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1.
Development ; 151(11)2024 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-38856047

RESUMO

The shoot apical meristem is a key stem cell niche in plants, and proper stem cell maintenance is partly regulated by CLAVATA3 (CLV3). Without CLV3 meristems overgrow, but the mechanistic basis of this phenotype was unclear. A new paper in Development suggests that CLV3 modulates the physical properties of meristematic stem cells, and that these properties help shape meristem morphology. To learn more about the story behind the paper, we caught up with first author Léa Rambaud-Lavigne and corresponding authors Namrata Gundiah, Arezki Boudaoud and Pradeep Das.


Assuntos
Meristema , Meristema/crescimento & desenvolvimento , Meristema/citologia , Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Arabidopsis/crescimento & desenvolvimento , História do Século XXI , Biologia do Desenvolvimento/história , História do Século XX
2.
Science ; 384(6701): 1241-1247, 2024 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-38870308

RESUMO

Plant stems comprise nodes and internodes that specialize in solute exchange and elongation. However, their boundaries are not well defined, and how these basic units arise remains elusive. In rice with clear nodes and internodes, we found that one subclade of class I knotted1-like homeobox (KNOX1) genes for shoot meristem indeterminacy restricts node differentiation and allows internode formation by repressing YABBY genes for leaf development and genes from another node-specific KNOX1 subclade. YABBYs promote nodal vascular differentiation and limit stem elongation. YABBY and node-specific KNOX1 genes specify the pulvinus, which further elaborates the nodal structure for gravitropism. Notably, this KNOX1 subclade organization is specific to seed plants. We propose that nodes and internodes are distinct domains specified by YABBY-KNOX1 cross-regulation that diverged in early seed plants.


Assuntos
Regulação da Expressão Gênica de Plantas , Proteínas de Homeodomínio , Meristema , Oryza , Proteínas de Plantas , Caules de Planta , Proteínas de Homeodomínio/genética , Proteínas de Homeodomínio/metabolismo , Caules de Planta/anatomia & histologia , Caules de Planta/genética , Caules de Planta/crescimento & desenvolvimento , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Meristema/genética , Meristema/crescimento & desenvolvimento , Oryza/genética , Oryza/crescimento & desenvolvimento , Gravitropismo/genética , Folhas de Planta/genética , Folhas de Planta/anatomia & histologia , Folhas de Planta/crescimento & desenvolvimento , Genes de Plantas
3.
Plant Cell Rep ; 43(7): 174, 2024 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-38878164

RESUMO

KEY MESSAGE: Interactor of WOX2, CDC48A, is crucial for early embryo patterning and shoot meristem stem cell initiation, but is not required for WOX2 protein turnover or subcellular localization. During Arabidopsis embryo patterning, the WUSCHEL HOMEOBOX 2 (WOX2) transcription factor is a major regulator of protoderm and shoot stem cell initiation. Loss of WOX2 function results in aberrant protodermal cell divisions and, redundantly with its paralogs WOX1, WOX3, and WOX5, compromised shoot meristem formation. To elucidate the molecular basis for WOX2 function, we searched for protein interactors by IP-MS/MS from WOX2-overexpression roots displaying reprogramming toward shoot-like cell fates. Here, we report that WOX2 directly interacts with the type II AAA ATPase molecular chaperone CELL DIVISION CYCLE 48A (CDC48A). We confirmed this interaction with bimolecular fluorescence complementation and co-immunoprecipitation and found that both proteins co-localize in the nucleus. We show that CDC48A loss of function results in protoderm and shoot meristem stem cell initiation defects similar to WOX2 loss of function. We also provide evidence that CDC48A promotes WOX2 activity independently of proteolysis or the regulation of nuclear localization, common mechanisms of CDC48A function in other processes. Our results point to a new role of CDC48A in potentiating WOX2 function during early embryo patterning.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Proteínas de Ciclo Celular , Regulação da Expressão Gênica de Plantas , Proteínas de Homeodomínio , Meristema , Arabidopsis/genética , Arabidopsis/metabolismo , Arabidopsis/embriologia , Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Homeodomínio/metabolismo , Proteínas de Homeodomínio/genética , Meristema/metabolismo , Meristema/genética , Meristema/embriologia , Proteínas de Ciclo Celular/metabolismo , Proteínas de Ciclo Celular/genética , Adenosina Trifosfatases/metabolismo , Adenosina Trifosfatases/genética , Sementes/metabolismo , Sementes/genética , Sementes/crescimento & desenvolvimento , Plantas Geneticamente Modificadas , ATPases Associadas a Diversas Atividades Celulares , Fatores de Transcrição
4.
Development ; 151(12)2024 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-38884589

RESUMO

Plants are dependent on divisions of stem cells to establish cell lineages required for growth. During embryogenesis, early division products are considered to be stem cells, whereas during post-embryonic development, stem cells are present in meristems at the root and shoot apex. PLETHORA/AINTEGUMENTA-LIKE (PLT/AIL) transcription factors are regulators of post-embryonic meristem function and are required to maintain stem cell pools. Despite the parallels between embryonic and post-embryonic stem cells, the role of PLTs during early embryogenesis has not been thoroughly investigated. Here, we demonstrate that the PLT regulome in the zygote, and apical and basal cells is in strong congruence with that of post-embryonic meristematic cells. We reveal that out of all six PLTs, only PLT2 and PLT4/BABY BOOM (BBM) are expressed in the zygote, and that these two factors are essential for progression of embryogenesis beyond the zygote stage and first divisions. Finally, we show that other PLTs can rescue plt2 bbm defects when expressed from the PLT2 and BBM promoters, establishing upstream regulation as a key factor in early embryogenesis. Our data indicate that generic PLT factors facilitate early embryo development in Arabidopsis by induction of meristematic potential.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Regulação da Expressão Gênica de Plantas , Meristema , Fatores de Transcrição , Meristema/metabolismo , Meristema/embriologia , Meristema/genética , Arabidopsis/genética , Arabidopsis/metabolismo , Arabidopsis/embriologia , Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Fatores de Transcrição/metabolismo , Fatores de Transcrição/genética , Regulação da Expressão Gênica no Desenvolvimento , Sementes/metabolismo , Sementes/genética , Sementes/crescimento & desenvolvimento , Zigoto/metabolismo
5.
Plant Mol Biol ; 114(3): 65, 2024 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-38816532

RESUMO

Telomeres are conserved chromosomal structures necessary for continued cell division and proliferation. In addition to the classical telomerase pathway, multiple other genes including those involved in ribosome metabolism and chromatin modification contribute to telomere length maintenance. We previously reported that Arabidopsis thaliana ribosome biogenesis genes OLI2/NOP2A, OLI5/RPL5A and OLI7/RPL5B have critical roles in telomere length regulation. These three OLIGOCELLULA genes were also shown to function in cell proliferation and expansion control and to genetically interact with the transcriptional co-activator ANGUSTIFOLIA3 (AN3). Here we show that AN3-deficient plants progressively lose telomeric DNA in early homozygous mutant generations, but ultimately establish a new shorter telomere length setpoint by the fifth mutant generation with a telomere length similar to oli2/nop2a -deficient plants. Analysis of double an3 oli2 mutants indicates that the two genes are epistatic for telomere length control. Telomere shortening in an3 and oli mutants is not caused by telomerase inhibition; wild type levels of telomerase activity are detected in all analyzed mutants in vitro. Late generations of an3 and oli mutants are prone to stem cell damage in the root apical meristem, implying that genes regulating telomere length may have conserved functional roles in stem cell maintenance mechanisms. Multiple instances of anaphase fusions in late generations of oli5 and oli7 mutants were observed, highlighting an unexpected effect of ribosome biogenesis factors on chromosome integrity. Overall, our data implicate AN3 transcription coactivator and OLIGOCELLULA proteins in the establishment of telomere length set point in plants and further suggest that multiple regulators with pleiotropic functions can connect telomere biology with cell proliferation and cell expansion pathways.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Divisão Celular , Telomerase , Telômero , Arabidopsis/genética , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Telômero/genética , Telômero/metabolismo , Divisão Celular/genética , Telomerase/genética , Telomerase/metabolismo , Homeostase do Telômero/genética , Regulação da Expressão Gênica de Plantas , Mutação , Fatores de Transcrição/metabolismo , Fatores de Transcrição/genética , Proliferação de Células/genética , Meristema/genética , Meristema/metabolismo
6.
Nat Plants ; 10(5): 815-827, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38745100

RESUMO

A comprehensive understanding of inflorescence development is crucial for crop genetic improvement, as inflorescence meristems give rise to reproductive organs and determine grain yield. However, dissecting inflorescence development at the cellular level has been challenging owing to a lack of specific marker genes to distinguish among cell types, particularly in different types of meristems that are vital for organ formation. In this study, we used spatial enhanced resolution omics-sequencing (Stereo-seq) to construct a precise spatial transcriptome map of the developing maize ear primordium, identifying 12 cell types, including 4 newly defined cell types found mainly in the inflorescence meristem. By extracting the meristem components for detailed clustering, we identified three subtypes of meristem and validated two MADS-box genes that were specifically expressed at the apex of determinate meristems and involved in stem cell determinacy. Furthermore, by integrating single-cell RNA transcriptomes, we identified a series of spatially specific networks and hub genes that may provide new insights into the formation of different tissues. In summary, this study provides a valuable resource for research on cereal inflorescence development, offering new clues for yield improvement.


Assuntos
Inflorescência , Meristema , Transcriptoma , Zea mays , Zea mays/genética , Zea mays/crescimento & desenvolvimento , Zea mays/metabolismo , Inflorescência/genética , Inflorescência/crescimento & desenvolvimento , Meristema/genética , Meristema/crescimento & desenvolvimento , Meristema/metabolismo , Regulação da Expressão Gênica de Plantas , Perfilação da Expressão Gênica
7.
Sci Rep ; 14(1): 11148, 2024 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-38750143

RESUMO

The one-leaf plant Monophyllaea glabra exhibits a unique developmental manner in which only one cotyledon continues growing without producing new vegetative organs. This morphology is formed by specific meristems, the groove meristem (GM) and the basal meristem (BM), which are thought to be modified shoot apical meristem (SAM) and leaf meristem. In this study, we analysed the expression of the organ boundary gene CUP-SHAPED COTYLEDON (CUC) and the SAM maintenance gene SHOOT MERISTEMLESS (STM) orthologs by whole-mount in situ hybridisation. We found that CUCs did not show clear border patterns around GM and BM during the vegetative phase. Furthermore, double-colour detection analysis at the cellular level revealed that CUC and STM expression overlapped in the GM region during the vegetative phase. We also found that this overlap is dissolved in the reproductive phase when normal shoot organogenesis is observed. Since co-expression of these genes occurs during SAM initiation under embryogenesis in Arabidopsis, our results demonstrate that GM is a prolonged stage of pre-mature SAM. Therefore, we propose that neotenic meristems could be a novel plant trait acquired by one-leaf plants.


Assuntos
Cotilédone , Regulação da Expressão Gênica de Plantas , Meristema , Meristema/genética , Meristema/crescimento & desenvolvimento , Meristema/metabolismo , Cotilédone/genética , Cotilédone/crescimento & desenvolvimento , Brotos de Planta/genética , Brotos de Planta/crescimento & desenvolvimento , Brotos de Planta/metabolismo , Folhas de Planta/genética , Folhas de Planta/metabolismo , Folhas de Planta/crescimento & desenvolvimento , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Arabidopsis/genética , Arabidopsis/crescimento & desenvolvimento
8.
Nat Commun ; 15(1): 4627, 2024 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-38821962

RESUMO

Stem cells in plants and animals are the source of new tissues and organs. In plants, stem cells are maintained in the central zone (CZ) of multicellular meristems, and large shoot meristems with an increased stem cell population hold promise for enhancing yield. The mobile homeodomain transcription factor WUSCHEL (WUS) is a central regulator of stem cell function in plant shoot meristems. Despite its central importance, the factors that directly modulate WUS protein stability have been a long-standing question. Here, we show that the peptidase DA1 physically interacts with and cleaves the WUS protein, leading to its destabilization. Furthermore, our results reveal that cytokinin signaling represses the level of DA1 protein in the shoot apical meristem, thereby increasing the accumulation of WUS protein. Consistent with these observations, loss of DA1 function results in larger shoot apical meristems with an increased stem cell population and also influences cytokinin-induced enlargement of shoot apical meristem. Collectively, our findings uncover a previously unrecognized mechanism by which the repression of DA1 by cytokinin signaling stabilizes WUS, resulting in the enlarged shoot apical meristems with the increased stem cell number during plant growth and development.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Citocininas , Regulação da Expressão Gênica de Plantas , Proteínas de Homeodomínio , Meristema , Meristema/metabolismo , Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Arabidopsis/metabolismo , Arabidopsis/genética , Arabidopsis/crescimento & desenvolvimento , Citocininas/metabolismo , Proteínas de Homeodomínio/metabolismo , Proteínas de Homeodomínio/genética , Transdução de Sinais , Brotos de Planta/metabolismo , Brotos de Planta/crescimento & desenvolvimento , Plantas Geneticamente Modificadas , Estabilidade Proteica
9.
Planta ; 259(6): 148, 2024 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-38717679

RESUMO

MAIN CONCLUSION: Mutation of OsSHR2 adversely impacted root and shoot growth and impaired plant response to N conditions, further reducing the yield per plant. Nitrogen (N) is a crucial factor that regulates the plant architecture. There is still a lack of research on it. In our study, it was observed that the knockout of the SHORTROOT 2 (OsSHR2) which was induced by N deficiency, can significantly affect the regulation of plant architecture response to N in rice. Under N deficiency, the mutation of OsSHR2 significantly reduced root growth, and impaired the sensitivity of the root meristem length to N deficiency. The mutants were found to have approximately a 15% reduction in plant height compared to wild type. But mutants showed a significant increase in tillering at post-heading stage, approximately 26% more than the wild type, particularly in high N conditions. In addition, due to reduced seed setting rate and 1000-grain weight, mutant yield was significantly decreased by approximately 33% under low N fertilizer supply. The mutation also changed the distribution of N between the vegetative and reproductive organs. Our findings suggest that the transcription factor OsSHR2 plays a regulatory role in the response of plant architecture and yield per plant to N in rice.


Assuntos
Regulação da Expressão Gênica de Plantas , Nitrogênio , Oryza , Fatores de Transcrição , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Meristema/genética , Meristema/crescimento & desenvolvimento , Meristema/efeitos dos fármacos , Mutação , Nitrogênio/metabolismo , Nitrogênio/farmacologia , Oryza/genética , Oryza/crescimento & desenvolvimento , Oryza/metabolismo , Oryza/efeitos dos fármacos , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/genética , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
10.
Curr Opin Plant Biol ; 80: 102544, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38759482

RESUMO

Underground storage organs occur in phylogenetically diverse plant taxa and arise from multiple tissue types including roots and stems. Thickening growth allows underground storage organs to accommodate carbohydrates and other nutrients and requires proliferation at various lateral meristems followed by cell expansion. The WOX-CLE module regulates thickening growth via the vascular cambium in several eudicot systems, but the molecular mechanisms of proliferation at other lateral meristems are not well understood. In potato, onion, and other systems, members of the phosphatidylethanolamine-binding protein (PEBP) gene family induce underground storage organ development in response to photoperiod cues. While molecular mechanisms of tuber development in potato are well understood, we lack detailed mechanistic knowledge for the extensive morphological and taxonomic diversity of underground storage organs in plants.


Assuntos
Tubérculos , Tubérculos/crescimento & desenvolvimento , Tubérculos/metabolismo , Tubérculos/genética , Tubérculos/anatomia & histologia , Proteínas de Plantas/metabolismo , Proteínas de Plantas/genética , Regulação da Expressão Gênica de Plantas , Meristema/crescimento & desenvolvimento , Meristema/genética , Meristema/metabolismo , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/metabolismo , Raízes de Plantas/genética , Raízes de Plantas/anatomia & histologia , Solanum tuberosum/crescimento & desenvolvimento , Solanum tuberosum/genética , Solanum tuberosum/metabolismo , Solanum tuberosum/anatomia & histologia
11.
Curr Biol ; 34(11): 2344-2358.e5, 2024 Jun 03.
Artigo em Inglês | MEDLINE | ID: mdl-38781954

RESUMO

Inflorescence architecture and crop productivity are often tightly coupled in our major cereal crops. However, the underlying genetic mechanisms controlling cereal inflorescence development remain poorly understood. Here, we identified recessive alleles of barley (Hordeum vulgare L.) HvALOG1 (Arabidopsis thaliana LSH1 and Oryza G1) that produce non-canonical extra spikelets and fused glumes abaxially to the central spikelet from the upper-mid portion until the tip of the inflorescence. Notably, we found that HvALOG1 exhibits a boundary-specific expression pattern that specifically excludes reproductive meristems, implying the involvement of previously proposed localized signaling centers for branch regulation. Importantly, during early spikelet formation, non-cell-autonomous signals associated with HvALOG1 expression may specify spikelet meristem determinacy, while boundary formation of floret organs appears to be coordinated in a cell-autonomous manner. Moreover, barley ALOG family members synergistically modulate inflorescence morphology, with HvALOG1 predominantly governing meristem maintenance and floral organ development. We further propose that spatiotemporal redundancies of expressed HvALOG members specifically in the basal inflorescence may be accountable for proper patterning of spikelet formation in mutant plants. Our research offers new perspectives on regulatory signaling roles of ALOG transcription factors during the development of reproductive meristems in cereal inflorescences.


Assuntos
Hordeum , Inflorescência , Meristema , Proteínas de Plantas , Transdução de Sinais , Hordeum/genética , Hordeum/crescimento & desenvolvimento , Hordeum/metabolismo , Meristema/crescimento & desenvolvimento , Meristema/genética , Meristema/metabolismo , Inflorescência/crescimento & desenvolvimento , Inflorescência/genética , Inflorescência/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Regulação da Expressão Gênica de Plantas
12.
Mol Biol Rep ; 51(1): 605, 2024 May 03.
Artigo em Inglês | MEDLINE | ID: mdl-38700570

RESUMO

BACKGROUND: Cultivation of Crocus sativus (saffron) faces challenges due to inconsistent flowering patterns and variations in yield. Flowering takes place in a graded way with smaller corms unable to produce flowers. Enhancing the productivity requires a comprehensive understanding of the underlying genetic mechanisms that govern this size-based flowering initiation and commitment. Therefore, samples enriched with non-flowering and flowering apical buds from small (< 6 g) and large (> 14 g) corms were sequenced. METHODS AND RESULTS: Apical bud enriched samples from small and large corms were collected immediately after dormancy break in July. RNA sequencing was performed using Illumina Novaseq 6000 to access the gene expression profiles associated with size dependent flowering. De novo transcriptome assembly and analysis using flowering committed buds from large corms at post-dormancy and their comparison with vegetative shoot primordia from small corms pointed out the major role of starch and sucrose metabolism, Auxin and ABA hormonal regulation. Many genes with known dual responses in flowering development and circadian rhythm like Flowering locus T and Cryptochrome 1 along with a transcript showing homology with small auxin upregulated RNA (SAUR) exhibited induced expression in flowering buds. Thorough prediction of Crocus sativus non-coding RNA repertoire has been carried out for the first time. Enolase was found to be acting as a major hub with protein-protein interaction analysis using Arabidopsis counterparts. CONCLUSION: Transcripts belong to key pathways including phenylpropanoid biosynthesis, hormone signaling and carbon metabolism were found significantly modulated. KEGG assessment and protein-protein interaction analysis confirm the expression data. Findings unravel the genetic determinants driving the size dependent flowering in Crocus sativus.


Assuntos
Crocus , Flores , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Ácidos Indolacéticos , Meristema , Transdução de Sinais , Flores/genética , Flores/crescimento & desenvolvimento , Flores/metabolismo , Crocus/genética , Crocus/crescimento & desenvolvimento , Crocus/metabolismo , Regulação da Expressão Gênica de Plantas/genética , Ácidos Indolacéticos/metabolismo , Perfilação da Expressão Gênica/métodos , Meristema/genética , Meristema/crescimento & desenvolvimento , Meristema/metabolismo , Transdução de Sinais/genética , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Transcriptoma/genética , Açúcares/metabolismo , Reguladores de Crescimento de Plantas/metabolismo
13.
Nat Commun ; 15(1): 3895, 2024 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-38719832

RESUMO

Growth at the shoot apical meristem (SAM) is essential for shoot architecture construction. The phytohormones gibberellins (GA) play a pivotal role in coordinating plant growth, but their role in the SAM remains mostly unknown. Here, we developed a ratiometric GA signaling biosensor by engineering one of the DELLA proteins, to suppress its master regulatory function in GA transcriptional responses while preserving its degradation upon GA sensing. We demonstrate that this degradation-based biosensor accurately reports on cellular changes in GA levels and perception during development. We used this biosensor to map GA signaling activity in the SAM. We show that high GA signaling is found primarily in cells located between organ primordia that are the precursors of internodes. By gain- and loss-of-function approaches, we further demonstrate that GAs regulate cell division plane orientation to establish the typical cellular organization of internodes, thus contributing to internode specification in the SAM.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Técnicas Biossensoriais , Regulação da Expressão Gênica de Plantas , Giberelinas , Meristema , Transdução de Sinais , Giberelinas/metabolismo , Meristema/metabolismo , Meristema/crescimento & desenvolvimento , Arabidopsis/metabolismo , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Reguladores de Crescimento de Plantas/metabolismo , Brotos de Planta/metabolismo , Brotos de Planta/crescimento & desenvolvimento , Plantas Geneticamente Modificadas
14.
Development ; 151(11)2024 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-38752444

RESUMO

Stem cell homeostasis in the shoot apical meristem involves a core regulatory feedback loop between the signalling peptide CLAVATA3 (CLV3), produced in stem cells, and the transcription factor WUSCHEL, expressed in the underlying organising centre. clv3 mutant meristems display massive overgrowth, which is thought to be caused by stem cell overproliferation, although it is unknown how uncontrolled stem cell divisions lead to this altered morphology. Here, we reveal local buckling defects in mutant meristems, and use analytical models to show how mechanical properties and growth rates may contribute to the phenotype. Indeed, clv3 mutant meristems are mechanically more heterogeneous than the wild type, and also display regional growth heterogeneities. Furthermore, stereotypical wild-type meristem organisation, in which cells simultaneously express distinct fate markers, is lost in mutants. Finally, cells in mutant meristems are auxin responsive, suggesting that they are functionally distinguishable from wild-type stem cells. Thus, all benchmarks show that clv3 mutant meristem cells are different from wild-type stem cells, suggesting that overgrowth is caused by the disruption of a more complex regulatory framework that maintains distinct genetic and functional domains in the meristem.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Ácidos Indolacéticos , Meristema , Mutação , Brotos de Planta , Células-Tronco , Arabidopsis/genética , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/metabolismo , Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Meristema/metabolismo , Meristema/citologia , Meristema/crescimento & desenvolvimento , Meristema/genética , Mutação/genética , Células-Tronco/metabolismo , Células-Tronco/citologia , Brotos de Planta/crescimento & desenvolvimento , Brotos de Planta/genética , Brotos de Planta/metabolismo , Ácidos Indolacéticos/metabolismo , Regulação da Expressão Gênica de Plantas , Fenótipo , Proteínas de Homeodomínio/metabolismo , Proteínas de Homeodomínio/genética
15.
EMBO J ; 43(9): 1843-1869, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38565948

RESUMO

The RNA-silencing effector ARGONAUTE10 influences cell fate in plant shoot and floral meristems. ARGONAUTE10 also accumulates in the root apical meristem (RAM), yet its function(s) therein remain elusive. Here, we show that ARGONAUTE10 is expressed in the root cell initials where it controls overall RAM activity and length. ARGONAUTE10 is also expressed in the stele, where post-transcriptional regulation confines it to the root tip's pro-vascular region. There, variations in ARGONAUTE10 levels modulate metaxylem-vs-protoxylem specification. Both ARGONAUTE10 functions entail its selective, high-affinity binding to mobile miR165/166 transcribed in the neighboring endodermis. ARGONAUTE10-bound miR165/166 is degraded, likely via SMALL-RNA-DEGRADING-NUCLEASES1/2, thus reducing miR165/166 ability to silence, via ARGONAUTE1, the transcripts of cell fate-influencing transcription factors. These include PHABULOSA (PHB), which controls meristem activity in the initials and xylem differentiation in the pro-vasculature. During early germination, PHB transcription increases while dynamic, spatially-restricted transcriptional and post-transcriptional mechanisms reduce and confine ARGONAUTE10 accumulation to the provascular cells surrounding the newly-forming xylem axis. Adequate miR165/166 concentrations are thereby channeled along the ARGONAUTE10-deficient yet ARGONAUTE1-proficient axis. Consequently, inversely-correlated miR165/166 and PHB gradients form preferentially along the axis despite ubiquitous PHB transcription and widespread miR165/166 delivery inside the whole vascular cylinder.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Proteínas Argonautas , Regulação da Expressão Gênica de Plantas , Meristema , MicroRNAs , Raízes de Plantas , Xilema , Arabidopsis/genética , Arabidopsis/metabolismo , Arabidopsis/crescimento & desenvolvimento , MicroRNAs/metabolismo , MicroRNAs/genética , Meristema/metabolismo , Meristema/crescimento & desenvolvimento , Meristema/genética , Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas Argonautas/metabolismo , Proteínas Argonautas/genética , Xilema/metabolismo , Xilema/crescimento & desenvolvimento , Xilema/genética , Raízes de Plantas/metabolismo , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/genética
16.
Sci Rep ; 14(1): 8679, 2024 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-38622223

RESUMO

Roots are crucial in plant adaptation through the exudation of various compounds which are influenced and modified by environmental factors. Buckwheat root exudate and root system response to neighbouring plants (buckwheat or redroot pigweed) and how these exudates affect redroot pigweed was investigated. Characterising root exudates in plant-plant interactions presents challenges, therefore a split-root system which enabled the application of differential treatments to parts of a single root system and non-destructive sampling was developed. Non-targeted metabolome profiling revealed that neighbour presence and identity induces systemic changes. Buckwheat and redroot pigweed neighbour presence upregulated 64 and 46 metabolites, respectively, with an overlap of only 7 metabolites. Root morphology analysis showed that, while the presence of redroot pigweed decreased the number of root tips in buckwheat, buckwheat decreased total root length and volume, surface area, number of root tips, and forks of redroot pigweed. Treatment with exudates (from the roots of buckwheat and redroot pigweed closely interacting) on redroot pigweed decreased the total root length and number of forks of redroot pigweed seedlings when compared to controls. These findings provide understanding of how plants modify their root exudate composition in the presence of neighbours and how this impacts each other's root systems.


Assuntos
Amaranthus , Produtos Biológicos , Fagopyrum , Metaboloma , Meristema , Plântula , Produtos Biológicos/metabolismo , Raízes de Plantas/metabolismo
17.
Plant Physiol Biochem ; 211: 108635, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38688114

RESUMO

Meristem activity is important for normal plant growth as well as adaptive plastic development under abiotic stresses. Cytokinin has been recognized to have a major role in regulating meristem function which is controlled by cytokinin activating enzymes by fine-tuning the concentrations and spatial distribution of its bioactive forms. It was previously reported that LONELY GUY (LOG) acts in the direct activation pathway of cytokinin in rice shoot meristems. LOG has a cytokinin specific phosphoribohydrolase activity, which transforms inactive cytokinin nucleotides into active free bases. Here, we explored the role of OsLOG in controlling meristem activity mediated by cytokinin and its effects on growth, development, and stress resilience of rice plants. Overexpression of OsLOG in rice led to significant alterations in cytokinin levels in the inflorescence meristem, leading to enhanced plant growth, biomass and grain yield under both non-stress as well as stress conditions such as drought and salinity. Moreover, our study provides insight into how overexpression of OsLOG improves the ability of plants to withstand stress. The OsLOG-overexpressing lines exhibit reduced accumulation of H2O2 along with elevated antioxidant enzyme activities, thereby maintaining better redox homeostasis under stress conditions. This ultimately reduces the negative impact of stresses on grain yield and improves harvest index, as evidenced by observations in the OsLOG-overexpressing lines. In summary, our study emphasizes the diverse role of OsLOG, not only in regulating plant growth and yield via cytokinin but also in enhancing adaptability to abiotic stresses. This highlights its potential to improve crop yield and promote sustainable agriculture.


Assuntos
Citocininas , Oryza , Proteínas de Plantas , Estresse Fisiológico , Oryza/genética , Oryza/enzimologia , Oryza/crescimento & desenvolvimento , Oryza/metabolismo , Citocininas/metabolismo , Proteínas de Plantas/metabolismo , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas , Grão Comestível/crescimento & desenvolvimento , Grão Comestível/genética , Regulação da Expressão Gênica de Plantas , Meristema/crescimento & desenvolvimento , Meristema/genética , Meristema/metabolismo , Secas
18.
Sci Rep ; 14(1): 8651, 2024 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-38622233

RESUMO

In this study, the multifaceted toxicity induced by high doses of the essential trace element molybdenum in Allium cepa L. was investigated. Germination, root elongation, weight gain, mitotic index (MI), micronucleus (MN), chromosomal abnormalities (CAs), Comet assay, malondialdehyde (MDA), proline, superoxide dismutase (SOD), catalase (CAT) and anatomical parameters were used as biomarkers of toxicity. In addition, detailed correlation and PCA analyzes were performed for all parameters discussed. On the other hand, this study focused on the development of a two hidden layer deep neural network (DNN) using Matlab. Four experimental groups were designed: control group bulbs were germinated in tap water and application group bulbs were germinated with 1000, 2000 and 4000 mg/L doses of molybdenum for 72 h. After germination, root tips were collected and prepared for analysis. As a result, molybdenum exposure caused a dose-dependent decrease (p < 0.05) in the investigated physiological parameter values, and an increase (p < 0.05) in the cytogenetic (except MI) and biochemical parameter values. Molybdenum exposure induced different types of CAs and various anatomical damages in root meristem cells. Comet assay results showed that the severity of DNA damage increased depending on the increasing molybdenum dose. Detailed correlation and PCA analysis results determined significant positive and negative interactions between the investigated parameters and confirmed the relationships of these parameters with molybdenum doses. It has been found that the DNN model is in close agreement with the actual data showing the accuracy of the predictions. MAE, MAPE, RMSE and R2 were used to evaluate the effectiveness of the DNN model. Collective analysis of these metrics showed that the DNN model performed well. As a result, it has been determined once again that high doses of molybdenum cause multiple toxicity in A. cepa and the Allium test is a reliable universal test for determining this toxicity. Therefore, periodic measurement of molybdenum levels in agricultural soils should be the first priority in preventing molybdenum toxicity.


Assuntos
Allium , Molibdênio/toxicidade , Raízes de Plantas , Meristema , Cebolas/fisiologia , Aberrações Cromossômicas
19.
Yi Chuan ; 46(3): 242-255, 2024 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-38632102

RESUMO

To understand the genome-wide information of the GRF family genes in broomcorn millet and their expression profile in the vegetative meristems, bioinformatic methods and transcriptome sequencing were used to analyze the characteristics, physical and chemical properties, phylogenetic relationship, chromosome distribution, gene structure, cis-acting elements and expression profile in stem meristem for the GRF family members. The results showed that the GRF gene family of millet contains 21 members, and the PmGRF gene is unevenly distributed on 12 chromosomes. The lengths of PmGRF proteins vary from 224 to 618 amino acids, and the isoelectric points are between 4.93-9.69. Each member of the family has 1-4 introns and 2-5 exons. The protein PmGRF13 is localized in both the nucleus and chloroplast, and the rest PmGRF proteins are located in the nucleus. Phylogenetic analysis showed that the 21 GRF genes were divided into 4 subfamilies (A,B,C and D) in broomcorn millet. The analysis of cis-acting elements showed that there were many cis-acting elements involved in light response, hormone response, drought induction, low temperature response and other environmental stress responses in the 2000 bp sequence upstream of the GRF genes. Transcriptome sequencing and qRT-PCR analyses showed that the expression levels of PmGRF3 and PmGRF12 in the dwarf variety Zhang778 were significantly higher than those of the tall variety Longmi12 in the internode and node meristems at the jointing stage, while the expression patterns of PmGRF4, PmGRF16 and PmGRF21 were reverse. In addition, the expression levels of PmGRF2 and PmGRF5 in the internode of Zhang778 were significantly higher than Longmi12. The other GRF genes were not or insignificantly expressed. These results indicated that seven genes, PmGRF2, PmGRF3, PmGRF4, PmGRF5, PmGRF12, PmGRF16 and PmGRF21, were related to the formation of plant height in broomcorn millet.


Assuntos
Panicum , Filogenia , Panicum/química , Panicum/genética , Fatores de Transcrição/genética , Meristema , Genoma de Planta
20.
Physiol Plant ; 176(3): e14320, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38686642

RESUMO

Many nucleoside triphosphate-diphosphohydrolases (NTPDases/APYRASEs, APYs) play a key role in modulating extracellular nucleotide levels. However, the Golgi-localized APYs, which help control glycosylation, have rarely been studied. Here, we identified AtAPY1, a gene encoding an NTPDase in the Golgi apparatus, which is required for cell wall integrity and plant growth under boron (B) limited availability. Loss of function in AtAPY1 hindered cell elongation and division in root tips while increasing the number of cortical cell layers, leading to swelling of the root tip and abundant root hairs under low B stress. Further, expression pattern analysis revealed that B deficiency significantly induced AtAPY1, especially in the root meristem and stele. Fluorescent-labeled AtAPY1-GFP localized to the Golgi stack. Biochemical analysis showed that AtAPY1 exhibited a preference of UDP and GDP hydrolysis activities. Consequently, the loss of function in AtAPY1 might disturb the homoeostasis of NMP-driven NDP-sugar transport, which was closely related to the synthesis of cell wall polysaccharides. Further, cell wall-composition analysis showed that pectin content increased and borate-dimerized RG-II decreased in apy1 mutants, along with a decrease in cellulose content. Eventually, altered polysaccharide characteristics presumably cause growth defects in apy1 mutants under B deficiency. Altogether, these data strongly support a novel role for AtAPY1 in mediating responses to low B availability by regulating cell wall integrity.


Assuntos
Apirase , Proteínas de Arabidopsis , Arabidopsis , Boro , Parede Celular , Complexo de Golgi , Arabidopsis/genética , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/enzimologia , Arabidopsis/metabolismo , Parede Celular/metabolismo , Boro/metabolismo , Boro/deficiência , Complexo de Golgi/metabolismo , Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Apirase/metabolismo , Apirase/genética , Regulação da Expressão Gênica de Plantas , Raízes de Plantas/crescimento & desenvolvimento , Raízes de Plantas/genética , Raízes de Plantas/metabolismo , Meristema/genética , Meristema/crescimento & desenvolvimento , Meristema/metabolismo , Pectinas/metabolismo
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