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1.
Plant Signal Behav ; : 1899487, 2021 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-33715572

RESUMO

The zinc finger transcription factor STOP1 plays a crucial role in aluminum (Al) resistance and low phosphate (Pi) response. Al stress and low Pi availability do not affect STOP1 mRNA expression but are able to induce STOP1 protein accumulation by post-transcriptional regulatory mechanisms. We recently reported that STOP1 can be mono-SUMOylated at K40, K212, or K395 sites, and deSUMOylated by the SUMO protease ESD4. SUMOylation of STOP1 is important for the regulation of STOP1 protein function and Al resistance. In the present study, we further characterized the role of the SUMO E3 ligase SIZ1 in STOP1 SUMOylation, Al resistance and low Pi response. We found that mutation of SIZ1 reduced but not eliminated STOP1 SUMOylation, suggesting that SIZ1-dependent and -independent pathways are involved in the regulation of STOP1 SUMOylation. The STOP1 protein levels were decreased in siz1 mutants. Nevertheless, the expression of STOP1-target gene AtALMT1 was increased instead of reduced in siz1 mutants. The mutants showed enhanced Al resistance and low Pi response. Our results suggest that SIZ1 regulates Al resistance and low Pi response likely through the modulation of AtALMT1 expression.

2.
Sci Rep ; 11(1): 5060, 2021 Mar 03.
Artigo em Inglês | MEDLINE | ID: mdl-33658526

RESUMO

The CLAVATA3 (CLV3)/EMBRYO SURROUNDING REGION (ESR)-RELATED (CLE) gene family encodes a large number of polypeptide signaling molecules involved in the regulation of shoot apical meristem division and root and vascular bundle development in a variety of plants. CLE family genes encode important short peptide hormones; however, the functions of these signaling polypeptides in cotton remain largely unknown. In the current work, we studied the effects of the CLE family genes on growth and development in cotton. Based on the presence of a conserved CLE motif of 13 amino acids, 93 genes were characterized as GhCLE gene family members, and these were subcategorized into 7 groups. A preliminary analysis of the cotton CLE gene family indicated that the activity of its members tends to be conserved in terms of both the 13-residue conserved domain at the C-terminus and their subcellular localization pattern. Among the 14 tested genes, the ectopic overexpression of GhCLE5::GFP partially mimicked the phenotype of the clv3 mutant in Arabidopsis. GhCLE5 could affect the endogenous CLV3 in binding to the receptor complex, comprised of CLV1, CLV2, and CRN, in the yeast two-hybrid assay and split-luciferase assay. Silencing GhCLE5 in cotton caused a short seedling phenotype. Therefore, we concluded that the cotton GhCLE gene family is functionally conserved in apical shoot development regulation. These results indicate that CLE also plays roles in cotton development as a short peptide hormone.

3.
Nano Lett ; 20(12): 8926-8932, 2020 Dec 09.
Artigo em Inglês | MEDLINE | ID: mdl-33186046

RESUMO

Plasmonic polymers consisting of metallic nanoparticles (NPs) are able to squeeze light into the deep-subwavelength space and transfer along a highly confined nanoscale path in long range. DNA nanotechnology, particularly benefiting from the molecular programmability of DNA origami, has provided otherwise nearly impossible platforms for constructing plasmonic nanoparticle polymers with designer configurations and nanoscale gaps. Here, we design and assemble a DNA origami hashtag tile that is able to polymerize into one-dimensional chains with high rigidity. The DNA origami hashtag chains are used as frames to enable robust, versatile, and precise arrangement of metallic NPs into micrometer-long chiral and magnetic plasmonic polymers, which are capable of efficiently transporting plasmonic angular momentum and magnetic surface plasmonic polaritons at the deep-subwavelength scale. Our work provides a molecular platform for the fabrication of long, straight, and structurally complex nanoparticle polymers with emerging plasmonic properties that are appealing to a variety of fields.

4.
Mol Plant ; 13(10): 1402-1419, 2020 10 05.
Artigo em Inglês | MEDLINE | ID: mdl-32979566

RESUMO

Crop diseases are major factors responsible for substantial yield losses worldwide, which affects global food security. The use of resistance (R) genes is an effective and sustainable approach to controlling crop diseases. Here, we review recent advances on R gene studies in the major crops and related wild species. Current understanding of the molecular mechanisms underlying R gene activation and signaling, and susceptibility (S) gene-mediated resistance in crops are summarized and discussed. Furthermore, we propose some new strategies for R gene discovery, how to balance resistance and yield, and how to generate crops with broad-spectrum disease resistance. With the rapid development of new genome-editing technologies and the availability of increasing crop genome sequences, the goal of breeding next-generation crops with durable resistance to pathogens is achievable, and will be a key step toward increasing crop production in a sustainable way.

5.
ACS Nano ; 14(11): 14616-14626, 2020 11 24.
Artigo em Inglês | MEDLINE | ID: mdl-32897687

RESUMO

Biological membrane channels, considered as molecular gatekeepers, control the transportation of molecules and ions across live cell membranes. Developing synthetic passable channels with predictable structures, high transport efficiency, and low cytotoxicity on live cells is of great interest for replicating the functions of endogenous protein channels, but remains challenging. The development of DNA nanotechnology provides possible solutions for making synthetic channels with precise structures and controllable functionalization. Therefore, in this work, we constructed a phosphorothioate-modified DNA nanopore able to structurally mimic biological channels for molecular transport across live cell membranes. With its stable structure with small hollow size (<2 nm) and the ability to interact with the lipid molecules, this DNA nanopore could show stable insertion into the plasma membrane. We further proved that this membrane-spanning channel could transport ions and antitumor drugs to neurons and cancer cells, respectively, and do so within a certain time window. We expect that this live cell membrane-spanning synthetic DNA nanopore will provide a tool for studying cellular communication, building synthetic cells, and achieving controlled transmembrane transport to cells.

6.
Nat Plants ; 6(6): 661-674, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32514141

RESUMO

It is generally assumed that DNA methylation changes at genomic regions targeted by the de novo RNA-directed DNA methylation (RdDM) pathway are unstable. Here, we show that RdDM targets in Arabidopsis can be classified into two groups on the basis of whether there is remethylation following the restoration of NRPD1 function in nrpd1 mutant plants-remethylable loci and non-remethylable loci. In contrast to the remethylable loci, the non-remethylable loci contain higher levels of the euchromatic marks of trimethylation at Lys 4 of histone H3 (H3K4me3), which interferes with the recruitment of the RdDM molecular machinery, and acetylation at Lys 18 of histone H3 (H3K18ac), which helps to recruit the DNA demethylase ROS1 to antagonize RdDM. Here, using targeted methylation erasure by CRISPR-dCas9-TET1, we demonstrate that methylated CG (mCG) and mCHG (where H represents A, C or T) are memory marks that are required for targeting the RdDM machinery to remethylable loci. Our results show that histone and DNA methylation marks are critical in determining the ability of RdDM target loci to form stable epialleles, and contribute to understanding the formation and transmission of epialleles.

7.
Nano Lett ; 20(5): 3155-3159, 2020 05 13.
Artigo em Inglês | MEDLINE | ID: mdl-32286079

RESUMO

DNA origami holds an unprecedented capability on assembling metallic nanoparticles into designer plasmonic metamolecules of emerging properties, including surface-enhanced Raman scattering (SERS). SERS metamolecules were produced by positioning nanoparticles in close proximity to each other on a DNA origami template for Raman enhancement. In earlier reports, SERS metamolecules were generally assembled into clusters containing small number of nanoparticles (2, 3, or 4) and thus had limited programmability over SERS. Herein, we expanded the structural complexity of SERS metamolecules by increasing the number of nanoparticles and by arranging them into sophisticated configurations. DNA origami hexagon tile was used as the assembling template to fabricate clusters consisting of 6, 7, 12, 18, and 30+ metallic nanoparticles. Programmable SERS was realized via controlling the size, number, or spatial arrangement of nanoparticles. We believe this method offers a general platform for fabricating sophisticated nanodevices with programmable SERS that may be applied to a variety of fields including plasmonics, nanophotonics, and sensing.

8.
Clin Chim Acta ; 505: 141-147, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32119835

RESUMO

BACKGROUND: Previous studies have used a modified version of the Child-Turcotte-Pugh (CTP) score to include insulin-like growth factor 1 (IGF-1) concentrations, denoted the Insulin-like Growth Factor 1-Child-Turcotte-Pugh (IGF-CTP) system. We evaluated the predictive power of IGF-CTP for 1-year mortality in patients with decompensated cirrhosis (DC). METHODS: A total of 386 patients with DC were retrospectively analyzed. Comparison of distribution of patients with decompensated cirrhosis according to Insulin-like Growth Factor-1-Child-Turcotte-Pugh and Child-Turcotte-Pugh scores were performed. Area under the receiver operating characteristic curves (AUROCs) for IGF-CTP, CTP and the Model for End-stage Liver Disease (MELD) scores were evaluated to compare predictive value. Univariate and multivariate analyses were carried out to determine potential risk factors for 1-y mortality. RESULTS: During the 1-y follow-up, 94 patients died. Significantly more patients (both surviving and non-surviving) were classified as IGF-CTP stage C than CTP stage C. The AUROC of IGF-CTP was significantly higher than that of CTP and MELD in the training and validation cohorts. Multivariate analysis indicated IGF-CTP score and IGF-1 to be independently associated with mortality. CONCLUSION: The IGF-CTP score is independently associated with mortality for patients with DC, and offers more accurate prediction of 1-y mortality than either CTP or MELD score for these patients.


Assuntos
Algoritmos , Fibrose/sangue , Fator de Crescimento Insulin-Like I/análise , Adulto , Idoso , Área Sob a Curva , Estudos de Coortes , Doença Hepática Terminal/sangue , Feminino , Fibrose/mortalidade , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Estudos Retrospectivos , Fatores de Risco , Análise de Sobrevida
9.
Nanoscale ; 11(31): 14569-14572, 2019 Aug 08.
Artigo em Inglês | MEDLINE | ID: mdl-31348481

RESUMO

We demonstrate twist and curvature engineering in DNA nanostructures from the scaffold-free approach. The DNA 'LEGO' bricks adopted in this study are double-C-shaped motifs, and extended nanostructures are constructed to visualize the structural details of twist or curvature. By systematically deleting and inserting base pairs at certain domains of the component motifs, we are able to study various levels of the twist and curvature of the resulting nanostructures comprehensively.


Assuntos
DNA/química , Nanoestruturas/química , Microscopia de Força Atômica , Conformação de Ácido Nucleico
10.
Angew Chem Int Ed Engl ; 58(35): 12123-12127, 2019 08 26.
Artigo em Inglês | MEDLINE | ID: mdl-31190457

RESUMO

Wireframe frameworks have been investigated for the construction of complex nanostructures from a scaffolded DNA origami approach; however, a similar framework is yet to be fully explored in a scaffold-free "LEGO" approach. Herein, we describe a general design scheme to construct wireframe DNA nanostructures entirely from short synthetic strands. A typical edge of the resulting structures in this study is composed of two parallel duplexes with crossovers on both ends, and three, four, or five edges radiate out from a certain vertex. By using such a self-assembly scheme, we produced planar lattices and polyhedral objects.

11.
Nat Plants ; 5(8): 902, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31097775

RESUMO

In the Supplementary Information file originally published with this Article, the authors mistakenly omitted accompanying legends for Supplementary Figures 1-15; this has now been amended.

12.
Nat Plants ; 5(4): 389-400, 2019 04.
Artigo em Inglês | MEDLINE | ID: mdl-30886331

RESUMO

Breeding crops with resistance is an efficient way to control diseases. However, increased resistance often has a fitness penalty. Thus, simultaneously increasing disease resistance and yield potential is a challenge in crop breeding. In this study, we found that downregulation of microRNA-156 (miR-156) and overexpression of Ideal Plant Architecture1 (IPA1) and OsSPL7, two target genes of miR-156, enhanced disease resistance against bacterial blight caused by Xanthomonas oryzae pv. oryzae (Xoo), but reduced rice yield. We discovered that gibberellin signalling might be partially responsible for the disease resistance and developmental defects in IPA1 overexpressors. We then generated transgenic rice plants expressing IPA1 with the pathogen-inducible promoter of OsHEN1; these plants had both enhanced disease resistance and enhanced yield-related traits. Thus, we have identified miR-156-IPA1 as a novel regulator of the crosstalk between growth and defence, and we have established a new strategy for obtaining both high disease resistance and high yield.


Assuntos
Produção Agrícola/métodos , Resistência à Doença/fisiologia , Oryza/crescimento & desenvolvimento , Proteínas de Plantas/fisiologia , Regulação da Expressão Gênica de Plantas , MicroRNAs/fisiologia , Oryza/fisiologia , Doenças das Plantas/imunologia , Doenças das Plantas/microbiologia , Xanthomonas
13.
Food Chem ; 277: 135-144, 2019 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-30502129

RESUMO

Nitrogen fertilization regimes significantly affect both grain quality and yield. Wheat plants were subjected to different application timing of topdressed nitrogen at the emergence of the top fifth (TL5), top third (TL3) and top first leaf (TL1), respectively. The iTRAQ (isobaric tag for relative and absolute quantitation) technology was adopted to obtain the complete proteome of wheat flour and to identify the differentially expressed proteins (DEPs) as regulated by nitrogen topdressing timing. Collectively, 591 proteins into 17 functional categories in flour of mature grains were identified. In comparison to TL3, 50 and 63 DEPs were identified in TL5 and TL1, respectively. Nine of the DEPs commonly dependent on nitrogen topdressing timing are the γ-gliadins or high-molecular-weight glutenin subunits. Additionally, delaying nitrogen topdressing modified the grain hardness and allergic protein content. The results suggested that altering nitrogen topdressing timing is a potential strategy for pursuing targeted processing quality of wheat flour.


Assuntos
Grão Comestível/efeitos dos fármacos , Grão Comestível/metabolismo , Glutens/metabolismo , Dureza/efeitos dos fármacos , Nitrogênio/farmacologia , Farinha/análise , Qualidade dos Alimentos , Folhas de Planta/metabolismo , Proteômica , Fatores de Tempo
14.
BMC Plant Biol ; 18(1): 353, 2018 Dec 13.
Artigo em Inglês | MEDLINE | ID: mdl-30545290

RESUMO

BACKGROUND: Nitrogen is one basic element of amino acids and grain protein in wheat. In field experiments, wheat plants were subjected to different timing of nitrogen topdressing treatments: at the stages of emergence of the top fifth leaf (TL5), top third leaf (TL3) and top first leaf (TL1) to test the regulatory effects of nitrogen topdressing timing on grain protein quality. The underlying mechanisms were elucidated by clarifying the relationship between proteolysis in vegetative organs and accumulation of amino acids in the endosperm cavity, conversion of amino acids, and storage protein synthesis in endosperm of wheat grain. RESULTS: Delayed nitrogen topdressing up-regulated gene expression related to nitrogen metabolism and protease synthesis in the flag leaf, followed by more free amino acids being transported to both the cavity and the endosperm from 7 days after anthesis (DAA) to 13 DAA in TL1. TL1 enhanced the conversion between free amino acids in endosperm and upregulated the expression of genes encoding high molecular weight (HMW) and low molecular weight (LMW) subunits and protein disulfide isomerases-like (PDIL) proteins, indicating that the synthesis and folding of glutenin were enhanched by delayed nitrogen topdressing. As a consequense, the content of glutenin macropolymers (GMP) and glutenin increased with delaying nitrogen topdressing. CONCLUSIONS: The results highlight the relationship between nitrogen remobilization and final grain protein production and suggest that the nitrogen remobilization processes could be a potential target for improving the quality of wheat grain. Additionally, specific gene expression related to nitrogen topdressing was identified, which conferred more detailed insights into underlying mechanism on the modification protein quality.


Assuntos
Aminoácidos/metabolismo , Grão Comestível/metabolismo , Nitrogênio/metabolismo , Proteínas de Plantas/metabolismo , Triticum/metabolismo , Aminoácidos/análise , Grão Comestível/química , Endosperma/química , Endosperma/metabolismo , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Nitrogênio/administração & dosagem , Folhas de Planta/metabolismo , Reação em Cadeia da Polimerase em Tempo Real
15.
Mol Plant ; 11(12): 1492-1508, 2018 12 03.
Artigo em Inglês | MEDLINE | ID: mdl-30448535

RESUMO

N6-Methyladenine (6mA) DNA methylation has recently been implicated as a potential new epigenetic marker in eukaryotes, including the dicot model Arabidopsis thaliana. However, the conservation and divergence of 6mA distribution patterns and functions in plants remain elusive. Here we report high-quality 6mA methylomes at single-nucleotide resolution in rice based on substantially improved genome sequences of two rice cultivars, Nipponbare (Nip; Japonica) and 93-11 (Indica). Analysis of 6mA genomic distribution and its association with transcription suggest that 6mA distribution and function is rather conserved between rice and Arabidopsis. We found that 6mA levels are positively correlated with the expression of key stress-related genes, which may be responsible for the difference in stress tolerance between Nip and 93-11. Moreover, we showed that mutations in DDM1 cause defects in plant growth and decreased 6mA level. Our results reveal that 6mA is a conserved DNA modification that is positively associated with gene expression and contributes to key agronomic traits in plants.


Assuntos
Adenina/análogos & derivados , Metilação de DNA , Regulação da Expressão Gênica de Plantas , Genoma de Planta/genética , Oryza/genética , Oryza/fisiologia , Estresse Fisiológico/genética , Adenina/metabolismo , Resposta ao Choque Térmico/genética , Oryza/crescimento & desenvolvimento
16.
Cell Discov ; 4: 55, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30345072

RESUMO

DNA methylation is a conserved epigenetic mark that is critical for many biological processes in plants and mammals. In Arabidopsis, the antagonistic activities of RNA-directed DNA methylation (RdDM) and ROS1-dependent active DNA demethylation are key for the dynamic regulation of locus-specific DNA methylation. However, the molecular factors that coordinate RdDM and active demethylation are largely unknown. Here we report that CLSY4 and its three paralogous SWI2/SNF2-type chromatin-remodeling proteins function in both RdDM and DNA demethylation in Arabidopsis. We initially identified CLSY4 in a genetic screen for DNA demethylation factors and subsequently demonstrated that it also is important in RdDM. Comprehensive genetic analyses using single and high order mutants of CLSY family proteins revealed their roles as double agents in the balance between methylation and demethylation reactions. The four CLSY proteins collectively are necessary for the canonical RdDM pathway; at the same time, each CLSY likely mediates DNA demethylation at specific loci where DNA methylation depends on RdDM. These results indicate that the four chromatin-remodeling proteins have dual functions in regulating genomic DNA methylation, and thus provide new insights into the dynamic regulation of DNA methylation in a model multicellular eukaryotic organism.

17.
Int J Mol Sci ; 19(6)2018 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-29914054

RESUMO

Calcium plays an important role in plant growth, development, and response to environmental stimuli. Copines are conserved plasma membrane-localized calcium-binding proteins which regulate plant immune responses and development. In this study, we found that copine proteins BON2 and BON3, the paralogs of BON1, physically interact with calcium pumps ACA8 and ACA10 in Arabidopsis. Notably, ACA9, the closest homologue of ACA8 and ACA10 functioning in pollen tube growth, interacts with all three copines. This is consistent with the protein⁻protein interactions between the two protein families, the aca8, aca10, aca8/aca10, bon1/2/3 mutants as well as aca9 mutant exhibited defects on pollen germination and seed production. Taken together, plasma membrane-localized interacting calcium pumps and copines coordinately control pollen tube growth, likely through manipulating calcium efflux.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/genética , ATPases Transportadoras de Cálcio/metabolismo , Proteínas de Transporte/metabolismo , Germinação , Infertilidade das Plantas , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Cálcio/metabolismo , ATPases Transportadoras de Cálcio/genética , Proteínas de Transporte/genética , Pólen/genética , Pólen/crescimento & desenvolvimento
18.
Theor Appl Genet ; 131(9): 1825-1834, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-29855673

RESUMO

The domesticated gene Q on wheat chromosome 5A (5AQ) encodes an AP2 transcription factor. The 5AQ was originated from a G to A mutation in exon 8 and/or C to T transition in exon 10 and resulted in free-threshing and subcompact spike characters of bread wheat. The Q homeoalleles on 5B and 5D are either a pseudogene or expressed at a low level. Our previous study identified a mutant, named NAUH164, by EMS treatment of wheat variety Sumai 3. The mutant exhibits compact spike and dwarfness, and the mutated locus Rht23 was mapped to the distal of the long arm of chromosome 5D, where 5Dq was located. To investigate the relationship of Rht23 and 5Dq, sequences and expression patterns of 5Dq from Sumai 3 and NAUH164 were compared. The two genotypes had a G3147A single nucleotide polymorphism (SNP), which was predicted to be located within the miR172 binding site of 5Dq. Based on this SNP, an SNP marker was developed and linkage analysis using a (NAUH164 × Alondra's) RIL population showed the marker was co-segregated with the Rht23 mutant traits. The qRT-PCR and Northern blot showed that in NAUH164, the expression of 5Dq was significantly up-regulated, and consistently, the expression of Ta-miR172 was down-regulated in leaves, stems and spikes. Our results demonstrated that point mutation in the miR172 binding site of the 5Dq likely increased its transcript level via a reduction in miRNA-dependent degradation, and this resulted in pleiotropic effects on spike compactness and plant dwarfness.


Assuntos
Genes de Plantas , Fator de Transcrição AP-2/genética , Triticum/crescimento & desenvolvimento , Triticum/genética , Mapeamento Cromossômico , Clonagem Molecular , Regulação da Expressão Gênica de Plantas , Ligação Genética , Marcadores Genéticos , Pleiotropia Genética , Genótipo , MicroRNAs , Fenótipo , Mutação Puntual , Polimorfismo de Nucleotídeo Único
19.
Phytopathology ; 108(1): 60-69, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-28876208

RESUMO

Small RNA (sRNA) is a class of noncoding RNA that can silence the expression of target genes. In rice, the majority of characterized sRNAs are within the range of 21 to 24 nucleotides (nt) long, whose biogenesis and function are associated with a specific sets of components, such as Dicer-like (OsDCLs) and Argonaute proteins (OsAGOs). Rice sRNAs longer than 24 nt are occasionally reported, with biogenesis and functional mechanism uninvestigated, especially in a context of defense responses against pathogen infection. By using deep sequencing, we identified a group of rice long small interfering RNAs (lsiRNAs) that are within the range of 25 to 40 nt in length. Our results show that some rice lsiRNAs are differentially expressed upon infection of Rhizoctonia solani, the causal agent of the rice sheath blight disease. Bioinformatic analysis and experimental validation indicate that some rice lsiRNAs can target defense-related genes. We further demonstrate that rice lsiRNAs are neither derived from RNA degradation nor originated as secondary small interfering RNAs (siRNAs). Moreover, lsiRNAs require OsDCL4 for biogenesis and OsAGO18 for function. Therefore, our study indicates that rice lsiRNAs are a unique class of endogenous sRNAs produced in rice, which may participate in response against pathogens.


Assuntos
Oryza/genética , Doenças das Plantas/imunologia , Imunidade Vegetal , RNA Interferente Pequeno/genética , Rhizoctonia/fisiologia , Biblioteca Gênica , Sequenciamento de Nucleotídeos em Larga Escala , Oryza/imunologia , Doenças das Plantas/microbiologia , Doenças das Plantas/prevenção & controle , RNA de Plantas/genética , Análise de Sequência de DNA , Tabaco/imunologia , Tabaco/microbiologia
20.
Mol Plant ; 11(2): 300-314, 2018 02 05.
Artigo em Inglês | MEDLINE | ID: mdl-29269023

RESUMO

Seed development in angiosperms requires a 2:1 maternal-to-paternal genome ratio (2m:1p) in the endosperm. When the ratio is disrupted, the seed development is impaired. Rice interploidy crosses result in endosperm failures, but the underlying molecular mechanisms remain unclear. Here, we report that the defective endosperm in rice interploidy crosses was associated with nonadditive expression of small RNAs and protein-coding genes. Interestingly, 24-nt small interfering RNAs were enriched in the 5' and 3' flanking sequences of nonadditively expressed genes in the interploidy crosses and were negatively associated with the expression of imprinted genes. Furthermore, some PRC2 family genes and DNA methylation-related genes including OsMET1b and OsCMT3a were upregulated in the 2×4 cross (pollinating a diploid "mother" with a tetraploid "father") but repressed in the reciprocal cross. These different epigenetic effects could lead to precocious or delayed cellularization during endosperm development. Notably, many endosperm-preferred genes, including starch metabolic and storage protein genes during grain filling, were found to be associated with DNA methylation or H3K27me3, which are repressed in both 2×4 and 4×2 crosses. WUSCHEL homeobox2 (WOX2)-like (WOX2L), an endosperm-preferred gene, was expressed specifically in the rice endosperm, in contrast to WOX2 expression in the Arabidopsis embryo. Disruption of WOX2L in transgenic rice by CRISPR/Cas9-mediated gene editing blocked starch and protein accumulation, resulting in seed abortion. In addition to gene repression, disrupting epigenetic process in the interploidy crosses also induced expression of stress-responsive genes. Thus, maintaining the 2m:1p genome ratio in the endosperm is essential for normal grain development in rice and other cereal crops.


Assuntos
Oryza/genética , Sementes/metabolismo , Epigenômica , Regulação da Expressão Gênica de Plantas , Oryza/crescimento & desenvolvimento , Poliploidia , Sementes/crescimento & desenvolvimento
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