ABSTRACT
Rice blast is one of the most widespread and devastating diseases in rice production. Tremendous success has been achieved in the identification and characterization of genes and quantitative trait loci (QTLs) conferring seedling blast resistance, however, genetic studies on panicle blast resistance have lagged far behind. In this study, two advanced backcross inbred sister lines (MSJ13 and MSJ18) were obtained in the process of introducing Pigm into C134S and showed significant differences in the panicle blast resistance. One F2 population derived from the crossing MSJ13/MSJ18 was used to QTL mapping for panicle blast resistance using genotyping by sequencing (GBS) method. A total of seven QTLs were identified, including a major QTL qPBR10-1 on chromosome 10 that explains 24.21% of phenotypic variance with LOD scores of 6.62. Furthermore, qPBR10-1 was verified using the BC1F2 and BC1F3 population and narrowed to a 60.6-kb region with six candidate genes predicted, including two genes encoding exonuclease family protein, two genes encoding hypothetical protein, and two genes encoding transposon protein. The nucleotide variations and the expression patterns of the candidate genes were identified and analyzed between MSJ13 and MSJ18 through sequence comparison and RT-PCR approach, and results indicated that ORF1 and ORF2 encoding exonuclease family protein might be the causal candidate genes for panicle blast resistance in the qPBR10-1 locus. Supplementary Information: The online version contains supplementary material available at 10.1007/s11032-021-01268-3.
ABSTRACT
Currently, more and more studies show that aberrantly expressed microRNAs (miRNAs) are important driving factors for the pathogenesis of hepatocellular carcinoma (HCC). Based on the TCGA and GEO databases, miR-660-5p was identified as a possible target for HCC in this study.In HCC tissues, miR-660-5pexpressionwasparticularly high, and this was confirmed inHCC cell lines. The upregulatedmiR-660-5p showed correlations with tumor size, tumor number, TNM stage and histological grade. In vitro experimental data, aswellas in vivo evidence showed that miR-660-5p has the ability to significantly enhance the cell proliferation rate, clone formation, migration, invasion, and tumorigenic capacity of HCC cells. YWHAH is validated that targeted by miR-660-5p using dual luciferase reporter assay. Knockdown of YWHAH has been shown to partially reverse the tumor suppressive function of miR-660-5p inhibitor. Furthermore, miR-660-5p/YWHAH axis could activate PI3K/AKT pathway, which promoted EMT and cell cycle processes. In conclusion, this study illustrated the function of miR-660-5p/YWHAH axis in HCC and provided potential targets for treating HCC.
Subject(s)
14-3-3 Proteins/genetics , Carcinoma, Hepatocellular/pathology , Liver Neoplasms/pathology , MicroRNAs/genetics , 14-3-3 Proteins/metabolism , Animals , Carcinoma, Hepatocellular/genetics , Carcinoma, Hepatocellular/metabolism , Cell Line, Tumor , Cell Movement/genetics , Cell Proliferation/genetics , Female , Gene Expression Regulation, Neoplastic , Humans , Liver Neoplasms/genetics , Liver Neoplasms/metabolism , Male , Mice, Inbred BALB C , MicroRNAs/metabolism , Middle Aged , Phosphatidylinositol 3-Kinases/metabolism , Signal Transduction/genetics , Xenograft Model Antitumor AssaysABSTRACT
BACKGROUND This study aimed to identify important marker genes in lung adenocarcinoma (LACC) and establish a prognostic risk model to predict the risk of LACC in patients. MATERIAL AND METHODS Gene expression and methylation profiles for LACC and clinical information about cases were downloaded from the Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA) databases, respectively. Differentially expressed genes (DEGs) and differentially methylated genes (DMGs) between cancer and control groups were selected through meta-analysis. Pearson coefficient correlation analysis was performed to identify intersections between DEGs and DMGs and a functional analysis was performed on the genes that were correlated. Marker genes and clinical factors significantly related to prognosis were identified using univariate and multivariate Cox regression analyses. Risk prediction models were then created based on the marker genes and clinical factors. RESULTS In total, 1975 DEGs and 2095 DMGs were identified. After comparison, 16 prognosis-related genes (EFNB2, TSPAN7, INPP5A, VAMP2, CALML5, SNAI2, RHOBTB1, CKB, ATF7IP2, RIMS2, RCBTB2, YBX1, RAB27B, NFATC1, TCEAL4, and SLC16A3) were selected from 265 overlapping genes. Four clinical factors (pathologic N [node], pathologic T [tumor], pathologic stage, and new tumor) were associated with prognosis. The prognostic risk prediction models were constructed and validated with other independent datasets. CONCLUSIONS An integrated model that combines clinical factors and gene markers is useful for predicting risk of LACC in patients. The 16 genes that were identified, including EFNB2, TSPAN7, INPP5A, VAMP2, and CALML5, may serve as novel biomarkers for diagnosis of LACC and prediction of disease prognosis.
Subject(s)
Adenocarcinoma of Lung , Biomarkers, Tumor , DNA Methylation , DNA, Neoplasm , Databases, Genetic , Gene Expression Regulation, Neoplastic , Lung Neoplasms , Models, Biological , Adenocarcinoma of Lung/diagnosis , Adenocarcinoma of Lung/genetics , Adenocarcinoma of Lung/metabolism , Biomarkers, Tumor/genetics , Biomarkers, Tumor/metabolism , DNA, Neoplasm/genetics , DNA, Neoplasm/metabolism , Humans , Lung Neoplasms/diagnosis , Lung Neoplasms/genetics , Lung Neoplasms/metabolism , Predictive Value of Tests , TranscriptomeABSTRACT
Cold stress is a major factor limiting rice (Oryza sativa) production worldwide, especially at the seedling and booting stages. The identification of genes associated with cold tolerance (CT) in rice is important for sustainable food production. Here, we report the results of a genome-wide association study to identify the genetic loci associated with CT by using a 1,033-accession diversity panel. We identified five CT-related genetic loci at the booting stage. Accessions carrying multiple cold-tolerant alleles displayed a higher seed-setting rate than did accessions that had no cold-tolerant alleles or carried a single allele. At the seedling stage, eight genetic loci related to CT have been identified. Among these, LOC_Os10g34840 was identified as the candidate gene for the qPSR10 genetic locus that is associated with CT in rice seedlings. A single-nucleotide polymorphism (SNP), SNP2G, at position 343 in LOC_Os10g34840 is responsible for conferring CT at the seedling stage in rice. Further analysis of the haplotype network revealed that SNP2G was present in 80.08% of the temperate japonica accessions but only 3.8% of the indica ones. We used marker-assisted selection to construct a series of BC4F3 near-isogenic lines possessing the cold-tolerant allele SNP2G When subjected to cold stress, plants carrying SNP2G survived better as seedlings and showed higher grain weight than plants carrying the SNP2A allele. The CT-related loci identified here and the functional verification of LOC_Os10g34840 will provide genetic resources for breeding cold-tolerant varieties and for studying the molecular basis of CT in rice.
Subject(s)
Alleles , Cold-Shock Response/genetics , Oryza/genetics , Plant Proteins/genetics , Cold-Shock Response/physiology , Genome-Wide Association Study , Haplotypes , Oryza/physiology , Phylogeny , Plants, Genetically Modified , Polymorphism, Single Nucleotide , Quantitative Trait Loci , Seedlings/genetics , Seedlings/physiologyABSTRACT
Mammalian cardiac myocytes (CMs) stop proliferating soon after birth and subsequent heart growth comes from hypertrophy, limiting the adult heart's regenerative potential after injury. The molecular events that mediate CM cell cycle exit are poorly understood. To determine the epigenetic mechanisms limiting CM cycling in adult CMs (ACMs) and whether trimethylation of lysine 9 of histone H3 (H3K9me3), a histone modification associated with repressed chromatin, is required for the silencing of cell cycle genes, we developed a transgenic mouse model where H3K9me3 is specifically removed in CMs by overexpression of histone demethylase, KDM4D. Although H3K9me3 is found across the genome, its loss in CMs preferentially disrupts cell cycle gene silencing. KDM4D binds directly to cell cycle genes and reduces H3K9me3 levels at these promotors. Loss of H3K9me3 preferentially leads to increased cell cycle gene expression resulting in enhanced CM cycling. Heart mass was increased in KDM4D overexpressing mice by postnatal day 14 (P14) and continued to increase until 9-weeks of age. ACM number, but not size, was significantly increased in KDM4D expressing hearts, suggesting CM hyperplasia accounts for the increased heart mass. Inducing KDM4D after normal development specifically in ACMs resulted in increased cell cycle gene expression and cycling. We demonstrated that H3K9me3 is required for CM cell cycle exit and terminal differentiation in ACMs. Depletion of H3K9me3 in adult hearts prevents and reverses permanent cell cycle exit and allows hyperplastic growth in adult hearts in vivo.
Subject(s)
Cell Differentiation/genetics , Epigenesis, Genetic , Heart/growth & development , Jumonji Domain-Containing Histone Demethylases/genetics , Animals , Cell Cycle/genetics , Cell Proliferation/genetics , Chromatin/genetics , Gene Expression Regulation, Developmental , Histone-Lysine N-Methyltransferase/genetics , Humans , Methylation , Mice, Transgenic , Myocytes, Cardiac/cytology , Myocytes, Cardiac/metabolismABSTRACT
Heikezijing, a japonica rice landrace from the Taihu region of China, exhibited broad-spectrum resistance to more than 300 isolates of the blast pathogen (Magnaporthe oryzae). In our previous research, we fine mapped a broad-spectrum resistance gene, Pi-hk1, in chromosome 11. In this research, 2010-9(G1), one of the predominant races of blast in the Taihu Lake region of China, was inoculated into 162 recombinant inbred lines (RIL) and two parents, Heikezijing and Suyunuo, for mapping the resistance-blast quantitative trait loci (QTL). Three QTL (Lsqtl4-1, Lsqtl9-1, and Lsqtl11-1) associated with lesion scores were detected on chromosomes 4, 9, and 11 and two QTL (Lnqtl1-1 and Lnqtl9-1) associated with average lesion numbers were detected on chromosomes 1 and 9. The QTL Lsqtl9-1 conferring race-specific resistance to 2010-9(G1) at seedling stages showed logarithm of the odds scores of 9.10 and phenotypic variance of 46.19% and might be a major QTL, named Pi-hk2. The line RIL84 with Pi-hk2 derived from a cross between Heikezijing and Suyunuo was selected as Pi-hk2 gene donor for developing fine mapping populations. According to the resistance evaluation of recombinants of three generations (BC1F2, BC1F3, and BC1F4), Pi-hk2 was finally mapped to a 143-kb region between ILP-19 and RM24048, and 18 candidate genes were predicted, including genes that encode pleiotropic drug resistance protein 4 (n = 2), WRKY74 (n = 1), cytochrome b5-like heme/steroid-binding domain containing protein (n = 1), protein kinase (n = 1), and ankyrin repeat family protein (n = 1). These results provide essential information for cloning of Pi-hk2 and its potential utility in breeding resistant rice cultivars by marker-assisted selection.
Subject(s)
Disease Resistance/genetics , Magnaporthe/physiology , Oryza/genetics , Plant Diseases/immunology , Plant Proteins/genetics , Quantitative Trait Loci/genetics , Breeding , China , Chromosome Mapping , Gene Expression Profiling , Genetic Markers/genetics , Oligonucleotide Array Sequence Analysis , Organ Specificity , Oryza/immunology , Oryza/microbiology , Phenotype , Plant Diseases/microbiology , Plant Leaves/genetics , Plant Leaves/immunology , Plant Leaves/microbiology , Plant Proteins/metabolism , Seedlings/genetics , Seedlings/immunology , Seedlings/microbiologyABSTRACT
Rice blast, caused by Magnaporthe oryzae, threatens rice production in most of the rice-growing areas in China, especially in regions that have grown Oryza sativa subsp. japonica in recent years. The use of resistance genes is the most effective and economical approach for blast control. In our study, a set of six near-isogenic lines (NIL) were developed by introgression of six resistance alleles of the Piz locus (Pi2, Pigm, Pi40, Pi9, Piz, and Pizt) into a blast-susceptible, high-yielding, high-quality japonica '07GY31' via marker-assisted backcross breeding. Artificial inoculation using 144 M. oryzae isolates collected from the lower region of the Yangtze River, China, revealed that most of the NIL, including NIL-Pi2, NIL-Pigm, NIL-Pi40, NIL-Pi9, and NIL-Pizt, exhibited broad-spectrum resistance against rice blast at the seedling stage, with resistance frequencies (RF) of 93.06 to 98.61%. NIL-Piz was an exception, with an RF of 21.53%, which was slightly higher than the recurrent parent 07GY31. NIL-Pi40 and NIL-Pigm had broad-spectrum resistance (RF of 93.33 and 71.67%, respectively) at the heading stage following inoculation of 60 isolates of M. oryzae. Field trials with artificial inoculation at the seedling and heading stage showed that NIL-Pigm and NIL-Pi40 were highly resistant in four locations under high disease pressure. NIL-Pizt showed effective resistance in three locations from Zhejiang and Jiangsu Provinces. This study shows that O. sativa subsp. japonica alleles of the Piz locus confer resistance to M. oryzae, and provides an effective method to enhance seedling and panicle blast resistance in rice plants in the lower region of the Yangtze River, China.
ABSTRACT
Grain size and shape are important components determining rice grain yield, and they are controlled by quantitative trait loci (QTLs). Here, we report the cloning and functional characterization of a major grain length QTL, qGL3, which encodes a putative protein phosphatase with Kelch-like repeat domain (OsPPKL1). We found a rare allele qgl3 that leads to a long grain phenotype by an aspartate-to-glutamate transition in a conserved AVLDT motif of the second Kelch domain in OsPPKL1. The rice genome has other two OsPPKL1 homologs, OsPPKL2 and OsPPKL3. Transgenic studies showed that OsPPKL1 and OsPPKL3 function as negative regulators of grain length, whereas OsPPKL2 as a positive regulator. The Kelch domains are essential for the OsPPKL1 biological function. Field trials showed that the application of the qgl3 allele could significantly increase grain yield in both inbred and hybrid rice varieties, due to its favorable effect on grain length, filling, and weight.
Subject(s)
Alleles , Genes, Plant/genetics , Oryza/growth & development , Oryza/genetics , Plant Proteins/genetics , Seeds/anatomy & histology , Seeds/genetics , Agriculture , Base Sequence , Cloning, Molecular , Hybridization, Genetic , Inbreeding , Oryza/anatomy & histology , Oryza/ultrastructure , Plant Proteins/metabolism , Polymorphism, Genetic , Quantitative Trait Loci/genetics , Quantitative Trait, Heritable , Reproducibility of Results , Seeds/ultrastructure , Sequence Homology, Amino AcidSubject(s)
Acute Pain/etiology , Genital Diseases, Male/diagnosis , Scrotum/diagnostic imaging , Spermatic Cord Torsion/diagnosis , Genital Diseases, Male/pathology , Humans , Male , Orchiopexy/methods , Scrotum/blood supply , Scrotum/pathology , Spermatic Cord Torsion/prevention & control , Spermatic Cord Torsion/therapy , Treatment Outcome , Ultrasonography/methods , Young AdultABSTRACT
Top managers' past experiences (e.g., foreign experience) significantly impact their decision-making behavior, which may influence firms' sustainable development. The available literature, focusing on the role of the increase in the number of top executives with foreign experience in corporate social responsibility (CSR), yields mixed results. In order to clarify the ambiguous relationship between executive foreign experience and CSR, we empirically examine the effect of the geographic diversity of top executives' foreign experience on CSR. Based on a hand-collected dataset of the top management team's (TMT's) foreign experience, we demonstrate the positive impact of the geographic diversity of returnee executives' foreign experience on firms' CSR using Chinese A-share listed firms from 2009 to 2018. Moreover, this impact is stronger in firms with political connections with the central government and in regions with good market development. Furthermore, the mechanism analysis shows that returnee executives drive firms' CSR by promoting corporate donations and green innovation. This paper offers clear policy implications by suggesting that hiring returnees with a broad geographic scope of foreign experience as corporate executives is an efficient way to enhance firms' CSR.
Subject(s)
Asian People , Humans , Federal Government , Internationality , Personnel Selection , Social Responsibility , ChinaABSTRACT
Understanding the environmental response patterns of riverine microbiota is essential for predicting the potential impact of future environmental change on river ecosystems. Vulnerable plateau ecosystems are particularly sensitive to climate and local environmental changes, however, the environmental response patterns of the taxonomic and functional diversity of riverine microbiota remain unclear. Here, we conducted a systematic investigation of the taxonomic and functional diversity of bacteria and archaea from riparian soils, sediments, and water across the elevation of 1800- 4800 m in the Qinghai-Tibet Plateau rivers. We found that within the elevation range of 1800 to 3800 m, riparian soils and sediments exhibited similarities and stabilities in microbial taxonomic and functional diversity, and water microbiomes were more sensitive with great fluctuations in microbial diversity. Beyond the elevation of 3800 m, microbial diversity declined across all riverine matrixes. Local environmental conditions can influence the sensitivity of microbiomes to climate change. The combination of critical climate and local environmental factors, including total nitrogen, total organic carbon, as well as climate variables associated with temperature and precipitation, provided better explanations for microbial diversity than single-factor analyses. Under the extremely adverse scenario of high greenhouse gas emission concentrations (SSP585), we anticipate that by the end of this century, the bacterial, archaeal, and microbial functional diversity across the river network of the Yangtze and Yellow source basin would potentially change by -16.9- 5.2 %, -16.1- 5.7 %, and -9.3- 6.4 %, respectively. Overall, climate and local environments jointly shaped the microbial diversity in plateau river ecosystems, and water microbiomes would provide early signs of environmental changes. Our study provides effective theoretical foundations for the conservation of river biodiversity and functional stability under environmental changes.
Subject(s)
Archaea , Microbiota , Tibet , Ecosystem , Rivers/microbiology , Bacteria , Soil , WaterABSTRACT
One Japonica rice landrace, Heikezijing, from the Taihu Lake region of China, exhibits broad-spectrum resistance to rice blast. As characterized in our previous research, a main-effect resistance (R) gene, Pi-hk1, in Heikezijing against five isolates (GD10-279a, JS2004-141-1, JS2004-185, JS90-78, and Hoku1) was roughly mapped on the long arm of chromosome 11. To fine map Pi-hk1, one recombinant inbred line (RIL), RIL72 (F2:8), from the cross between Heikezijing and blast-susceptible variety Suyunuo, was further crossed and backcrossed with Suyunuo to produce a BC1F2 population of 477 individuals. Inoculation experiments with the representative isolate Hoku 1 indicated that RIL72 carries a single dominant R gene for blast resistance. With the help of advanced BC1F3 (915 plants), BC1F4 (4,459 plants), and BC1F5 (2,000 plants) mapping populations, Pi-hk1 was finally mapped to a 107-kb region between molecular markers P3586 and ILP3, and co-segregated with the markers P4098, RM7654, and P4099. By sequence analysis of Heikezijing bacterial artificial chromosome clones covering Pi-hk1 region, 16 predicted genes were identified within this region, including three nucleotide-binding site leucine-rich repeat candidate genes. These results provide essential information for cloning of Pi-hk1 and its application in rice breeding for broad-spectrum blast resistance by marker-assisted selection.
Subject(s)
Disease Resistance/genetics , Magnaporthe/pathogenicity , Oryza/genetics , Plant Diseases/immunology , Plant Proteins/genetics , Breeding , China , Chromosome Mapping , Chromosomes, Artificial, Bacterial , Gene Expression Regulation, Plant , Oryza/immunology , Oryza/microbiology , Plant Diseases/microbiologyABSTRACT
The existing literature on corporate social responsibility (CSR) drivers focuses on firm- and institution-level factors and rarely on the role of political incentives. Public officials control enormous resources in China, and their political incentives substantially shape certain firm behaviors. As CSR is one of the critical measures that the central government uses to evaluate the performance of local government, local officials have the incentive to channel firms into accomplishing their political goals. Correspondingly, local firms may strategically implement CSR to build a good relationship with local governments. This study investigates the impact of local officials' political incentives (measured by tenure) on firms' CSR. Using a panel of publicly listed Chinese firms covering 2009-2019, it documents a U-shaped effect of government officials' tenure on the CSR performance of firms within their jurisdiction. To wit, the firm's CSR decreases first and then increases with the growth of tenure. Moreover, this U-shaped effect will be strengthened in regions with a high priority of gross domestic product (GDP) growth and will be weakened in regions with good market development. In addition, there is no significant evidence that party officials' tenure affects firms' CSR. Overall, this study advances our understanding of the political determinants of CSR in emerging markets.
Subject(s)
Local Government , Motivation , Federal Government , Social Responsibility , ChinaABSTRACT
BACKGROUND: As a small G protein of Ras family, Ras-like-without-CAAX-1 (RIT1) plays a critical role in various tumors. Our previous study has demonstrated the involvement of RIT1 in promoting malignant progression of hepatocellular carcinoma (HCC). However, its underlying mechanism remains unclear. METHODS: Gene set enrichment analysis (GSEA) was conducted in the TCGA LIHC cohort to investigate the underlying biological mechanism of RIT1. Live cell imaging, immunofluorescence (IF) and flow cytometry assays were used to verify biological function of RIT1 in HCC mitosis. Subcutaneous xenografting of human HCC cells in BALB/c nude mice was utilized to assess tumor proliferation in vivo. RNA-seq, co-immunoprecipitation (Co-IP), mass spectrometry analyses, western blot and IF assays were employed to elucidate the mechanisms by which RIT1 regulates mitosis and promotes proliferation in HCC. RESULTS: Our findings demonstrate that RIT1 plays a crucial role in regulating mitosis in HCC. Knockdown of RIT1 disrupts cell division, leading to G2/M phase arrest, mitotic catastrophe, and apoptosis in HCC cells. SMC3 is found to interact with RIT1 and knockdown of SMC3 attenuates the proliferative effects mediated by RIT1 both in vitro and in vivo. Mechanistically, RIT1 protects and maintains SMC3 acetylation by binding to SMC3 and PDS5 during mitosis, thereby promoting rapid cell division and proliferation in HCC. Notably, we have observed an upregulation of SMC3 expression in HCC tissues, which is associated with poor patient survival and promotion of HCC cell proliferation. Furthermore, there is a significant positive correlation between the expression levels of RIT1, SMC3, and PDS5. Importantly, HCC patients with high expression of both RIT1 and SMC3 exhibit worse prognosis compared to those with high RIT1 but low SMC3 expression. CONCLUSIONS: Our findings underscore the crucial role of RIT1 in regulating mitosis in HCC and further demonstrate its potential as a promising therapeutic target for HCC treatment.
Subject(s)
Carcinoma, Hepatocellular , Liver Neoplasms , Animals , Mice , Humans , Carcinoma, Hepatocellular/pathology , Liver Neoplasms/pathology , Mice, Nude , Cell Proliferation/genetics , Mitosis , Gene Expression Regulation, Neoplastic , Cell Line, Tumor , Chromosomal Proteins, Non-Histone/metabolism , Chondroitin Sulfate Proteoglycans/genetics , Chondroitin Sulfate Proteoglycans/metabolism , Cell Cycle Proteins/genetics , ras Proteins/metabolismABSTRACT
This study reports the creation of herbicide-resistant rice lines via CRISPR-Cas9-mediated editing of the 3' UTR of OsHPPD. Resistance index calculations revealed that two resistant lines, TS8-2#-10 and TS8-8#-6, exhibited 4.8-fold and 3.7-fold greater resistance to HPPD-inhibiting herbicides compared with the wild type, YG3012.
Subject(s)
Herbicides , Oryza , CRISPR-Cas Systems/genetics , Oryza/genetics , 3' Untranslated Regions , Herbicides/pharmacologyABSTRACT
Rice blast, caused by the fungal pathogen Magnaporthe oryzae, is one of the most important diseases of rice. Utilization of blast-resistance genes is the most economical, effective, and environmentally friendly way to control the disease. However, genetic resources with broad-spectrum resistance (BSR) that is effective throughout the rice growth period are rare. In this work, using a genome-wide association study, we identify a new blast-resistance gene, Pijx, which encodes a typical CC-NBS-LRR protein. Pijx is derived from a wild rice species and confers BSR to M. oryzae at both the seedling and panicle stages. The functions of the resistant haplotypes of Pijx are confirmed by gene knockout and overexpression experiments. Mechanistically, the LRR domain in Pijx interacts with and promotes the degradation of the ATP synthase ß subunit (ATPb) via the 26S proteasome pathway. ATPb acts as a negative regulator of Pijx-mediated panicle blast resistance, and interacts with OsRbohC to promote its degradation. Consistently, loss of ATPb function causes an increase in NAPDH content and ROS burst. Remarkably, when Pijx is introgressed into two japonica rice varieties, the introgression lines show BSR and increased yields that are approximately 51.59% and 79.31% higher compared with those of their parents in a natural blast disease nursery. In addition, we generate PPLPijx Pigm and PPLPijx Piz-t pyramided lines and these lines also have higher BSR to panicle blast compared with Pigm- or Piz-t-containing rice plants. Collectively, this study demonstrates that Pijx not only confers BSR to M. oryzae but also maintains high and stable rice yield, providing new genetic resources and molecular targets for breeding rice varieties with broad-spectrum blast resistance.
Subject(s)
Magnaporthe , Oryza , Plant Proteins/genetics , Plant Proteins/metabolism , Reactive Oxygen Species/metabolism , Seedlings/genetics , Seedlings/metabolism , Disease Resistance/genetics , Genome-Wide Association Study , Plant Breeding , Adenosine Triphosphate/metabolism , Oryza/metabolism , Plant Diseases/genetics , Plant Diseases/microbiology , Magnaporthe/geneticsABSTRACT
Increasing rice yield is essential for alleviating global food crisis. High soil nutrient level guarantees high rice yields in conventional rice monoculture (RM) systems, but excessive unconsumed nutrients act as pollutants and can even threaten rice growth. The integrated rice-crayfish (IRC) system aims to transfer the excess nutrients from crayfish to paddy fields to improve the comprehensive utilization rate of nutrients and create additional profits, while the responding characteristics of IRC microbial communities in paddy fields and rice yields to the nutrient status remain unclear. Considering the crucial roles of microbiomes in promoting nutrient cycling for crop absorption in rice production progresses, the composition and functional characteristics of soil microbial communities from six IRC farms with variant nutrient statuses in the Yangtze River Delta were surveyed in this study. Compared with RM systems, IRC systems with appropriately improved (p < 0.05) soil quality created favorable nutrient (FN) status accompanied by 15% rice yields increase, while IRC systems with extremely high nutrients (HN) status (p < 0.01) accompanied by 14% rice yields reduction. Soil microbial diversity and network complexity were maintained in FN-IRC systems, but declined in HN-IRC systems, with the Shannon index significantly decreased by 9.2% and network density decreased from 0.135 (in RM) to 0.062. In the FN-IRC systems, the keystone taxa identified by co-occurrence networks displayed inextricably positive correlations with soil nitrification potential (calculated by normalization of amoA gene abundance) and rice yields. While in HN-IRC systems, the large loss of keystone taxa might limit soil nitrogen fixation potential (calculated by normalization of nifH gene abundance), and further rice yields. Our study indicates that soil nutrient management in IRC systems claim attention, and the improvement of nitrogen metabolism is the key to realize agricultural cleaner production.
Subject(s)
Oryza , Agriculture , Animals , Astacoidea/metabolism , Nitrogen/analysis , Nutrients , Soil , Soil MicrobiologyABSTRACT
Rice blast, caused by Magnaporthe oryzae (M. oryzae), is one of the most destructive diseases threatening rice production worldwide. Development of resistant cultivars using broad-spectrum resistance (R) genes with high breeding value is the most effective and economical approach to control this disease. In this study, the breeding potential of Pigm gene in geng/japonica rice breeding practice in Jiangsu province was comprehensively evaluated. Through backcross and marker-assisted selection (MAS), Pigm was introduced into two geng rice cultivars (Wuyungeng 32/WYG32 and Huageng 8/HG8). In each genetic background, five advanced backcross lines with Pigm (ABLs) and the same genotypes as the respective recurrent parent in the other 13 known R gene loci were developed. Compared with the corresponding recurrent parent, all these ABLs exhibited stronger resistance in seedling inoculation assay using 184 isolates collected from rice growing regions of the lower region of the Yangtze River. With respect to panicle blast resistance, all ABLs reached a high resistance level to blast disease in tests conducted in three consecutive years with the inoculation of seven mixed conidial suspensions collected from different regions of Jiangsu province. In natural field nursery assays, the ABLs showed significantly higher resistance than the recurrent parents. No common change on importantly morphological traits and yield-associated components was found among the ABLs, demonstrating the introduction of Pigm had no tightly linked undesirable effect on rice economically important traits and its associated grain weight reduction effect could be probably offset by others grain weight genes or at least in the background of the aforementioned two varieties. Notably, one rice line with Pigm, designated as Yangnonggeng 3091, had been authorized as a new variety in Jiangsu province in 2021, showing excellent performance on both grain yield and quality, as well as the blast resistance. Together, these results suggest that the Pigm gene has a high breeding value in developing rice varieties with durable and broad-spectrum resistance to blast disease.
ABSTRACT
The amyloplast is a specialized plastid in rice endosperm cells where starch is synthesized and stored as starch granules (SGs). However, little is known about the molecular mechanism underlying amyloplast and SG development. In this study, a novel mutant (c134) demonstrating a floury endosperm with enlarged SGs and amyloplasts was identified. The floury endosperm was caused by rounder, loosely packed SG. Grain-quality profile and expression analysis showed reduced contents of total starch and amylose in the c134 mutant, as well as reduced expression of a number of genes involved in starch biosynthesis. Galactosyldiacylglycerol (GDG) content and fatty acid synthesis play important roles in plastid development, and in the c134 endosperm, an obvious decrease in GDG and various fatty acids was observed, with down-regulated expression of various genes involved in lipid biosynthesis. Furthermore, map-based cloning revealed an amino acid substitution (glycine to aspartic acid) in the substandard starch grain4 (SSG4) protein. The results of this study suggest that SSG4 influences the regulation of starch and lipid metabolism as well as amyloplast development, a finding that is useful for potential genetic improvement of rice grain quality in future starch and lipid breeding and biotechnology.
ABSTRACT
STUDY OBJECTIVE: The purpose of this feasibility study is to develop and validate a new assessment tool and scoring system for multitasking competency for physicians in-training in a timed simulated setting. The multitasking competency includes ability to appropriately prioritize and implement tasks for different patients who present simultaneously. METHODS: We designed three single task stations with different levels of difficulty and priority. These skill stations were then combined to create a multitasking simulation scenario. Skill checklists and the global rating scale were utilized to assess the participants' performance. A multitasking score, multitasking index, and priority score were developed to measure the multitasking ability of participants. RESULTS: Thirty-three first-year postgraduate physicians were recruited for this prospective study. The total performance scores were significantly higher for the single-tasking stations than for the multitasking scenario. In terms of the time needed to complete the tasks, the participants spent more time on the multitasking scenario than on the single-tasking scenario. There were significant correlations between the global rating scale and the multitasking score (rho = 0.693, p < 0.001) and between the global rating scale and the multitasking index (rho = 0.515, p < 0.001). The multitasking score, multitasking index, and priority score did not have any significant correlations with the total single-tasking score. CONCLUSION: We demonstrated that the use of a simulated multitasking scenario could be an effective method of assessing multitasking ability and allow assessors to offer better quality feedback.