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1.
Plant Sci ; 320: 111274, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35643616

RESUMO

TaGW2 has been identified as a key determinant of the grain weight in wheat (Triticum aestivum L.). In our previous study, we found that the grain size differs in Chinese Spring (CS) and its TaGW2-6A allelic variant (NIL31). In addition, the expression of the key starch biosynthesis enzyme gene TaAGPS differs significantly in the two materials. However, the underlying molecular mechanism associated with the action of TaGW2-6A has not been reported. In the present study, we found that TaGW2-6A-CS interacted with TaAGPS, whereas TaGW2-6A-NIL31 did not interact with it in vitro and in vivo. Furthermore, we found that the C-terminal LXLX domain (376-424 aa) of TaGW2-6A recognized TaAGPS. However, the TaGW2-6A allelic variant lacked this key interaction region due to premature translation termination. We also found that TaGW2-6A-CS can ubiquitinate TaAGPS and degrade it via the 26 S proteasome pathway. In addition, our analysis of the activity of ADP-glucose pyrophosphorylase (AGPase) indicated that the AGPase level in the endosperm cells was lower in CS than NIL31. Cytological observations demonstrated that the average number of starch granules and the average area of starch granules in endosperm cells were lower in CS than NIL31. The overexpression of TaAGPS positively regulated the seed size in transgenic Arabidopsis. Our findings provide novel insights into the molecular mechanism that allows TaGW2-6A-TaAGPS to regulate seed size via the starch synthesis pathway.


Assuntos
Triticum , Ubiquitina-Proteína Ligases , Grão Comestível/metabolismo , Endosperma/metabolismo , Sementes/genética , Sementes/metabolismo , Amido/metabolismo , Triticum/genética , Triticum/metabolismo , Ubiquitina-Proteína Ligases/metabolismo
2.
Proc Natl Acad Sci U S A ; 119(25): e2201761119, 2022 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-35709319

RESUMO

The BABY BOOM (BBM) AINTEGUMENTA-LIKE (AIL) AP2/ERF domain transcription factor is a major regulator of plant cell totipotency, as it induces asexual embryo formation when ectopically expressed. Surprisingly, only limited information is available on the role of BBM during zygotic embryogenesis. Here we reexamined BBM expression and function in the model plant Arabidopsis thaliana (Arabidopsis) using reporter analysis and newly developed CRISPR mutants. BBM was expressed in the embryo from the zygote stage and also in the maternal (nucellus) and filial (endosperm) seed tissues. Analysis of CRISPR mutant alleles for BBM (bbm-cr) and the redundantly acting AIL gene PLETHORA2 (PLT2) (plt2-cr) uncovered individual roles for these genes in the timing of embryo progression. We also identified redundant roles for BBM and PLT2 in endosperm proliferation and cellularization and the maintenance of zygotic embryo development. Finally, we show that ectopic BBM expression in the egg cell of Arabidopsis and the dicot crops Brassica napus and Solanum lycopersicon is sufficient to bypass the fertilization requirement for embryo development. Together these results highlight roles for BBM and PLT2 in seed development and demonstrate the utility of BBM genes for engineering asexual embryo development in dicot species.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Brassica napus , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Brassica napus/genética , Endosperma/genética , Endosperma/metabolismo , Regulação da Expressão Gênica de Plantas , Crescimento Demográfico , Sementes/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
3.
Food Chem ; 383: 132635, 2022 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-35413766

RESUMO

In vitro digestibility of starch in sorghum grains differing in endosperm hardness and flour particle size was investigated. The starch digestibility increased as the particle size of flour decreased, but no clear trend was observed in digestibility of starch in sorghum flours milled from grains with different hardness. The protein matrix affected the digestion of starch. The pH value (2.0 vs. 1.3) was a critical factor affecting protein digestion. Optimum pH (pH 2.0 for pepsin) digested more protein, resulting in a greater digestion of starch. Resistant starch (RS) content was 8.5-26.3% in isolated sorghum starch but higher (10.6-29.5%) in sorghum flours. Protein digestibility decreased after cooking while starch digestibility increased compared to native sorghum flours; disulfide bonds formed between protein molecules. RS content of cooked sorghum flour was much higher without pepsin treatment (16.93-23.99%) than that of cooked sorghum flour with pepsin treatment (4.86-12.53%).


Assuntos
Farinha , Sorghum , Digestão , Grão Comestível/metabolismo , Endosperma/metabolismo , Farinha/análise , Dureza , Tamanho da Partícula , Pepsina A/metabolismo , Proteólise , Sorghum/química , Amido/química
4.
PLoS Biol ; 20(4): e3001602, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35389984

RESUMO

Gene expression in endosperm-a seed tissue that mediates transfer of maternal resources to offspring-is under complex epigenetic control. We show here that plant-specific RNA polymerase IV (Pol IV) mediates parental control of endosperm gene expression. Pol IV is required for the production of small interfering RNAs that typically direct DNA methylation. We compared small RNAs (sRNAs), DNA methylation, and mRNAs in Arabidopsis thaliana endosperm from heterozygotes produced by reciprocally crossing wild-type (WT) plants to Pol IV mutants. We find that maternally and paternally acting Pol IV induce distinct effects on endosperm. Loss of maternal or paternal Pol IV impacts sRNAs and DNA methylation at different genomic sites. Strikingly, maternally and paternally acting Pol IV have antagonistic impacts on gene expression at some loci, divergently promoting or repressing endosperm gene expression. Antagonistic parent-of-origin effects have only rarely been described and are consistent with a gene regulatory system evolving under parental conflict.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Arabidopsis/genética , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Metilação de DNA/genética , RNA Polimerases Dirigidas por DNA/genética , RNA Polimerases Dirigidas por DNA/metabolismo , Endosperma/genética , Endosperma/metabolismo , Regulação da Expressão Gênica de Plantas , Impressão Genômica , Plantas/genética , RNA de Plantas/metabolismo , RNA Interferente Pequeno/metabolismo
5.
Methods Mol Biol ; 2464: 105-121, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35258828

RESUMO

Endosperm of cereal crops is the main component of its grain. Improvement of endosperm traits will bolster grain yield and quality. Functional analysis of endosperm trait-related genes often requires the use of an endosperm cell system. Here, we describe a protocol for the isolation and transfection of maize endosperm cell protoplast. The endosperm protoplast system can be used for several molecular studies including protein subcellular localization, protein-protein interaction by bimolecular fluorescence complementation (BiFC), protein immunoblotting, transient gene expression, and regulatory analyses by qRT-PCR.


Assuntos
Endosperma , Zea mays , Endosperma/genética , Endosperma/metabolismo , Regulação da Expressão Gênica de Plantas , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Protoplastos/metabolismo , Transfecção , Zea mays/genética , Zea mays/metabolismo
6.
Plant Physiol Biochem ; 178: 31-39, 2022 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-35276594

RESUMO

Seed germination is a crucial stage in a plant's life cycle, during which the embryo, surrounded by several tissues, undergoes a transition from the quiescent to a highly active state. Endosperm weakening, a key step in this transition, plays an important role in radicle protrusion. Endosperm weakening is initiated upon water uptake, followed by multiple key molecular events occurring within and outside endosperm cells. Although available transcriptomes have provided information about pivotal genes involved in this process, a complete understanding of the signaling pathways are yet to be elucidated. Much remains to be learnt about the diverse intercellular signals, such as reactive oxygen species-mediated redox signals, phytohormone crosstalk, environmental cue-dependent oxidative phosphorylation, peroxisomal-mediated pectin degradation, and storage protein mobilization during endosperm cell wall loosening. This review discusses the evidences from recent researches into the mechanism of endosperm weakening. Further, given that the endosperm has great potential for manipulation by crop breeding and biotechnology, we offer several novel insights, which will be helpful in this research field and in its application to the improvement of crop production.


Assuntos
Endosperma , Germinação , Ácido Abscísico/metabolismo , Endosperma/metabolismo , Melhoramento Vegetal , Sementes/metabolismo
7.
Genome Biol ; 23(1): 77, 2022 03 09.
Artigo em Inglês | MEDLINE | ID: mdl-35264226

RESUMO

BACKGROUND: DNA demethylation occurs in many species and is involved in diverse biological processes. However, the occurrence and role of DNA demethylation in maize remain unknown. RESULTS: We analyze loss-of-function mutants of two major genes encoding DNA demethylases. No significant change in DNA methylation has been detected in these mutants. However, we detect increased DNA methylation levels in the mutants around genes and some transposons. The increase in DNA methylation is accompanied by alteration in gene expression, with a tendency to show downregulation, especially for the genes that are preferentially expressed in endosperm. Imprinted expression of both maternally and paternally expressed genes changes in F1 hybrid with the mutant as female and the wild-type as male parental line, but not in the reciprocal hybrid. This alteration in gene expression is accompanied by allele-specific DNA methylation differences, suggesting that removal of DNA methylation of the maternal allele is required for the proper expression of these imprinted genes. Finally, we demonstrate that hypermethylation in the double mutant is associated with reduced binding of transcription factor to its target, and altered gene expression. CONCLUSIONS: Our results suggest that active removal of DNA methylation is important for transcription factor binding and proper gene expression in maize endosperm.


Assuntos
Endosperma , Zea mays , Alelos , Desmetilação do DNA , Metilação de DNA , Endosperma/genética , Endosperma/metabolismo , Expressão Gênica , Regulação da Expressão Gênica de Plantas , Impressão Genômica , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Zea mays/genética , Zea mays/metabolismo
8.
Plant Mol Biol ; 109(1-2): 101-113, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35332427

RESUMO

KEY MESSAGE: TaPTST1, a wheat homolog of AtPTST1 containing CBM can interact with GBSSI and regulate starch metabolism in wheat endosperm. In cereal endosperm, native starch comprising amylose and amylopectin is synthesized by the coordinated activities of several pathway enzymes. Amylose in starch influences its physio-chemical properties resulting in several human health benefits. The Granule-Bound Starch Synthase I (GBSSI) is the most abundant starch-associated protein. GBSSI lacks dedicated Carbohydrate-binding module (CBM). Previously, Protein Targeting To Starch 1 (PTST1) was identified as a crucial protein for the localization of GBSSI to the starch granules in Arabidopsis. The function of its homologous protein in the wheat endosperm is not known. In this study, TaPTST1, an AtPTST1 homolog, containing a CBM and a coiled-coil domain was identified in wheat. Protein-coding nucleotide sequence of TaPTST1 from Indian wheat variety 'C 306' was cloned and characterized. Homology modelling and molecular docking suggested the potential interaction of TaPTST1 with glucans and GBSSI. The TaPTST1 expression was higher in wheat grain than the other tissues, suggesting a grain-specific function. In vitro binding assays demonstrated different binding affinities of TaPTST1 for native starch, amylose, and amylopectin. Furthermore, the immunoaffinity pull-down assay revealed that TaPTST1 directly interacts with GBSSI, and the interaction is mediated by a coiled-coil domain. The direct protein-protein interaction was further confirmed by bimolecular fluorescence complementation assay (BiFC) in planta. Based on our findings we postulate a functional role for TaPTST1 in starch metabolism by targeting GBSSI to starch granules in wheat endosperm.


Assuntos
Arabidopsis , Sintase do Amido , Amilopectina/metabolismo , Amilose/metabolismo , Arabidopsis/metabolismo , Grão Comestível/metabolismo , Endosperma/metabolismo , Simulação de Acoplamento Molecular , Amido/metabolismo , Sintase do Amido/genética , Sintase do Amido/metabolismo , Triticum/metabolismo
9.
J Exp Bot ; 73(11): 3417-3430, 2022 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-35182423

RESUMO

Starch biosynthesis during rice endosperm development is important for grain quality, as it influences grain size and physico-chemical properties, which together determine rice eating quality. Cereal starch biosynthetic pathways have been comprehensively investigated; however, their regulation, especially by transcriptional repressors remains largely unknown. Here, we identified a DUF1645 domain-containing protein, STRESS_tolerance and GRAIN_LENGTH (OsSGL), that participates in regulating rice starch biosynthesis. Overexpression of OsSGL reduced total starch and amylose content in the endosperm compared with the wild type. Chromatin immunoprecipitation sequencing and RNA-seq analyses indicated that OsSGL targets the transcriptional activity of several starch and sucrose metabolism genes. In addition, ChIP-qPCR, yeast one-hybrid, EMSA and dual-luciferase assays demonstrated that OsSGL directly inhibits the expression of SUCROSE SYNTHASE 1 (OsSUS1) in the endosperm. Furthermore, OsSUS1 interacts with OsSGL to release its transcriptional repression ability. Unexpectedly, our results also show that knock down and mutation of OsSGL disrupts the starch biosynthetic pathway, causing lower starch and amylose content. Therefore, our findings demonstrate that accurate control of OsSGL homeostasis is essential for starch synthesis and grain quality. In addition, we revealed the molecular mechanism of OsSGL in regulating starch biosynthesis-related genes, which are required for grain quality.


Assuntos
Oryza , Amilose/metabolismo , Grão Comestível , Endosperma/genética , Endosperma/metabolismo , Regulação da Expressão Gênica de Plantas , Oryza/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Amido/metabolismo , Fatores de Transcrição/metabolismo
10.
Annu Rev Plant Biol ; 73: 255-291, 2022 05 20.
Artigo em Inglês | MEDLINE | ID: mdl-35226815

RESUMO

The persistent triploid endosperms of cereal crops are the most important source of human food and animal feed. The development of cereal endosperms progresses through coenocytic nuclear division, cellularization, aleurone and starchy endosperm differentiation, and storage product accumulation. In the past few decades, the cell biological processes involved in endosperm formation in most cereals have been described. Molecular genetic studies performed in recent years led to the identification of the genes underlying endosperm differentiation, regulatory network governing storage product accumulation, and epigenetic mechanism underlying imprinted gene expression. In this article, we outline recent progress in this area and propose hypothetical models to illustrate machineries that control aleurone and starchy endosperm differentiation, sugar loading, and storage product accumulations. A future challenge in this area is to decipher the molecular mechanisms underlying coenocytic nuclear division, endosperm cellularization, and programmed cell death.


Assuntos
Grão Comestível , Endosperma , Diferenciação Celular , Grão Comestível/genética , Grão Comestível/metabolismo , Endosperma/genética , Endosperma/metabolismo , Regulação da Expressão Gênica de Plantas , Amido/metabolismo
11.
Plant Physiol ; 189(1): 360-374, 2022 05 03.
Artigo em Inglês | MEDLINE | ID: mdl-35166840

RESUMO

A-type ATP-binding cassette (ABCA) proteins transport lipids and lipid-based molecules in humans, and their malfunction is associated with various inherited diseases. Although plant genomes encode many ABCA transporters, their molecular and physiological functions remain largely unknown. Seeds are rapidly developing organs that rely on the biosynthesis and transport of large quantities of lipids to generate new membranes and storage lipids. In this study, we characterized the Arabidopsis (Arabidopsis thaliana) ABCA10 transporter, which is selectively expressed in female gametophytes and early developing seeds. By 3 d after flowering (DAF), seeds from the abca10 loss-of-function mutant exhibited a smaller chalazal endosperm than those of the wild-type. By 4 DAF, their endosperm nuclei occupied a smaller area than those of the wild-type. The endosperm nuclei of the mutants also failed to distribute evenly inside the seed coat and stayed aggregated instead, possibly due to inadequate expansion of abca10 endosperm. This endosperm defect might have retarded abca10 embryo development. At 7 DAF, a substantial portion of abca10 embryos remained at the globular or earlier developmental stages, whereas wild-type embryos were at the torpedo or later stages. ABCA10 is likely involved in lipid metabolism, as ABCA10 overexpression induced the overaccumulation of triacylglycerol but did not change the carbohydrate or protein contents in seeds. In agreement, ABCA10 localized to the endoplasmic reticulum (ER), the major site of lipid biosynthesis. Our results reveal that ABCA10 plays an essential role in early seed development, possibly by transporting substrates for lipid metabolism to the ER.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Trifosfato de Adenosina/metabolismo , Proteínas de Arabidopsis/metabolismo , Endosperma/metabolismo , Regulação da Expressão Gênica de Plantas , Humanos , Lipídeos/análise , Sementes
12.
Plant Cell ; 34(5): 1933-1956, 2022 04 26.
Artigo em Inglês | MEDLINE | ID: mdl-35157077

RESUMO

Opaque2 (O2) functions as a central regulator of the synthesis of starch and storage proteins and the O2 gene is transcriptionally regulated by a hub coordinator of seed development and grain filling, ABSCISIC ACID INSENSITIVE 19 (ZmABI19), in maize (Zea mays). Here, we identified a second hub coordinator, basic Leucine Zipper 29 (ZmbZIP29) that interacts with ZmABI19 to regulate O2 expression. Like zmabi19, zmbzip29 mutations resulted in a dramatic decrease of transcript and protein levels of O2 and thus a significant reduction of starch and storage proteins. zmbzip29 seeds developed slower and had a smaller size at maturity than those of the wild type. The zmbzip29;zmabi19 double mutant displayed more severe seed phenotypes and a greater reduction of storage reserves compared to the single mutants, whereas overexpression of the two transcription factors enhanced O2 expression, storage-reserve accumulation, and kernel weight. ZmbZIP29, ZmABI19, and O2 expression was induced by abscisic acid (ABA). With ABA treatment, ZmbZIP29 and ZmABI19 synergistically transactivated the O2 promoter. Through liquid chromatography tandem-mass spectrometry analysis, we established that the residues threonine(T) 57 in ZmABI19, T75 in ZmbZIP29, and T387 in O2 were phosphorylated, and that SnRK2.2 was responsible for the phosphorylation. The ABA-induced phosphorylation at these sites was essential for maximum transactivation of downstream target genes for endosperm filling in maize.


Assuntos
Endosperma , Zea mays , Ácido Abscísico/metabolismo , Ácido Abscísico/farmacologia , Endosperma/genética , Endosperma/metabolismo , Regulação da Expressão Gênica de Plantas , Zíper de Leucina , Fosforilação , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Amido/metabolismo , Ativação Transcricional , Zea mays/genética , Zea mays/metabolismo
13.
J Genet Genomics ; 49(5): 414-426, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35189403

RESUMO

Grain chalkiness, an undesirable trait caused by complex factors, has great negative impacts on the quality and economic value of rice. However, little is known about the regulatory mechanism of grain chalkiness, particularly the effect of endoplasmic reticulum (ER) stress. Here, a genome-wide association study (GWAS) reveals that the transcription factor OsbZIP60 is a vital regulator of rice grain chalkiness. Genetic analysis demonstrates that knockout of OsbZIP60 results in extremely high grain chalkiness and aberrant structure of storage substances. Notably, the expression of unfolded protein response (UPR) genes, such as OsbZIP50, OsBiP1, OsBiP2 and OsBiP3, is up-regulated in the endosperm cells of osbzip60, and overexpression of all these UPR genes causes various degrees of chalkiness. Furthermore, OsbZIP60 is found to activate the expression of key genes related to grain chalkiness, such as GPA3, FSE1, FLO7, Chalk5, OsNF-YB1, and OsPK2, whose expression is significantly suppressed in osbzip60 and overexpression lines of OsbZIP50, OsBiP1, OsBiP2, and OsBiP3. Our study provides novel insights into the function of OsbZIP60 and the role of the UPR pathway in the formation of grain chalkiness in rice.


Assuntos
Oryza , Grão Comestível/genética , Endosperma/genética , Endosperma/metabolismo , Regulação da Expressão Gênica de Plantas/genética , Estudo de Associação Genômica Ampla , Oryza/genética , Oryza/metabolismo , Resposta a Proteínas não Dobradas/genética
14.
New Phytol ; 234(1): 77-92, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35067957

RESUMO

Starch synthesis makes a dramatic contribution to the yield and nutritional value of cereal crops. Although several starch synthesis enzymes and related regulators have been reported, the underlying regulatory mechanisms of starch synthesis remain largely unknown. OsMADS14 is a FRUITFULL (FUL)-like MADS-box gene in rice (Oryza sativa). Here we show that two null mutations of OsMADS14 result in a shrunken and chalky grain phenotype. It is caused by obviously defective compound starch granules and a significantly reduced content of both total starch and amylose in the endosperm. Transcriptomic profiling analyses revealed that the loss-of-function of OsMADS14 leads to significantly downregulated expression of many core starch synthesis genes, including OsAGPL2 and Waxy. Both in vitro and in vivo assays demonstrate that the OsMADS14 protein directly binds to stretches of DNA with a CArG-box consensus in the putative regulatory regions of OsAGPL2 and Waxy. Protein-protein interaction experiments also suggest that OsMADS14 interacts with nuclear factor NF-YB1 to promote the transcription of OsAGPL2 and Waxy. Our study thus demonstrates that OsMADS14 plays an essential role in the synthesis of storage starch and provides novel insights into the underlying molecular mechanism that may be used to improve rice cultivars by molecular breeding.


Assuntos
Endosperma , Oryza , Endosperma/metabolismo , Oryza/metabolismo , Proteínas de Plantas/metabolismo , Amido/metabolismo , Ceras/metabolismo
15.
Carbohydr Polym ; 278: 118942, 2022 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-34973760

RESUMO

Heteroxylans (HX) from vitreous and floury parts of maize endosperm were isolated. Structural analysis showed a xylan backbone with few unsubstituted xylose residues (<9%) demonstrating the high content in side chains in both fractions. HX from floury endosperm contained more arabinose and galactose than vitreous HX. The mono-substitution rate was 15% higher in the vitreous endosperm HX. Similar amounts of uronic acids were present in both fractions (~7% DM). Galactose in the floury endosperm HX was present exclusively in terminal position. A xylanase preparation solubilized more material from floury (40.5%) than from vitreous endosperm cell walls (15%). This could be a consequence of the structural differences between the two fractions and/or of the impact of structure on the interaction abilities of these fractions with other cell wall polysaccharides. Our study advances the understanding of cell wall polysaccharides in maize endosperm and their role in enzymatic susceptibility of maize grain.


Assuntos
Endo-1,4-beta-Xilanases/metabolismo , Endosperma/metabolismo , Farinha , Amido/metabolismo , Xilanos/metabolismo , Zea mays/metabolismo , Endosperma/química , Amido/química , Xilanos/química , Zea mays/química
16.
Plant Reprod ; 35(2): 141-151, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35088155

RESUMO

Complex epigenetic changes occur during plant reproduction. These regulations ensure the proper transmission of epigenetic information as well as allowing for zygotic totipotency. In Arabidopsis, the main DNA methyltransferase is called MET1 and is responsible for methylating cytosine in the CG context. The Arabidopsis genome encodes for three additional reproduction-specific homologs of MET1, namely MET2a, MET2b and MET3. In this paper, we show that the DNA methyltransferase MET3 is expressed in the seed endosperm and its expression is later restricted to the chalazal endosperm. MET3 is biallelically expressed in the endosperm but displays a paternal expression bias. We found that MET3 expression is regulated by the Polycomb complex proteins FIE and MSI1. Seed development is not impaired in met3 mutant, and we could not observe significant transcriptional changes in met3 mutant. MET3 might regulates gene expression in a Polycomb mutant background suggesting a further complexification of the interplay between H3K27me3 and DNA methylation in the seed endosperm. KEY MESSAGE: The DNA METHYLTRANSFERASE MET3 is controlled by Polycomb group complex during endosperm development.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , DNA/metabolismo , DNA (Citosina-5-)-Metiltransferases/genética , DNA (Citosina-5-)-Metiltransferases/metabolismo , Metilação de DNA , Endosperma/metabolismo , Regulação da Expressão Gênica de Plantas , Metiltransferases/genética , Metiltransferases/metabolismo , Proteínas do Grupo Polycomb/genética , Proteínas do Grupo Polycomb/metabolismo , Reprodução , Sementes/genética , Sementes/metabolismo
17.
BMC Plant Biol ; 22(1): 18, 2022 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-34991468

RESUMO

BACKGROUND: Nuclear endosperm development is a common mechanism among Angiosperms, including Arabidopsis. During nuclear development, the endosperm nuclei divide rapidly after fertilization without cytokinesis to enter the syncytial phase, which is then followed by the cellularized phase. The endosperm can be divided into three spatial domains with distinct functions: the micropylar, peripheral, and chalazal domains. Previously, we identified two putative small invertase inhibitors, InvINH1 and InvINH2, that are specifically expressed in the micropylar region of the syncytial endosperm. In addition, ectopically expressing InvINH1 in the cellularized endosperm led to a reduction in embryo growth rate. However, it is not clear what are the upstream regulators responsible for the specific expression of InvINHs in the syncytial endosperm. RESULTS: Using protoplast transient expression system, we discovered that a group of type I MADS box transcription factors can form dimers to activate InvINH1 promoter. Promoter deletion assays carried out in the protoplast system revealed the presence of an enhancer region in InvINH1 promoter, which contains several consensus cis-elements for the MADS box proteins. Using promoter deletion assay in planta, we further demonstrated that this enhancer region is required for InvINH1 expression in the syncytial endosperm. One of the MADS box genes, AGL62, is a key transcription factor required for syncytial endosperm development. Using promoter-GFP reporter assay, we demonstrated that InvINH1 and InvINH2 are not expressed in agl62 mutant seeds. Collectively, our data supports the role of AGL62 and other type I MADS box genes as the upstream activators of InvINHs expression in the syncytial endosperm. CONCLUSIONS: Our findings revealed several type I MADS box genes that are responsible for activating InvINH1 in the syncytial endosperm, which in turn regulates embryo growth rate during early stage of seed development.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/genética , Endosperma/metabolismo , Proteínas de Domínio MADS/genética , beta-Frutofuranosidase/antagonistas & inibidores , Arabidopsis/enzimologia , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Endosperma/genética , Elementos Facilitadores Genéticos , Regulação da Expressão Gênica de Plantas , Proteínas de Domínio MADS/metabolismo , Regiões Promotoras Genéticas , Protoplastos/metabolismo , Fatores de Transcrição/metabolismo
18.
Plant Mol Biol ; 108(4-5): 443-467, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35098404

RESUMO

KEY MESSAGE: Laser microdissection applied on the developing rice endosperm revealed tissue- and stage-specific regulators modulating programmed cell death and desiccation tolerance mechanisms in the central starchy endosperm following starch metabolism. Rice (Oryza sativa L.) filial seed tissues are heterozygous in its function, which accumulate distinct storage compounds spatially in starchy endosperm and aleurone. In this study, we identified the 18 tissue- and stage-specific gene co-regulons in the developing endosperm by isolating four fine tissues dorsal aleurone layer (AL), central starchy endosperm (CSE), dorsal starchy endosperm (DSE), and lateral starchy endosperm (LSE) at two developmental stages (7 days after flowering, DAF and 12DAF) using laser microdissection (LM) coupled with gene expression analysis of a 44 K microarray. The derived co-expression regulatory networks depict that distinct set of starch biosynthesis genes expressed preferentially at first in CSE at 7 DAF and extend its spatial expression to LSE and DSE by 12 DAF. Interestingly, along with the peak of starch metabolism we noticed accumulation of transcripts related to phospholipid and glycolipid metabolism in CSE during 12 DAF. The spatial distribution of starch accumulation in distinct zones of starchy endosperm contains specific transcriptional factors and hormonal-regulated genes. Genes related to programmed cell death (PCD) were specifically expressed in CSE at 12DAF, when starch accumulation was already completed in that tissue. The aleurone layer present in the outermost endosperm accumulates transcripts of lipid, tricarboxylic acid metabolism, several transporters, while starch metabolism and PCD is not pronounced. These regulatory cascades are likely to play a critical role in determining the positional fate of cells and offer novel insights into the molecular physiological mechanisms of endosperm development from early to middle storage phase.


Assuntos
Endosperma/metabolismo , Oryza/genética , Oryza/metabolismo , Amido/metabolismo , Apoptose , Endosperma/genética , Regulação da Expressão Gênica de Plantas , Redes Reguladoras de Genes , Lasers , Microdissecção/métodos , Microscopia Confocal , Amido/genética , Transcriptoma
19.
Plant Mol Biol ; 108(4-5): 481-496, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35099666

RESUMO

KEY MESSAGE: BEIIb plays a specific role in determining the structure of amylopectin in rice endosperm, whereas BEIIa plays the similar role in the culm where BEIIb is absent. Cereals have three types of starch branching enzymes (BEs), BEI, BEIIa, and BEIIb. It is widely known that BEIIb is specifically expressed in the endosperm and plays a distinct role in the structure of amylopectin because in its absence the amylopectin type changes to the amylose-extender-type (ae-type) or B-type from the wild-type or A-type and this causes the starch crystalline allomorph to the B-type from the wild-type A-type. This study aimed to clarify the role of BEIIa in the culm where BEIIb is not expressed, by using a be2a mutant in comparison with results with be2b and be1 mutants. The results showed that the amylopectin structure exhibited the B-type in the be2a culm compared with the A-type in the wild-type culm. The starch granules from the be2a culm also showed the B-type like allomorph when examined by X-ray diffraction analysis and optical sum frequency generation spectroscopy. Both amylopectin chain-length profile and starch crystalline properties were found to be the A-type at the very early stage of endosperm development at 4-6 days after pollination (DAP) even in the be2b mutant. All these results support a view that in the culm as well as in the endosperm at 4-6 DAP, BEIIa can play the role of BEIIb which has been well documented in maturing endosperm. The possible mechanism as to how BEIIa can play its role is discussed.


Assuntos
Enzima Ramificadora de 1,4-alfa-Glucana/metabolismo , Amilopectina/química , Amilopectina/metabolismo , Endosperma/metabolismo , Oryza/enzimologia , Amido/metabolismo , Configuração de Carboidratos , Eletroforese em Gel de Poliacrilamida , Imageamento por Ressonância Magnética , Mutação , Oryza/metabolismo , Conformação Proteica , Análise Espectral , Amido/química , Difração de Raios X
20.
Plant J ; 110(1): 228-242, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35020972

RESUMO

Developing seed depends on sugar supply for its growth and yield formation. Maize (Zea mays L.) produces the largest grains among cereals. However, there is a lack of holistic understanding of the transcriptional landscape of genes controlling sucrose transport to, and utilization within, maize grains. By performing in-depth data mining of spatio-temporal transcriptomes coupled with histological and heterologous functional analyses, we identified transporter genes specifically expressed in the maternal-filial interface, including (i) ZmSWEET11/13b in the placento-chalazal zone, where sucrose is exported into the apoplasmic space, and (ii) ZmSTP3, ZmSWEET3a/4c (monosaccharide transporters), ZmSUT1, and ZmSWEET11/13a (sucrose transporters) in the basal endosperm transfer cells for retrieval of apoplasmic sucrose or hexoses after hydrolysis by extracellular invertase. In the embryo and its surrounding regions, an embryo-localized ZmSUT4 and a cohort of ZmSWEETs were specifically expressed. Interestingly, drought repressed those ZmSWEETs likely exporting sucrose but enhanced the expression of most transporter genes for uptake of apoplasmic sugars. Importantly, this drought-induced fluctuation in gene expression was largely attenuated by an increased C supply via controlled pollination, indicating that the altered gene expression is conditioned by C availability. Based on the analyses above, we proposed a holistic model on the spatio-temporal expression of genes that likely govern sugar transport and utilization across maize maternal and endosperm and embryo tissues during the critical stage of grain set. Collectively, the findings represent an advancement towards a holistic understanding of the transcriptional landscape underlying post-phloem sugar transport in maize grain and indicate that the drought-induced changes in gene expression are attributable to low C status.


Assuntos
Açúcares , Zea mays , Grão Comestível/genética , Grão Comestível/metabolismo , Endosperma/genética , Endosperma/metabolismo , Regulação da Expressão Gênica de Plantas/genética , Humanos , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Sacarose/metabolismo , Açúcares/metabolismo , Zea mays/metabolismo
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