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1.
Plant Physiol Biochem ; 151: 743-750, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32361224

RESUMO

Split application could improve nitrogen (N) uptake and increase sweetpotato yields under reduced N supply; however, little is known about how it affects the process of starch production in storage roots. An experiment was conducted to determine the effects of three N management strategies [conventional basal N management; 80% of the conventional N rate applied as a basal fertilizer; 80% of the conventional N rate equally split at transplanting and 35 days after transplanting] on starch accumulation, enzyme activity and genes expression in the conversion of sucrose to starch and the relationships among them. The results showed that, compared with conventional basal N management, split application decreased sucrose accumulation by 11.78%, but increased starch accumulation by 11.12% through improving the starch accumulation rate under reduced N supply. The ratio of sucrose synthetase to sucrose phosphate synthase, the enzymatic activity of ADP-glucose pyrophosphorylase (AGPP), starch synthase, and the expression of their corresponding genes were promoted by split application under reduced N supply and were positively correlated with starch accumulation rate. AGPP is the rate-limiting enzyme in starch synthesis in storage roots under different N management strategies. These results indicate that starch accumulation was enhanced by split application through regulating the activity and gene expression of key enzymes involved in the conversion of sucrose to starch under reduced N supply.


Assuntos
Ipomoea batatas , Nitrogênio , Amido , Sacarose , Ativação Enzimática/efeitos dos fármacos , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Glucose-1-Fosfato Adenililtransferase/genética , Glucose-1-Fosfato Adenililtransferase/metabolismo , Ipomoea batatas/efeitos dos fármacos , Ipomoea batatas/enzimologia , Ipomoea batatas/genética , Ipomoea batatas/metabolismo , Nitrogênio/farmacologia , Amido/biossíntese , Sacarose/metabolismo
2.
Plant Mol Biol ; 103(4-5): 457-471, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32274640

RESUMO

KEY MESSAGE: In this manuscript, we disclosed the influence of light on the accumulation of storage reserves in B. napus embryos.1.Light induced the gene expression in the developing embryos of B. napus.2.Light promoted the starch synthesis in chloroplasts of B. napus embryos.3.Light enhanced the metabolic activity of storage reserve synthesis in B. napus embryos. Light influences the accumulation of storage reserves in embryos, but the molecular mechanism was not fully understood. Here, we monitored the effects of light on reserve biosynthesis in Brassica napus by comparing embryos from siliques grown in normal light conditions to those that were shaded or masked (i.e., darkened completely). Masked embryos developed more slowly, weighed less, and contained fewer proteins and lipids than control embryos. They also had fewer and smaller oil bodies than control embryos and lacked chloroplasts, where starch grains are usually synthesized. The levels of most amino acids, carbohydrates, and fatty acids were higher in masked embryos than in control or shaded embryos, whereas the levels of these metabolites in the masked endosperms were lower than those in control and shaded endosperm. Transcriptome analysis indicated that genes involved in photosynthesis (42 genes), amino acid biosynthesis (51 genes), lipid metabolism (61 genes), and sugar transport (13 genes) were significantly repressed in masked embryos. Our results suggest that light contributes to reserve accumulation in embryos by inducing the expression of metabolic genes, thereby enhancing the biosynthesis of storage reserves.


Assuntos
Brassica napus/embriologia , Brassica napus/genética , Brassica napus/efeitos da radiação , Regulação da Expressão Gênica de Plantas/efeitos da radiação , Luz , Sementes/genética , Sementes/efeitos da radiação , Aminoácidos/metabolismo , Brassica napus/crescimento & desenvolvimento , Metabolismo dos Carboidratos , Clorofila/análise , Cloroplastos/metabolismo , Cloroplastos/ultraestrutura , Endosperma/metabolismo , Endosperma/efeitos da radiação , Ácidos Graxos/metabolismo , Perfilação da Expressão Gênica , Metabolismo dos Lipídeos , Fotossíntese , Óleos Vegetais/metabolismo , Proteínas de Plantas/genética , Sementes/citologia , Sementes/crescimento & desenvolvimento , Amido/biossíntese , Transcriptoma
3.
Carbohydr Polym ; 237: 116118, 2020 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-32241419

RESUMO

The underlying mechanisms behind the genetics, structure and functionality relations in starches from various origins have not been fully understood. For better control of the genotypic background, rice starches from four chalky mutants and their parent were employed to investigate the above relations, and some interesting relations were revealed. GBSSI and SSIIIa were shown to affect the height of amylose in the debranched starch fraction (hAM) which reflects true amylose content (TAC), and then hAM was correlated with the AAC, RS, HD, COH, To, ΔHg, ΔHr, and R%. GBSSI also affected the average chain length (X)¯ of amylopectin, which was associated with the AAC, TAC, RS, HPV, HD, COH, ΔHg, ΔHr, and R%. The SSI, SSIIa and SSIIIa affected the amylose size (Rh,AM), which was correlated with the TAC, AAC, RS, HD, COH, To and Tp. Furthermore, both SSIIa and PUL affected the XAP2, and XAP2 was correlated with the To.


Assuntos
Oryza/metabolismo , Proteínas de Plantas/metabolismo , Sintase do Amido/metabolismo , Amido/biossíntese , Genótipo , Oryza/genética
4.
Sci Rep ; 10(1): 4242, 2020 03 06.
Artigo em Inglês | MEDLINE | ID: mdl-32144321

RESUMO

It have been significantly demonstrated that Hexokinase (HXK), Granule-bound starch synthase (GBSS) and ADP-glucose pyrophosphorylase (AGPase) are three critical enzymes in the starch biosynthetic pathway and are related to starch (amylose, amylopectin and total starch) content in lotus. It is important to develop functional markers in marker-assisted selection of lotus breeding. So far there have been few reports about lotus functional markers. In this study, based on insertion-deletions (INDELs) and single-nucleotide polymorphisms (SNPs), we developed three functional markers, FMHXK-E1, FMGBSS-I8 and FMAGPL-I1. FMHXK-E1 was developed based on polymorphisms of two haplotypes of NnHXK. 26 lotus cultivars that the 320-bp fragment presented in NnHXK had a lower content of amylose and a higher content of amylopectin. FMGBSS-I8 was developed based on polymorphisms of two haplotypes of NnGBSS. The group containing 32 lotus cultivars with the 210-bp fragment had less amylose content and more amylopectin content. FMAGPL-I1 was developed based on polymorphisms of two haplotypes of NnAGPL (ADP-glucose pyrophosphorylase large subunit gene). The group containing 40 lotus cultivars with the 362-bp fragment had less amylopectin, total starch content and more amylose content. According to the study, FMHXK-E1, FMGBSS-I8 and FMAGPL-I1 are closely related to lotus starch content. It could be provided research basis for molecular assisted selection of lotus starch content improve breeding efficiency.


Assuntos
Lotus/genética , Locos de Características Quantitativas , Característica Quantitativa Herdável , Amido , Sequência de Bases , Hexoquinase/química , Hexoquinase/genética , Hexoquinase/metabolismo , Mutação INDEL , Lotus/metabolismo , Melhoramento Vegetal , Polimorfismo de Nucleotídeo Único , Amido/biossíntese , Sintase do Amido/química , Sintase do Amido/genética , Sintase do Amido/metabolismo
5.
Biochem J ; 477(2): 341-356, 2020 01 31.
Artigo em Inglês | MEDLINE | ID: mdl-31967651

RESUMO

Plant polysaccharides (cellulose, hemicellulose, pectin, starch) are either direct (i.e. leaf starch) or indirect products of photosynthesis, and they belong to the most abundant organic compounds in nature. Although each of these polymers is made by a specific enzymatic machinery, frequently in different cell locations, details of their synthesis share certain common features. Thus, the production of these polysaccharides is preceded by the formation of nucleotide sugars catalyzed by fully reversible reactions of various enzymes, mostly pyrophosphorylases. These 'buffering' enzymes are, generally, quite active and operate close to equilibrium. The nucleotide sugars are then used as substrates for irreversible reactions of various polysaccharide-synthesizing glycosyltransferases ('engine' enzymes), e.g. plastidial starch synthases, or plasma membrane-bound cellulose synthase and callose synthase, or ER/Golgi-located variety of glycosyltransferases forming hemicellulose and pectin backbones. Alternatively, the irreversible step might also be provided by a carrier transporting a given immediate precursor across a membrane. Here, we argue that local equilibria, established within metabolic pathways and cycles resulting in polysaccharide production, bring stability to the system via the arrangement of a flexible supply of nucleotide sugars. This metabolic system is itself under control of adenylate kinase and nucleoside-diphosphate kinase, which determine the availability of nucleotides (adenylates, uridylates, guanylates and cytidylates) and Mg2+, the latter serving as a feedback signal from the nucleotide metabolome. Under these conditions, the supply of nucleotide sugars to engine enzymes is stable and constant, and the metabolic process becomes optimized in its load and consumption, making the system steady and self-regulated.


Assuntos
Redes e Vias Metabólicas/genética , Fosfotransferases/genética , Fotossíntese/genética , Polissacarídeos/genética , Adenilato Quinase/genética , Parede Celular/genética , Parede Celular/metabolismo , Celulose/biossíntese , Celulose/genética , Celulose/metabolismo , Metabolismo Energético/genética , Glucose-1-Fosfato Adenililtransferase/genética , Núcleosídeo-Difosfato Quinase/genética , Pectinas/biossíntese , Pectinas/genética , Pectinas/metabolismo , Fosfotransferases/metabolismo , Plantas , Polissacarídeos/biossíntese , Polissacarídeos/metabolismo , Amido/biossíntese , Amido/genética , Amido/metabolismo
6.
Crit Rev Biotechnol ; 40(3): 380-396, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-31996051

RESUMO

The 1,4-α-glucan branching enzymes (GBEs) are ubiquitously distributed in animals, microorganisms and plants. These enzymes modify the structure of both starch and glycogen; changing the frequency and position of branches by forming new α-1,6-glucosidic linkages. In organisms, controlling the number and distribution of branches is an irreplaceable process that maintains the physiological state of starch and glycogen in the cell. The process is also the foundation for the industrial applications of GBEs. So far, a number of GBEs have been identified in eukaryotes and prokaryotes as researchers searched for GBEs with optimal properties. Among them, bacterial GBEs have received particular attention due to the convenience of heterologous expression and industrial applications of GBEs from bacteria than GBEs from other sources. The advantages of bacterial GBEs in potential applications stimulated the investigations of bacterial GBEs in terms of their structure and properties. However, full exploitation of GBEs in commercial applications is still in its infancy because of the disadvantages of currently available enzymes and of limited imagination with respect to future possibilities. Thus, in this review, we present an overview of the bacterial GBEs including their structure, biochemical properties and commercial applications in order to depict the whole picture of bacterial GBEs.


Assuntos
Enzima Ramificadora de 1,4-alfa-Glucana/química , Enzima Ramificadora de 1,4-alfa-Glucana/metabolismo , Bactérias/enzimologia , Enzima Ramificadora de 1,4-alfa-Glucana/genética , Animais , Bactérias/genética , Proteínas de Bactérias , Biotecnologia , Glucanos , Humanos , Modelos Moleculares , Amido/biossíntese
7.
Plant Biotechnol J ; 18(1): 83-95, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31131526

RESUMO

Pyrophosphate-fructose 6-phosphate 1-phosphotransferase (PFP1) reversibly converts fructose 6-phosphate and pyrophosphate to fructose 1, 6-bisphosphate and orthophosphate during glycolysis, and has diverse functions in plants. However, mechanisms underlying the regulation of starch metabolism by PFP1 remain elusive. This study addressed the function of PFP1 in rice floury endosperm and defective grain filling. Compared with the wild type, pfp1-3 exhibited remarkably low grain weight and starch content, significantly increased protein and lipid content, and altered starch physicochemical properties and changes in embryo development. Map-based cloning revealed that pfp1-3 is a novel allele and encodes the regulatory ß-subunit of PFP1 (PFP1ß). Measurement of nicotinamide adenine dinucleotide (NAD+) showed that mutation of PFP1ß markedly decreased its enzyme activity. PFP1ß and three of four putative catalytic α-subunits of PFP1, PFP1α1, PFP1α2, and PFP1α4, interacted with each other to form a heterotetramer. Additionally, PFP1ß, PFP1α1 and PFP1α2 also formed homodimers. Furthermore, transcriptome analysis revealed that mutation of PFP1ß significantly altered expression of many essential enzymes in starch biosynthesis pathways. Concentrations of multiple lipid and glycolytic intermediates and trehalose metabolites were elevated in pfp1-3 endosperm, indicating that PFP1 modulates endosperm metabolism, potentially through reversible adjustments to metabolic fluxes. Taken together, these findings provide new insights into seed endosperm development and starch biosynthesis and will help in the breeding of rice cultivars with higher grain yield and quality.


Assuntos
Oryza/enzimologia , Fosfotransferases/fisiologia , Proteínas de Plantas/fisiologia , Sementes/crescimento & desenvolvimento , Amido/biossíntese , Endosperma , Regulação da Expressão Gênica de Plantas
8.
Biochimie ; 169: 54-61, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31563539

RESUMO

The use of algal biomass for biofuel production requires improvements in both biomass productivity and its energy density. Green microalgae store starch and oil as two major forms of carbon reserves. Current strategies to increase the amount of carbon reserves often compromise algal growth. To better understand the cellular mechanisms connecting cell division to carbon storage, we examined starch and oil accumulation in two Chlamydomonas mutants deficient in a gene encoding a homolog of the Arabidopsis Cell Division Cycle 5 (CDC5), a MYB DNA binding protein known to be involved in cell cycle in higher plants. The two crcdc5 mutants (crcdc5-1 and crcdc5-2) were found to accumulate significantly higher amount of starch and oil than their corresponding parental lines. Flow cytometry analysis on synchronized cultures cultivated in a diurnal light/dark cycle revealed an abnormal division of the two mutants, characterized by a prolonged S/M phase, therefore demonstrating its implication in cell cycle in Chlamydomonas. Taken together, these results suggest that the energy saved by a slowdown in cell division is used for the synthesis of reserve compounds. This work highlights the importance in understanding the interplay between cell cycle and starch/oil homeostasis, which should have a critical impact on improving lipid/starch productivity.


Assuntos
Proteínas de Algas/genética , Chlamydomonas reinhardtii/genética , Redes e Vias Metabólicas/genética , Mutação , Amido/biossíntese , Proteínas de Algas/metabolismo , Arabidopsis/genética , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Biocombustíveis , Biomassa , Carbono/metabolismo , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Divisão Celular , Chlamydomonas reinhardtii/metabolismo , Expressão Gênica , Óleos Vegetais , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Pontos de Checagem da Fase S do Ciclo Celular/genética , Amido/genética
9.
Sci Rep ; 9(1): 18567, 2019 12 06.
Artigo em Inglês | MEDLINE | ID: mdl-31811177

RESUMO

In the recent time, Submergence1 (Sub1)QTL, responsible for imparting tolerance to flash flooding, has been introduced in many rice cultivars, but resilience of the QTL to stagnant flooding (SF) is not known. The response of Sub1-introgression has been tested on physiology, molecular biology and yield of two popular rice cultivars (Swarna and Savitri) by comparison of the parental and Sub1-introgression lines (SwarnaSub1 and SavitriSub1) under SF. Compared to control condition SF reduced grain yield and tiller number and increased plant height and Sub1- introgression mostly matched these effects. SF increased ethylene production by over-expression of ACC-synthase and ACC-oxidase enzyme genes of panicle before anthesis in the parental lines. Expression of the genes changed with Sub1-introgression, where some enzyme isoform genes over-expressed after anthesis under SF. Activities of endosperm starch synthesizing enzymes SUS and AGPase declined concomitantly with rise ethylene production in the Sub1-introgressed lines resulting in low starch synthesis and accumulation of soluble carbohydrates in the developing spikelets. In conclusion, Sub1-introgression into the cultivars increased susceptibility to SF. Subjected to SF, the QTL promoted genesis of ethylene in the panicle at anthesis to the detriment of grain yield, while compromising with morphological features like tiller production and stem elongation.


Assuntos
Etilenos/biossíntese , Genes de Plantas/genética , Introgressão Genética , Oryza/fisiologia , Locos de Características Quantitativas , Adaptação Fisiológica/genética , Grão Comestível/crescimento & desenvolvimento , Grão Comestível/metabolismo , Endosperma/crescimento & desenvolvimento , Endosperma/metabolismo , Inundações , Regulação da Expressão Gênica de Plantas , Reguladores de Crescimento de Planta/biossíntese , Brotos de Planta/crescimento & desenvolvimento , Brotos de Planta/metabolismo , Plantas Geneticamente Modificadas/fisiologia , Amido/biossíntese
10.
PLoS One ; 14(10): e0223783, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31603940

RESUMO

Starch is synthesized from a series of reactions catalyzed by enzymes. ADP-glucose pyrophosphorylase (AGPase) initiates the synthesis pathway and synthesizes ADP-glucose, the substrate of starch synthase (SS), of which SSIV is an isoform. Mutations of the AGPase subunit and SSIV-coding genes affect starch content and cause variation in the number of granules. Here, we pyramided the functional mutation alleles of the AGPase subunit gene TaAGP.L-B1 and the SSIV-coding gene TaSSIVb-D to elucidate their synergistic effects on other key starch biosynthesis genes and their impact on starch content. Both the TaAGP.L-B1 and TaSSIVb-D genes were expressed in wheat grain development, and the expression level of TaAGP.L-B1 was higher than that of TaSSIVb-D. The TaAGP.L-B1 gene was downregulated in the agp.L-B1 single and agp.L-B1/ssIV-D double mutants at 12 to 18 days after flowering (DAF). TaSSIVb-D expression was significantly reduced at 6 DAF in both ssIV-D single and double mutants. In the agp.L-B1/ssIV-D double mutant, TaGBSSII was upregulated, while TaAGPSS, TaSSI, and TaSBEII were downregulated. Under the interaction of these genes, the total starch and amylopectin contents were significantly decreased in agp.L-B1 and agp.L-B1/ssIV-D mutants. The results suggested that the mutations of TaAGP.L-B1 and TaSSIVb-D genes resulted in variation in the expression patterns of the other four starch synthetic genes and led to a reduction in starch and amylopectin contents. These mutants could be used further as germplasm for resistant starch analysis.


Assuntos
Glucose-1-Fosfato Adenililtransferase/genética , Mutação , Sintase do Amido/genética , Amido/biossíntese , Triticum/crescimento & desenvolvimento , Amilopectina/metabolismo , Vias Biossintéticas , Grão Comestível/genética , Grão Comestível/crescimento & desenvolvimento , Grão Comestível/metabolismo , Perfilação da Expressão Gênica , Regulação da Expressão Gênica no Desenvolvimento , Regulação da Expressão Gênica de Plantas , Glucose-1-Fosfato Adenililtransferase/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Sintase do Amido/metabolismo , Triticum/genética , Triticum/metabolismo
11.
Int J Mol Sci ; 20(19)2019 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-31547486

RESUMO

CRISPR/Cas9-mediated genome editing is a powerful technology that has been used for the genetic modification of a number of crop species. In order to evaluate the efficacy of CRISPR/Cas9 technology in the root crop, sweet potato (Ipomoea batatas), two starch biosynthetic pathway genes, IbGBSSI (encoding granule-bound starch synthase I), and IbSBEII (encoding starch branching enzyme II), were targeted in the starch-type cultivar Xushu22 and carotenoid-rich cultivar Taizhong6. I. batatas was transformed using a binary vector, in which the Cas9 gene is driven by the Arabidopsis AtUBQ promoter and the guide RNA is controlled by the Arabidopsis AtU6 promoter. A total of 72 Xushu22 and 35 Taizhong6 transgenic lines were generated and analyzed for mutations. The mutation efficiency was 62-92% with multi-allelic mutations in both cultivars. Most of the mutations were nucleotide substitutions that lead to amino acid changes and, less frequently, stop codons. In addition, short nucleotide insertions or deletions were also found in both IbGBSSI and IbSBEII. Furthermore, a 2658 bp deletion was found in one IbSBEII transgenic line. The total starch contents were not significantly changed in IbGBSSI- and IbSBEII-knockout transgenic lines compared to the wild-type control. However, in the allopolyploid sweet potato, the IbGBSSI-knockout reduced, while the IbSBEII-knockout increased, the amylose percentage. Our results demonstrate that CRISPR/Cas9 technology is an effective tool for the improvement of starch qualities in sweet potato and breeding of polyploid root crops.


Assuntos
Sistemas CRISPR-Cas , Genes de Plantas , Ipomoea batatas , Mutagênese , Plantas Geneticamente Modificadas , Amido , Arabidopsis/genética , Ipomoea batatas/genética , Ipomoea batatas/metabolismo , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/metabolismo , Regiões Promotoras Genéticas , Amido/biossíntese , Amido/genética
12.
PLoS One ; 14(8): e0221351, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31437204

RESUMO

In recent years, the sweet potato cultivar Jishu 25 has exhibited good characteristics for starch processing in northern China. The storage root dry matter yields of this cultivar can exceed one ton per mu (1/15 of a hectare) at nitrogen (N) rates of 60-90 kg ha-1 based on soil nutrient content. However, the effect of N fertilizer on the physicochemical properties of starches isolated from this cultivar has not been reported. In order to evaluate these effects, three different N rates, 0 (control, N0), 75 (N1), and 150 kg ha-1 (N2), were selected for a field experiment in 2017. The results showed that N1 exhibited the highest storage root yield and starch yield. Compared to the control group, N fertilizer significantly increased the total starch content while no significant difference was found in these between the N1 and N2 groups. The amylose (AM) content was highest in the N2 group and lowest in the N0 group. In addition, N fertilizer exhibited no significant effects on the values of [D(v, 0.9)], D [4, 3] and D [3, 2]. Compared to the control group, N1 demonstrated significantly higher setback viscosity (SV), while N2 showed significantly higher peak viscosity (PV), cold paste viscosity (CPV) and SV. However, there were no significant differences in the hot paste viscosity (HPV), peak time and pasting temperature between the N1 and N2 groups. For the thermal properties of starch, there were no significant differences in peak temperature (Tp), conclusion temperature (Tc) or gelatinization enthalpy (ΔH) between the N1 and N2 groups. Overall, for the starch samples of cultivar Jishu 25, N fertilizer exerts significant effects on the starch content, AM content and viscosity properties but little effect on the particle size distribution and ΔH. 75 kg N ha-1 can easily lead to substantial planting benefits from the high storage root yield, dry matter yield and total starch content of this cultivar.


Assuntos
Fertilizantes , Ipomoea batatas/efeitos dos fármacos , Nitrogênio/farmacologia , Raízes de Plantas/efeitos dos fármacos , Amido/química , China , Análise de Alimentos/métodos , Humanos , Ipomoea batatas/crescimento & desenvolvimento , Ipomoea batatas/metabolismo , Nitrogênio/metabolismo , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/metabolismo , Amido/biossíntese , Amido/isolamento & purificação , Temperatura , Viscosidade
13.
BMC Genomics ; 20(1): 574, 2019 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-31296166

RESUMO

BACKGROUND: Starch biosynthesis in endosperm is a key process influencing grain yield and quality in maize. Although a number of starch biosynthetic genes have been well characterized, the mechanisms by which the expression of these genes is regulated, especially in regard to microRNAs (miRNAs), remain largely unclear. RESULTS: Sequence data for small RNAs, degradome, and transcriptome of maize endosperm at 15 and 25 d after pollination (DAP) from inbred lines Mo17 and Ji419, which exhibit distinct starch content and starch granule structure, revealed the mediation of starch biosynthetic pathways by miRNAs. Transcriptome analysis of these two lines indicated that 33 of 40 starch biosynthetic genes were differentially expressed, of which 12 were up-regulated in Ji419 at 15 DAP, one was up-regulated in Ji419 at 25 DAP, 14 were up-regulated in Ji419 at both 15 and 25 DAP, one was down-regulated in Ji419 at 15 DAP, two were down-regulated in Ji419 at 25 DAP, and three were up-regulated in Ji419 at 15 DAP and down-regulated in Ji419 at 25 DAP, compared with Mo17. Through combined analyses of small RNA and degradome sequences, 22 differentially expressed miRNAs were identified, including 14 known and eight previously unknown miRNAs that could target 35 genes. Furthermore, a complex co-expression regulatory network was constructed, in which 19 miRNAs could modulate starch biosynthesis in endosperm by tuning the expression of 19 target genes. Moreover, the potential operation of four miRNA-mediated pathways involving transcription factors, miR169a-NF-YA1-GBSSI/SSIIIa and miR169o-GATA9-SSIIIa/SBEIIb, was validated via analyses of expression pattern, transient transformation assays, and transactivation assays. CONCLUSION: Our results suggest that miRNAs play a critical role in starch biosynthesis in endosperm, and that miRNA-mediated networks could modulate starch biosynthesis in this tissue. These results have provided important insights into the molecular mechanism of starch biosynthesis in developing maize endosperm.


Assuntos
Perfilação da Expressão Gênica , MicroRNAs/genética , Amido/biossíntese , Zea mays/genética , Zea mays/metabolismo , Endosperma/genética , Endosperma/crescimento & desenvolvimento , Endosperma/metabolismo , Genes de Plantas/genética , Zea mays/crescimento & desenvolvimento
14.
Sci Rep ; 9(1): 9856, 2019 07 08.
Artigo em Inglês | MEDLINE | ID: mdl-31285472

RESUMO

Autophagy is a self-degradation system wherein cellular materials are recycled. Although autophagy has been extensively studied in yeast and mammalian systems, integrated stress responses in microalgae remain poorly understood. Accordingly, we carried out a comparative study on the oxidative stress responses of Chlamydomonas reinhardtii wild-type and a starchless (sta6) mutant previously shown to accumulate high lipid content under adverse conditions. To our surprise, the sta6 mutant exhibited significantly higher levels of lipid peroxidation in the same growth conditions compared to controls. The sta6 mutant was more sensitive to oxidative stress induced by H2O2, whereas the wild-type was relatively more resistant. In addition, significantly up-regulated autophagy-related factors including ATG1, ATG101, and ATG8 were maintained in the sta6 mutant regardless of nitrogen availability. Also, the sta6 mutant exhibited relatively higher ATG8 protein level compared to wild-type under non-stress condition, and quickly reached a saturation point of autophagy when H2O2 was applied. Our results indicate that, in addition to the impact of carbon allocation, the increased lipid phenotype of the sta6 mutant may result from alterations in the cellular oxidative state, which in turn activates autophagy to clean up oxidatively damaged components and fuel lipid production.


Assuntos
Autofagia/fisiologia , Chlamydomonas reinhardtii/metabolismo , Chlamydomonas reinhardtii/fisiologia , Estresse Oxidativo/fisiologia , Amido/biossíntese , Metabolismo dos Carboidratos/fisiologia , Carbono/metabolismo , Peroxidação de Lipídeos/fisiologia , Lipídeos/fisiologia , Nitrogênio/metabolismo , Oxirredução , Fenótipo , Regulação para Cima/fisiologia
15.
Mol Biol Rep ; 46(4): 4565-4580, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31243724

RESUMO

Polysaccharides including resistant starch are categorized as dietary fiber and are used as an important prebiotic. Similar to soluble fibers, resistant starch also has a number of physiological effects that have been shown to be beneficial for health. Starch hydrolyzing enzymes, most importantly amylases, play essential roles in the production of resistant starch. This study aimed to develop α-amylase-treated maize flour with slow digestibility and unique physicochemical characteristics compared to native maize flour. In the current study, resistant starch type III from maize flour was prepared using α-amylase obtained from indigenously isolated Bacillus licheniformis. The α-amylase gene from B. licheniformis was amplified and cloned into the pET-24(a) vector, expressed in E. coli BL21 (DE3) cells and purified by metal ion affinity chromatography. The purified enzyme enhanced the yield of resistant starch 16-fold in maize flour. Scanning electron microscopy revealed that the granular structure of maize flour was disrupted into a dense network with irregular structure, and X-ray diffractograms confirmed the transformation from an amorphous to a crystalline structure upon α-amylase treatment. Thermogravimetric analysis revealed increased amylose content of α-amylase-treated maize flour. Moreover, α-amylase-treated maize flour resulted in a significant enhancement of the desired properties of maize flour, such as resistant starch content, amylose, milk absorption capacity, and iodine and fatty acid complexing ability, and a reduction in swelling power, water binding, oil absorption capacity, and in vitro digestibility compared to untreated maize flour. Resistant starch type III showed low digestibility and increased complexing ability with iodine and fatty acid and therefore could be a safe and beneficial alternative as a coating material for the delivery of active, sensitive ingredients to the colon.


Assuntos
Amido/biossíntese , Zea mays/metabolismo , alfa-Amilases/metabolismo , Amilose , Bacillus licheniformis/enzimologia , Bacillus licheniformis/metabolismo , Farinha , Hidrólise , Polissacarídeos/química , alfa-Amilases/genética
16.
PLoS One ; 14(6): e0217593, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31163077

RESUMO

Pueraria thomsonii Benth is an important medicinal plant. Transcriptome sequencing, unigene assembly, the annotation of transcripts and the study of gene expression profiles play vital roles in gene function research. However, the full-length transcriptome of P. thomsonii remains unknown. Here, we obtained 44,339 nonredundant transcripts of P. thomsonii by using the PacBio RS II Isoform and Illumina sequencing platforms, of which 43,195 were annotated genes. Compared with the expression levels in the plant roots, those of transcripts with a |fold change| ≥ 4 and FDR < 0.01 in the leaves or stems were assigned as differentially expressed transcripts (DETs). In total, we found 9,225 DETs, 32 of which came from structural genes that were potentially involved in isoflavone biosynthesis. The expression profiles of 8 structural genes from the RNA-Seq data were validated by qRT-PCR. We identified 437 transcription factors (TFs) that were positively or negatively correlated with at least 1 of the structural genes involved in isoflavone biosynthesis using Pearson correlation coefficients (r) (r > 0.8 or r < -0.8). We also identified a total of 32 microRNAs (miRNAs), which targeted 805 transcripts. These miRNAs caused enriched function in 'ATP binding', 'defense response', 'ADP binding', and 'signal transduction'. Interestingly, MIR156a potentially promoted isoflavone biosynthesis by repressing SBP, and MIR319 promoted isoflavone biosynthesis by repressing TCP and HB-HD-ZIP. Finally, we identified 2,690 alternative splicing events, including that of the structural genes of trans-cinnamate 4-monooxygenase and pullulanase, which are potentially involved in the biosynthesis of isoflavone and starch, respectively, and of three TFs potentially involved in isoflavone biosynthesis. Together, these results provide us with comprehensive insight into the gene expression and regulation of P. thomsonii.


Assuntos
Vias Biossintéticas/genética , Perfilação da Expressão Gênica , Genes de Plantas , Isoflavonas/biossíntese , Pueraria/genética , Processamento Alternativo/genética , Sequência de Bases , Regulação da Expressão Gênica de Plantas , Ontologia Genética , MicroRNAs/química , MicroRNAs/genética , MicroRNAs/metabolismo , Anotação de Sequência Molecular , Conformação de Ácido Nucleico , Folhas de Planta/genética , Raízes de Plantas/genética , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Amido/biossíntese , Fatores de Transcrição/metabolismo
17.
Biosci Biotechnol Biochem ; 83(10): 1807-1814, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31179846

RESUMO

WRINKLED1 (WRI1) belongs to AP2/EREBP transcription factor. Its function in dicots for fatty acids synthesis has been deeply studied, but its role in monocot, especially in rice, is still poorly understood. Here, with the overexpression of AtWRI1 in rice, we found its overexpression increased fatty acids content in vegetative organs and seed coat including aleurone layer (SCAL) but decreased fatty acids content in endosperm. Meanwhile, the overexpression of AtWRI1 increased starch content in endosperm. These results provide a new insight into the function of AtWRI1in monocot and make a previous basement for the study of the connection of fatty acids and starch synthesis in rice.


Assuntos
Proteínas de Arabidopsis/genética , Ácidos Graxos/biossíntese , Oryza/metabolismo , Amido/biossíntese , Fatores de Transcrição/genética , Endosperma/metabolismo , Ácidos Graxos/metabolismo , Regulação da Expressão Gênica de Plantas , Oryza/embriologia , Oryza/genética , Amido/metabolismo
18.
BMC Plant Biol ; 19(1): 136, 2019 Apr 11.
Artigo em Inglês | MEDLINE | ID: mdl-30971210

RESUMO

BACKGROUND: Sweet potato (Ipomoea batatas L.) is the sixth most important food crop in the world. The formation and development of storage roots in sweet potato is a highly complicated and genetically programmed process. However, the underlying mechanisms of storage root development have not yet been elucidated. RESULTS: To better understand the molecular mechanisms involved in storage root development, a combined analysis of the transcriptome and proteome of sweet potato fibrous roots (F) and storage roots at four different stages (D1, D3, D5 and D10) was performed in the present study. A total of 26,273 differentially expressed genes were identified in a comparison between the fibrous root library and four storage root libraries, while 2558 proteins showed a 1.0-fold or greater expression difference as indicated by isobaric tags for relative and absolute quantitation (iTRAQ) analysis. The combination of the transcriptome and proteome analyses and morphological and physiological data revealed several critical pathways involved in storage root formation and development. First, genes/proteins involved in the development of meristems/cambia and starch biosynthesis were all significantly upregulated in storage roots compared with fibrous roots. Second, multiple phytohormones and the genes related to their biosynthesis showed differential expression between fibrous roots and storage roots. Third, a large number of transcription factors were differentially expressed during storage root initiation and development, which suggests the importance of transcription factor regulation in the development of storage roots. Fourth, inconsistent gene expression was found between the transcriptome and proteome data, which indicated posttranscriptional regulatory activity during the development of storage roots. CONCLUSION: Overall, these results reveal multiple events associated with storage root development and provide new insights into the molecular mechanisms underlying the regulatory networks involved in storage root development.


Assuntos
Regulação da Expressão Gênica de Plantas , Ipomoea batatas/genética , Raízes de Plantas/genética , Proteoma , Amido/biossíntese , Transcriptoma , Redes Reguladoras de Genes , Ipomoea batatas/crescimento & desenvolvimento , Ipomoea batatas/metabolismo , Reguladores de Crescimento de Planta/metabolismo , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/metabolismo , Proteômica , Análise de Sequência de RNA
19.
Int J Biol Macromol ; 132: 710-721, 2019 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-30946904

RESUMO

The starch market is very diverse and demanding regarding the functional characteristics of the product. However, no technique based on the management of cassava root harvest time has been applied to obtain starches with different properties. Thus, in this study, cassava roots were harvested at different times and the structure and physicochemical properties of their starches were analyzed. Results indicated the time points in the first growth cycle of plants when all parameters associated with root growth were at their highest values. It was also observed that changes in the time of harvest leads to the production of starches with different granule size, crystallinity, and content of amylose and phosphorus, which resulted in changes in the thermal and pasting properties, as well as in the solubility of the starches and swelling power; that is, on the main determinant characteristics for applicability of the starches. Planned agricultural production monitoring, coupled with the analysis of the main starches characteristics for large-scale cassava crops, can provide commercial benefits for both farmers and industry, as it is possible to obtain starches with desired physicochemical characteristics for varied applications.


Assuntos
Manihot/crescimento & desenvolvimento , Manihot/metabolismo , Amido/biossíntese , Fenômenos Químicos , Amido/química , Temperatura , Fatores de Tempo
20.
Genes (Basel) ; 10(4)2019 04 18.
Artigo em Inglês | MEDLINE | ID: mdl-31003564

RESUMO

Wheat is a staple food commodity grown worldwide, and wheat starch is a valuable source of energy and carbon that constitutes 80% of the grain weight. Manipulation of genes involved in starch synthesis significantly affects wheat grain weight and yield. TaSSIV plays an important role in starch synthesis and its main function is granule formation. To mine and stack more favorable alleles, single nucleotide polymorphisms (SNPs) of TaSSIV-A, B, and D were investigated across 362 wheat accessions by Ecotype-Targeting Induced Local Lesions IN Genome (EcoTILLING). As a result, a total of 38 SNPs in the amplified regions of three TaSSIV genes were identified, of which 10, 15, and 13 were in TaSSIV-A, B, and D, respectively. These 38 SNPs were evaluated by using KASP and six SNPs showed an allele frequency >5% whereas the rest were <5%, i.e., considered to be minor alleles. In the Chinese mini core collection, three haplotypes were detected for TaSSIV-A and three for TaSSIV-B. The results of an association study in the Chinese mini core collection with thousand grain weight (TGW) and spike length (SPL) showed that Hap-2-1A was significantly associated with TGW and Hap-3-1B with SPL. Allelic frequency and geographic distribution indicated that the favored haplotype (Hap-2-1A) has been positively selected in Chinese wheat breeding. These results suggested that the Kompetitive Allele Specific PCR (KASP) markers can be applied in starch improvement to ultimately improve wheat yield by marker assisted selection in wheat breeding.


Assuntos
Polimorfismo de Nucleotídeo Único , Análise de Sequência de DNA/métodos , Sintase do Amido/genética , Triticum/crescimento & desenvolvimento , China , Grão Comestível/genética , Grão Comestível/crescimento & desenvolvimento , Grão Comestível/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Regulação da Expressão Gênica de Plantas , Frequência do Gene , Haplótipos , Tamanho do Órgão , Proteínas de Plantas/genética , Característica Quantitativa Herdável , Amido/biossíntese , Triticum/genética , Triticum/metabolismo
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