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1.
Proc Natl Acad Sci U S A ; 121(14): e2321612121, 2024 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-38530890

RESUMO

To preserve germination ability, plant seeds must be protected from environmental stresses during the storage period. Here, we demonstrate that autophagy, an intracellular degradation system, maintains seed germination ability in Arabidopsis thaliana. The germination ability of long-term (>5 years) stored dry seeds of autophagy-defective (atg) mutant and wild-type (WT) plants was compared. Long-term stored (old) seeds of atg mutants showed lower germination ability than WT seeds, although short-term stored (new) seeds of atg mutants did not show such a phenotype. After removal of the seed coat and endosperm from old atg mutant seeds, the embryos developed into seedlings. Autophagic flux was maintained in endosperm cells during the storage period, and autophagy defect resulted in the accumulation of oxidized proteins and accelerated endosperm cell death. Consistent with these findings, the transcripts of genes, ENDO-ß-MANNANASE 7 and EXPANSIN 2, which are responsible for degradation/remodeling of the endosperm cell wall during germination, were reduced in old atg mutant seeds. We conclude that autophagy maintains endosperm quality during seed storage by suppressing aging-dependent oxidative damage and cell death, which allows the endosperm to perform optimal functions during germination, i.e., cell wall degradation/remodeling, even after long-term storage.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Arabidopsis/genética , Endosperma/genética , Germinação/fisiologia , Sementes/genética , Proteínas de Arabidopsis/metabolismo , Autofagia , Regulação da Expressão Gênica de Plantas
2.
Genes Dev ; 33(7-8): 466-476, 2019 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-30819818

RESUMO

The endosperm is an ephemeral tissue that nourishes the developing embryo, similar to the placenta in mammals. In most angiosperms, endosperm development starts as a syncytium, in which nuclear divisions are not followed by cytokinesis. The timing of endosperm cellularization largely varies between species, and the event triggering this transition remains unknown. Here we show that increased auxin biosynthesis in the endosperm prevents its cellularization, leading to seed arrest. Auxin-overproducing seeds phenocopy paternal-excess triploid seeds derived from hybridizations of diploid maternal plants with tetraploid fathers. Concurrently, auxin-related genes are strongly overexpressed in triploid seeds, correlating with increased auxin activity. Reducing auxin biosynthesis and signaling reestablishes endosperm cellularization in triploid seeds and restores their viability, highlighting a causal role of increased auxin in preventing endosperm cellularization. We propose that auxin determines the time of endosperm cellularization, and thereby uncovered a central role of auxin in establishing hybridization barriers in plants.


Assuntos
Arabidopsis/crescimento & desenvolvimento , Arabidopsis/genética , Endosperma , Regulação da Expressão Gênica de Plantas/genética , Ácidos Indolacéticos/metabolismo , Proteínas de Arabidopsis/genética , Regulação para Baixo , Endosperma/citologia , Endosperma/genética , Endosperma/crescimento & desenvolvimento , Mutação , Poliploidia , Sementes/genética , Sementes/crescimento & desenvolvimento , Transdução de Sinais/genética
3.
Genes Dev ; 32(7-8): 479-490, 2018 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-29692356

RESUMO

The evolution of seeds defines a remarkable landmark in the history of land plants. A developing seed contains three genetically distinct structures: the embryo, the nourishing tissue, and the seed coat. While fertilization is necessary to initiate seed development in most plant species, apomicts have evolved mechanisms allowing seed formation independently of fertilization. Despite their socio-economical relevance, the molecular mechanisms driving seed development have only recently begun to be understood. Here we review the current knowledge on the role of the hormone auxin for the initial development of the three seed structures and as a trigger of fertilization-independent seed development.


Assuntos
Ácidos Indolacéticos/metabolismo , Sementes/embriologia , Padronização Corporal , Endosperma/embriologia , Endosperma/metabolismo , Frutas/crescimento & desenvolvimento , Sementes/metabolismo , Transdução de Sinais
4.
Plant J ; 119(2): 1134-1157, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38709819

RESUMO

The evolutionary and ecological success of spermatophytes is intrinsically linked to the seed habit, which provides a protective environment for the initial development of the new generation. This environment includes an ephemeral nourishing tissue that supports embryo growth. In gymnosperms this tissue originates from the asexual proliferation of the maternal megagametophyte, while in angiosperms it is a product of fertilization, and is called the endosperm. The emergence of these nourishing tissues is of profound evolutionary value, and they are also food staples for most of the world's population. Here, using Orthofinder to infer orthologue genes among newly generated and previously published datasets, we provide a comparative transcriptomic analysis of seed nourishing tissues from species of several angiosperm clades, including those of early diverging lineages, as well as of one gymnosperm. Our results show that, although the structure and composition of seed nourishing tissues has seen significant divergence along evolution, there are signatures that are conserved throughout the phylogeny. Conversely, we identified processes that are specific to species within the clades studied, and thus illustrate their functional divergence. With this, we aimed to provide a foundation for future studies on the evolutionary history of seed nourishing structures, as well as a resource for gene discovery in future functional studies.


Assuntos
Cycadopsida , Magnoliopsida , Filogenia , Sementes , Transcriptoma , Sementes/genética , Sementes/metabolismo , Magnoliopsida/genética , Magnoliopsida/metabolismo , Cycadopsida/genética , Regulação da Expressão Gênica de Plantas , Endosperma/genética , Endosperma/metabolismo , Perfilação da Expressão Gênica , Evolução Biológica
5.
Proc Natl Acad Sci U S A ; 119(25): e2201761119, 2022 06 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 , Endosperma , Arabidopsis/genética , Arabidopsis/crescimento & desenvolvimento , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Brassica napus/genética , Brassica napus/crescimento & desenvolvimento , Endosperma/genética , Endosperma/crescimento & desenvolvimento , Regulação da Expressão Gênica de Plantas , Solanum lycopersicum/genética , Solanum lycopersicum/crescimento & desenvolvimento , Sementes/genética , Sementes/crescimento & desenvolvimento , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
6.
Genes Dev ; 31(12): 1272-1287, 2017 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-28743695

RESUMO

Hybrid seed lethality as a consequence of interspecies or interploidy hybridizations is a major mechanism of reproductive isolation in plants. This mechanism is manifested in the endosperm, a dosage-sensitive tissue supporting embryo growth. Deregulated expression of imprinted genes such as ADMETOS (ADM) underpin the interploidy hybridization barrier in Arabidopsis thaliana; however, the mechanisms of their action remained unknown. In this study, we show that ADM interacts with the AT hook domain protein AHL10 and the SET domain-containing SU(VAR)3-9 homolog SUVH9 and ectopically recruits the heterochromatic mark H3K9me2 to AT-rich transposable elements (TEs), causing deregulated expression of neighboring genes. Several hybrid incompatibility genes identified in Drosophila encode for dosage-sensitive heterochromatin-interacting proteins, which has led to the suggestion that hybrid incompatibilities evolve as a consequence of interspecies divergence of selfish DNA elements and their regulation. Our data show that imbalance of dosage-sensitive chromatin regulators underpins the barrier to interploidy hybridization in Arabidopsis, suggesting that reproductive isolation as a consequence of epigenetic regulation of TEs is a conserved feature in animals and plants.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/efeitos dos fármacos , Arabidopsis/fisiologia , Proteínas de Ciclo Celular/metabolismo , Epigênese Genética , Histona-Lisina N-Metiltransferase/farmacologia , Isolamento Reprodutivo , Arabidopsis/genética , Proteínas de Arabidopsis/genética , Proteínas de Ciclo Celular/genética , Regulação da Expressão Gênica de Plantas , Histona Metiltransferases , Histona-Lisina N-Metiltransferase/metabolismo , Hibridização Genética
7.
Plant J ; 116(3): 942-961, 2023 11.
Artigo em Inglês | MEDLINE | ID: mdl-37517071

RESUMO

Arabidopsis thaliana diverged from A. arenosa and A. lyrata at least 6 million years ago. The three species differ by genome-wide polymorphisms and morphological traits. The species are to a high degree reproductively isolated, but hybridization barriers are incomplete. A special type of hybridization barrier is based on the triploid endosperm of the seed, where embryo lethality is caused by endosperm failure to support the developing embryo. The MADS-box type I family of transcription factors is specifically expressed in the endosperm and has been proposed to play a role in endosperm-based hybridization barriers. The gene family is well known for its high evolutionary duplication rate, as well as being regulated by genomic imprinting. Here we address MADS-box type I gene family evolution and the role of type I genes in the context of hybridization. Using two de-novo assembled and annotated chromosome-level genomes of A. arenosa and A. lyrata ssp. petraea we analyzed the MADS-box type I gene family in Arabidopsis to predict orthologs, copy number, and structural genomic variation related to the type I loci. Our findings were compared to gene expression profiles sampled before and after the transition to endosperm cellularization in order to investigate the involvement of MADS-box type I loci in endosperm-based hybridization barriers. We observed substantial differences in type-I expression in the endosperm of A. arenosa and A. lyrata ssp. petraea, suggesting a genetic cause for the endosperm-based hybridization barrier between A. arenosa and A. lyrata ssp. petraea.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Arabidopsis/genética , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Endosperma/genética , Endosperma/metabolismo , Sementes/genética , Fatores de Transcrição/metabolismo , Proteínas de Domínio MADS/genética , Proteínas de Domínio MADS/metabolismo , Regulação da Expressão Gênica de Plantas/genética
8.
Plant J ; 115(5): 1261-1276, 2023 09.
Artigo em Inglês | MEDLINE | ID: mdl-37256847

RESUMO

Grain chalkiness is a major concern in rice production because it impacts milling yield and cooking quality, eventually reducing market value of the rice. A gene encoding vacuolar H+ translocating pyrophosphatase (V-PPase) is a major quantitative trait locus in indica rice, controlling grain chalkiness. Higher transcriptional activity of this gene is associated with increased chalk content. However, whether the suppression of V-PPase could reduce chalkiness is not clear. Furthermore, natural variation in the chalkiness of japonica rice has not been linked with V-PPase. Here, we describe promoter targeting of the japonica V-PPase allele that led to reduced grain chalkiness and the development of more translucent grains. Disruption of a putative GATA element by clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 suppressed V-PPase activity, reduced grain chalkiness and impacted post-germination growth that could be rescued by the exogenous supply of sucrose. The mature grains of the targeted lines showed a much lower percentage of large or medium chalk. Interestingly, the targeted lines developed a significantly lower chalk under heat stress, a major inducer of grain chalk. Metabolomic analysis showed that pathways related to starch and sugar metabolism were affected in the developing grains of the targeted lines that correlated with higher inorganic pyrophosphate and starch contents and upregulation of starch biosynthesis genes. In summary, we show a biotechnology approach of reducing grain chalkiness in rice by downregulating the transcriptional activity of V-PPase that presumably leads to altered metabolic rates, including starch biosynthesis, resulting in more compact packing of starch granules and formation of translucent rice grains.


Assuntos
Oryza , Oryza/metabolismo , Pirofosfatase Inorgânica/genética , Pirofosfatase Inorgânica/metabolismo , Grão Comestível/genética , Grão Comestível/metabolismo , Amido/metabolismo , Mutagênese
9.
BMC Genomics ; 25(1): 795, 2024 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-39174916

RESUMO

BACKGROUND: Bread wheat (Triticum aestivum L.) endosperm contains starch and proteins, which determine the final yield, quality, and nutritional value of wheat grain. The preferentially expressed endosperm genes can precisely provide targets in the endosperm for improving wheat grain quality and nutrition using modern bioengineering technologies. However, the genes specifically expressed in developing endosperms remain largely unknown. RESULTS: In this study, 315 preferentially expressed endosperm genes (PEEGs) in the spring wheat landrace, Chinese Spring, were screened using data obtained from an open bioinformatics database, which reveals a unique grain reserve deposition process and special signal transduction in a developing wheat endosperm. Furthermore, transcription and accumulation of storage proteins in the wheat cultivar, XC26 were evaluated. The results revealed that 315 PEEG plays a critical role in storage protein fragment deposition and is a potential candidate for modifying grain quality and nutrition. CONCLUSION: These results provide new insights into endosperm development and candidate genes and promoters for improving wheat grain quality through genetic engineering and plant breeding techniques.


Assuntos
Grão Comestível , Endosperma , Regulação da Expressão Gênica de Plantas , Triticum , Triticum/genética , Triticum/metabolismo , Triticum/crescimento & desenvolvimento , Endosperma/genética , Endosperma/metabolismo , Grão Comestível/genética , Grão Comestível/metabolismo , Grão Comestível/crescimento & desenvolvimento , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Genes de Plantas , Perfilação da Expressão Gênica
10.
Development ; 148(19)2021 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-34495331

RESUMO

Plant sexual and asexual reproduction through seeds (apomixis) is tightly controlled by complex gene regulatory programs, which are not yet fully understood. Recent findings suggest that RNA helicases are required for plant germline development. This resembles their crucial roles in animals, where they are involved in controlling gene activity and the maintenance of genome integrity. Here, we identified previously unknown roles of Arabidopsis RH17 during reproductive development. Interestingly, RH17 is involved in repression of reproductive fate and of elements of seed development in the absence of fertilization. In lines carrying a mutant rh17 allele, development of supernumerary reproductive cell lineages in the female flower tissues (ovules) was observed, occasionally leading to formation of two embryos per seed. Furthermore, seed coat, and putatively also endosperm development, frequently initiated autonomously. Such induction of several features phenocopying distinct elements of apomixis by a single mutation is unusual and suggests that RH17 acts in regulatory control of plant reproductive development. Furthermore, an in-depth understanding of its action might be of use for agricultural applications.


Assuntos
Proteínas de Arabidopsis/genética , RNA Helicases DEAD-box/genética , Sementes/genética , Apomixia , Arabidopsis , Proteínas de Arabidopsis/metabolismo , RNA Helicases DEAD-box/metabolismo , Endosperma/genética , Endosperma/fisiologia , Mutação , Óvulo Vegetal/genética , Óvulo Vegetal/metabolismo , Óvulo Vegetal/fisiologia , Pólen/genética , Pólen/metabolismo , Pólen/fisiologia , Sementes/metabolismo , Sementes/fisiologia
11.
BMC Plant Biol ; 24(1): 458, 2024 May 27.
Artigo em Inglês | MEDLINE | ID: mdl-38797860

RESUMO

BACKGROUND: The endosperm serves as the primary source of nutrients for maize (Zea mays L.) kernel embryo development and germination. Positioned at the base of the endosperm, the transfer cells (TCs) of the basal endosperm transfer layer (BETL) generate cell wall ingrowths, which enhance the connectivity between the maternal plant and the developing kernels. These TCs play a crucial role in nutrient transport and defense against pathogens. The molecular mechanism underlying BETL development in maize remains unraveled. RESULTS: This study demonstrated that the MYB-related transcription factor ZmMYBR29, exhibited specific expression in the basal cellularized endosperm, as evidenced by in situ hybridization analysis. Utilizing the CRISPR/Cas9 system, we successfully generated a loss-of-function homozygous zmmybr29 mutant, which presented with smaller kernel size. Observation of histological sections revealed abnormal development and disrupted morphology of the cell wall ingrowths in the BETL. The average grain filling rate decreased significantly by 26.7% in zmmybr29 mutant in comparison to the wild type, which impacted the dry matter accumulation within the kernels and ultimately led to a decrease in grain weight. Analysis of RNA-seq data revealed downregulated expression of genes associated with starch synthesis and carbohydrate metabolism in the mutant. Furthermore, transcriptomic profiling identified 23 genes that expressed specifically in BETL, and the majority of these genes exhibited altered expression patterns in zmmybr29 mutant. CONCLUSIONS: In summary, ZmMYBR29 encodes a MYB-related transcription factor that is expressed specifically in BETL, resulting in the downregulation of genes associated with kernel development. Furthermore, ZmMYBR29 influences kernels weight by affecting the grain filling rate, providing a new perspective for the complementation of the molecular regulatory network in maize endosperm development.


Assuntos
Grão Comestível , Endosperma , Regulação da Expressão Gênica de Plantas , Proteínas de Plantas , Fatores de Transcrição , Zea mays , Zea mays/genética , Zea mays/crescimento & desenvolvimento , Zea mays/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Grão Comestível/genética , Grão Comestível/crescimento & desenvolvimento , Grão Comestível/metabolismo , Endosperma/genética , Endosperma/crescimento & desenvolvimento , Endosperma/metabolismo , Parede Celular/metabolismo , Parede Celular/genética , Sementes/genética , Sementes/crescimento & desenvolvimento , Sementes/metabolismo , Sistemas CRISPR-Cas
12.
Plant Biotechnol J ; 22(3): 555-571, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38050335

RESUMO

The nutritional value of wheat grains, particularly their protein and metabolite composition, is a result of the grain-filling process, especially in the endosperm. Here, we employ laser microdissection (LMD) combined with shotgun proteomics and metabolomics to generate a cell type-specific proteome and metabolome inventory of developing wheat endosperm at the early (15 DAA) and late (26 DAA) grain-filling stages. We identified 1803 proteins and 41 metabolites from four different cell types (aleurone (AL), sub-aleurone (SA), starchy endosperm (SE) and endosperm transfer cells (ETCs). Differentially expressed proteins were detected, 67 in the AL, 31 in the SA, 27 in the SE and 50 in the ETCs between these two-time points. Cell-type accumulation of specific SUT and GLUT transporters, sucrose converting and starch biosynthesis enzymes correlate well with the respective sugar metabolites, suggesting sugar upload and starch accumulation via nucellar projection and ETC at 15 DAA in contrast to the later stage at 26 DAA. Changes in various protein levels between AL, SA and ETC support this metabolic switch from 15 to 26 DAA. The distinct spatial and temporal abundances of proteins and metabolites revealed a contrasting activity of nitrogen assimilation pathways, e.g. for GOGAT, GDH and glutamic acid, in the different cell types from 15 to 26 DAA, which can be correlated with specific protein accumulation in the endosperm. The integration of cell-type specific proteome and metabolome data revealed a complex metabolic interplay of the different cell types and a functional switch during grain development and grain-filling processes.


Assuntos
Endosperma , Triticum , Endosperma/metabolismo , Triticum/metabolismo , Proteoma/metabolismo , Proteômica , Antivirais/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Grão Comestível , Amido/metabolismo , Açúcares/metabolismo
13.
Plant Biotechnol J ; 2024 Aug 24.
Artigo em Inglês | MEDLINE | ID: mdl-39180364

RESUMO

Starch is synthesized as insoluble, semicrystalline particles within plant chloroplast and amyloplast, which are referred to as starch grains (SGs). The size and morphology of SGs in the cereal endosperm are diverse and species-specific, representing a key determinant of the suitability of starch for industrial applications. However, the molecular mechanisms modulating SG size in cereal endosperm remain elusive. Here, we functionally characterized the rice (Oryza sativa) mutant substandard starch grain7 (ssg7), which exhibits enlarged SGs and defective endosperm development. SSG7 encodes a plant-specific DUF1001 domain-containing protein homologous to Arabidopsis (Arabidopsis thaliana) CRUMPLED LEAF (AtCRL). SSG7 localizes to the amyloplast membrane in developing endosperm. Several lines of evidence suggest that SSG7 functions together with SSG4 and SSG6, known as two regulators essential for SG development, to control SG size, by interacting with translocon-associated components, which unveils a molecular link between SG development and protein import. Genetically, SSG7 acts synergistically with SSG4 and appears to be functional redundancy with SSG6 in modulating SG size and endosperm development. Collectively, our findings uncover a multimeric functional protein complex involved in SG development in rice. SSG7 represents a promising target gene for the biotechnological modification of SG size, particularly for breeding programs aimed at improving starch quality.

14.
Plant Biotechnol J ; 22(6): 1453-1467, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38163293

RESUMO

Kernel weight is a critical factor that essentially affects maize (Zea mays) yield. In natural inbred lines, popcorn kernels exhibit overtly smaller sizes compared to dent corn kernels, and kernel weight, which is controlled by multiple genetic loci, varies widely. Here, we characterized a major quantitative trait locus on chromosome 1, responsible for controlling kernel weight (qKW1) and size. The qKW1 locus encodes a protein containing a seven in absentia domain with E3 ubiquitin ligase activity, expressed prominently from the top to the middle region of the endosperm. The presence and function of qKW1 were confirmed through ZmKW1 gene editing, where the mutations in ZmKW1 within dent corn significantly increased kernel weight, consistent with alterations in kernel size, while overexpression of ZmKW1 had the opposite effect. ZmKW1 acts as a negative regulator of kernel weight and size by reducing both the number and size of the endosperm cells and impacting endosperm filling. Notably, the popcorn allele qKW1N and the dent corn allele qKW1D encode identical proteins; however, the differences in promoter activity arise due to the insertion of an Indel-1346 sequence in the qKW1N promoter, resulting in higher expression levels compared to qKW1D, thus contributing to the variation in kernel weight and size between popcorn and dent corn kernels. Linkage disequilibrium analysis of the 2.8 kb promoter region of ZmKW1 in a dataset comprising 111 maize association panels identified two distinct haplotypes. Our results provide insight into the mechanisms underlying kernel development and yield regulation in dent corn and popcorn, with a specific focus on the role of the ubiquitination system.


Assuntos
Proteínas de Plantas , Locos de Características Quantitativas , Zea mays , Zea mays/genética , Zea mays/crescimento & desenvolvimento , Zea mays/metabolismo , Locos de Características Quantitativas/genética , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Variação Genética , Endosperma/genética , Endosperma/metabolismo , Endosperma/crescimento & desenvolvimento , Sementes/genética , Sementes/crescimento & desenvolvimento , Sementes/metabolismo , Regulação da Expressão Gênica de Plantas
15.
New Phytol ; 241(5): 2075-2089, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38095260

RESUMO

Nuclear-cytoplasmic trafficking is crucial for protein synthesis in eukaryotic cells due to the spatial separation of transcription and translation by the nuclear envelope. However, the mechanism underlying this process remains largely unknown in plants. In this study, we isolated a maize (Zea mays) mutant designated developmentally delayed kernel 1 (ddk1), which exhibits delayed seed development and slower filling. Ddk1 encodes a plant-specific protein known as Importin-4 ß, and its mutation results in reduced 80S monosomes and suppressed protein synthesis. Through our investigations, we found that DDK1 interacts with eIF1A proteins in vivo. However, in vitro experiments revealed that this interaction exhibits low affinity in the absence of RanGTP. Additionally, while the eIF1A protein primarily localizes to the cytoplasm in the wild-type, it remains significantly retained within the nuclei of ddk1 mutants. These observations suggest that DDK1 functions as an exportin and collaborates with RanGTP to facilitate the nuclear export of eIF1A, consequently regulating endosperm development at the translational level. Importantly, both DDK1 and eIF1A are conserved among various plant species, implying the preservation of this regulatory module across diverse plants.


Assuntos
Sementes , Zea mays , Transporte Ativo do Núcleo Celular , Zea mays/metabolismo , Sementes/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Carioferinas/genética , Carioferinas/metabolismo , Grão Comestível/metabolismo
16.
New Phytol ; 242(6): 2635-2651, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38634187

RESUMO

Endosperm is the main storage organ in cereal grain and determines grain yield and quality. The molecular mechanisms of heat shock proteins in regulating starch biosynthesis and endosperm development remain obscure. Here, we report a rice floury endosperm mutant flo24 that develops abnormal starch grains in the central starchy endosperm cells. Map-based cloning and complementation test showed that FLO24 encodes a heat shock protein HSP101, which is localized in plastids. The mutated protein FLO24T296I dramatically lost its ability to hydrolyze ATP and to rescue the thermotolerance defects of the yeast hsp104 mutant. The flo24 mutant develops more severe floury endosperm when grown under high-temperature conditions than normal conditions. And the FLO24 protein was dramatically induced at high temperature. FLO24 physically interacts with several key enzymes required for starch biosynthesis, including AGPL1, AGPL3 and PHO1. Combined biochemical and genetic evidence suggests that FLO24 acts cooperatively with HSP70cp-2 to regulate starch biosynthesis and endosperm development in rice. Our results reveal that FLO24 acts as an important regulator of endosperm development, which might function in maintaining the activities of enzymes involved in starch biosynthesis in rice.


Assuntos
Endosperma , Oryza , Proteínas de Plantas , Amido , Trifosfato de Adenosina/metabolismo , Trifosfato de Adenosina/biossíntese , Endosperma/genética , Endosperma/crescimento & desenvolvimento , Endosperma/metabolismo , Regulação da Expressão Gênica de Plantas , Teste de Complementação Genética , Mutação/genética , Oryza/genética , Oryza/metabolismo , Oryza/crescimento & desenvolvimento , Proteínas de Plantas/metabolismo , Proteínas de Plantas/genética , Plastídeos/metabolismo , Ligação Proteica , Amido/biossíntese , Amido/genética , Termotolerância , Fatores de Transcrição
17.
New Phytol ; 243(5): 1855-1869, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-38962989

RESUMO

Grain filling in maize (Zea mays) is intricately linked to cell development, involving the regulation of genes responsible for the biosynthesis of storage reserves (starch, proteins, and lipids) and phytohormones. However, the regulatory network coordinating these biological functions remains unclear. In this study, we identified 1744 high-confidence target genes co-regulated by the transcription factors (TFs) ZmNAC128 and ZmNAC130 (ZmNAC128/130) through chromatin immunoprecipitation sequencing coupled with RNA-seq analysis in the zmnac128/130 loss-of-function mutants. We further constructed a hierarchical regulatory network using DNA affinity purification sequencing analysis of downstream TFs regulated by ZmNAC128/130. In addition to target genes involved in the biosynthesis of starch and zeins, we discovered novel target genes of ZmNAC128/130 involved in the biosynthesis of lipids and indole-3-acetic acid (IAA). Consistently, the number of oil bodies, as well as the contents of triacylglycerol, and IAA were significantly reduced in zmnac128/130. The hierarchical regulatory network centered by ZmNAC128/130 revealed a significant overlap between the direct target genes of ZmNAC128/130 and their downstream TFs, particularly in regulating the biosynthesis of storage reserves and IAA. Our results indicated that the biosynthesis of storage reserves and IAA is coordinated by a multi-TFs hierarchical regulatory network in maize endosperm.


Assuntos
Endosperma , Regulação da Expressão Gênica de Plantas , Redes Reguladoras de Genes , Ácidos Indolacéticos , Proteínas de Plantas , Fatores de Transcrição , Zea mays , Zea mays/genética , Zea mays/metabolismo , Ácidos Indolacéticos/metabolismo , Endosperma/metabolismo , Endosperma/genética , Proteínas de Plantas/metabolismo , Proteínas de Plantas/genética , Fatores de Transcrição/metabolismo , Fatores de Transcrição/genética , Genes de Plantas , Mutação/genética , Amido/metabolismo , Amido/biossíntese
18.
New Phytol ; 243(1): 213-228, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38715414

RESUMO

Arabidopsis lamin analogs CROWDED NUCLEIs (CRWNs) are necessary to maintain nuclear structure, genome function, and proper plant growth. However, whether and how CRWNs impact reproduction and genome-wide epigenetic modifications is unknown. Here, we investigate the role of CRWNs during the development of gametophytes, seeds, and endosperm, using genomic and epigenomic profiling methods. We observed defects in crwn mutant seeds including seed abortion and reduced germination rate. Quadruple crwn null genotypes were rarely transmitted through gametophytes. Because defects in seeds often stem from abnormal endosperm development, we focused on crwn1 crwn2 (crwn1/2) endosperm. These mutant seeds exhibited enlarged chalazal endosperm cysts and increased expression of stress-related genes and the MADS-box transcription factor PHERES1 and its targets. Previously, it was shown that PHERES1 expression is regulated by H3K27me3 and that CRWN1 interacts with the PRC2 interactor PWO1. Thus, we tested whether crwn1/2 alters H3K27me3 patterns. We observed a mild loss of H3K27me3 at several hundred loci, which differed between endosperm and leaves. These data indicate that CRWNs are necessary to maintain the H3K27me3 landscape, with tissue-specific chromatin and transcriptional consequences.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Endosperma , Regulação da Expressão Gênica de Plantas , Histonas , Mutação , Reprodução , Arabidopsis/genética , Arabidopsis/fisiologia , Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Histonas/metabolismo , Endosperma/genética , Endosperma/metabolismo , Mutação/genética , Sementes/genética , Sementes/crescimento & desenvolvimento , Núcleo Celular/metabolismo , Metilação
19.
J Exp Bot ; 75(14): 4346-4359, 2024 Jul 23.
Artigo em Inglês | MEDLINE | ID: mdl-38364847

RESUMO

Double fertilization in angiosperms results in the formation of a second zygote, the fertilized endosperm. Unlike its embryo sibling, the endosperm is a transient structure that eventually undergoes developmentally controlled programmed cell death (PCD) at specific time points of seed development or germination. The nature of endosperm PCD exhibits a considerable diversity, both across different angiosperm taxa and within distinct endosperm tissues. In endosperm-less species, PCD might cause central cell degeneration as a mechanism preventing the formation of a fertilized endosperm. In most other angiosperms, embryo growth necessitates the elimination of surrounding endosperm cells. Nevertheless, complete elimination of the endosperm is rare and, in most cases, specific endosperm tissues persist. In mature seeds, these persisting cells may be dead, such as the starchy endosperm in cereals, or remain alive to die only during germination, like the cereal aleurone or the endosperm of castor beans. In this review, we explore current knowledge surrounding the cellular, molecular, and genetic aspects of endosperm PCD, and the influence environmental stresses have on PCD processes. Overall, this review provides an exhaustive overview of endosperm PCD processes in angiosperms, shedding light on its diverse mechanisms and its significance in seed development and seedling establishment.


Assuntos
Endosperma , Magnoliopsida , Endosperma/crescimento & desenvolvimento , Endosperma/fisiologia , Magnoliopsida/fisiologia , Fenômenos Fisiológicos Vegetais , Apoptose , Amido , Ricinus communis , Germinação
20.
Transgenic Res ; 33(1-2): 47-57, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38451380

RESUMO

Cellobiohydrolase II (CBH II) is an exo-glucanase that is part of a fungal mixture of enzymes from a wood-rot fungus, Trichoderma reesei. It is therefore difficult to purify and to establish a specific activity assay. The gene for this enzyme, driven by the rice Os glutelin promoter, was transformed into High II tissue culture competent corn, and the enzyme accumulated in the endosperm of the seed. The transgenic line recovered from tissue culture was bred into male and female elite Stine inbred corn lines, stiff stalk 16083-025 (female) and Lancaster MSO411 (male), for future production in their hybrid. The enzyme increases its accumulation throughout its 6 generations of back crosses, 27-266-fold between T1 and T2, and 2-10-fold between T2 and T3 generations with lesser increases in T4-T6. The germplasm of the inbred lines replaces the tissue culture corn variety germplasm with each generation, with the ultimate goal of producing a high-yielding hybrid with the transgene. The CBH II enzyme was purified from T5 inbred male grain 10-fold to homogeneity with 47.5% recovery. The specific activity was determined to be 1.544 units per µg protein. The corn-derived CBH II works in biopolishing of cotton by removing surface fibers to improve dyeability and increasing glucose from corn flour for increasing ethanol yield from starch-based first-generation processes.


Assuntos
Celulase , Trichoderma , Celulose 1,4-beta-Celobiosidase/genética , Celulose 1,4-beta-Celobiosidase/metabolismo , Zea mays/genética , Zea mays/metabolismo , Endosperma/genética , Endosperma/metabolismo , Trichoderma/genética , Trichoderma/metabolismo , Melhoramento Vegetal , Celulase/genética
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