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1.
Plant Mol Biol ; 101(4-5): 403-414, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31420780

RESUMO

Anther dehiscence, one of the essential steps in pollination and double fertilization, is regulated by a complex signaling pathway encompassing hormones and environmental factors. However, key components underlying the signaling pathway that regulate anther dehiscence remain largely elusive. Here, we isolated a rice mutant anther dehiscence defected 1 (Osadd1) that exhibited defects in anther dehiscence and glume open. Map-based cloning revealed that OsADD1 encoded a GARP (Golden2, ARR-B and Psr1) transcription factor. Sequence analysis showed that a single base deletion in Osadd1 mutant resulted in pre-termination of the GARP domain. OsADD1 was constitutively expressed in various tissues, with more abundance in the panicles. The major genes associated with anther dehiscence were affected in the Osadd1 mutant, and the expression level of the cellulose synthase-like D sub-family 4 (OsCSLD4) was significantly decreased. We demonstrate that OsADD1 regulated the expression of OsCSLD4 by binding to its promoter, and affects rice anther dehiscence.


Assuntos
Flores/fisiologia , Oryza/fisiologia , Proteínas de Plantas/fisiologia , Fatores de Transcrição/fisiologia , Clonagem Molecular , Flores/ultraestrutura , Regulação da Expressão Gênica de Plantas , Oryza/crescimento & desenvolvimento , Oryza/ultraestrutura , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo
2.
Ecol Lett ; 22(9): 1483-1492, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31286633

RESUMO

Can plants sense natural airborne sounds and respond to them rapidly? We show that Oenothera drummondii flowers, exposed to playback sound of a flying bee or to synthetic sound signals at similar frequencies, produce sweeter nectar within 3 min, potentially increasing the chances of cross pollination. We found that the flowers vibrated mechanically in response to these sounds, suggesting a plausible mechanism where the flower serves as an auditory sensory organ. Both the vibration and the nectar response were frequency-specific: the flowers responded and vibrated to pollinator sounds, but not to higher frequency sound. Our results document for the first time that plants can rapidly respond to pollinator sounds in an ecologically relevant way. Potential implications include plant resource allocation, the evolution of flower shape and the evolution of pollinators sound. Finally, our results suggest that plants may be affected by other sounds as well, including anthropogenic ones.


Assuntos
Flores/fisiologia , Néctar de Plantas/química , Polinização , Som , Açúcares/análise , Animais , Abelhas , Plantas
3.
Plant Sci ; 285: 224-229, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31203887

RESUMO

Why evergreen fruit tree species accumulate starch in the ovary during flower bud differentiation in spring, as deciduous species do during flower bud dormancy, is not fully understood. This is because in evergreen species carbon supply is assured by leaves during flower development. We suggest the existence of an autonomous mechanism in the flowers which counteracts the competition for photoassimilates with new leaves, until they become source organs. Our hypothesis is that starch accumulated during Citrus ovary ontogeny originates from 1) its own photosynthetic capacity and 2) the mobilization of reserves. Through defoliation experiments, we found that ovaries accumulate starch during flower ontogeny using a dual mechanism: 1) the autotrophic route of source organs activating Rubisco (RbcS) genes expression, and 2) the heterotrophic route of sink organs that hydrolyze sucrose in the cytosol. Defoliation 40 days before anthesis did not significantly reduce ovary growth, flower abscission or starch concentration up to 20 days after anthesis (i.e. 60 days later). Control flowers activated the energy depletion signaling system (i.e. SnRK1) and RbcS gene expression around athesis. Defoliation accelerated and boosted both activities, increasing SPS gene expression (sucrose synthesis), and SUS1, SUS3 and cwINV (sucrose hydrolysis) to maintain a glucose threshold which satisfied its need to avoid abscission.


Assuntos
Metabolismo dos Carboidratos/fisiologia , Citrus/crescimento & desenvolvimento , Flores/fisiologia , Frutas/crescimento & desenvolvimento , Citrus/metabolismo , Citrus/fisiologia , Flores/crescimento & desenvolvimento , Flores/metabolismo , Reação em Cadeia da Polimerase em Tempo Real , Transcriptoma
4.
Int J Mol Sci ; 20(11)2019 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-31167420

RESUMO

Grasses represent a major family of monocots comprising mostly cereals. When compared to their eudicot counterparts, cereals show a remarkable morphological diversity. Understanding the molecular basis of floral organ identity and inflorescence development is crucial to gain insight into the grain development for yield improvement purposes in cereals, however, the exact genetic mechanism of floral organogenesis remains elusive due to their complex inflorescence architecture. Extensive molecular analyses of Arabidopsis and other plant genera and species have established the ABCDE floral organ identity model. According to this model, hierarchical combinatorial activities of A, B, C, D, and E classes of homeotic genes regulate the identity of different floral organs with partial conservation and partial diversification between eudicots and cereals. Here, we review the developmental role of A, B, C, D, and E gene classes and explore the recent advances in understanding the floral development and subsequent organ specification in major cereals with reference to model plants. Furthermore, we discuss the evolutionary relationships among known floral organ identity genes. This comparative overview of floral developmental genes and associated regulatory factors, within and between species, will provide a thorough understanding of underlying complex genetic and molecular control of flower development and floral organ identity, which can be helpful to devise innovative strategies for grain yield improvement in cereals.


Assuntos
Grão Comestível/fisiologia , Evolução Molecular , Flores/fisiologia , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Biodiversidade , Grão Comestível/classificação , Filogenia , Desenvolvimento Vegetal/genética
5.
Plant Biol (Stuttg) ; 21(5): 967-974, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31050864

RESUMO

The trait-fitness relationship influences the strength and direction of floral evolution. To fully understand and predict the evolutionary trajectories of floral traits, it is critical to disentangle the direct and indirect effects of floral traits on plant fitness in natural populations. We experimentally quantified phenotypic selection on floral traits through female fitness and estimated the casual effects of nectar robbing with different nectar robbing intensities on trait-fitness relationships in both the L- (long-style and short-anther phenotype) and S-morph (short-style and long-anther phenotype) flowers among Primula secundiflora populations. A larger number of flowers and wider corolla tubes had both direct and indirect positive effects on female fitness in the P. secundiflora populations. The indirect effects of these two traits on female fitness were mediated by nectar robbers. The indirect effect of the number of flowers on female fitness increased with increasing nectar robbing intensity. In most populations, the direct and/or indirect effects of floral traits on female fitness were stronger in the S-morph flowers than in the L-morph flowers. In addition, nectar robbers had a direct positive effect on female fitness, but this effect varied between the L- and S-morph flowers. These results show the potential role of nectar robbers in influencing the trait-fitness relationships in this primrose species.


Assuntos
Flores/anatomia & histologia , Aptidão Genética , Néctar de Plantas , Primula/anatomia & histologia , Flores/fisiologia , Aptidão Genética/fisiologia , Fenótipo , Néctar de Plantas/fisiologia , Polinização/fisiologia , Primula/fisiologia
6.
Plant Cell Physiol ; 60(8): 1702-1721, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31077318

RESUMO

In plants, DNA methylation (i.e. chromatin modification) is important for various biological processes, including growth, development and flowering. Because 'Fuji' apple trees are alternate bearing and have a long ripening period and poor-quality flower buds, we used bud types with diverse flowering capabilities to investigate the epigenetic regulatory mechanisms influencing flower bud formation. We examined the DNA methylation changes and the transcriptional responses in the selected apple bud types. We observed that in the apple genome, approximately 79.5%, 67.4% and 23.7% of the CG, CHG and CHH sequences are methylated, respectively. For each sequence context, differentially methylated regions exhibited distinct methylation patterns among the analyzed apple bud types. Global methylation and transcriptional analyses revealed that nonexpressed genes or genes expressed at low levels were highly methylated in the gene-body regions, suggesting that gene-body methylation is negatively correlated with gene expression. Moreover, genes with methylated promoters were more highly expressed than genes with unmethylated promoters, implying promoter methylation and gene expression are positively correlated. Additionally, flowering-related genes (e.g. SOC1, AP1 and SPLs) and some transcription factor genes (e.g. GATA, bHLH, bZIP and WOX) were highly expressed in spur buds (highest flowering rate), but were associated with low methylation levels in the gene-body regions. Our findings indicate a potential correlation between DNA methylation and gene expression in apple buds with diverse flowering capabilities, suggesting an epigenetic regulatory mechanism influences apple flower bud formation.


Assuntos
Flores/fisiologia , Malus/genética , Malus/fisiologia , Proteínas de Plantas/metabolismo , Análise de Sequência de RNA/métodos , Metilação de DNA/genética , Metilação de DNA/fisiologia , Flores/genética , Regulação da Expressão Gênica de Plantas/genética , Regulação da Expressão Gênica de Plantas/fisiologia , Proteínas de Plantas/genética , Transdução de Sinais/genética , Transdução de Sinais/fisiologia
7.
PLoS Genet ; 15(5): e1008131, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-31083657

RESUMO

Allopolyploidy has played a major role in plant evolution but its impact on genome diversity and expression patterns remains to be understood. Some studies found important genomic and transcriptomic changes in allopolyploids, whereas others detected a strong parental legacy and more subtle changes. The allotetraploid C. bursa-pastoris originated around 100,000 years ago and one could expect the genetic polymorphism of the two subgenomes to follow similar trajectories and their transcriptomes to start functioning together. To test this hypothesis, we sequenced the genomes and the transcriptomes (three tissues) of allotetraploid C. bursa-pastoris and its parental species, the outcrossing C. grandiflora and the self-fertilizing C. orientalis. Comparison of the divergence in expression between subgenomes, on the one hand, and divergence in expression between the parental species, on the other hand, indicated a strong parental legacy with a majority of genes exhibiting a conserved pattern and cis-regulation. However, a large proportion of the genes that were differentially expressed between the two subgenomes, were also under trans-regulation reflecting the establishment of a new regulatory pattern. Parental dominance varied among tissues: expression in flowers was closer to that of C. orientalis and expression in root and leaf to that of C. grandiflora. Since deleterious mutations accumulated preferentially on the C. orientalis subgenome, the bias in expression towards C. orientalis observed in flowers indicates that expression changes could be adaptive and related to the selfing syndrome, while biases in the roots and leaves towards the C. grandiflora subgenome may be reflective of the differential genetic load.


Assuntos
Capsella/genética , Evolução Biológica , Flores/fisiologia , Genoma de Planta/genética , Genômica , Hibridização Genética , Poliploidia , Autofertilização , Transcriptoma/genética
8.
Int J Mol Sci ; 20(9)2019 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-31085987

RESUMO

Sheepgrass (Leymus chinensis (Trin.) Tzvel.) is an economically and ecologically important forage in the grass family. Self-incompatibility (SI) limits its seed production due to the low seed-setting rate after self-pollination. However, investigations into the molecular mechanisms of sheepgrass SI are lacking. Therefore, microscopic observation of pollen germination and pollen tube growth, as well as transcriptomic analyses of pistils after self- and cross-pollination, were performed. The results indicated that pollen tube growth was rapidly inhibited from 10 to 30 min after self-pollination and subsequently stopped but preceded normally after cross-pollination. Time course comparative transcriptomics revealed different transcriptome dynamics between self- and cross-pollination. A pool of SI-related signaling genes and pathways was generated, including genes related to calcium (Ca2+) signaling, protein phosphorylation, plant hormone, reactive oxygen species (ROS), nitric oxide (NO), cytoskeleton, and programmed cell death (PCD). A putative SI response molecular model in sheepgrass was presented. The model shows that SI may trigger a comprehensive calcium- and phytohormone-dominated signaling cascade and activate PCD, which may explain the rapid inhibition of self-pollen tube growth as observed by cytological analyses. These results provided new insight into the molecular mechanisms of sheepgrass (grass family) SI.


Assuntos
Perfilação da Expressão Gênica/métodos , Poaceae/genética , Transcriptoma/genética , Cálcio/metabolismo , Flores/genética , Flores/fisiologia , Regulação da Expressão Gênica de Plantas/genética , Regulação da Expressão Gênica de Plantas/fisiologia , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Polinização/genética , Polinização/fisiologia , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais/genética , Transdução de Sinais/fisiologia
9.
BMC Plant Biol ; 19(1): 184, 2019 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-31060496

RESUMO

BACKGROUND: Since their discovery, vacuolar processing enzymes (VPEs) have consistently been investigated as programmed cell death (PCD) initiators and participants in plant development and responses to biotic or abiotic stresses, in part due to similarities with the apoptosis regulator caspase-1. However, recent studies show additional functions of VPE in tomatoes, specifically in sucrose accumulation and fruit ripening. RESULTS: Herein, we evaluated the functions of VPE from sweetpotato, initially in expression pattern analyses of IbVPE1 during development and senescence. Subsequently, we identified physiological functions by overexpressing IbVPE1 in Arabidopsis thaliana, and showed reduced leaf sizes and numbers and early flowering, and elucidated the underlying molecular mechanisms. CONCLUSIONS: The present data demonstrate functions of the VPE gene family in development and senescence and in regulation of flowering times, leaf sizes and numbers, and senescence phenotypes in Arabidopsis thaliana.


Assuntos
Arabidopsis/crescimento & desenvolvimento , Arabidopsis/genética , Clorofila/metabolismo , Flores/fisiologia , Regulação da Expressão Gênica de Plantas , Ipomoea batatas/metabolismo , Folhas de Planta/crescimento & desenvolvimento , Proteínas de Plantas/metabolismo , Sequência de Aminoácidos , Escuridão , Especificidade de Órgãos/genética , Fenótipo , Complexo de Proteína do Fotossistema II/metabolismo , Filogenia , Folhas de Planta/anatomia & histologia , Proteínas de Plantas/química , Proteínas de Plantas/genética , Plantas Geneticamente Modificadas , Fatores de Transcrição/metabolismo
10.
Planta ; 250(1): 367-379, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31069523

RESUMO

MAIN CONCLUSION: This study provides first evidence of a thrips species pollinating Sambucus nigra and describes how interactions are driven by plant biochemical signalling and moderated by temporal changes in floral chemistry. The concept of flower-feeding thrips as pollinating insects in temperate regions is rarely considered as they are more frequently regarded to be destructive florivores feeding on pollen and surrounding plant tissue. Combining laboratory and field-based studies we examined interactions between Sambucus nigra (elderflower) and Thrips major within their native range to ascertain the role of thrips in the pollination of this species and to determine if floral chemicals mediated flower visits. If thrips provide a pollination service to S. nigra, then this will likely manifest in traits that attract the pollinating taxa at temporally critical points in floral development. T. major were highly abundant in inflorescences of S. nigra, entering flowers when stigmas were pollen-receptive and anthers were immature. When thrips were excluded from the inflorescences, fruit-set failed. Linalool was the major component of the inflorescence headspace with peak abundance coinciding with the highest number of adult thrips visiting flowers. Thrips were absent in buds and their numbers declined again in senescing flowers inversely correlating with the concentration of cyanogenic glycosides recorded in the floral tissue. Our data show that S. nigra floral chemistry mediates the behaviour of pollen-feeding thrips by attracting adults in high numbers to the flowers at pre-anthesis stage, while producing deterrent compounds prior to fruit development. Taking an integrative approach to studying thrips behaviour and floral biology we provide a new insight into the previously ambiguously defined pollination strategies of S. nigra and provide evidence suggesting that the relationship between T. major and S. nigra is mutualistic.


Assuntos
Comportamento Alimentar , Sambucus nigra/química , Transdução de Sinais , Tisanópteros/fisiologia , Compostos Orgânicos Voláteis/análise , Animais , Feminino , Flores/química , Flores/crescimento & desenvolvimento , Flores/fisiologia , Inflorescência/química , Inflorescência/crescimento & desenvolvimento , Inflorescência/fisiologia , Masculino , Pólen/química , Pólen/crescimento & desenvolvimento , Pólen/fisiologia , Polinização , Reprodução , Sambucus nigra/crescimento & desenvolvimento , Sambucus nigra/fisiologia , Simbiose , Compostos Orgânicos Voláteis/metabolismo
11.
Gene ; 707: 65-77, 2019 Jul 30.
Artigo em Inglês | MEDLINE | ID: mdl-31059736

RESUMO

The genic male sterility (MS) plays a major role in melon hybrids production, it could reduce the cost of pollination and increase the yield and quality. However, the molecular mechanism underlying genetic male sterility is yet poorly understood. The morphological differences of flower buds of melon were observed showed that the flower buds were tetrad when they were 1 mm stage and monocyte microspore when they were 2 mm stage. Electron microscopy showed that there was significant difference between MS lines and MF (male fertility) lines. In order to detect the global expression of the genes during the melon anther development and association with MS, 12 DEGs (differentially expressed genes) libraries were constructed from the anther of MS and MF in the bud stage with 1 and 2 mm diameter, respectively. A total of 765 DEGs expressed in anther during different developmental stage (MS 1 mm vs. MS 2 mm), 148 and 309 DEGs were found to be related to MS as compared to MF (MS 1 mm vs. MF 1 mm, and MS 2 mm vs. MF 2 mm) at a false discovery rate FDR <0.01. Among these, 10 DEGs were expressed in all the three comparisons, including transcription factor bHLH genes. Among the DEGs in RNA-seq analysis, 28 were validated by qRT-PCR. Of these, a number of genes were involved in ABC transfactor B family, cytochrome-related genes, hormone-related genes (auxin transporter, gibberellin-regulated protein), MADS-box protein genes, F-box protein genes, peroxidase-related, and Zinc finger protein genes. These genes are involved in many biological pathways, including starch and sucrose metabolism, signal transduction mechanisms and transcription factors, etc. Compared to the same developmental stage of MS and MF, the different developmental stages of MS indicated diverse gene regulation pathways involved in the anther development in MS. These results would provide novel insight into the global network to male sterility in melon.


Assuntos
Cucumis melo/fisiologia , Perfilação da Expressão Gênica/métodos , Infertilidade das Plantas , Proteínas de Plantas/genética , Quimera/genética , Quimera/fisiologia , Cucumis melo/genética , Cucumis melo/ultraestrutura , Flores/genética , Flores/fisiologia , Flores/ultraestrutura , Regulação da Expressão Gênica no Desenvolvimento , Regulação da Expressão Gênica de Plantas , Redes Reguladoras de Genes , Microscopia Eletrônica , Análise de Sequência de RNA
12.
Plant Sci ; 283: 247-255, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31128695

RESUMO

Chrysanthemums require continuous short-days (SD) for anthesis. FTL3 (FLOWERING LOCUS T-like 3), a floral promoter expressed in chrysanthemum leaf, forms a complex with its interacting partner FDL1 to induce floral meristem identity gene AFL1. We explored the FTL3 induction mechanism during SD repeats in Chrysanthemum seticuspe. CsFTL3 expression was not immediately induced by a shift from long-day (LD) to SD, but gradually increased until the capitulum development stage under repeated SDs. Overexpression of CsFTL3 transgene increased endogenous leaf CsFTL3 induction under SD but not LD. Overexpression of CsFDL1 promoted anthesis and increased CsAFL1 and CsFTL3 expression under SD. Loss-of-function of CsFDL1 by RNAi resulted in delayed anthesis and downregulation of leaf CsAFL1 and CsFTL3, indicating the necessity of CsFDL1 for CsFTL3 induction. Overexpression of an antagonistic protein of CsFTL3 or CsFDL1 inhibited leaf CsFTL3 induction. CsFTL3 expression was positively regulated during SDs by a feedback mechanism involving the CsFTL3-CsFDL1 complex. Furthermore, flowering was accomplished by feedback with high levels of CsFTL3 induction under repeated SDs.


Assuntos
Chrysanthemum/crescimento & desenvolvimento , Flores/crescimento & desenvolvimento , Proteínas de Plantas/fisiologia , Chrysanthemum/metabolismo , Chrysanthemum/fisiologia , Retroalimentação Fisiológica , Flores/metabolismo , Flores/fisiologia , Técnicas de Silenciamento de Genes , Fotoperíodo , Folhas de Planta/metabolismo , Folhas de Planta/fisiologia , Regiões Promotoras Genéticas/fisiologia , Transcriptoma
13.
BMC Plant Biol ; 19(1): 217, 2019 May 23.
Artigo em Inglês | MEDLINE | ID: mdl-31122203

RESUMO

BACKGROUND: Color directly affects fruit quality and consumer preference. In fig syconia, the female flower tissue is contained in a receptacle. Anthocyanin pigmentation of this tissue and the peel differs temporally and spatially. A transcriptome study was carried out to elucidate key genes and transcription factors regulating differences in fig coloring. RESULTS: Anthocyanins in the female flower tissue were identified mainly as pelargonidin-3-glucoside and cyanidin-3-rutinoside; in the peel, the major anthocyanins were cyanidin 3-O-glucoside and cyanidin-3-rutinoside. Anthocyanin content was significantly higher in the female flower tissue vs. peel before fig ripening, whereas at ripening, the anthocyanin content in the peel was 5.39 times higher than that in the female flower tissue. Light-deprivation treatment strongly inhibited peel, but not female flower tissue, anthocyanin pigmentation. RNA-Seq revealed 522 differentially expressed genes (recruited with criteria log2 ≥ 2 and P < 0.05) at fig ripening, with 50 upregulated and 472 downregulated genes in the female flower tissue. Light deprivation upregulated 1180 and downregulated 856 genes in the peel, and upregulated 909 and downregulated 817 genes in the female flower tissue. KEGG enrichment revealed significantly changed expression in the phenylpropanoid-biosynthesis and flavonoid-biosynthesis pathways in the peel, but not in the female flower tissue, with significant repression of FcCHS, FcCHI, FcF3H, FcF3'H, FcDFR and FcUFGT transcripts. Light deprivation led to differential expression of 71 and 80 transcription factor genes in the peel and female flower tissue, respectively. Yeast one-hybrid screen revealed that FcHY5 and FcMYB114 bind the promoter regions of FcCHS and FcDFR, respectively in the flavonoid-biosynthesis pathway. CONCLUSIONS: Phenylpropanoid- and flavonoid-biosynthesis pathways were differentially expressed spatially and temporally in the peel and female flower tissue of fig syconia; pathway expression in the peel was strongly regulated by light signal. Differentially expressed transcription factors were recruited as candidates to screen important expression regulators in the light-dependent and light-independent anthocyanin-synthesis pathway. Our study lays the groundwork for further elucidation of crucial players in fig pigmentation.


Assuntos
Ficus/fisiologia , Pigmentação , Transcriptoma , Ficus/genética , Ficus/crescimento & desenvolvimento , Ficus/efeitos da radiação , Flores/genética , Flores/crescimento & desenvolvimento , Flores/fisiologia , Flores/efeitos da radiação , Frutas/genética , Frutas/crescimento & desenvolvimento , Frutas/fisiologia , Frutas/efeitos da radiação , Pigmentação/efeitos da radiação , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Transcriptoma/efeitos da radiação
14.
Plant Physiol Biochem ; 139: 642-650, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31048121

RESUMO

The Bromeliaceae family, which is distributed pantropically, is one of the most morphologically diverse families. Except for the edible pineapple (Ananas comosus), the vast majority of bromeliads cultivated worldwide are appreciated mainly for their ornamental value. As subtropical and tropical flowering plants, these bromeliads, among with Aechmea fasciata, have significant economic importance. However, the molecular mechanism of flowering in bromeliads remains unrevealed. In this study, an APETALA2 (AP2) homologue, AfAP2-2, which belongs to the AP2/ethylene response element binding protein (AP2/EREBP) transcription factor superfamily, was identified in A. fasciata. AfAP2-2 contains two conserved AP2 domains and is a nuclear-localized transactivator. The expression level of AfAP2-2 was predominantly higher in vegetative organs of the reproductive phase than in those of the vegetative phase. Ectopic expression of AfAP2-2 in Arabidopsis specifically delayed flowering in short-day (SD) conditions. Furthermore, the size and weight of seeds of AfAP2-2-overexpressing Arabidopsis plants were significantly reduced compared to those of the wild type (WT). Our findings suggest that AfAP2-2 might be a negative regulator of flowering and seed size and weight. These results may help facilitate the molecular breeding of bromeliads.


Assuntos
Arabidopsis/metabolismo , Proteínas de Plantas/metabolismo , Sementes/metabolismo , Arabidopsis/genética , Arabidopsis/fisiologia , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/fisiologia , Expressão Ectópica do Gene , Flores/genética , Flores/metabolismo , Flores/fisiologia , Regulação da Expressão Gênica de Plantas/genética , Regulação da Expressão Gênica de Plantas/fisiologia , Sementes/genética , Sementes/fisiologia
15.
J Zhejiang Univ Sci B ; 20(4): 322-331, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30932377

RESUMO

We investigated the microRNA172 (miR172)-mediated regulatory network for the perception of changes in external and endogenous signals to identify a universally applicable floral regulation system in ornamental plants, manipulation of which could be economically beneficial. Transgenic gloxinia plants, in which miR172 was either overexpressed or suppressed, were generated using Agrobacterium-mediated transformation. They were used to study the effect of altering the expression of this miRNA on time of flowering and to identify its mRNA target. Early or late flowering was observed in transgenic plants in which miR172 was overexpressed or suppressed, respectively. A full-length complementary DNA (cDNA) of gloxinia (Sinningia speciosa) APETALA2-like (SsAP2-like) was identified as a target of miR172. The altered expression levels of miR172 caused up- or down-regulation of SsAP2-like during flower development, which affected the time of flowering. Quantitative real-time reverse transcription PCR analysis of different gloxinia tissues revealed that the accumulation of SsAP2-like was negatively correlated with the expression of miR172a, whereas the expression pattern of miR172a was negatively correlated with that of miR156a. Our results suggest that transgenic manipulation of miR172 could be used as a universal strategy for regulating time of flowering in ornamental plants.


Assuntos
Proteínas de Arabidopsis/genética , Flores/fisiologia , Proteínas de Homeodomínio/genética , Lamiales/fisiologia , MicroRNAs/genética , Proteínas Nucleares/genética , Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Clonagem Molecular , DNA Complementar/metabolismo , Flores/genética , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Proteínas de Homeodomínio/metabolismo , Lamiales/genética , MicroRNAs/metabolismo , Proteínas Nucleares/metabolismo , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/fisiologia , Plasmídeos/metabolismo , Reação em Cadeia da Polimerase , Transgenes
16.
Theor Appl Genet ; 132(7): 2039-2053, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30949717

RESUMO

KEY MESSAGE: Fine-mapping separated Qfhs.ifa-5A into a major QTL mapping across the centromere and a minor effect QTL positioned at the distal half of 5AS. Both increase Fusarium resistance and anther extrusion. The Fusarium head blight (FHB) resistance QTL Qfhs.ifa-5A resides in the low-recombinogenic pericentromeric region of chromosome 5A making fine-mapping particularly arduous. Qfhs.ifa-5A primarily contributes resistance to fungal entry with the favorable allele descending from the highly Fusarium resistant cultivar Sumai-3. Fine-mapping a near-isogenic recombinant inbred line population partitioned the Qfhs.ifa-5A interval into 12 bins. Near-isogenic lines recombining at the interval were phenotyped for FHB severity, anther retention and plant height. Composite interval mapping separated the initially single QTL into two QTL. The major effect QTL Qfhs.ifa-5Ac mapped across the centromere and the smaller effect QTL Qfhs.ifa-5AS mapped to the distal half of 5AS. Although Qfhs.ifa-5Ac and Qfhs.ifa-5AS intervals were as small as 0.1 and 0.2 cM, their corresponding physical distances were large, comprising 44.1 Mbp and 49.2 Mbp, respectively. Sumai-3 alleles at either QTL improved FHB resistance and increased anther extrusion suggesting a pleiotropic effect of anthers on resistance. This hypothesis was supported by greenhouse experiments using the susceptible cultivar Remus and its resistant near-isogenic line NIL3 carrying the entire Qfhs.ifa-5A segment. By manually removing anthers prior to spray inoculation both, Remus and NIL3 became almost equally resistant in the early phase of the disease development and were significantly less diseased than variants without anther manipulation. At late time points the positive effect of the anther removal became smaller for Remus and disappeared completely for NIL3. Results affirm that absence of anthers enhanced resistance to initial infection but did not protect plants from fungal spreading within spikes.


Assuntos
Mapeamento Cromossômico , Resistência à Doença/genética , Flores/fisiologia , Locos de Características Quantitativas , Triticum/genética , Alelos , Flores/genética , Fusarium/patogenicidade , Fenótipo , Doenças das Plantas/genética , Doenças das Plantas/microbiologia
17.
Theor Appl Genet ; 132(7): 2137-2154, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31016347

RESUMO

KEY MESSAGE: Genome-wide analysis of maize GPAT gene family, cytological characterization of ZmMs33/ZmGPAT6 gene encoding an ER-localized protein with four conserved motifs, and its molecular breeding application in maize. Glycerol-3-phosphate acyltransferase (GPAT) mediates the initial step of glycerolipid biosynthesis and plays pivotal roles in plant growth and development. Compared with GPAT genes in Arabidopsis, our understanding to maize GPAT gene family is very limited. Recently, ZmMs33 gene has been identified to encode a sn-2 GPAT protein and control maize male fertility in our laboratory (Xie et al. in Theor Appl Genet 131:1363-1378, 2018). However, the functional mechanism of ZmMs33 remains elusive. Here, we reported the genome-wide analysis of maize GPAT gene family and found that 20 maize GPAT genes (ZmGPAT1-20) could be classified into three distinct clades similar to those of ten GPAT genes in Arabidopsis. Expression analyses of these ZmGPAT genes in six tissues and in anther during six developmental stages suggested that some of ZmGPATs may play crucial roles in maize growth and anther development. Among them, ZmGPAT6 corresponds to the ZmMs33 gene. Systemic cytological observations indicated that loss function of ZmMs33/ZmGPAT6 led to defective anther cuticle, arrested degeneration of anther wall layers, abnormal formation of Ubisch bodies and exine and ultimately complete male sterility in maize. The endoplasmic reticulum-localized ZmMs33/ZmGPAT6 possessed four conserved amino acid motifs essential for acyltransferase activity, while ZmMs33/ZmGPAT6 locus and its surrounding genomic region have greatly diversified during evolution of gramineous species. Finally, a multi-control sterility system was developed to produce ms33 male-sterile lines by using a combination strategy of transgene and marker-assisted selection. This work will provide useful information for further deciphering functional mechanism of ZmGPAT genes and facilitate molecular breeding application of ZmMs33/ZmGPAT6 gene in maize.


Assuntos
Família Multigênica , Melhoramento Vegetal , Infertilidade das Plantas/genética , Zea mays/genética , Sequência de Aminoácidos , Flores/genética , Flores/fisiologia , Genes de Plantas , Estudos de Associação Genética , Microscopia Eletrônica de Varredura , Filogenia , Plantas Geneticamente Modificadas , Pólen/ultraestrutura , Sintenia , Zea mays/fisiologia
18.
Theor Appl Genet ; 132(7): 2125-2135, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31020387

RESUMO

KEY MESSAGE: Tomato male sterile-1526 locus was fine-mapped to an interval of 44.6 kb, and a B-class MADS-box gene TM6 was identified as the candidate gene. Male sterile lines have been widely used for hybrid seed production in many crop plants. The tomato male sterile-1526 (ms-1526) mutant displays abnormal stamens and exerted stigmas and is suitable for practical use. In this study, the ms-1526 locus was fine-mapped to a 44.6 kb interval that contained four putative genes. Thereinto, Solyc02g084630 encodes tomato B-class MADS-box gene TM6 (syn. TDR6), which plays an important role in stamen development. Sequencing revealed that there was a 12.7 kb deletion in the ms-1526 region, where the promoter and first four exons of the TM6 gene were absent. ms-1547, an allele of ms-1526, also contained the same deletion in the TM6 gene. And the other allele ms-15 mutant contained a single-nucleotide polymorphism (SNP, C to A) in the coding region of the TM6 gene, which led to a missense mutation (G to W). The codominant insertion/deletion (InDel) marker MS26D and codominant derived cleaved amplified polymorphic sequence (dCAPS) marker MS15C were developed based on the deletion and SNP, respectively. A real-time quantitative reverse-transcription PCR showed that expression of the TM6 gene was barely detectable in the flowers of the ms-1526 and ms-1547 mutants. In addition, other floral organ identity genes, pollen development marker genes, and pistil marker genes were differentially expressed between wild type and mutant flowers. These findings may facilitate functional analysis of the TM6 gene and help in the marker-assisted selection of ms-15 and its alleles in tomato breeding.


Assuntos
Flores/fisiologia , Lycopersicon esculentum/genética , Proteínas de Domínio MADS/genética , Infertilidade das Plantas/genética , Proteínas de Plantas/genética , Alelos , Mapeamento Cromossômico , Flores/genética , Marcadores Genéticos , Genótipo , Mutação INDEL , Lycopersicon esculentum/fisiologia , Fenótipo , Polimorfismo de Nucleotídeo Único , Deleção de Sequência
19.
Plant Biol (Stuttg) ; 21(5): 961-966, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-30945419

RESUMO

The lock and key hypothesis assumes that male and female genitalia match in a unique system to prevent interspecific crosses. This hypothesis is largely investigated in animals, while there is a distinct lack of studies on plants. Nevertheless, we expect the lock and key hypothesis could apply to plants with complex floral morphologies, such as orchids. Here we apply a comparative approach to examine the variation of floral functional traits in food- and sex-deceptive orchids. To understand if a specific deception strategy is related to a specific variation in floral traits evaluated the variation in sterile and fertile traits among species and subsequently examined the correlations between male and female reproductive organs of the same species with the aim of investigating the role of the lock and key hypothesis in deceptive orchids. Our results show that the functional morphology of fertile traits plays a pivotal role in limiting gene flow in species that grow in sympatry. In particular, it was observed that the Reproductive Standardisation Index (RSI) is significantly different in the two pollination strategies and that the correlation between pollinarium length and stigmatic cavity length is stronger in food-deceptive species when compared to the sex-deceptive species. These results reveal that the lock and key hypothesis contributes to maintain boundaries in plants with very complex floral morphology.


Assuntos
Flores/anatomia & histologia , Orchidaceae/anatomia & histologia , Polinização , Flores/fisiologia , Fluxo Gênico , Orchidaceae/fisiologia , Polinização/fisiologia , Simpatria
20.
Plant Biol (Stuttg) ; 21(5): 920-926, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31034724

RESUMO

The composition of pollenkitt and its role in the progamic phase of reproduction are poorly understood. With the aim of extending knowledge on these topics, we chose to study two monocotyledons rich in pollenkitt, with bi-celled and long-lived pollen and dry-type stigma: Crocus vernus Hill subsp. vernus and Narcissus poeticus L. Fatty acids of pollenkitt were assayed with gas chromatography. Germination tests were performed in vivo by pollinating the stigmas with a beard hair under a stereomicroscope, and in vitro in liquid culture medium using pollen, either treated or not, with carbon disulphide to remove pollenkitt. The pollen tube percentages were evaluated using fluorescence microscopy techniques. Scanning electron microscopy was used to examine pollen and to follow the early post-pollination stages. Pollenkitt forms bridges between pollen grains but not between grains and stigma papillae. It consists of a mixture of 25 fatty acids, most with long and unsaturated chains, among which are some omega acids. The same acids with different percentages persist on the peritapetal membrane. After its removal, the pollen loses adhesiveness and dries quickly, but retains full capacity for germination on the papillae and can even trigger germination in contiguous pollen grains that do not touch the papillae. The results, while confirming the key role of pollenkitt in protecting pollen and favouring pollination, suggest secondary roles in the progamic phase, and highlight the interactive ability of the pollen regardless of lipid shell. The predominance of fatty acids with 18:3 and 16:0, as already noted in Brassica napus pollenkitt, suggests their hierarchy independent of plant species.


Assuntos
Germinação , Lipídeos/análise , Pólen/fisiologia , Cromatografia Gasosa , Crocus/metabolismo , Crocus/fisiologia , Ácidos Graxos/análise , Ácidos Graxos/metabolismo , Flores/fisiologia , Germinação/fisiologia , Microscopia Eletrônica de Varredura , Narcissus/metabolismo , Narcissus/fisiologia , Pólen/química , Pólen/ultraestrutura , Polinização
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