillators (CRT-Ds). Hence, we conducted this meta-analysis to assess the effect of digitalis on ICD or CRT-D recipients. METHODS: We systematically retrieved relevant studies using the Cochrane Library, PubMed, and Embase database. A random effect model was used to pool the effect estimates (hazard ratios (HRs) and 95% confidence intervals (CIs)) when the studies were of high heterogeneity, otherwise a fixed effect model was used. RESULTS: Twenty-one articles containing 44,761 ICD or CRT-D recipients were included. Digitalis was associated with an increased rate of appropriate shocks (HR = 1.65, 95% CI: 1.46-1.86, p < 0.001) and a shortened time to first appropriate shock (HR = 1.76, 95% CI: 1.17-2.65, p = 0.007) in ICD or CRT-D recipients. Furthermore, the all-cause mortality increased in ICD recipients with digitalis therapy (HR = 1.70, 95% CI: 1.34-2.16, p < 0.01), but the all-cause mortality was unchanged in CRT-D recipients (HR = 1.55, 95% CI: 0.92-2.60, p = 0.10) or patients who received ICD or CRT-D therapy (HR = 1.09, 95% CI: 0.80-1.48, p = 0.20). The sensitivity analyses confirmed the robustness of the results. CONCLUSION: ICD recipients with digitalis therapy may tend to have higher mortality rates, but digitalis may not be associated with the mortality rate of CRT-D recipients. Further studies are required to confirm the effects of digitalis on ICD or CRT-D recipients.
ABSTRACT
INTRODUCTION: Drug-induced QT interval prolongation has been reported to be related to life-threatening polymorphic ventricular tachycardia (torsade de pointes). Proton pump inhibitors (PPIs) are prescribed widely for hospitalized patients; the QT interval prolongation and torsade de pointes caused by PPIs were reported. We conducted a study to determine the association between PPI treatment and QT interval prolongation in critically ill patients. METHODS: This study included patients with electrocardiography (ECG) reports from the Medical Information Mart for Intensive Care III database (MIMIC-III). Patients younger than 18 years, missing baseline laboratories and with QT interval prolongation before intensive care unit (ICU) admission were excluded. The end point was the diagnosis of QT interval prolongation reported by ECG. RESULTS: This study included 24,512 ICU patients. Of them, 11,327 patients were treated with PPIs, 4181 with histamine 2 receptor antagonists (H2RAs) and 6351 without acid suppression therapy (non-AST); the incidence of QT interval prolongation were 8.5%, 3.3% and 3.4% respectively. After adjustment for demographics, electrolytes, comorbidities and medications, PPIs were associated a higher risk of QT interval prolongation compared with H2RAs (OR 1.66, 95% CI 1.36 - 2.03) and non-AST (OR 1.54, 95% CI 1.31 - 1.82), while there was not significant difference between H2RAs and non-AST (OR 0.93, 95% CI 0.73 - 1.17). In the propensity score matching population, the results were consistent. Pantoprazole (OR 2.14, 95% CI 1.52 - 3.03) and lansoprazole (OR 1.80, 95% CI: 1.18 - 2.76) showed a higher QT prolongation risk than omeprazole. Several drugs caused higher QT prolongation risk when used in combination with PPIs. CONCLUSION: In ICU patients, the association between PPI prescription and increased risk of QT interval prolongation was independent of known QT-prolonging factors; pantoprazole and lansoprazole had a higher risk compared with omeprazole. The combination of PPIs and other QT-prolonging drugs should be avoided.
ABSTRACT
AIMS: There are limited data about the relationship between body mass index (BMI) and left ventricular ejection fraction (EF) in patients with heart failure (HF). The study aims to assess the correlation between BMI and left ventricular EF under HF conditions. METHODS AND RESULTS: We derived the data from the Dryad Digital Repository for analysis, and the information of the original patients was obtained from the MIMIC-III database by the data uploader. We performed smooth curve and two piecewise linear regression analyses to evaluate the association between BMI and EF in HF patients. A total of 962 participants were included in this study, with age of 73.7 ± 13.5 years, and 475 participants were male (49.4%). The results of the smooth curve supported a U-shaped relationship between BMI and EF, and the inflection point was found to be a BMI of 23.3 kg/m2 in these HF patients. After adjusting for potential confounders, we found that EF decreased with increasing BMI up to the inflection point (ß = -0.7, 95% CI -1.3 to -0.1, P = 0.028), whereas beyond the turning point, the relationship between EF and BMI showed a positive correlation (ß = 0.2, 95% CI 0.1-0.3 P < 0.001). Importantly, ischaemic heart disease (interaction P = 0.0499) and hyperlipidaemia (interaction P = 0.0162) affected the association between BMI and EF in the lower BMI group (BMI < 23.3 kg/m2 ), although only diabetes mellitus (interaction P = 0.0255) altered the association between BMI and EF in the higher BMI group (BMI ≥ 23.3 kg/m2 ). CONCLUSIONS: In addition to higher BMI, we also found that lower BMI is related to higher EF in intensive care unit patients with HF, supporting a U-shaped association between BMI and EF.
Subject(s)
Heart Failure , Ventricular Function, Left , Humans , Male , Middle Aged , Aged , Aged, 80 and over , Female , Stroke Volume , Body Mass Index , Intensive Care UnitsABSTRACT
Drought stress at jointing-booting directly affects plant growth and productivity in rice. Limited by natural factors, the jointing and booting stages of short-growth-period rice varieties are highly overlapped in high-latitude areas, which are more sensitive to water deficit. However, little is known about the dry matter translocation in rice and the strategies of starch synthesis and filling of superior and inferior grains under different drought stress was unclear. In this study, the rice plants were subjected to three degrees of drought stress (-10 kPa, -25 kPa, -40 kPa) for 15 days during the jointing-booting stage; we investigated dry matter accumulation and translocation, grain filling and enzyme activities to starch synthesis of superior and inferior grains in rice with overlapping growth stages from 2016 to 2017. The results showed that drought stress significantly reduced dry matter accumulation in the stems and leaves. Mild and moderate drought increased dry matter translocation efficiency. However, severe drought stress largely limited the dry matter accumulation and translocation. A large amount of dry matter remains in vegetative organs under severe drought stress. The high content in NSC in stem and sheath plays a key role in resisting drought stress. The drought stress at jointing-booting directly caused a change in the grain filling strategy. Under moderate and severe drought, the grain-filling active period of the superior grains was shortened to complete the necessary reproductive growth. The grain-filling active period of the inferior grains was significantly prolonged to avoid a decrease in grain yield. The significant decrease in the grain-filling rate of the superior and inferior grains caused a reduction in the thousand-grain weight. In particular, the influence of the grain-filling rate of inferior grains on the thousand-grain weight was more significant. Drought stress changed the starch synthesis strategies of the superior and inferior grains. Soluble starch synthase and starch branching enzyme activities of inferior grains increased significantly under drought stress. GBSS activity was not sensitive to drought stress. Therefore, amylose content was decreased and amylopectin synthesis was enhanced under drought stress, especially in inferior grains.
Subject(s)
1,4-alpha-Glucan Branching Enzyme , Oryza , Starch Synthase , Amylopectin , Amylose , Dehydration , Edible Grain , StarchABSTRACT
Nitrogen is not only a macronutrient essential for crop growth and development, but also one of the most critical nutrients in farmland ecosystem. Insufficient nitrogen supply will lead to crop yield reduction, while excessive application of nitrogen fertilizer will cause agricultural and eco-environment damage. Therefore, mining low-nitrogen tolerant rice genes and improving nitrogen use efficiency are of great significance to the sustainable development of agriculture. This study was conducted by Genome-wide association study on a basis of two root morphological traits (root length and root diameter) and 788,396 SNPs of a natural population of 295 rice varieties. The transcriptome of low-nitrogen tolerant variety (Longjing 31) and low-nitrogen sensitive variety (Songjing 10) were sequenced between low and high nitrogen treatments. A total of 35 QTLs containing 493 genes were mapped. 3085 differential expressed genes were identified. Among these 493 genes, 174 genes showed different haplotype patterns. There were significant phenotype differences among different haplotypes of 58 genes with haplotype differences. These 58 genes were hypothesized as candidate genes for low nitrogen tolerance related to root morphology. Finally, six genes (Os07g0471300, Os11g0230400, Os11g0229300, Os11g0229400, Os11g0618300 and Os11g0229333) which expressed differentially in Longjing 31 were defined as more valuable candidate genes for low-nitrogen tolerance. The results revealed the response characteristics of rice to low-nitrogen, and provided insights into regulatory mechanisms of rice to nitrogen deficiency.
ABSTRACT
Caffeic acid O-methyltransferase (COMT) is one of the core enzymes involved in lignin synthesis. However, there is no systematic study on the rice COMT gene family. We identified 33 COMT genes containing the methyltransferase-2 domain in the rice genome using bioinformatic methods and divided them into Group I (a and b) and Group II. Motifs, conserved domains, gene structure and SNPs density are related to the classification of OsCOMTs. The tandem phenomenon plays a key role in the expansion of OsCOMTs. The expression levels of fourteen and thirteen OsCOMTs increased or decreased under salt stress and drought stress, respectively. OsCOMTs showed higher expression levels in the stem. The lignin content of rice was measured in five stages; combined with the expression analysis of OsCOMTs and multiple sequence alignment, we found that OsCOMT8, OsCOMT9 and OsCOMT15 play a key role in the synthesis of lignin. Targeted miRNAs and gene ontology annotation revealed that OsCOMTs were involved in abiotic stress responses. Our study contributes to the analysis of the biological function of OsCOMTs, which may provide information for future rice breeding and editing of the rice genome.
Subject(s)
Oryza , Gene Expression Regulation, Plant , Lignin/metabolism , Methyltransferases/genetics , Methyltransferases/metabolism , Oryza/genetics , Oryza/metabolism , Phylogeny , Plant Breeding , Plant Proteins/metabolism , Stress, Physiological/geneticsABSTRACT
BACKGROUND: The influence of diabetes on the mortality and risk of implantable cardioverter defibrillator (ICD) therapies is still controversial, and a comprehensive assessment is lacking. We performed this systematic review and meta-analysis to address this controversy. METHODS: We systematically searched the PubMed, Embase, Web of Science and Cochrane Library databases to collect relevant literature. Fixed and random effects models were used to estimate the hazard ratio (HR) with 95% CIs. RESULTS: Thirty-six articles reporting on 162,780 ICD recipients were included in this analysis. Compared with nondiabetic ICD recipients, diabetic ICD recipients had higher all-cause mortality (HR = 1.45, 95% CI 1.36-1.55). The subgroup analysis showed that secondary prevention patients with diabetes may suffer a higher risk of all-cause mortality (HR = 1.89, 95% CI 1.56-2.28) (for subgroup analysis, P = 0.03). Cardiac mortality was also higher in ICD recipients with diabetes (HR = 1.68, 95% CI 1.35-2.08). However, diabetes had no significant effect on the risks of ICD therapies, including appropriate or inappropriate therapy, appropriate or inappropriate shock and appropriate anti-tachycardia pacing (ATP). Diabetes was associated with a decreased risk of inappropriate ATP (HR = 0.56, 95% CI 0.39-0.79). CONCLUSION: Diabetes is associated with an increased risk of mortality in ICD recipients, especially in the secondary prevention patients, but does not significantly influence the risks of ICD therapies, indicating that the increased mortality of ICD recipients with diabetes may not be caused by arrhythmias. The survival benefits of ICD treatment in diabetes patients are limited.