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1.
Plant Biotechnol (Tokyo) ; 36(3): 181-185, 2019 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-31768120

RESUMO

Hybrid Oncidium orchids, such as Oncidium Gower Ramsey and Oncidium "Honey Angel," are popular cut flowers in Japan and Taiwan. Due to pollen sterility, no new varieties have been created by conventional breeding methods. Recently, we employed RNA interference (RNAi) technology to suppress phytoene synthase and successfully modified floret hue from yellow to white (Liu et al. 2019). Transgenic white Oncidium orchids, Honey Snow MF-1, have been grown to test their genetic stability, and their environmental biosafety was assessed for approximately one year under government regulatory instructions from the Council of Agriculture, Taiwan. In the present study, pollen sterility was demonstrated by cytological observation of the microsporogenesis step, pollen morphology abortion, and failure of pollen germination. Assays on allelopathic effect on the other plants and the soil rhizospheric microbial flora-revealed that transgenic Oncidium orchids are potentially safe with regard to environmental biodiversity. Therefore, the general release permissions have been granted and an application for licensing for commercial production is under way.

2.
Front Plant Sci ; 9: 1043, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30065747

RESUMO

The phytohormone abscisic acid (ABA) is involved in regulating seed dormancy and germination. A crucial step of ABA biosynthesis in higher plants is the oxidative cleavage of cis-epoxycarotenoids by 9-cis-epoxycarotenoid dioxygenase (NCED). Seed development in orchids is unusual because the embryos are minute in size, without obvious histodifferentiation, and lack endosperm. To understand the regulation of ABA biosynthesis in orchid seeds, we isolated and characterized a full-length cDNA encoding an NCED homolog, PtNCED1, from developing seeds of an ornamental orchid, Phaius tankervilliae. Germination percentage was high at 90 days after pollination (DAP), when a globular embryo proper with a degenerating suspensor was evident. After 90 DAP, seed maturation was accompanied by a decrease in water content and a concomitant increase in ABA content and PtNCED1 mRNA level along with a marked decrease in germination percentage. Mature seeds pretreated with NaOCl solution lowered ABA content and improved seed germination. Moreover, after seed germination, developing protocorms could respond to dehydration stress. Dehydration of protocorms stimulated an increase in PtNCED1 level along with ABA content. Our results provide evidence of the involvement of PtNCED1 in regulating endogenous ABA content in developing seeds and protocorms. The accumulation of endogenous ABA content in orchid seeds may have a critical role in seed dormancy and the protocorm response to water stress after seed germination.

3.
Bot Stud ; 58(1): 39, 2017 Sep 19.
Artigo em Inglês | MEDLINE | ID: mdl-28929370

RESUMO

BACKGROUND: Termitomyces mushrooms are mutualistically associated with fungus-growing termites, which are widely considered to cultivate a monogenotypic Termitomyces symbiont within a colony. Termitomyces cultures isolated directly from termite colonies are heterokaryotic, likely through mating between compatible homokaryons. RESULTS: After pairing homokaryons carrying different haplotypes at marker gene loci MIP and RCB from a Termitomyces fruiting body associated with Odontotermes formosanus, we observed nuclear fusion and division, which greatly resembled meiosis, during each hyphal cell division and conidial formation in the resulting heterokaryons. Surprisingly, nuclei in homokaryons also behaved similarly. To confirm if meiotic-like recombination occurred within mycelia, we constructed whole-genome sequencing libraries from mycelia of two homokaryons and a heterokaryon resulting from mating of the two homokaryons. Obtained reads were aligned to the reference genome of Termitomyces sp. J132 for haplotype reconstruction. After removal of the recombinant haplotypes shared between the heterokaryon and either homokaryons, we inferred that 5.04% of the haplotypes from the heterokaryon were the recombinants resulting from homologous recombination distributed genome-wide. With RNA transcripts of four meiosis-specific genes, including SPO11, DMC1, MSH4, and MLH1, detected from a mycelial sample by real-time quantitative PCR, the nuclear behavior in mycelia was reconfirmed meiotic-like. CONCLUSION: Unlike other basidiomycetes where sex is largely restricted to basidia, Termitomyces maximizes sexuality at somatic stage, resulting in an ever-changing genotype composed of a myriad of coexisting heterogeneous nuclei in a heterokaryon. Somatic meiotic-like recombination may endow Termitomyces with agility to cope with termite consumption by maximized genetic variability.

4.
Bot Stud ; 58(1): 16, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28510199

RESUMO

BACKGROUND: Paphiopedilum rungsuriyanum from Northern Laos was discovered and described in 2014. It is characterized by having miniature tessellated leaves, a flower having a helmet shaped lip with a V-shaped neckline, and a semi-lunate, 3-dentate staminode with an umbo. These morphological features distinguish P. rungsuriyanum from the other known sections/subgenera of Paphiopedilum, making it difficult to group with existing infrageneric units. RESULTS: Paphiopedilum rungsuriyanum has chromosome number of 2n = 26. Fluorescence in situ hybridization study demonstrates that there are two 45S rDNA signals in the telomeric region of chromosomes, and more than 20 5S rDNA signals dispersed signals in the pericentromeric and centromeric regions. Phylogenetic analyses based on four nuclear (i.e. ITS, ACO, DEF4 and RAD51) and four plastid (i.e. atpI-atpH, matK, trnS-trnfM and ycf1) gene regions indicate that P. rungsuriyanum is nested in subgenus Paphiopedilum and is a sister to section Paphiopedilum. CONCLUSIONS: The results in combination with karyomorphological, rDNA FISH patterns, morphological and phylogenetic analyses suggest a new section Laosianum to accommodate this species in the current sectional circumscription of subgenus Paphiopedilum.

5.
Ann Bot ; 116(3): 403-11, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26105185

RESUMO

BACKGROUND AND AIMS: Although abscisic acid (ABA) is commonly recognized as a primary cause of seed dormancy, there is a lack of information on the role of ABA during orchid seed development. In order to address this issue, the localization and quantification of ABA were determined in developing seeds of Cypripedium formosanum. METHODS: The endogenous ABA profile of seeds was measured by enzyme-linked immunosorbent assay (ELISA). Temporal and spatial distributions of ABA in developing seeds were visualized by immunohistochemical staining with monoclonal ABA antibodies. Fluoridone was applied to test the causal relationship between ABA content and seed germinability. KEY RESULTS: ABA content was low at the proembryo stage, then increased rapidly from 120 to 150 days after pollination (DAP), accompanied by a progressive decrease in water content and seed germination. Immunofluorescence signals indicated an increase in fluorescence over time from the proembryo stage to seed maturation. From immunogold labelling, gold particles could be seen within the cytoplasm of embryo-proper cells during the early stages of seed development. As seeds approached maturity, increased localization of gold particles was observed in the periplasmic space, the plasmalemma between embryo-proper cells, the surface wall of the embryo proper, and the inner walls of inner seed-coat cells. At maturity, gold particles were found mainly in the apoplast, such as the surface wall of the embryo proper, and the shrivelled inner and outer seed coats. Injection of fluoridone into capsules resulted in enhanced germination of mature seeds. CONCLUSIONS: The results indicate that ABA is the key inhibitor of germination in C. formosanum. The distinct accumulation pattern of ABA suggests that it is synthesized in the cytosol of embryo cells during the early stages of seed development, and then exported to the apoplastic region of the cells for subsequent regulatory processes as seeds approach maturity.


Assuntos
Ácido Abscísico/metabolismo , Orchidaceae/crescimento & desenvolvimento , Orchidaceae/metabolismo , Reguladores de Crescimento de Planta/metabolismo , Sementes/crescimento & desenvolvimento , Sementes/metabolismo
6.
Bot Stud ; 56(1): 22, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28510831

RESUMO

The repeat sequences occupied more than 50 % of soybean genome. In order to understand where these repeat sequences distributed in soybean genome and its related Glycine species, we examined three new repeat sequences-soybean repeat sequence (SBRS1, SBRS2 and SBRS3), some nonspecific repeat sequences and 45S rDNA on several Glycine species, including annual and perennial accessions in this study. In the annual species, G. soja, signals for SBRS1 and ATT repeat can be found on each chromosome in GG genome, but those for SBRS2 and SBRS3 were located at three specific loci. In perennial Glycine species, these three SBR repeat frequently co-localized with 45S rDNA, two major 45S rDNA loci were found in all tetraploid species. However, an extra minor locus was found in one accession of the G. pescadrensis (Tab074), but not in another accession (Tab004). We demonstrate that some repetitive sequences are present in all Glycine species used in the study, but the abundancy is different in annual or perennial species. We suggest this study may provide additional information in investigations of the phylogeny in the Glycine species.

7.
PLoS One ; 9(12): e114617, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25514186

RESUMO

Aneuploidy features a numerical chromosome variant that the number of chromosomes in the nucleus of a cell is not an exact multiple of the haploid number, which may have an impact on morphology and gene expression. Here we report a tertiary trisomy uncovered by characterizing a T-DNA insertion mutant (aur2-1/+) in the Arabidopsis (Arabidopsis thaliana) AURORA2 locus. Whole-genome analysis with DNA tiling arrays revealed a chromosomal translocation linked to the aur2-1 allele, which collectively accounted for a tertiary trisomy 2. Morphologic, cytogenetic and genetic analyses of aur2-1 progeny showed impaired male and female gametogenesis to various degrees and a tight association of the aur2-1 allele with the tertiary trisomy that was preferentially inherited. Transcriptome analysis showed overlapping and distinct gene expression profiles between primary and tertiary trisomy 2 plants, particularly genes involved in response to stress and various types of external and internal stimuli. Additionally, transcriptome and gene ontology analyses revealed an overrepresentation of nuclear-encoded organelle-related genes functionally involved in plastids, mitochondria and peroxisomes that were differentially expressed in at least three if not all Arabidopsis trisomics. These observations support a previous hypothesis that aneuploid cells have higher energy requirement to overcome the detrimental effects of an unbalanced genome. Moreover, our findings extend the knowledge of the complex nature of the T-DNA insertion event influencing plant genomic integrity by creating high-grade trisomy. Finally, gene expression profiling results provide useful information for future research to compare primary and tertiary trisomics for the effects of aneuploidy on plant cell physiology.


Assuntos
Arabidopsis/genética , Gametogênese Vegetal/genética , Regulação da Expressão Gênica de Plantas/genética , Trissomia , Arabidopsis/fisiologia , Aurora Quinase A/genética , Primers do DNA , Metabolismo Energético/genética , Gametogênese Vegetal/fisiologia , Perfilação da Expressão Gênica , Microscopia de Interferência , Mutagênese Insercional/genética , Pólen/citologia , Pólen/fisiologia
8.
J Exp Bot ; 65(8): 2023-37, 2014 May.
Artigo em Inglês | MEDLINE | ID: mdl-24591055

RESUMO

The anther-specific gene LLA1271 isolated from lily (Lilium longiflorum Thunb.) anthers is novel and exists in two forms. The protein encoded by LLA1271 may represent an adhesin-like protein first found in higher plants. The protein contains a typical N-terminal signal peptide followed by a highly conserved repeat domain. The LLA1271 gene is temporally expressed at the phase of microspore development. RNA blot and RNA in situ hybridization analyses demonstrated that the gene was expressed both in the tapetum and in the microspore. The gene is endo- and exogenously induced by gibberellin. Studies with the gibberellin biosynthesis inhibitor uniconazole and an inhibitor of ethylene activity, 2,5-norbornadien (NBD), revealed that LLA1271 is negatively regulated by ethylene, and a cross-talk of regulation between gibberellin and ethylene occurs in young anthers. The treatment with NBD caused the tapetum to become densely cytoplasmic and highly polarized, whereas uniconazole arrested tapetal development in a state close to that of a tapetum without treatment. The LLA1271 protein is heat stable and heterogeneous. An immunoblot of separated protein fractions of the anther revealed that the LLA1271 protein was detected in protein fraction of the microspore released from the cell wall by treatment with either 0.5% or 2% Triton X-100. Ectopic expression of LLA1271 resulted in impaired stamen and low pollen germination. Scanning electron microscopy of TAP::LLA1271 pollen showed distorted exine formation and patterning. The LLA1271 protein once synthesized in both the tapetum and microspore is secreted and deposited on the surface of microspores, moderately affecting exine formation and patterning.


Assuntos
Flores/genética , Regulação da Expressão Gênica de Plantas , Lilium/genética , Proteínas de Plantas/genética , Sequência de Aminoácidos , Sequência de Bases , Etilenos/metabolismo , Flores/crescimento & desenvolvimento , Flores/metabolismo , Giberelinas/genética , Giberelinas/metabolismo , Lilium/crescimento & desenvolvimento , Lilium/metabolismo , Lilium/ultraestrutura , Microscopia Eletrônica de Varredura , Proteínas de Plantas/química , Proteínas de Plantas/metabolismo , Pólen/crescimento & desenvolvimento , Pólen/ultraestrutura , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Alinhamento de Sequência
9.
New Phytol ; 202(3): 1024-42, 2014 May.
Artigo em Inglês | MEDLINE | ID: mdl-24571782

RESUMO

The Phalaenopsis orchid produces complex flowers that are commercially valuable, which has promoted the study of its flower development. E-class MADS-box genes, SEPALLATA (SEP), combined with B-, C- and D-class MADS-box genes, are involved in various aspects of plant development, such as floral meristem determination, organ identity, fruit maturation, seed formation and plant architecture. Four SEP-like genes were cloned from Phalaenopsis orchid, and the duplicated PeSEPs were grouped into PeSEP1/3 and PeSEP2/4. All PeSEPs were expressed in all floral organs. PeSEP2 expression was detectable in vegetative tissues. The study of protein-protein interactions suggested that PeSEPs may form higher order complexes with the B-, C-, D-class and AGAMOUS LIKE6-related MADS-box proteins to determine floral organ identity. The tepal became a leaf-like organ when PeSEP3 was silenced by virus-induced silencing, with alterations in epidermis identity and contents of anthocyanin and chlorophyll. Silencing of PeSEP2 had minor effects on the floral phenotype. Silencing of the E-class genes PeSEP2 and PeSEP3 resulted in the downregulation of B-class PeMADS2-6 genes, which indicates an association of PeSEP functions and B-class gene expression. These findings reveal the important roles of PeSEP in Phalaenopsis floral organ formation throughout the developmental process by the formation of various multiple protein complexes.


Assuntos
Flores/crescimento & desenvolvimento , Flores/genética , Genes de Plantas , Orchidaceae/crescimento & desenvolvimento , Orchidaceae/genética , Proteínas de Plantas/genética , Sequência de Aminoácidos , Forma Celular/genética , Clonagem Molecular , Flores/ultraestrutura , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Redes Reguladoras de Genes , Inativação Gênica , Proteínas de Domínio MADS/genética , Proteínas de Domínio MADS/metabolismo , Modelos Biológicos , Dados de Sequência Molecular , Especificidade de Órgãos/genética , Organogênese/genética , Fenótipo , Filogenia , Epiderme Vegetal/citologia , Epiderme Vegetal/ultraestrutura , Proteínas de Plantas/química , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas , Regiões Promotoras Genéticas/genética , Ligação Proteica
10.
J Exp Bot ; 64(12): 3869-84, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23956416

RESUMO

Orchidaceae, one of the largest angiosperm families, has significant commercial value. Isolation of genes involved in orchid floral development and morphogenesis, scent production, and colouration will advance knowledge of orchid flower formation and facilitate breeding new varieties to increase the commercial value. With high-throughput virus-induced gene silencing (VIGS), this study identified five transcription factors involved in various aspects of flower morphogenesis in the orchid Phalaenopsis equestris. These genes are PeMADS1, PeMADS7, PeHB, PebHLH, and PeZIP. Silencing PeMADS1 and PebHLH resulted in reduced flower size together with a pelaloid column containing petal-like epidermal cells and alterations of epidermal cell arrangement in lip lateral lobes, respectively. Silencing PeMADS7, PeHB, and PeZIP alone resulted in abortion of the first three fully developed flower buds of an inflorescence, which indicates the roles of the genes in late flower development. Furthermore, double silencing PeMADS1 and PeMADS6, C- and B-class MADS-box genes, respectively, produced a combinatorial phenotype with two genes cloned in separate vectors. Both PeMADS1 and PeMADS6 are required to ensure the normal development of the lip and column as well as the cuticle formation on the floral epidermal cell surface. Thus, VIGS allows for unravelling the interaction between two classes of MADS transcription factors for dictating orchid floral morphogenesis.


Assuntos
Regulação da Expressão Gênica de Plantas , Orchidaceae/crescimento & desenvolvimento , Orchidaceae/genética , Proteínas de Plantas/genética , Fatores de Transcrição/genética , Etiquetas de Sequências Expressas , Flores/genética , Flores/crescimento & desenvolvimento , Flores/metabolismo , Inativação Gênica , Dados de Sequência Molecular , Orchidaceae/metabolismo , Orchidaceae/virologia , Fenótipo , Filogenia , Proteínas de Plantas/metabolismo , Potexvirus/genética , Alinhamento de Sequência , Análise de Sequência de DNA , Fatores de Transcrição/metabolismo
11.
Plant Sci ; 185-186: 156-60, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-22325876

RESUMO

Based mainly on morphological features and geographical distribution, Begonia×chungii (2n=22) was recently reported as a natural hybrid between B. longifolia and B. palmata in Taiwan. This study aims to confirm the hybridity of B.×chungii and to sort out the genome constitutions of its putative parents, using genomic in situ hybridization (GISH). Genomic DNAs of both parental species were used as probes for B.×chungii and the experimental F(1) hybrid, B. palmata×B. longifolia, in GISH analyses. Bicolor-GISH analyses in B.×chungii showed that the 22 chromosomes consisted of six chromosomes hybridized with a probe derived from the B. palmata genome, six with another probe from the B. longifolia genome and the remaining ten with both genomes overlapped. Meanwhile, bicolor-GISH in B. palmata×B. longifolia showed a remarkable similarity to that of B.×chungii. The reciprocal GISH results between B. longifolia and B. palmata were comparable. Our GISH analyses confirmed that B.×chungii is a natural F(1) hybrid between B. longifolia and B. palmata. Genomes of the parental species were shown to be partially homologous, suggesting a derived common ancestral genome in them.


Assuntos
Begoniaceae/genética , Quimera/genética , Genoma de Planta/genética , Hibridização In Situ/métodos , Cromossomos de Plantas/genética , DNA de Plantas/genética , Diploide , Hibridização Genética , Meristema/genética , Taiwan
12.
Plant Sci ; 181(3): 300-8, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-21763541

RESUMO

Wild species of rice with many valuable agronomic traits are an important genetic resource for improving cultivated rice by wide hybridization. Genome- or chromosome-specific markers are useful for monitoring genome introgression and for identifying genome components. From 47 random amplified polymorphic DNAs (RAPDs) of nine Oryza species, three bands (Ogla225, Opun225, and Opun246) were found to be genome specific with distinct sizes. Their specificities were further characterized by Southern hybridization, sequence analysis, and fluorescent in situ hybridization (FISH). Ogla225 is specifically amplified from the AA genome but homologous sequences were conserved among Oryza species. Opun225 occurs at a low copy number although is specifically amplified from Oryza punctata. There are estimated 2000-3300 repeats of Opun246 in each haploid genome of Oryza species with the BB or BBCC genome. Clusters of Opun246 repeats were detected at heterochromatic regions on almost all chromosomes of the BB genomes by FISH. Opun246 may be a useful marker for monitoring the introgression of BB genome or for identifying the conserved components of BB genome in genetic resource. The results from this study and our previous study both indicate that numerous unique repeats play role in the differentiation of the BB genome from other Oryza genomes.


Assuntos
DNA de Plantas/genética , Genoma de Planta , Oryza/genética , Marcadores Genéticos , Variação Genética , Hibridização in Situ Fluorescente , Técnica de Amplificação ao Acaso de DNA Polimórfico , Sequências Repetitivas de Ácido Nucleico
13.
Plant Cell Physiol ; 52(9): 1546-59, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-21771867

RESUMO

Pollination is composed of cell-cell communication and complicated signaling cascades that regulate pollen tube growth and guidance toward the ovules for double fertilization, and is critical for successful sexual reproduction. Exploring expression profiles of in vivo grown pollen tubes is important. Nevertheless, it is difficult to obtain accessible pollen tubes for profiling studies in most model plants. By taking advantage of the hollow styles of lily (Lilium longiflorum), in vivo pollen tubes harvested from pollinated styles which had been cut open were used here to study their protein and transcript profiles. Pollination quantitatively and qualitatively altered the total protein composition of elongating pollen tubes. cDNAs generated and amplified from total RNAs of 24 h in vivo grown and 12 h in vitro cultured pollen tubes were used for suppression subtractive hybridization analyses and preparation of home-made array chips. Microarray analyses conducted with different probe sets revealed 16 transcripts specifically present and/or enriched in in vivo pollen tubes. Reverse transcription-PCR (RT-PCR), in situ hybridization and Northern blotting were applied to validate their unique pollination-induced expression features. Interestingly, several transcripts were simultaneously detected on the stylar transmitting tract epidermis, where in vivo pollen tubes tightly adhered during pollination. Their deduced amino acid sequences showed that most of them encoded small proteins and could be classified into several families. Transient assay revealed filament-like structures decorated by these proteins and one probably localized in the generative cell. These small peptides might be critical for pollen tube growth during pollination, and further exploration of their biological functions and mechanisms of action are of great interest.


Assuntos
Lilium/metabolismo , Proteínas de Plantas/metabolismo , Tubo Polínico/metabolismo , Polinização , Sequência de Aminoácidos , Clonagem Molecular , DNA Complementar/genética , DNA de Plantas/genética , Regulação da Expressão Gênica de Plantas , Lilium/genética , Dados de Sequência Molecular , Análise de Sequência com Séries de Oligonucleotídeos , Proteínas de Plantas/genética , Tubo Polínico/genética , Transcriptoma
14.
Plant Cell Physiol ; 52(9): 1515-31, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-21757456

RESUMO

Orchidaceae are an excellent model to examine perianth development because of their sophisticated floral architecture. In this study, we identified 24 APETALA3 (AP3)-like and 13 PISTILLA (PI)-like genes from 11 species of orchids and characterized them into four AP3- and two PI-duplicated homologs. The first duplication event in AP3 homologs occurring in the early evolutionary history of the Orchidaceae gave rise to AP3A and AP3B clades. Further duplication events resulted in four subclades, namely AP3A1, AP3A2, AP3B1 and AP3B2, during the evolution of Orchidaceae. The AP3 paralogous genes were expressed throughout inflorescence and floral bud development. From the in situ hybridization results, we noticed that the transition timings from ubiquitous to constrained expression in floral organs for both clades are different. The transition point of expression of the AP3A clade (clades 3 and 4) was at the late floral organ primordia stage. In contrast, that for the AP3B clade (clades 1 and 2) was not observed until the late inflorescence and floral bud stages. In addition, the AP3 orthologous genes revealed diverse expression patterns in various species of orchids, whereas the PI homologs were uniformly expressed in all floral whorls. AP3A2 orthologs play a noticeable role in lip formation because of their exclusive expression in the lip. Further evidence comes from the ectopic expression of AP3A2 detected in the lip-like petals extending from the lip in four sets of peloric mutants. Finally, a Homeotic Orchid Tepal (HOT) model is proposed, in which dualistic characters of duplicated B-class MADS-box genes are involved in orchid perianth development and growth.


Assuntos
Flores/crescimento & desenvolvimento , Genes Duplicados , Proteínas de Domínio MADS/metabolismo , Orchidaceae/genética , Clonagem Molecular , Flores/genética , Regulação da Expressão Gênica no Desenvolvimento , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Proteínas de Domínio MADS/genética , Orchidaceae/crescimento & desenvolvimento , Filogenia , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo
15.
Ann Bot ; 108(1): 113-21, 2011 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-21576078

RESUMO

BACKGROUND AND AIMS: Lady's slipper orchids (Paphiopedilum) are of high value in floriculture, and interspecific hybridization has long been used for breeding improved cultivars; however, information regarding the genome affinities of species and chromosome pairing behaviour of the hybrids remains almost unknown. The present work analyses the meiotic behaviour of interspecific hybrids by genomic in situ hybridization and cytologically evaluates the genomic relationships among parental species. METHODS: Eight interspecific F(1) hybrids of Paphiopedilum species in various subgenera or sections were investigated in this study. The chromosome behaviour in meiosis of these interspecific hybrids was analysed and subjected to genomic in situ hybridization and fluorescent in situ hybridization. KEY RESULTS: Genomic in situ hybridization was demonstrated as an efficient method to differentiate between Paphiopedilum genomes and to visualize the chromosome pairing affinities in interspecific F(1) hybrids, clarifying the phylogenetic distances among these species. Comparatively regular chromosome pairing observed in the hybrids of P. delenatii × P. bellatulum, P. delenatii × P. rothschildianum and P. rothschildianum × P. bellatulum suggested high genomic affinities and close relationships between parents of each hybrid. In contrast, irregular chromosome associations, such as univalents, trivalents and quadrivalents occurred frequently in the hybrids derived from distant parents with divergent karyotypes, such as P. delenatii × P. callosum, P. delenatii × P. glaucophyllum, P. rothschildianum × P. micranthum and P. rothschildianum × P. moquetteanum. The existence of multivalents and autosyndesis demonstrated by genomic in situ hybridization in this study indicates that some micro-rearrangements and other structural alterations may also play a part in differentiating Paphiopedilum species at chromosomal level, demonstrated as different chromosome pairing affinities in interspecific hybrids. CONCLUSIONS: The results indicate that genome homology and the interaction of genetic factors, but not chromosome number nor karyotype similarity, determine the chromosome pairing behaviour in Paphiopedilum hybrids.


Assuntos
Pareamento Cromossômico/genética , Transferência Genética Horizontal/genética , Genoma de Planta/genética , Hibridização In Situ/métodos , Orchidaceae/genética , Cruzamento , DNA Ribossômico/genética , Loci Gênicos , Hibridização in Situ Fluorescente , Cariotipagem , Meiose/genética , Orchidaceae/ultraestrutura , Filogenia , Pólen/genética , Especificidade da Espécie
16.
Genomics ; 96(3): 181-90, 2010 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-20580815

RESUMO

Contrary to the chromosomal polymorphism of 45S ribosomal genes (45S rDNA) loci in other Oryza species, each of Oryza australiensis and Oryza brachyantha has only one 45S rDNA locus at the most conserved position of 45S rDNAs in Oryza. O. australiensis and O. brachyantha are known phylogenetically distant and have extremely different genome sizes among diploid Oryza species. This study reveals that the sequences and organizations of intergenic spacer (IGS) for 45S rDNA of both O. australiensis and O. brachyantha are different from other Oryza species. The IGS of O. australiensis contains 13 tandem repeats and only one transcriptional initiation site, while there are four tandem repeats and three transcriptional initiation sites in the IGS of O. brachyantha. Our results suggest different evolution processes of orthologous rDNA loci in the genus Oryza. Here we also demonstrate an efficient strategy to study locus-specific IGS before whole genome sequences data are available.


Assuntos
Cromossomos de Plantas/genética , DNA Espaçador Ribossômico/genética , Evolução Molecular , Variação Genética , Oryza/genética , RNA Ribossômico/genética , Southern Blotting , Componentes do Gene , Hibridização in Situ Fluorescente , Reação em Cadeia da Polimerase , Especificidade da Espécie , Sequências de Repetição em Tandem/genética , Sítio de Iniciação de Transcrição
17.
J Agric Food Chem ; 57(22): 10916-21, 2009 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-19919123

RESUMO

Adlay (Coix lachryma-jobi L. var. ma-yuen Stapf) is regarded as a nutritive food source as well as herbal medicine. The food nutrition is a consequence of its high protein content and superior amino acid composition. From ca. 200 expressed sequence tag (EST) sequences in maturing adlay grains, clones encoding precursor polypeptides of 10 seed storage proteins in the prolamin family, including 8 alpha-coixin isoforms, 1 delta-coixin, and 1 gamma-coixin, were identified. Full-length cDNA fragments encoding these 10 coixins were obtained by PCR cloning. Mass spectrometric analyses confirmed the presence of these 10 coixins in the extract of adlay grain. Calculated amino acid compositions indicate that all 10 coixins are rich in glutamine (>20% in alpha-coixin isoforms, 13.3% in delta-coixin, and 31.2% in gamma-coixin). The 8 alpha-coixin isoforms are low in methionine, cysteine, and lysine (on average, 0.8, 0.6, and 0.1%, respectively). However, the delta-coixin is a sulfur-rich protein (18.2% methionine and 9.1% cysteine), and the gamma-coixin is a nutritive protein composed of 2.0% methionine, 6.6% cysteine, 2.6% lysine, and 8.9% histidine. The company of delta-coixin and gamma-coixin with alpha-coixin isoforms enhances the nutritional value of alday grain for human consumption.


Assuntos
Clonagem Molecular , Coix/química , Espectrometria de Massas , Valor Nutritivo , Proteínas de Plantas/química , Proteínas de Plantas/genética , Sequência de Aminoácidos , Aminoácidos/análise , DNA Complementar/genética , DNA de Plantas/análise , DNA de Plantas/genética , Dados de Sequência Molecular , Reação em Cadeia da Polimerase , Sementes/química , Alinhamento de Sequência
18.
J Plant Physiol ; 166(4): 417-27, 2009 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-19013663

RESUMO

Two stage-specific genes have been isolated from a subtractive cDNA library constructed from developing anthers of lily (Lilium longiflorum). The proteins encoded by the two genes have a strong hydrophobic region at the N-terminus, indicating the presence of a signal peptide. The deduced LLA-67 is a new type of small cysteine-rich protein whose sequence exhibits four consecutive CX(3)CX(6-10) repeats that could form signal-receiving finger motifs, while the deduced LLA-115 protein shows significant similarities to a rice unknown protein, and putative cell wall proteins of Medicago truncatula and Arabidopsis. The transcripts of LLA-67 and LLA-115 were anther specific and differentially detected at the phase of microspore development. In situ hybridization with antisense riboprobes of the two genes in the anther showed strong signals localized to the tapetal layer of the anther wall. The LLA-67 mRNA was also detected in the microspore at the phase of microspore development but the LLA-115 mRNA was not. The LLA-115 gene can be exogenously induced by gibberellin (GA), whereas the LLA-67 gene cannot be induced. Studies with the GA biosynthesis inhibitor uniconazole and an inhibitor of ethylene activity, 2,5-norbornadien (NBD), revealed that the two genes were negatively regulated by ethylene and a cross-talk between GA and ethylene was involved in the regulation of the two genes occurring in young anthers. The treatment of NBD caused the tapetum to become densely cytoplasmic and highly polarized, whereas uniconazole arrested tapetal development to a status close to that of control. DNA blots of lily genomic DNA indicated that the two genes were encoded by a small gene family. The different actions of hormones on gene expression and the possible function of the gene products in young anthers are discussed.


Assuntos
Regulação da Expressão Gênica de Plantas , Genes de Plantas , Lilium/genética , Proteínas de Plantas/genética , Pólen/genética , Sequência de Aminoácidos , DNA Complementar/genética , DNA de Plantas/genética , Etilenos/farmacologia , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Giberelinas/farmacologia , Lilium/citologia , Lilium/efeitos dos fármacos , Lilium/crescimento & desenvolvimento , Dados de Sequência Molecular , Especificidade de Órgãos/efeitos dos fármacos , Especificidade de Órgãos/genética , Proteínas de Plantas/química , Proteínas de Plantas/metabolismo , Pólen/citologia , Pólen/efeitos dos fármacos , Pólen/crescimento & desenvolvimento , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Alinhamento de Sequência , Fatores de Tempo
19.
Theor Appl Genet ; 116(6): 745-53, 2008 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-18214422

RESUMO

The genes encoding for 18S-5.8S-28S ribosomal RNA (rDNA) are both conserved and diversified. We used rDNA as probe in the fluorescent in situ hybridization (rDNA-FISH) to localized rDNAs on chromosomes of 15 accessions representing ten Oryza species. These included cultivated and wild species of rice, and four of them are tetraploids. Our results reveal polymorphism in the number of rDNA loci, in the number of rDNA repeats, and in their chromosomal positions among Oryza species. The numbers of rDNA loci varies from one to eight among Oryza species. The rDNA locus located at the end of the short arm of chromosome 9 is conserved among the genus Oryza. The rDNA locus at the end of the short arm of chromosome 10 was lost in some of the accessions. In this study, we report two genome specific rDNA loci in the genus Oryza. One is specific to the BB genome, which was localized at the end of the short arm of chromosome 4. Another may be specific to the CC genome, which was localized in the proximal region of the short arm of chromosome 5. A particular rDNA locus was detected as stretched chromatin with bright signals at the proximal region of the short arm of chromosome 4 in O. grandiglumis by rDNA-FISH. We suggest that chromosomal inversion and the amplification and transposition of rDNA might occur during Oryza species evolution. The possible mechanisms of cyto-evolution in tetraploid Oryza species are discussed.


Assuntos
Cromossomos de Plantas/genética , DNA Ribossômico/genética , Genoma de Planta , Oryza/genética , Polimorfismo Genético , RNA Ribossômico 18S/genética , RNA Ribossômico 28S/genética , RNA Ribossômico 5S/genética , DNA Espaçador Ribossômico , Hibridização in Situ Fluorescente
20.
J Plant Physiol ; 165(5): 553-63, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-17391804

RESUMO

We successfully identify anther-specific/predominant genes induced by gibberellin (GA) at the microspore stage of lily (Lilium longiflorum) anthers. We used a suppression-subtractive hybridization strategy to identify 22 individual cDNAs followed by a reverse RNA dot plot to determine their specificities at the microspore stage. Of the 22 genes, 12 are clearly anther-specific and three are anther-predominant. Sequence analysis revealed that five anther-specific/predominant genes are novel. The transcripts of anther-specific/predominant genes were differentially detected at the microspore development phase; some began accumulating in level as early as the occurrence of meiosis. When uniconazole, an inhibitor of GA biosynthesis was applied in young lily plants we found that all of the anther-specific/predominant genes, with the exception of LLA-139, were up-regulated by GAs in the anther while only some were responsive to the exogenous addition of 100 microM GA3. In situ hybridization with antisense riboprobes of selected genes in the anther showed a strong signal localized to the tapetal layer. The different actions of GA on gene expression in anthers are discussed.


Assuntos
Flores/genética , Regulação da Expressão Gênica no Desenvolvimento/efeitos dos fármacos , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Giberelinas/farmacologia , Lilium/genética , Flores/crescimento & desenvolvimento , Hibridização In Situ , Lilium/crescimento & desenvolvimento , Dados de Sequência Molecular , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , RNA de Plantas/genética , RNA de Plantas/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa
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