RESUMO
Rice feeds half the world's population, and rice blast is often a destructive disease that results in significant crop loss. Non-race-specific resistance has been more effective in controlling crop diseases than race-specific resistance because of its broad spectrum and durability. Through a genome-wide association study, we report the identification of a natural allele of a C2H2-type transcription factor in rice that confers non-race-specific resistance to blast. A survey of 3,000 sequenced rice genomes reveals that this allele exists in 10% of rice, suggesting that this favorable trait has been selected through breeding. This allele causes a single nucleotide change in the promoter of the bsr-d1 gene, which results in reduced expression of the gene through the binding of the repressive MYB transcription factor and, consequently, an inhibition of H2O2 degradation and enhanced disease resistance. Our discovery highlights this novel allele as a strategy for breeding durable resistance in rice.
Assuntos
Oryza/genética , Proteínas de Plantas/genética , Fatores de Transcrição/genética , Sequência de Bases , Cruzamento , Resistência à Doença , Técnicas de Inativação de Genes , Genoma de Planta , Estudo de Associação Genômica Ampla , Doenças das Plantas , Regiões Promotoras GenéticasRESUMO
Pre-harvest sprouting (PHS) is a significant threat to global food security due to its association with losses in both yield and quality. Among the genes involved in PHS resistance in wheat, PHS-3D (TaMyb10-D) plays a crucial role. Here, we characterized the sequence variations of TaMyb10 genes in 416 bread wheat and 302 Aegilops tauschii accessions. Within TaMyb10-A sequences, we identified a deletion ranging from 214 to 305 bp in the signal and amino acid coding region, present in 61.3% of the accessions. Similarly, 79.3% of the TaMyb10-B sequences within the third exon region exhibited a 19 bp deletion. Additionally, 40.8% of the accessions lacked the 2.4 Mb fragment (in/del mutations) on Chr3D, where TaMyb10-D/PHS-3D was located. Interestingly, the geographical distribution of accessions showed little correlation with the divergence of TaMyb10. TaMyb10-A-IIIDele, TaMyb10-B-IVDele, and TaMyb10-D-VDele genotypes were prevalent in wheat populations across continents. Despite their structural variations, the five distinct protein types exhibited comparable ability to bind the promoters of downstream genes in the flavonoid and ABA pathways, such as CHS, DFR, and NCED. Furthermore, the combination of TaMyb10 homologs was significantly associated with grain color and germination percentages. Accessions exclusively harboring TaMyb10-D displayed red seed color and reduced germination percentages, indicating the predominant role of TaMyb10-D compared to TaMyb10-A and TaMyb10-B. This comprehensive investigation enhances our understanding of the structural variations and functional divergence of TaMyb10, providing valuable insights and resources for improving PHS resistance in wheat.
Assuntos
Proteínas de Plantas , Triticum , Triticum/genética , Triticum/fisiologia , Triticum/crescimento & desenvolvimento , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Grão Comestível/genética , Grão Comestível/crescimento & desenvolvimento , Aegilops/genética , Germinação/genética , Variação Genética , Sementes/genética , Sementes/crescimento & desenvolvimento , Sementes/fisiologiaRESUMO
BACKGROUND: Wheat grain endosperm is mainly composed of proteins and starch. The contents and the overall composition of seed storage proteins (SSP) markedly affect the processing quality of wheat flour. Polyploidization results in duplicated chromosomes, and the genomes are often unstable and may result in a large number of gene losses and gene rearrangements. However, the instability of the genome itself, as well as the large number of duplicated genes generated during polyploidy, is an important driving force for genetic innovation. In this study, we compared the differences in starch and SSP, and analyzed the transcriptome and metabolome among Aegilops sharonensis (R7), durum wheat (Z636) and amphidiploid (Z636×R7) to reveal the effects of polyploidization on the synthesis of seed reserve polymers. RESULTS: The total starch and amylose content of Z636×R7 was significantly higher than R7 and lower than Z636. The gliadin and glutenin contents of Z636×R7 were higher than those in Z636 and R7. Through transcriptome analysis, there were 21,037, 2197, 15,090 differentially expressed genes (DEGs) in the three comparison groups of R7 vs Z636, Z636 vs Z636×R7, and Z636×R7 vs R7, respectively, which were mainly enriched in carbon metabolism and amino acid biosynthesis pathways. Transcriptome data and qRT-PCR were combined to analyze the expression levels of genes related to storage polymers. It was found that the expression levels of some starch synthase genes, namely AGP-L, AGP-S and GBSSI in Z636×R7 were higher than in R7 and among the 17 DEGs related to storage proteins, the expression levels of 14 genes in R7 were lower than those in Z636 and Z636×R7. According to the classification analysis of all differential metabolites, most belonged to carboxylic acids and derivatives, and fatty acyls were enriched in the biosynthesis of unsaturated fatty acids, niacin and nicotinamide metabolism, one-carbon pool by folate, etc. CONCLUSION: After allopolyploidization, the expression of genes related to starch synthesis was down-regulated in Z636×R7, and the process of starch synthesis was inhibited, resulting in delayed starch accumulation and prolongation of the seed development process. Therefore, at the same development time point, the starch accumulation of Z636×R7 lagged behind that of Z636. In this study, the expression of the GSe2 gene in Z636×R7 was higher than that of the two parents, which was beneficial to protein synthesis, and increased the protein content. These results eventually led to changes in the synthesis of seed reserve polymers. The current study provided a basis for a greater in-depth understanding of the mechanism of wheat allopolyploid formation and its stable preservation, and also promoted the effective exploitation of high-value alleles.
Assuntos
Aegilops , Sementes , Triticum , Triticum/genética , Triticum/metabolismo , Aegilops/genética , Aegilops/metabolismo , Sementes/genética , Sementes/metabolismo , Hibridização Genética , Poliploidia , Amido/biossíntese , Amido/metabolismo , Transcriptoma , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Proteômica/métodos , MultiômicaRESUMO
Hypertrophic pachymeningitis (HP) is a rare disorder marked by thickening of the dura mater due to diverse etiologies. MPO-ANCA-positive HP represents a variant of AAV confined to the central nervous system, distinguished by the presence of serum MPO antibodies. Distinguishing HP triggered by MPO-ANCA from other causes can be challenging.In this study, we present two cases of MPO-ANCA-positive HP initially misdiagnosed as intracranial infections. Case 1 underwent surgery for chronic suppurative otitis media, with histopathological findings revealing inflammatory changes without definitive suppuration. He was presumed to have a secondary intracranial infection resulting from the surgery. However, his condition deteriorated despite two weeks of antibiotic and antiviral treatment. Case 2 presented with headache and was initially suspected of having intracranial Brucellosis given his serum Brucella positivity. Despite treatment for brucellosis, his symptoms persisted, and he developed visual and hearing impairments. Both patients were ultimately diagnosed with MPO-ANCA-positive HP, exhibiting serum MPO antibody positivity. Their symptoms showed improvement with glucocorticoid and immunosuppressive therapy.Based on these observations, we propose that MPO-ANCA-positive HP may initially present as intracranial infection. For HP patients presenting with headache, mastoiditis, otitis media, and visual loss, it is imperative to conduct ANCA antibody-related tests to enhance diagnostic precision.
Assuntos
Anticorpos Anticitoplasma de Neutrófilos , Meningite , Humanos , Masculino , Meningite/diagnóstico , Meningite/imunologia , Anticorpos Anticitoplasma de Neutrófilos/sangue , Diagnóstico Diferencial , Pessoa de Meia-Idade , Peroxidase/imunologia , Hipertrofia/diagnóstico , Adulto , Brucelose/diagnóstico , Brucelose/complicaçõesRESUMO
The field of nanotechnology continues to grow with the ongoing discovery and characterization of novel nanomaterials with unconventional size-dependent properties; however, the ability to apply modern manufacturing strategies for practical device design of these nanoscale structures is significantly limited by their small size. Although interconnection has been previously demonstrated between nanoscale components, such approaches often require the use of expensive oxidation-resistant noble metal materials and time-consuming or untargeted strategies for welded interconnection such as laser ablation or plasmonic resonance across randomly oriented component networks. In this work, a three-segment gold-nickel-gold nanowire structure is synthesized using templated electrodeposition and modified via monolayer-directed aqueous chemical reduction of tin solder selectively on the gold segments. This core/shell nanowire structure is capable of directed magnetic assembly tip-to-tip and along substrate pads in network orientation. Upon infrared heating in a flux vapor atmosphere, the solder payload melts and establishes robust and highly conductive wire-wire joints. The targeted solder deposition strategy has been applied to various other multi-segment gold/nickel nanowire configurations and other metallic systems to demonstrate the capability of the approach. This core/shell technique of pre-loading magnetically active nanowires with solder material simplifies the associated challenges of size-dependent component orientation in the manufacture of nanoscale electronic devices.
RESUMO
To investigate the effects of different initial processing methods on the quality of Fritillaria taipaiensis, this study explored the effects of anti-browning treatment, drying methods, and drying temperatures on the commercial characters, chromaticity values, and alkaloid and nucleoside components of Fritillariae Taipaiensis Bulbus. The results were comprehensively evaluated through correlation analysis(CA), principal component analysis(PCA), and hierarchical clustering analysis(HCA). Compared with those of the direct drying group(WD60), the chromaticity values(ΔE*) of the groups with scraped outer skin( FHB1) and mixed lime powder treatments(FHB2) were significantly reduced, indicating the inhibition of the browning process. The total alkaloid content of the group with mixed raw soil treatment(FHB3) and the FHB2 group showed no significant change, whereas that of the group with 5%Na Cl O solution rinse treatment(FHB4) was the lowest. Compared with air-blast dried(WD50) samples, the ΔE* values of freezedried(FS6) and vacuum-dried(FS5) samples were significantly decreased, with an increase in total alkaloid contents. Conversely,the ΔE* values of shade-dried(FS1) and sun-dried(FS2) samples were significantly increased, with severe browning and low total alkaloid contents. The total alkaloid contents of heat-pump-dried(FS4) samples showed no significant change, and their ΔE* value was significantly decreased, with a light degree of browning and favorable commercial characters. The total alkaloid content of air-blast dried samples initially increased and then decreased within the range of 40-80 â, and the highest content was recorded at 70 â. The ΔE* values of high-temperature air-blast dried samples(70-80 â) were smaller with a light degree of browning, whereas their texture was compact and lacked powder. CA revealed a significant relationship between the uracil content and chromaticity value of the samples(P< 0. 05). The clustering relationships among samples subjected to different treatments were visualized via PCA and HCA. The results showed that FHB2 and air-blast drying(50-60 â) were more suitable for large-scale production, and heat pump drying could be a promising direction for future development. This study provides a scientific basis for optimizing the initial processing methods of Fritillaria taipaiensis.
Assuntos
Alcaloides , Medicamentos de Ervas Chinesas , Fritillaria , Fritillaria/química , Alcaloides/análise , Alcaloides/química , Medicamentos de Ervas Chinesas/química , Medicamentos de Ervas Chinesas/análise , Análise de Componente Principal , Dessecação/métodosRESUMO
BACKGROUND: Fusarium crown rot (FCR) is a chronic disease of cereals worldwide. Compared with tetraploid wheat, hexaploid wheat is more resistant to FCR infection. The underlying reasons for the differences are still not clear. In this study, we compared FCR responses of 10 synthetic hexaploid wheats (SHWs) and their tetraploid and diploid parents. We then performed transcriptome analysis to uncover the molecular mechanism of FCR on these SHWs and their parents. RESULTS: We observed higher levels of FCR resistance in the SHWs compared with their tetraploid parents. The transcriptome analysis suggested that multiple defense pathways responsive to FCR infection were upregulated in the SHWs. Notably, phenylalanine ammonia lyase (PAL) genes, involved in lignin and salicylic acid (SA) biosynthesis, exhibited a higher level of expression to FCR infection in the SHWs. Physiological and biochemical analysis validated that PAL activity and SA and lignin contents of the stem bases were higher in SHWs than in their tetraploid parents. CONCLUSION: Overall, these findings imply that improved FCR resistance in SHWs compared with their tetraploid parents is probably related to higher levels of response on PAL-mediated lignin and SA biosynthesis pathways.
Assuntos
Fusarium , Fusarium/fisiologia , Tetraploidia , Lignina , Poaceae , Genótipo , Doenças das Plantas/genética , Resistência à Doença/genéticaRESUMO
KEY MESSAGE: A novel and stably expressed QTL QSNS.sicau-SSY-7A for spikelet number per spike in wheat without negative effects on thousand-kernel weight was identified and validated in different genetic backgrounds. Spikelet number per spike (SNS) is an important determinant of yield in wheat. In the present study, we combined bulked segregant analysis (BSA) and the wheat 660 K single-nucleotide polymorphism (SNP) array to rapidly identify genomic regions associated with SNS from a recombinant inbred line (RIL) population derived from a cross between the wheat lines S849-8 and SY95-71. A genetic map was constructed using Kompetitive Allele Specific PCR markers in the SNP-enriched region on the long arm of chromosome 7A. A major and stably expressed QTL, QSNS.sicau-SSY-7A, was detected in multiple environments. It was located in a 1.6 cM interval on chromosome arm 7AL flanked by the markers AX-109983514 and AX-109820548. This QTL explained 6.86-15.72% of the phenotypic variance, with LOD values ranging from 3.66 to 8.66. Several genes associated with plant growth and development were identified in the interval where QSNS.sicau-SSY-7A was located on the 'Chinese Spring' wheat and wild emmer reference genomes. Furthermore, the effects of QSNS.sicau-SSY-7A and WHEAT ORTHOLOG OFAPO1(WAPO1) on SNS were analyzed. Interestingly, QSNS.sicau-SSY-7A significantly increased SNS without negative effects on thousand-kernel weight, anthesis date and plant height, demonstrating its great potential for breeding aimed at improving grain yield. Taken together, these results indicate that QSNS.sicau-SSY-7A is a promising locus for yield improvement, and its linkage markers are helpful for fine mapping and molecular breeding.
Assuntos
Melhoramento Vegetal , Triticum , Triticum/genética , Alelos , Embaralhamento de DNA , Grão ComestívelRESUMO
BACKGROUND: Eighteen wheat (Triticum aestivum-Aegilops sharonensis) introgression lines were generated in the previous study. These lines possessed four types of high molecular weight glutenin subunit (HMW-GS) combinations consisting of one glutenin from Ae. sharonensis (Glu-1Ssh ) plus one or more HMW-GSs from common wheat (Glu-A1, Glu-B1, or Glu-D1). RESULTS: In this study, we conducted quality tests to explore the effects of 1Ssh x2.3 and 1Ssh y2.9 on the processing quality of 18 wheat-Aegilops sharonensis introgression lines. Our data showed that the 1Ssh x2.3 and 1Ssh y2.9 subunits had a positive effect on gluten and baking quality. The bread volume of all these lines was higher than that of the parental wheat line LM3. In these lines, the HMW-GS content and the HMW/LMW ratio of 66-36-11 were higher than those of LM3, and the 66-36-11 line exhibited greatly improved quality parameters in comparison with the parent LM3. CONCLUSION: These results demonstrated that the 1Ssh x2.3 and 1Ssh y2.9 subunits from Ae. sharonensis contributed immensely to gluten strength and bread-baking quality, and proved a positive relationship between the HMW-GS sizes and their effects on dough strength in vivo. The materials developed could be used by breeding programs aiming to increase bread-making quality. © 2022 Society of Chemical Industry.
Assuntos
Aegilops , Triticum , Triticum/genética , Triticum/química , Pão , Peso Molecular , Melhoramento Vegetal , Glutens/químicaRESUMO
Despite being of vital importance for seed establishment and grain quality, starch degradation remains poorly understood in organs such as cereal or legume seeds. In cereals, starch degradation requires the synergetic action of different isoforms of α-amylases. Ubiquitous overexpression of TaAmy2 resulted in a 2.0-437.6-fold increase of total α-amylase activity in developing leaf and harvested grains. These increases led to dramatic alterations of starch visco-properties and augmentation of soluble carbohydrate levels (mainly sucrose and α-gluco-oligosaccharide) in grain. Interestingly, the overexpression of TaAMY2 led to an absence of dormancy in ripened grain due to abscisic acid (ABA) insensitivity. Using an allosteric α-amylase inhibitor (acarbose), we demonstrated that ABA insensitivity was due to the increased soluble carbohydrate generated by the α-amylase excess. Independent from the TaAMY2 overexpression, inhibition of α-amylase during germination led to the accumulation of soluble α-gluco-oligosaccharides without affecting the first stage of germination. These findings support the hypotheses that (i) endosperm sugar may overcome ABA signalling and promote sprouting, and (ii) α-amylase may not be required for the initial stage of grain germination, an observation that questions the function of the amylolytic enzyme in the starch degradation process during germination.
Assuntos
Germinação/fisiologia , Sementes/metabolismo , Amido/metabolismo , Triticum/metabolismo , alfa-Amilases/genética , Ácido Abscísico/farmacologia , Regulação da Expressão Gênica de Plantas , Dormência de Plantas/efeitos dos fármacos , Dormência de Plantas/fisiologia , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas , Sementes/genética , Sementes/crescimento & desenvolvimento , Amido/química , Amido/genética , Açúcares/metabolismo , Triticum/genética , alfa-Amilases/metabolismoRESUMO
BACKGROUND: The present study intends to optimize the processing technology for the wine-processing of Rhizoma Coptidis, using alkaloids as indicators. METHOD: In the present study, the Box-Behnken design method was adopted to optimize the processing technology for Rhizoma Coptidis, using the alkaloid component quantities as the index. 100 g of Rhizoma Coptidis slices and 12.5 g of Rhizoma Coptidis wine were used. After full mixing, box-Behnken design method was used to optimize the processing time, processing temperature and processing time of coptis chinensis by taking alkaloid content as index. After mixing well, these components were fried in a container at 125 °C for 6 min and exhibited good parallelism. RESULTS: The content of alkaloids in coptis chinensis was the highest after roasting at 125 °C for 6 min. The characteristic components were berberine hydrochloride, and the relative content was about 15.96%. And showed good parallelism. The effective components of Rhizoma Coptidis were primarily alkaloids. CONCLUSION: The optimized processing technology for Rhizoma Coptidis is good.
Assuntos
Alcaloides , Coptis , Medicamentos de Ervas Chinesas , Cromatografia Líquida de Alta Pressão/métodos , Rizoma , TecnologiaRESUMO
Plant transcription factors (TFs), such as basic helix-loop-helix (bHLH) and AT-rich zinc-binding proteins (PLATZ), play critical roles in regulating the expression of developmental genes in cereals. We identified the bHLH protein TaPGS1 (T. aestivum Positive Regulator of Grain Size 1) specifically expressed in the seeds at 5-20 days post-anthesis in wheat. TaPGS1 was ectopically overexpressed (OE) in wheat and rice, leading to increased grain weight (up to 13.81% in wheat and 18.55% in rice lines) and grain size. Carbohydrate and total protein levels also increased. Scanning electron microscopy results indicated that the starch granules in the endosperm of TaPGS1 OE wheat and rice lines were smaller and tightly embedded in a proteinaceous matrix. Furthermore, TaPGS1 was bound directly to the E-box motif at the promoter of the PLATZ TF genes TaFl3 and OsFl3 and positively regulated their expression in wheat and rice. In rice, the OsFl3 CRISPR/Cas9 knockout lines showed reduced average thousand-grain weight, grain width, and grain length in rice. Our results reveal that TaPGS1 functions as a valuable trait-associated gene for improving cereal grain yield.
Assuntos
Grão Comestível , Oryza , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Regulação da Expressão Gênica de Plantas/genética , Oryza/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Sementes , Triticum/metabolismoRESUMO
KEY MESSAGE: A novel light intensity-dependent lesion mimic mutant with enhanced disease resistance was physiologically, biochemically, and genetically characterized, and the causative gene was fine mapped to a 1.28 Mbp interval containing 17 high-confidence genes. Lesion mimic mutants are ideal for studying disease resistance and programmed cell death photosynthesis in plants to improve crop yield. In this study, a novel light intensity-dependent lesion mimic mutant (MC21) was obtained from the wheat variety Chuannong16 (CN16) by ethyl methane sulfonate treatment. The mutant initially developed tiny lesion spots on the basal part of the leaves, which then gradually proceeded down to leaf sheaths, stems, shells, and awns at the flowering stage. The major agronomic traits were significantly altered in the mutant compared to that in the wild-type CN16. Furthermore, the mutant exhibited a lesion phenotype with degenerated chloroplast structure, decreased chlorophyll content, increased level of reactive oxygen species, and increased resistance to stripe rust and powdery mildew. Genetic analysis indicated that the lesion phenotype was controlled by a novel single semi-dominant nuclear gene. The target gene was mapped on chromosome arm 2AL located between Kompetitive Allele Specific PCR (KASP) markers, KASP-4211 and KASP-5353, and tentatively termed as lesion mimic 5 (Lm5). The fine mapping suggested that Lm5 was located in a 1.28 Mbp interval between markers KASP-5825 and KASP-9366; 17 high-confidence candidate genes were included in this genomic region. This study provides an important foundational step for further cloning of Lm5 using a map-based approach.
Assuntos
Basidiomycota , Triticum , Basidiomycota/fisiologia , Pão , Mapeamento Cromossômico , Resistência à Doença/genética , Doenças das Plantas/genética , Triticum/genética , Triticum/metabolismoRESUMO
Black point (BP) disease of wheat has become a noticeable problem in China. The symptoms are spots that are brown to black in color around the wheat kernel embryo or in the endosperm, resulting in a significant reduction of wheat grain quality. Here, we evaluated 272 Chinese wheat landraces for BP reaction and performed a genome-wide association study to identify BP resistance quantitative trait loci (QTLs) in five field environments without artificial inoculation. The BP incidence data showed continuous distributions and had low to moderate correlations between environments (r = 0.094 to 0.314). Among the 272 landraces, 11 had 0.1 to 4.9%, 144 had 5 to 14.9%, 100 had 15 to 29.9%, and 17 had >30% incidence. We found three resistant accessions: WH094 (3.33%), AS661463 (2.67%), and AS661231 (2.67%), which can be used in breeding programs to enhance BP resistance. We identified 11 QTLs, which explained 8.22 to 10.99% phenotypic BP variation, and mapped them to eight wheat chromosomes. Three of the QTLs were novel. The molecular markers for the BP resistance could facilitate molecular breeding for developing BP-resistant cultivars.
Assuntos
Estudo de Associação Genômica Ampla , Triticum , Resistência à Doença/genética , Melhoramento Vegetal , Doenças das Plantas/genética , Triticum/genéticaRESUMO
Stripe rust caused by Puccinia striiformis f. sp. tritici is one of the most destructive diseases of wheat. Identifying novel resistance genes applicable for developing disease-resistant cultivars is important for the sustainable control of wheat stripe rust. Chinese wheat landrace 'Xiaohemai' ('XHM') is an elite germplasm line with all-stage resistance (ASR) effective against predominant Chinese P. striiformis f. sp. tritici races. In this study, we performed a bulked segregant analysis coupled with exome capture sequencing (BSE-seq) to identify a candidate genomic region strongly associated with stripe rust resistance on chromosome 1AL in 173 F2:3 lines derived from the cross 'XHM' × 'Avocet S'. The gene, designated as YrXH-1AL, was validated by a conventional quantitative trait locus analysis using newly developed Kompetitive allele-specific PCR (KASP) markers, explaining up to 48.50% of the phenotypic variance. By testing a secondary mapping population comprising 144 lines from the same cross at the seedling stage with prevalent P. striiformis f. sp. tritici race CYR34, YrXH-1AL was identified as a single Mendelian factor in a 1.5-cM interval flanked by KASP markers KP1A_484.33 and KP1A_490.09. This region corresponded to a 5.76-Mb genomic interval on 'Chinese Spring' chromosome 1AL. Furthermore, two cosegregating KASP markers showed high polymorphisms among 130 Chinese wheat cultivars and could be used for marker-assisted selection. Because no other Yr genes for ASR that originated from common wheat have been detected on chromosome 1AL, YrXH-1AL is likely a novel gene that can be incorporated into modern breeding materials to develop wheat cultivars with enhanced stripe rust resistance.
Assuntos
Basidiomycota , Triticum , Basidiomycota/genética , China , Mapeamento Cromossômico , Cromossomos , Resistência à Doença/genética , Exoma , Melhoramento Vegetal , Doenças das Plantas/genética , Triticum/genéticaRESUMO
The granule-bound starch synthase I (GBSSI) encoded by the waxy gene is responsible for amylose synthesis in the endosperm of wheat grains. In the present study, a novel Wx-B1 null mutant line, M3-415, was identified from an ethyl methanesulfonate-mutagenized population of Chinese tetraploid wheat landrace Jianyangailanmai (LM47). The gene sequence indicated that the mutated Wx-B1 encoded a complete protein; this protein was incompatible with the protein profile obtained using sodium dodecyl sulfate-polyacrylamide gel electrophoresis, which showed the lack of Wx-B1 protein in the mutant line. The prediction of the protein structure showed an amino acid substitution (G470D) at the edge of the ADPG binding pocket, which might affect the binding of Wx-B1 to starch granules. Site-directed mutagenesis was further performed to artificially change the amino acid at the sequence position 469 from alanine (A) to threonine (T) (A469T) downstream of the mutated site in M3-415. Our results indicated that a single amino acid mutation in Wx-B1 reduces its activity by impairing its starch-binding capacity. The present study is the first to report the novel mechanism underlying Wx-1 deletion in wheat; moreover, it provided new insights into the inactivation of the waxy gene and revealed that fine regulation of wheat amylose content is possible by modifying the GBSSI activity.
Assuntos
Amilose , Triticum , Aminoácidos/metabolismo , Amilose/análise , Domínio Catalítico , Mutação , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Amido/metabolismo , Tetraploidia , Triticum/metabolismoRESUMO
Grain yield (GY) and grain protein content (GPC) are important traits for wheat breeding and production; however, they are usually negatively correlated. The Q gene is the most important domestication gene in cultivated wheat because it influences many traits, including GY and GPC. Allelic variations in the Q gene may positively affect both GY and GPC. Accordingly, we characterized two new Q alleles (Qs1 and Qc1-N8) obtained through ethyl methanesulfonate-induced mutagenesis. Compared with the wild-type Q allele, Qs1 contains a missense mutation in the sequence encoding the first AP2 domain, whereas Qc1-N8 has two missense mutations: one in the sequence encoding the second AP2 domain and the other in the microRNA172-binding site. The Qs1 allele did not significantly affect GPC or other processing quality parameters, but it adversely affected GY by decreasing the thousand kernel weight and grain number per spike. In contrast, Qc1-N8 positively affected GPC and GY by increasing the thousand kernel weight and grain number per spike. Thus, we generated novel germplasm relevant for wheat breeding. A specific molecular marker was developed to facilitate the use of the Qc1-N8 allele in breeding. Furthermore, our findings provide useful new information for enhancing cereal crops via non-transgenic approaches.
Assuntos
Proteínas de Grãos , Triticum , Alelos , Grão Comestível/química , Grão Comestível/genética , Metanossulfonato de Etila/metabolismo , Genes vif , Proteínas de Grãos/metabolismo , Mutação de Sentido Incorreto , Fenótipo , Melhoramento Vegetal , Locos de Características Quantitativas , Triticum/genética , Triticum/metabolismoRESUMO
Common wheat (Triticum aestivum L.) is an important food crop with a unique processing quality. The Q gene positively regulates the processing quality of wheat, but the underlying mechanism remains unclear. Here, a new Q allele (Qc5) responsible for compact spikes and good bread performance was identified. Compared with the Q allele widely distributed in modern common wheat cultivars, Qc5 had a missense mutation outside the miRNA172-binding site. This missense mutation led to a more compact messenger RNA (mRNA) secondary structure around the miRNA172-binding region, resulting in increased Qc5 expression during the spike development stage and a consequent increase in spike density. Furthermore, this missense mutation weakened the physical interaction between Qc5 and storage protein activator (SPA) in seeds and suppressed the expression of storage protein repressor (SPR). These changes increased the grain protein content and improved the bread-making quality of wheat. In conclusion, a missense mutation increases Q expression because of the resulting highly folded mRNA secondary structure around the miRNA172-binding site. Furthermore, this mutation improves the bread-making quality of wheat by repressing the expression of SPR and influencing the physical interaction between Q and SPA. These findings provide new insights into the miRNA172-directed regulation of gene expression, with implications for wheat breeding.
Assuntos
Pão , Triticum , Alelos , Pão/análise , Melhoramento Vegetal , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Ressonância de Plasmônio de Superfície , Triticum/metabolismoRESUMO
BACKGROUND: An increased demand for food has mirrored the increasing global population. Obesity and diabetes are two disorders induced by poor eating choices. Consequently, there is an urgent need to develop modified foods that can ameliorate such illnesses. The objective of this study was to explore the effect of Waxy genes on the structural and functional properties of starch, with the aim of improving food quality. Wild-type tetraploid wheat was compared with three mutants with different Waxy gene combinations. RESULTS: The proportion of B-type granules was higher in the mutants than in the wild-type (Wx-AB), and there were significant changes in the starch granule size, number, and phenotype in the Wx free mutant (Wx-ab). The lowest branch chain length was observed in Wx-ab, whereas Wx-AB had the highest branch chain length of DP ≥ 37. Wx-ab had the highest degree of crystallinity. The crystallinity trend followed the order Wx-ab>Wx-Ab>Wx-aB>Wx-AB. The amount of slowly digestible starch (SDS) was higher in native, gelatinized, and retrograded starch in the mutant. The amount of retrograded starch was closer to gelatinized starch than to native starch. CONCLUSION: Waxy proteins make a substantial contribution to starch structure. A lack of waxy proteins reduced the unit chains markedly compared with the control. Waxy proteins significantly affected the smaller and longer chains of starch. The lines with differing waxy composition had different effects on food digestion. The Wx-AB in native starch and Wx-Ab in gelatinized starch can control obesity and diabetes by slow-digesting carbohydrates and high resistance to digestion. © 2022 Society of Chemical Industry.
Assuntos
Sintase do Amido , Triticum , Obesidade , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Amido/química , Sintase do Amido/genética , Sintase do Amido/metabolismo , Tetraploidia , Triticum/químicaRESUMO
BACKGROUND: Wheat is an essential source of starch. The GBSS or waxy genes are responsible for synthesizing amylose in cereals. The present study identified a novel Wx-A1 null mutant line from an ethyl methanesulfonate (EMS)-mutagenized population of common wheat cv. SM126 using sodium dodecyl sulfate-polyacrylamide gel electrophoresis and agarose gel analyses. RESULTS: The alignment of the Wx-A1 gene sequences from the mutant and parental SM126 lines showed only one single nucleotide polymorphism causing the appearance of a premature stop codon and Wx-A1 inactivation. The lack of Wx-A1 protein resulted in decreased amylose, total starch and resistant starch. The starch morphology assessment revealed that starch from mutant seeds was more wrinkled, increasing its susceptibility to digestion. Regarding the starch thermodynamic properties, the gelatinization temperature was remarkably reduced in the mutant compared to parental line SM126. The digestibility of native, gelatinized, and retrograded starches was analyzed for mutant M4-627 and the parental SM126 line. In the M4-627 line, rapidly digestible starch contents were increased, whereas resistant starch was decreased in the three types of starch. CONCLUSION: Waxy protein is essential for starch synthesis. The thermodynamic characteristics were decreased in the Wx-A1 mutant line. The digestibility properties of starch were also affected. Therefore, the partial waxy mutant M3-627 might play a significant role in food improvement. Furthermore, it might also be used to produce high-quality noodles. © 2021 Society of Chemical Industry.