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1.
Plant Sci ; 287: 110174, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31481216

RESUMO

Asteraceae is the largest family of angiosperms, comprising approximately 24,000 species. Molecular genetic studies of Asteraceae are essential for understanding plant diversity. Chrysanthemum morifolium is the most industrially important ornamental species in Asteraceae. Most cultivars of C. morifolium are autohexaploid and self-incompatible. These properties are major obstacles to the genetic analysis and modern breeding of C. morifolium. Furthermore, high genome heterogeneity complicates molecular biological analyses. In this study, we developed a model strain in the genus Chrysanthemum. C. seticuspe is a diploid species with a similar flowering property and morphology to C. morifolium and can be subjected to Agrobacterium-mediated transformation. We isolated a natural self-compatible mutant of C. seticuspe and established a pure line through repeated selfing and selection. The resultant strain, named Gojo-0, was favorable for genetic analyses, including isolation of natural and induced mutants, and facilitated molecular biological analysis, including whole genome sequencing, owing to the simplicity and homogeneity of its genome. Interspecific hybridization with Chrysanthemum species was possible, enabling molecular genetic analysis of natural interspecific variations. The accumulation of research results and resources using Gojo-0 as a platform is expected to promote molecular genetic studies on the genus Chrysanthemum and the genetic improvement of chrysanthemum cultivars.


Assuntos
Chrysanthemum/genética , Chrysanthemum/ultraestrutura , DNA de Plantas/genética , Diploide , Flores/ultraestrutura , Hibridização Genética , Microscopia Eletrônica de Varredura , Modelos Biológicos , Mutação , Filogenia , Melhoramento Vegetal/métodos , Polinização , Autofertilização
2.
Plant Sci ; 287: 110200, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31481227

RESUMO

The cuticle plays a critical role as barrier between plant and environment. Here, cuticular wax morphology, cuticular wax and cutin monomer composition, and expression of associated genes in five above ground organs were examined in model extremophyte Thellungiella salsugineum. Alkanes, ketones, and 2-alcohols were the predominant wax constitutes in rosette leaves, inflorescence stem leaves, stems, and siliques, whereas alkanes and acids were the predominant cuticular lipids in whole flowers. Unsubstituted acids were the most abundant cutin monomers in vegetative organs, especially C18:2 dioic acids, which reached the highest levels in stems. Hydroxy fatty acids were the predominant cutin monomers in flowers, especially 16-OH C16:0 and diOH C16:0. High-throughput RNA-Seq analysis using the Hiseq4000 platform was performed on these five above organs of T. salsugineum, and the differentially expressed lipid-associated genes and their associated metabolic pathways were identified. Expression of genes associated in previous reports to cuticle production, including those having roles in cuticle lipid biosynthesis, transport, and regulation were examined. The association of cuticle lipid composition and gene expression within different organs of T. salsugineum, and potential relationships between T. salsugineum's extreme cuticle and its adaptation to extreme environments is discussed.


Assuntos
Brassicaceae/fisiologia , Lipídeos de Membrana/química , Adaptação Fisiológica , Brassicaceae/genética , Brassicaceae/ultraestrutura , Meio Ambiente , Ácidos Graxos/análise , Flores/genética , Flores/fisiologia , Flores/ultraestrutura , Lipídeos/análise , Epiderme Vegetal/genética , Epiderme Vegetal/fisiologia , Epiderme Vegetal/ultraestrutura , Folhas de Planta/genética , Folhas de Planta/fisiologia , Folhas de Planta/ultraestrutura , Caules de Planta/genética , Caules de Planta/fisiologia , Caules de Planta/ultraestrutura , Ceras/química
3.
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
4.
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
5.
Plant Reprod ; 32(3): 307-322, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31069543

RESUMO

KEY MESSAGE: We describe a function for a novel Arabidopsis gene, E6-like 1 (E6L1), that was identified as a highly expressed gene in the stigma and plays a role in early post-pollination stages. In Arabidopsis, successful pollen-stigma interactions are dependent on rapid recognition of compatible pollen by the stigmatic papillae located on the surface of the pistil and the subsequent regulation of pollen hydration and germination, and followed by the growth of pollen tubes through the stigma surface. Here we have described the function of a novel gene, E6-like 1 (E6L1), that was identified through the analysis of transcriptome datasets, as one of highest expressed genes in the stigma, and furthermore, its expression was largely restricted to the stigma and trichomes. The first E6 gene was initially identified as a highly expressed gene during cotton fiber development, and related E6-like predicted proteins are found throughout the Angiosperms. To date, no orthologous genes have been assigned a biological function. Both the Arabidopsis E6L1 and cotton E6 proteins are predicted to be secreted, and this was confirmed using an E6L1:RFP fusion construct. To further investigate E6L1's function, one T-DNA and two independent CRISPR-generated mutants were analyzed for compatible pollen-stigma interactions, and pollen hydration, pollen adhesion, and seed set were mildly impaired for the e6l1 mutants. This work identifies E6L1 as a novel stigmatic factor that plays a role during the early post-pollination stages in Arabidopsis.


Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/genética , Regulação da Expressão Gênica de Plantas , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Arabidopsis/fisiologia , Arabidopsis/ultraestrutura , Proteínas de Arabidopsis/genética , Flores/genética , Flores/fisiologia , Flores/ultraestrutura , Germinação , Peptídeos e Proteínas de Sinalização Intercelular/genética , Mutação , Especificidade de Órgãos , Filogenia , Pólen/genética , Pólen/fisiologia , Pólen/ultraestrutura , Tubo Polínico/genética , Tubo Polínico/fisiologia , Tubo Polínico/ultraestrutura , Polinização , Reprodução , Plântula/genética , Plântula/fisiologia , Plântula/ultraestrutura , Transcriptoma
6.
Mol Phylogenet Evol ; 137: 156-167, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31075505

RESUMO

Detarioideae is well known for its high diversity of floral traits, including flower symmetry, number of organs, and petal size and morphology. This diversity has been characterized and studied at higher taxonomic levels, but limited analyses have been performed among closely related genera with contrasting floral traits due to the lack of fully resolved phylogenetic relationships. Here, we used four representative transcriptomes to develop an exome capture (target enrichment) bait for the entire subfamily and applied it to the Anthonotha clade using a complete data set (61 specimens) representing all extant floral diversity. Our phylogenetic analyses recovered congruent topologies using ML and Bayesian methods. Anthonotha was recovered as monophyletic contrary to the remaining three genera (Englerodendron, Isomacrolobium and Pseudomacrolobium), which form a monophyletic group sister to Anthonotha. We inferred a total of 35 transitions for the seven floral traits (pertaining to flower symmetry, petals, stamens and staminodes) that we analyzed, suggesting that at least 30% of the species in this group display transitions from the ancestral condition reconstructed for the Anthonotha clade. The main transitions were towards a reduction in the number of organs (petals, stamens and staminodes). Despite the high number of transitions, our analyses indicate that the seven characters are evolving independently in these lineages. Petal morphology is the most labile floral trait with a total of seven independent transitions in number and seven independent transitions to modification in petal types. The diverse petal morphology along the dorsoventral axis of symmetry within the flower is not associated with differences at the micromorphology of petal surface, suggesting that in this group all petals within the flower might possess the same petal identity at the molecular level. Our results provide a solid evolutionary framework for further detailed analyses of the molecular basis of petal identity.


Assuntos
Biodiversidade , Fabaceae/genética , Flores/anatomia & histologia , Genômica , Filogenia , Teorema de Bayes , Fabaceae/anatomia & histologia , Flores/ultraestrutura , Fenótipo , Epiderme Vegetal/anatomia & histologia , Epiderme Vegetal/ultraestrutura
7.
BMC Plant Biol ; 19(1): 200, 2019 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-31092192

RESUMO

BACKGROUND: Rice (Oryza sativa L.) is a staple food crop worldwide. Its yield and quality are affected by its tillering pattern and spikelet development. Although many genes involved in the vegetative and reproductive development of rice have been characterized in previous studies, the genetic mechanisms that control axillary tillering, spikelet development, and panicle exsertion remain incompletely understood. RESULTS: Here, we characterized a novel rice recombinant inbred line (RIL), panicle exsertion defect and aberrant spikelet (pds). It was derived from a cross between two indica varieties, S142 and 430. Intriguingly, no abnormal phenotypes were observed in the parents of pds. This RIL exhibited sheathed panicles at heading stage. Still, a small number of tillers in pds plants were fully exserted from the flag leaves. Elongated sterile lemmas and rudimentary glumes (occurred occasionally) were observed in the spikelets of the exserted panicles and were transformed into palea/lemma-like structures. Furthermore, more interestingly, tillers occasionally grew from the axils of the elongated rudimentary glumes. Via genetic linkage analysis, we found that the abnormal phenotype of pds manifesting as genetic incompatibility or hybrid weakness was caused by genetic interaction between a recessive locus, pds1, which was derived from S142 and mapped to chromosome 8, and a locus pds2, which not yet mapped from 430. We fine-mapped pds1 to an approximately 55-kb interval delimited by the markers pds-4 and 8 M3.51. Six RGAP-annotated ORFs were included in this genomic region. qPCR analysis revealed that Loc_Os080595 might be the target of pds1 locus, and G1 gene might be involved in the genetic mechanism underlying the pds phenotype. CONCLUSIONS: In this study, histological and genetic analyses revealed that the pyramided pds loci resulted in genetic incompatibility or hybrid weakness in rice might be caused by a genetic interaction between pds loci derived from different rice varieties. Further isolation of pds1 and its interactor pds2, would provide new insight into the molecular regulation of grass inflorescence development and exsertion, and the evolution history of the extant rice.


Assuntos
Oryza/genética , Mapeamento Cromossômico , Flores/crescimento & desenvolvimento , Flores/ultraestrutura , Regulação da Expressão Gênica de Plantas , Genes de Plantas/genética , Genes de Plantas/fisiologia , Estudos de Associação Genética , Loci Gênicos , Microscopia Eletrônica de Varredura , Oryza/crescimento & desenvolvimento , Oryza/ultraestrutura , Reação em Cadeia da Polimerase em Tempo Real
8.
Plant Reprod ; 32(3): 323-330, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31115664

RESUMO

KEY MESSAGE: The developmental morphology of male and female kiwifruit flowers is tracked to delimit a framework of events to aid the study of divergence in floral gene expression. The transition from hermaphrodite to unisexual development of kiwifruit (Actinidia chinensis Planch) flowers has been reported previously, but differences in gene expression controlling sexual development for this species have not been associated with the major developmental changes occurring within pistils. We investigated the key stages in male and female flower development to define the point at which meristematic activities diverge in the two sexes. A combination of scanning electron microscopy and light microscopy was used to investigate pistil development from the earliest stages. We identified seven distinct stages characterized by differences in ovary size and shape, macrosporogenesis, ovule primordium development, anther locule lengthening, microspore wall thickening, and pollen degeneration. Sex differences were evident from the initial stage of development, with a laterally compacted gynoecium in male flowers. However, the key developmental stage, at which tissue differentiation clearly deviated between the two sexes, was stage 3, when flowers were 3.5 to 4.5 mm in length at approximately 10 d from initiation of stamen development. At this stage, male flowers lacked evident carpel meristem development as denoted by a lack of ovule primordium formation. Pollen degeneration in female flowers, probably driven by programmed cell death, occurred at the late stage 6, while the final stage 7 was represented by pollen release. As the seven developmental stages are associated with specific morphological differences, including flower size, the scheme suggested here can provide the required framework for the future study of gene expression during the regulation of flower development in this crop species.


Assuntos
Actinidia/crescimento & desenvolvimento , Flores/crescimento & desenvolvimento , Actinidia/genética , Actinidia/ultraestrutura , Flores/genética , Flores/ultraestrutura , Regulação da Expressão Gênica no Desenvolvimento , Regulação da Expressão Gênica de Plantas , Meristema/genética , Meristema/crescimento & desenvolvimento , Meristema/ultraestrutura , Microscopia Eletrônica de Varredura , Óvulo Vegetal/genética , Óvulo Vegetal/crescimento & desenvolvimento , Óvulo Vegetal/ultraestrutura , Pólen/genética , Pólen/crescimento & desenvolvimento , Pólen/ultraestrutura , Reprodução
9.
BMC Plant Biol ; 19(1): 104, 2019 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-30885140

RESUMO

BACKGROUND: During pollen wall formation in flowering plants, a conserved metabolon consisting of acyl-CoA synthetase (ACOS), polyketide synthase (PKS) and tetraketide α-pyrone reductase (TKPR), is required for sporopollenin synthesis. Despite this, the precise function of each of these components in different species remains unclear. RESULTS: In this study, we characterized the function of OsTKPR1, a rice orthologue of Arabidopsis TKPR1. Loss of function of OsTKPR1 delayed tapetum degradation, reduced the levels of anther cuticular lipids, and impaired Ubisch body and pollen exine formation, resulting in complete male sterility. In addition, the phenylpropanoid pathway in mutant anthers was remarkably altered. Localization studies suggest that OsTKPR1 accumulates in the endoplasmic reticulum, while specific accumulation of OsTKPR1 mRNA in the anther tapetum and microspores is consistent with its function in anther and pollen wall development. CONCLUSIONS: Our results show that OsTKPR1 is indispensable for anther cuticle development and pollen wall formation in rice, providing new insights into the biochemical mechanisms of the conserved sporopollenin metabolon in flowering plants.


Assuntos
Flores/crescimento & desenvolvimento , Oryza/genética , Proteínas de Plantas/fisiologia , Flores/metabolismo , Flores/ultraestrutura , Metabolismo dos Lipídeos , Mutação , Oryza/crescimento & desenvolvimento , Oryza/metabolismo , Oryza/ultraestrutura , Fenótipo
10.
Int J Mol Sci ; 20(5)2019 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-30813609

RESUMO

The lotus (Nelumbo Adans.) is a perennial aquatic plant with important value in horticulture, medicine, food, religion, and culture. It is rich in germplasm and more than 2000 cultivars have been cultivated through hybridization and natural selection. Microsporogenesis and male gametogenesis in the anther are important for hybridization in flowering plants. However, little is known about the cytological events, especially related to the stamen, during the reproduction of the lotus. To better understand the mechanism controlling the male reproductive development of the lotus, we investigated the flower structure of the Asian lotus (N. nucifera). The cytological analysis of anther morphogenesis showed both the common and specialized cytological events as well as the formation of mature pollen grains via meiosis and mitosis during lotus anther development. Intriguingly, an anatomical difference in anther appendage structures was observed between the Asian lotus and the American lotus (N. lutea). To facilitate future study on lotus male reproduction, we categorized pollen development into 11 stages according to the characterized cytological events. This discovery expands our knowledge on the pollen and appendage development of the lotus as well as improving the understanding of the species differentiation of N. nucifera and N. lutea.


Assuntos
Flores/citologia , Nelumbo/anatomia & histologia , Nelumbo/citologia , Parede Celular/ultraestrutura , Flores/ultraestrutura , Nelumbo/ultraestrutura , Pólen/citologia , Pólen/crescimento & desenvolvimento , Pólen/ultraestrutura
11.
PLoS One ; 14(3): e0212677, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30865720

RESUMO

Acianthera section Pleurobotryae is one of ten sections of the genus Acianthera and include four species endemic to the Atlantic Forest. The objective of this study was to describe comparatively the anatomy of vegetative organs and floral micromorphology of all species of Acianthera section Pleurobotryae in order to identify diagnostic characters between them and synapomorphies for the section in relation of other sections of the genus. We analyzed roots, ramicauls, leaves and flowers of 15 species, covering eight of the nine sections of Acianthera, using light microscopy and scanning electron microscopy. Acianthera section Pleurobotryae is a monophyletic group and the cladistic analyses of anatomical and flower micromorphology data, combined with molecular data, support internal relationship hypotheses among the representatives of this section. The synapomorphies identified for A. sect. Pleurobotryae are based on leaf anatomy: unifacial leaves, round or elliptical in cross-section, round leaves with vascular bundles organized in concentric circles, and mesophyll with 28 to 30 cell layers. Within the section, the clade (A. crepiniana + A. mantiquyrana) presented more differences in vegetative organ morphology and higher support values in combined analyses when compared to the second clade, (A. atropurpurea + A. hatschbachii). For each of these clades an exclusive set of homoplasies of vegetative and floral organs were also identified. The results support the argument that vegetative organs are more evolutionarily stable in comparison to reproductive organs and thus helpful for inference of internal phylogenetic relationships in Acianthera, while flowers are highly variable, perhaps due to the diversity of pollinator attraction mechanisms. The analyses indicate that the elliptical leaves observed in A. crepiniana have originated from round leaves observed in the other species of this section, suggesting an adaptation to increase the area of exposure of the leaf and better the efficiency of capture of sunlight in shaded environments such as the Atlantic Forest. The presence of papillose regions in both vegetative and floral organs indicated that micromorphological characters are also useful for the delimitation of species and sections within the genus.


Assuntos
Evolução Biológica , Flores , Orchidaceae , Filogenia , Folhas de Planta , Polinização , Flores/fisiologia , Flores/ultraestrutura , Microscopia Eletrônica de Varredura , Orchidaceae/classificação , Orchidaceae/fisiologia , Orchidaceae/ultraestrutura , Folhas de Planta/fisiologia , Folhas de Planta/ultraestrutura , Polinização/fisiologia
12.
Proc Natl Acad Sci U S A ; 116(11): 5176-5181, 2019 03 12.
Artigo em Inglês | MEDLINE | ID: mdl-30782811

RESUMO

Floral development is one of the model systems for investigating the mechanisms underlying organogenesis in plants. Floral organ identity is controlled by the well-known ABC model, which has been generalized to many flowering plants. Here, we report a previously uncharacterized MYB-like gene, AGAMOUS-LIKE FLOWER (AGLF), involved in flower development in the model legume Medicago truncatula Loss-of-function of AGLF results in flowers with stamens and carpel transformed into extra whorls of petals and sepals. Compared with the loss-of-function mutant of the class C gene AGAMOUS (MtAG) in M. truncatula, the defects in floral organ identity are similar between aglf and mtag, but the floral indeterminacy is enhanced in the aglf mutant. Knockout of AGLF in the mutants of the class A gene MtAP1 or the class B gene MtPI leads to an addition of a loss-of-C-function phenotype, reflecting a conventional relationship of AGLF with the canonical A and B genes. Furthermore, we demonstrate that AGLF activates MtAG in transcriptional levels in control of floral organ identity. These data shed light on the conserved and diverged molecular mechanisms that control flower development and morphology among plant species.


Assuntos
Flores/genética , Regulação da Expressão Gênica de Plantas , Medicago truncatula/genética , Especificidade de Órgãos/genética , Proteínas de Plantas/genética , Transcrição Genética , Flores/crescimento & desenvolvimento , Flores/ultraestrutura , Medicago truncatula/ultraestrutura , Mutação/genética , Fenótipo , Proteínas de Plantas/metabolismo
13.
Protoplasma ; 256(4): 971-981, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30796515

RESUMO

Caryocar brasiliense is a flagship species of the Brazilian Cerrado. It produces flowers with a strong peculiar scent, which are pollinated by bats and occasionally moths with short mouthparts. However, the cues responsible for attracting these nocturnal pollinators remain unknown. We aimed to identify osmophores of C. brasiliense, describe the ultrastructure of the cells involved in the synthesis and release of floral odour, and identify the constituents of the floral bouquet. We performed field observations and histochemical and ultrastructural analyses of flowers focusing on the androecium. Gas chromatography-mass spectrometry was used to analyse the scents emitted. Filament epidermal cells were found to possess an unusual shape and be responsible for the main production and release of odour. These cells, called foraminous cells, are elongate and possess pores where their cell walls are abruptly thin. The cuticle is practically absent over the pores, which facilitates odour emission. The foraminous cells have conspicuous nuclei and organelle-rich cytoplasm where oil droplets can be seen prior to anthesis. The features of these cells remain similar during anthesis, but many vesicles fuse with the plasma membrane and the number of oil droplets in the cytosol decreases. Twenty-nine components were found in the scent, especially fatty acid derivatives and N- and S-bearing compounds. Our analyses revealed that the androecium of C. brasiliense has a particular structure that acts as an osmophore. The scent from the androecium resembles that of the entire flower, which is an unprecedented finding for a plant with single flowers as the pollination unit.


Assuntos
Ericales/ultraestrutura , Flores/ultraestrutura , Odorantes/análise , Compostos Orgânicos Voláteis/análise , Ericales/fisiologia , Flores/química , Flores/citologia , Flores/fisiologia , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Células Vegetais/fisiologia , Células Vegetais/ultraestrutura , Polinização , Compostos Orgânicos Voláteis/química
14.
Plant Cell Physiol ; 60(6): 1284-1295, 2019 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-30715478

RESUMO

The ABC model in flower development represents a milestone of plant developmental studies and is essentially conserved across a wide range of angiosperm species. Despite this overall conservation, individual genes in the ABC model are not necessarily conserved and sometimes play a species-specific role, depending on the plant. We previously reported that carpels are specified by the YABBY gene DROOPING LEAF (DL) in rice (Oryza sativa), which bears flowers that are distinct from those of eudicots. In contrast, another group reported that carpels are specified by two class C genes, OsMADS3 and OsMADS58. Here, we have addressed this controversial issue by phenotypic characterization of floral homeotic gene mutants. Analysis of a complete loss-of-function mutant of OsMADS3 and OsMADS58 revealed that carpel-like organs expressing DL were formed in the absence of the two class C genes. Furthermore, no known flower organs including carpels were specified in a double mutant of DL and SUPERWOMAN1 (a class B gene), which expresses only class C genes in whorls 3 and 4. These results suggest that, in contrast to Arabidopsis, class C genes are not a key regulator for carpel specification in rice. Instead, they seem to be involved in the elaboration of carpel morphology rather than its specification. Our phenotypic analysis also revealed that, similar to its Arabidopsis ortholog CRABS CLAW, DL plays an important function in regulating flower meristem determinacy in addition to carpel specification.


Assuntos
Flores/crescimento & desenvolvimento , Meristema/crescimento & desenvolvimento , Oryza/crescimento & desenvolvimento , Flores/ultraestrutura , Regulação da Expressão Gênica no Desenvolvimento , Regulação da Expressão Gênica de Plantas , Genes de Plantas/fisiologia , Microscopia Eletrônica de Varredura , Oryza/genética , Oryza/ultraestrutura , Proteínas de Plantas/genética , Proteínas de Plantas/fisiologia
15.
BMC Genomics ; 20(1): 53, 2019 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-30654752

RESUMO

BACKGROUND: Cymbidium goeringii is one of the most horticulturally important and popular ornamental plants in the orchid family (Orchidaceae). It blooms in winter during January-March and a period of low temperature is necessary for its normal flowering, otherwise there is flower bud abortion, which seriously affects the economic benefits. However, the molecular mechanism underlying winter-blooming behavior in C. goeringii is unclear. RESULTS: In this research, we firstly study the flowering physiology of C. goeringii by cytobiology observations and physiological experiments. Using comparative transcriptome analysis, we identified 582 differentially expressed unigenes responding to cold treatment that were involved in metabolic process, flowering time, hormone signaling, stress response, and cell cycle, implying their potential roles in regulating winter-blooming of C. goeringii. Twelve MADS-box genes among them were investigated by full-length cDNA sequence analysis and expression validation, which indicated that three genes within the SHORT VEGETATIVE PHASE (SVP) sub-group had the most significant repressed expression after cold treatment. Further analysis revealed that the SVP genes showed population variation in expression that correlated with cold-regulated flowering and responded to low temperature earlier than the flowering pathway integrators CgAP1, CgSOC1, and CgLFY, suggesting a potential role of CgSVP genes in the early stage of low-temperature-induced blooming of C. goeringii. Moreover, a yeast two-hybrid experiment confirmed that CgSVP proteins interacted with CgAP1 and CgSOC1, suggesting that they may synergistically control the process of C. goeringii flowering in winter. CONCLUSIONS: This study represents the first exploration of flowering physiology of C. goeringii and provides gene expression information that could facilitate our understanding of molecular regulation of orchid plant winter-flowering, which could provide new insights and practical guidance for improving their flowering regulation and molecular breeding.


Assuntos
Temperatura Baixa , Flores/genética , Flores/fisiologia , Genes de Plantas , Orchidaceae/genética , Orchidaceae/fisiologia , Transcriptoma/genética , Flores/ultraestrutura , Regulação da Expressão Gênica de Plantas , Anotação de Sequência Molecular , Filogenia , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Mapas de Interação de Proteínas/genética , Reprodutibilidade dos Testes , Fatores de Tempo
16.
Protoplasma ; 256(3): 703-720, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30470901

RESUMO

The morpho-anatomical structure of nectaries, osmophores, and elaiophores, and the anatomical and micromorphological features of floral pieces of Cohniella cepula Hoffmans. and Cohniella jonesiana Rchb.f. were comparatively analyzed. In both species, bracteal and sepal nectaries are structured, i.e., they present a secretory epidermis, secretory parenchyma, and vascular bundles. Nectar secretion is released through stomata. The anatomical and micromorphological traits are similar in both nectaries, which can be detected only if the nectar drops are secreted. Considering the location of these nectaries, the secreted nectar would not be a reward to pollinators. Osmophores are located at the base of both callus and laterals lobes, and consist of a layer of secretory epidermis composed of quadrangular cells and papillae. Elaiophores are found on the callus of the labellum and are of the epithelial type. The anatomical features of floral pieces are similar in both species. The anatomical analysis of sepals and petals showed a few differences, which could be of potential taxonomic value. Our results contribute valuable and novel information for the knowledge of these species and the genus, which will be useful in future taxonomic evaluations.


Assuntos
Flores/anatomia & histologia , Orchidaceae/anatomia & histologia , Néctar de Plantas/fisiologia , Flores/citologia , Flores/ultraestrutura , Orchidaceae/citologia , Orchidaceae/ultraestrutura
17.
Ann Bot ; 123(1): 213-220, 2019 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-30169570

RESUMO

Background and Aims: Bird pollination is rare among species in the genus Utricularia, and has evolved independently in two lineages of this genus. In Western Australia, the Western Spinebill, Acanthorhynchus superciliosus, visits flowers of Utricularia menziesii (section Pleiochasia: subgenus Polypompholyx). This study aimed to examine the micromorphology of U. menziesii flowers to assess traits that might be linked to its pollination strategy. Methods: Light microscopy, histochemistry and scanning electron microscopy were used. Nectar sugar composition was analysed using high-performance liquid chromatography. Key Results: The flowers of U. menziesii fulfil many criteria that characterize bird-pollinated flowers: red colour, a large, tough nectary spur that can withstand contact with a hard beak, lack of visual nectar guides and fragrance. Trichomes at the palate and throat may act as tactile signals. Spur nectary trichomes did not form clearly visible patches, but were more frequently distributed along vascular bundles, and were small and sessile. Each trichome comprised a single basal cell, a unicellular short pedestal cell (barrier cell) and a multicelled head. These trichomes were much smaller than those of the U. vulgaris allies. Hexose-dominated nectar was detected in flower spurs. Fructose and glucose were present in equal quantities (43 ± 3.6 and 42 ± 3.6 g L-1). Sucrose was only detected in one sample, essentially at the limit of detection for the method used. This type of nectar is common in flowers pollinated by passerine perching birds. Conclusions: The architecture of nectary trichomes in U. menziesii was similar to that of capitate trichomes of insect-pollinated species in this genus; thus, the most important specializations to bird pollination were flower colour (red), and both spur shape and size modification. Bird pollination is probably a recent innovation in the genus Utricularia, subgenus Polypompholyx, and is likely to have evolved from bee-pollinated ancestors.


Assuntos
Flores/anatomia & histologia , Lamiales/anatomia & histologia , Polinização , Animais , Flores/fisiologia , Flores/ultraestrutura , Cadeia Alimentar , Lamiales/fisiologia , Lamiales/ultraestrutura , Microscopia Eletrônica de Varredura , Néctar de Plantas/análise , Aves Canoras/fisiologia , Austrália Ocidental
18.
Biosci Biotechnol Biochem ; 83(4): 666-674, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30585123

RESUMO

Asparagus (Asparagus officinalis) has several traits that make it a useful model for cytogenetic studies, however, few studies of the meiosis process have been made in asparagus. Here, we present in detail an atlas of male meiosis in asparagus, from preleptotene to telophase II. The meiosis process in asparagus is largely similar to those of the well-characterized model plants Arabidopsis thaliana, Zea mays, and Oryza sativa. However, most asparagus prophase I meiotic chromosomes show a strongly aggregated morphology, and this phenotype persists through the pachytene stage, highlighting a property in the control of chromosome migration and distribution in asparagus. Further, we observed no obvious banding of autofluorescent dots between divided nuclei of asparagus meiocytes, as one would expect in Arabidopsis. This description of wild-type asparagus meiosis will serve as a reference for the analyses of meiotic mutants, as well as for comparative studies among difference species. Abbreviations: DAPI: 4',6-diamidino-2-phenylindole; FISH: fluorescence in situ hybridization; PBS: phosphate-buffered saline; PMC: pollen mother cell; SEM: Scanning Electron Microscope.


Assuntos
Asparagus (Planta)/ultraestrutura , Cromossomos de Plantas/ultraestrutura , Meiose , Células Vegetais/ultraestrutura , Pólen/ultraestrutura , Arabidopsis/genética , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/ultraestrutura , Asparagus (Planta)/genética , Asparagus (Planta)/crescimento & desenvolvimento , Núcleo Celular/metabolismo , Núcleo Celular/ultraestrutura , Cromossomos de Plantas/química , Flores/genética , Flores/crescimento & desenvolvimento , Flores/ultraestrutura , Hibridização in Situ Fluorescente , Microscopia Eletrônica de Varredura , Células Vegetais/metabolismo , Pólen/genética , Pólen/crescimento & desenvolvimento
19.
BMC Plant Biol ; 18(1): 341, 2018 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-30526487

RESUMO

BACKGROUND: Great advances have been achieved in our understanding of flower development and evolution since the establishment of the ABC model. However, it remains a challenge to define the exact context of organ identity in the component interactions of the ABC model. RESULTS: Through hybridization, we detected a homeotic mutant in Petrocosmea (Gesneriaceae) uniquely displayed by the 'petaloid-stamen' in the third whorl with petal identity. Comparative Real-time PCR analyses demonstrate that both two B-class genes DEF2 and GLO are excessively expressed while the transcripts of the C-class gene PLE are reduced in the third floral whorl in the mutant compared to that in the wild-type F1 hybrids. Further allele-specific expression (ASE) analyses indicate that an allele-specific change in PgPLE might be responsible for up-regulation of both B-class genes and down-regulation of the C-class gene in the petaloid-stamen mutants. CONCLUSIONS: Our findings suggest that the petaloid-stamen is consequent upon an evident dosage imbalance between B- and C-class products that is probably triggered by a cis-regulatory change. In addition, the genetic pathway for the floral organ identity might be in parallel with that for the floral symmetry. The extreme variation in hybrids further suggests that interspecific hybridization may represent a major factor for evolutionary innovation and diversification in plants.


Assuntos
Flores/genética , Flores/crescimento & desenvolvimento , Flores/ultraestrutura , Dosagem de Genes/genética , Regulação da Expressão Gênica de Plantas/genética , Genes de Plantas/genética , Genes de Plantas/fisiologia , Magnoliopsida/genética , Magnoliopsida/crescimento & desenvolvimento , Microscopia Eletrônica de Varredura , Filogenia , Reação em Cadeia da Polimerase em Tempo Real
20.
BMC Plant Biol ; 18(1): 348, 2018 Dec 12.
Artigo em Inglês | MEDLINE | ID: mdl-30541444

RESUMO

BACKGROUND: Panicle architecture is one of the main important agronomical traits that determine branch number and grain number in rice. Although a large number of genes involved in panicle development have been identified in recent years, the complex processes of inflorescence patterning need to be further characterized in rice. Brassinosteroids (BRs) are a class of steroid phytohormones. A great understanding of how BRs contribute to plant height and leaf erectness have been reported, however, the molecular and genetic mechanisms of panicle architecture influenced by BRs remain unclear. RESULTS: Here, we identified PMM1, encoding a cytochrome P450 protein involved in BRs biosynthesis, and characterized its role in panicle architecture in rice. Three alleles of pmm1 were identified from our T-DNA insertional mutant library. Map-based cloning revealed that a large fragment deletion from the 2nd to 9th exons of PMM1 was responsible for the clustered primary branch morphology in pmm1-1. PMM1 is a new allele of DWARF11 (D11) PMM1 transcripts are preferentially expressed in young panicles, particularly expressed in the primordia of branches and spikelets during inflorescence development. Furthermore, overexpression of OsDWARF4 (D4), another gene encoding cytochrome P450, completely rescued the abnormal panicle phenotype of pmm1-1. Overall, it can be concluded that PMM1 is an important gene involved in BRs biosynthesis and affecting the differentiation of spikelet primordia and patterns of panicle branches in rice. CONCLUSIONS: PMM1 is a new allele of D11, which encodes a cytochrome P450 protein involved in BRs biosynthesis pathway. Overexpression of D4 could successfully rescue the abnormal panicle architecture of pmm1 plants, indicating that PMM1/D11 and D4 function redundantly in BRs biosynthesis. Thus, our results demonstrated that PMM1 determines the inflorescence architecture by controlling brassinosteroid biosynthesis in rice.


Assuntos
Brassinosteroides/biossíntese , Flores/genética , Oryza/genética , Proteínas de Plantas/genética , Clonagem Molecular , Flores/crescimento & desenvolvimento , Flores/metabolismo , Flores/ultraestrutura , Regulação da Expressão Gênica de Plantas , Microscopia Eletrônica de Varredura , Oryza/crescimento & desenvolvimento , Oryza/metabolismo , Oryza/ultraestrutura , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas
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