Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 8 de 8
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Plant Physiol ; 158(3): 1319-28, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-22218926

RESUMO

The S5 locus regulates spikelet fertility of indica/japonica hybrid rice (Oryza sativa). There are three alleles at the S5 locus, including an indica allele (S5i), a japonica allele (S5j), and a wide-compatibility allele (S5n). This study analyzed the molecular basis for S5-dependent reproductive isolation and compatibility of indica/japonica rice hybrids. Three S5 alleles were expressed at extremely low levels, and only in the ovary. S5n was more similar to S5i in both RNA and protein expression profiles. The S5 locus was not essential for embryo sac development, although deleterious interactions between S5i and S5j resulted in reduced rates of spikelet fertility. The yeast two-hybrid system was used to test direct interactions between S5-encoded proteins. The results indicated that the S5i- and S5j-encoded eukaryotic aspartyl proteases formed both homodimers and heterodimers, whereas the S5n-encoded aspartyl protease was incapable of dimerization. Site-directed mutagenesis revealed that a single amino acid difference between S5i- and S5j-encoded aspartyl proteases (phenylalanine/leucine at residue 273) was primarily responsible for embryo sac abortion. The S5 locus may have promoted the subspeciation of indica and japonica, but it also enables gene flow between them.


Assuntos
Ácido Aspártico Proteases/metabolismo , Hibridização Genética , Oryza/genética , Isolamento Reprodutivo , Alelos , Ácido Aspártico Proteases/genética , Western Blotting , Quimera/genética , Quimera/metabolismo , Fertilidade , Regulação da Expressão Gênica de Plantas , Fluxo Gênico , Técnicas de Silenciamento de Genes , Genes de Plantas , Loci Gênicos , Genótipo , Leucina/genética , Leucina/metabolismo , Mutagênese Sítio-Dirigida , Oryza/enzimologia , Oryza/fisiologia , Fenilalanina/genética , Fenilalanina/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas/genética , Plantas Geneticamente Modificadas/metabolismo , Plantas Geneticamente Modificadas/fisiologia , Mapeamento de Interação de Proteínas , Multimerização Proteica , Sementes/genética , Sementes/metabolismo , Sementes/fisiologia , Técnicas do Sistema de Duplo-Híbrido
2.
J Genet Genomics ; 37(1): 57-68, 2010 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-20171578

RESUMO

The rice indica/japonica hybrid shows strong heterosis. However, such inter-subspecific hybrid can't be directly used in rice production due to its low spikelet fertility. The S5 locus was proved to be associated with fertility of indica/japonica hybrid and its S5n allele from wide-compatibility variety (WCV) is capable to overcome fertility barrier. In the present study, we reported the causal sites in the S5 locus responsible for compatibility of indica/japonica hybrid. Fine-mapping of the S5 locus using the 11 test-cross families pinpoints a candidate S5 locus encoding aspartic protease (Asp). Intragenic recombination within the Asp gene happened in a number of recombinants, resulting in chimeric S5j-S5n alleles. Just like S5n, the chimeric S5j-S5n allele displayed higher spikelet fertility when combined with the S5i allele. In the complementary test, however, the S5n allele from WCVs failed to enhance fertilities of the indica/japonica hybrids. Compared to both indica and japonica varieties, all nine WCVs from different resources are characterized with a 136 bp deletion in the Asp N-terminus, which probably renders the S5n allele non-functional. Furthermore, an A/C polymorphic site is detected 1,233 bp downstream of the Asp start codon. The heterozygous A/C site of the Asp gene in indica/japonica hybrid is believed to be the casual factor to cause partial sterility. The functional makers based on the two polymorphic sites will be broadly used in developing wide-compatibility rice varieties.


Assuntos
Pareamento de Bases/genética , Loci Gênicos/genética , Hibridização Genética , Mutação INDEL/genética , Oryza/genética , Oryza/fisiologia , Polimorfismo Genético , Sequência de Bases , Mapeamento Cromossômico , Clonagem Molecular , Fertilidade/genética , Genes de Plantas/genética , Teste de Complementação Genética , Marcadores Genéticos/genética , Oryza/classificação , Recombinação Genética , Reprodutibilidade dos Testes
3.
J Cell Sci ; 122(Pt 12): 2055-63, 2009 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-19470578

RESUMO

MER3, a ZMM protein, is required for the formation of crossovers in Saccharomyces cerevisiae and Arabidopsis. Here, MER3, the first identified ZMM gene in a monocot, is characterized by map-based cloning in rice (Oryza sativa). The null mutation of MER3 results in complete sterility without any vegetative defects. Cytological analyses show that chiasma frequency is reduced dramatically in mer3 mutants and the remaining chiasmata distribute randomly among different pollen mother cells, implying possible coexistence of two kinds of crossover in rice. Immunocytological analyses reveal that MER3 only exists as foci in prophase I meiocytes. In addition, MER3 does not colocalize with PAIR2 at the beginning of prophase I, but locates on one end of PAIR2 fragments at later stages, whereas MER3 foci merely locate on one end of REC8 fragments when signals start to be seen in early prophase I. The normal loading of PAIR2 and REC8 in mer3 implies that their loading is independent of MER3. On the contrary, the absence of MER3 signal in pair2 mutants indicates that PAIR2 is essential for the loading and further function of MER3.


Assuntos
Pareamento Cromossômico/genética , Troca Genética/genética , Genes de Plantas/fisiologia , Oryza/genética , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Proteínas de Ciclo Celular/fisiologia , Clonagem Molecular , Troca Genética/fisiologia , Proteínas Mutantes/fisiologia , Proteínas de Plantas/química , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Plantas Geneticamente Modificadas , Ligação Proteica , Distribuição Tecidual
4.
Proc Natl Acad Sci U S A ; 105(32): 11436-41, 2008 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-18678896

RESUMO

Hybrid sterility is a major form of postzygotic reproductive isolation. Although reproductive isolation has been a key issue in evolutionary biology for many decades in a wide range of organisms, only very recently a few genes for reproductive isolation were identified. The Asian cultivated rice (Oryza sativa L.) is divided into two subspecies, indica and japonica. Hybrids between indica and japonica varieties are usually highly sterile. A special group of rice germplasm, referred to as wide-compatibility varieties, is able to produce highly fertile hybrids when crossed to both indica and japonica. In this study, we cloned S5, a major locus for indica-japonica hybrid sterility and wide compatibility, using a map-based cloning approach. We show that S5 encodes an aspartic protease conditioning embryo-sac fertility. The indica (S5-i) and japonica (S5-j) alleles differ by two nucleotides. The wide compatibility gene (S5-n) has a large deletion in the N terminus of the predicted S5 protein, causing subcellular mislocalization of the protein, and thus is presumably nonfunctional. This triallelic system has a profound implication in the evolution and artificial breeding of cultivated rice. Genetic differentiation between indica and japonica would have been enforced because of the reproductive barrier caused by S5-i and S5-j, and species coherence would have been maintained by gene flow enabled by the wide compatibility gene.


Assuntos
Alelos , Quimera/genética , Fluxo Gênico , Oryza/genética , Infertilidade das Plantas/genética , Locos de Características Quantitativas/genética , Sequência de Bases , Cruzamento , Clonagem Molecular , Dados de Sequência Molecular , Especificidade da Espécie
5.
Yi Chuan Xue Bao ; 33(5): 441-8, 2006 May.
Artigo em Inglês | MEDLINE | ID: mdl-16722339

RESUMO

Glucose-6-phosphate dehydrogenase is a rate-limiting enzyme of pentose phosphate pathway, existing in cytosolic and plastidic compartments of higher plants. A novel gene encoding plastidic glucose-6-phosphate dehydrogenase was isolated from rice (Oryza sativa L.) and designated OsG6PDH2 in this article. Through semiquantitative RT-PCR approach it was found that OsG6PDH2 mRNA was weakly expressed in rice leaves, stems, immature spikes or flowered spikes, and a little higher in roots. However, the expression of OsG6PDH2 in rice seedlings was significantly induced by dark treatment. The complete opening reading frame (ORF) of OsG6PDH2 was inserted into pET30a (+), and expressed in Escherichia coli strain BL21 (DE3). The enzyme activity assay of transformed bacterial cells indicated that OsG6PDH2 encoding product had a typical function of glucose-6-phosphate dehydrogenase.


Assuntos
Genes de Plantas , Glucosefosfato Desidrogenase/genética , Oryza/enzimologia , Oryza/genética , Plastídeos/genética , Sequência de Aminoácidos , Clonagem Molecular , DNA de Plantas/análise , DNA de Plantas/genética , Escherichia coli/enzimologia , Regulação Enzimológica da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Glucosefosfato Desidrogenase/metabolismo , Dados de Sequência Molecular , Fases de Leitura Aberta , Raízes de Plantas/enzimologia , Plastídeos/enzimologia , RNA Mensageiro/metabolismo , Plântula/enzimologia , Plântula/genética
6.
Theor Appl Genet ; 111(8): 1495-503, 2005 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-16133303

RESUMO

Wide-compatibility (WC) is one of the most important traits in rice, which can overcome the fertility barrier in the indica/japonica hybrids, and hence to make it possible to utilize the higher yield potential of inter-subspecific hybrids. The S5n gene located on chromosome 6 has been previously reported to be responsible for the wide-compatibility in rice. Here we report the precise location of the S5n gene. In the first-pass mapping, the S5n gene was restricted within a 200 kb region by using a population of 242 isogenic lines in combination with high-density markers developed in the S5 region. In the fine mapping, the S5 region was further saturated with newly developed markers and more isogenic lines (549 in total) were investigated. Eventually, the S5n gene was mapped within a 50 kb region delimited by the left marker J13 and the right marker J17. One BAC clone screened from the BAC library of the WC rice variety 02428 covered the whole S5 region. Sequence analysis of the 50 kb region revealed two candidate genes, coding an aspartyl protease and a hypothetical protein. This result would greatly accelerate both cloning and marker-assisted selection of this important S5n gene.


Assuntos
Mapeamento Cromossômico , Genes de Plantas/genética , Oryza/genética , Cromossomos Artificiais Bacterianos , Primers do DNA , Marcadores Genéticos/genética , Reprodução/genética , Análise de Sequência de DNA
7.
Yi Chuan Xue Bao ; 30(8): 711-6, 2003 Aug.
Artigo em Chinês | MEDLINE | ID: mdl-14682238

RESUMO

Appearance of rice grain represents a major character of rice quality in many rice-producing areas of the world, especially in hybrid rice production in China. In this study, we conducted a molecular marker-based genetic analysis of the traits that are determinants of the appearance quality of rice grains, including grain length, grain width and grain shape (measured as grain length to grain width ratio). Two typical indica/japonica varieties Balilla and Nantehao(NTH) were selected to construct Balilla/NTH//Balilla backcross population containing 142 individuals. In the population, grain length, grain width and grain shape all conform to the normal distribution with certain transgressive segregation. It can be deduced that all of three traits were controlled by some quantitative trait loci (QTLs). In order to explore the QTLs effect, number and location, a linkage map consisting of 108 SSR markers based on the backcross population was constructed, and QTLs mapping was carried out for grain length, grain width and grain shape. A QTL, qGL-12, was detected for grain length at the interval RM101-RM270 on chromosome 12, its additive effect was 0.26 mm, and can explain 16.7% genetic variation. As for grain width trait, two QTLs were found, qGW-2 located at RM154-RM211 interval on chromosome 2, and qGW-3 at interval RM257-RM175 on chromosome 3, accounting for 11.5% and 16.6% genetic variation, respectively. The alleles at qGW-2 and qGW-3 from parent Balilla can increase grain width by 0.10 mm and 0.12 mm. For grain shape, 3 QTLs, qLW-2, qLW-6 and qLW-7 were found, located on chromosome 2, 6, and 7, respectively. qLW-2 and qLW-7 had positive effect, and they can explain 12.7% and 18.3% genetic variation, while qLW-6 had negative effect and contributed 11.5% genetic variation to the backcross population. The prospects of application of linkage relationship between SSR marker and QTLs in marker based selection (MAS) in rice breeding, and the improvement of grain shape and rice appearance quality were discussed.


Assuntos
Cromossomos de Plantas/genética , Oryza/genética , Locos de Características Quantitativas/genética , Mapeamento Cromossômico , Endogamia , Repetições de Microssatélites , Oryza/anatomia & histologia
8.
Yi Chuan Xue Bao ; 30(3): 267-76, 2003 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-12812093

RESUMO

To explore the genes differentiated between typical indica and japonica varieties, two typical indica/japonica varieties, Balilla (japonica) and Nantehao (NTH, indica), were selected to construct genetic populations based on the widely surveying for spikelet and pollen fertility of 90 indica/japonica F1 hybrids, which also were used as the wide compatability testers. In order to analyze the genes (QTLs) related to spikelet and pollen fertility, two reciprocal backcross populations Balilla/NTH//Balilla and Balilla/NTH//NTH were constructed and the spikelet and pollen fertility of each individuals were assessed. In both populations, two traits all appeared distorted normal distribution, but in the first population, they forwarded to low-level fertility type, the later population, forwarded to high-level fertility type relatively. The results indicated that both of male and female gametophytes of Balilla/NTH hybrids were partial sterile. Then we analyzed the SSR marker genotype of each individuals of Balilla/NTH//Balilla population containing 142 individuals, and constructed a SSR linkage map, in which, there were 108 information markers distributing on all 12 chromosomes equably, average marker distance was about 11.9 cM. Therefore the linkage map was qualified for QTL analysis. Two methods were employed to conduct QTLs analysis, i.e., single marker analysis and interval mapping. According to single marker analysis, 17 and 12 markers were found significantly responsible for spikelet and pollen fertility, respectively. And further study by means of MAPMAKER/QTL software, for spikelet fertility trait, two QTLs were detected, qSPTF1 on chromosome 1 and qSPTF6 on chromosome 6, and their additive effect were 13.501 and -16.414, respectively. According to previous studies, qSPTF6 was deduced to be the same locus as S-5. For pollen fertility, qPLLN7 on chromosome 7 and qPLLN9 on chromosome 9 were detected, and their additive effects were -12.003 and -11.012, respectively. Because the QTLs detected cannot explain completely the total variance of mapping population, other genetic factors must be existed to be responsible for spikelet and pollen partial sterility. Hence we let two random markers as putative covariates, and divide the 142 individuals into four groups according to the two marker genotypes, then the average values of spikelet and pollen fertility of each groups were calculated for two-way ANOVA (analysis of variance). The results indicated that there existed strong interaction for both spikelet fertility and pollen fertility. At a significance level of 0.005, there over 61 and 51 pairs loci interactions detected playing an important role in spikelet and pollen sterility expression, respectively. These results indicated that epistasis also was one of major genetic components controlling indica/japonica hybrid sterility.


Assuntos
Hibridização Genética/genética , Repetições de Microssatélites/genética , Oryza/genética , Análise de Variância , Mapeamento Cromossômico , Cromossomos de Plantas/genética , Fertilidade/genética , Pólen/genética , Locos de Características Quantitativas/genética
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...