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在高等植物中,外源和内源因素共同调控着植物从营养生长到生殖生长的转换。拟南芥EMF1和EMF2基因缺失的突变体不经过任何营养生长,种子萌发后便开花,这说明EMF基因是植物花发育的抑制基因。目前已从水稻、玉米、拟南芥等植物中克隆得到EMF同源基因,但其功能研究大多停留在拟南芥上。研究表明,EMF基因决定着植物营养生长阶段的发育,抑制植物开花。因此,开展EMF基因的分离、克隆和功能研究,有利于阐述植物营养生长过程阶段的抑花机制。对EMF基因的研究进展进行了综述,并提出EMF基因表达调控的闸门模型,以对EMF基因功能的进一步分析提供参考。  相似文献   

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The FLOWERING LOCUS T-like gene family in barley (Hordeum vulgare)   总被引:7,自引:0,他引:7  
Faure S  Higgins J  Turner A  Laurie DA 《Genetics》2007,176(1):599-609
The FLOWERING LOCUS T (FT) gene plays a central role in integrating flowering signals in Arabidopsis because its expression is regulated antagonistically by the photoperiod and vernalization pathways. FT belongs to a family of six genes characterized by a phosphatidylethanolamine-binding protein (PEBP) domain. In rice (Oryza sativa), 19 PEBP genes were previously described, 13 of which are FT-like genes. Five FT-like genes were found in barley (Hordeum vulgare). HvFT1, HvFT2, HvFT3, and HvFT4 were highly homologous to OsFTL2 (the Hd3a QTL), OsFTL1, OsFTL10, and OsFTL12, respectively, and this relationship was supported by comparative mapping. No rice equivalent was found for HvFT5. HvFT1 was highly expressed under long-day (inductive) conditions at the time of the morphological switch of the shoot apex from vegetative to reproductive growth. HvFT2 and HvFT4 were expressed later in development. HvFT1 was therefore identified as the main barley FT-like gene involved in the switch to flowering. Mapping of HvFT genes suggests that they provide important sources of flowering-time variation in barley. HvFTI was a candidate for VRN-H3, a dominant mutation giving precocious flowering, while HvFT3 was a candidate for Ppd-H2, a major QTL affecting flowering time in short days.  相似文献   

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In higher plants, developmental phase changes are regulated by a complex gene network. Loss-of-function mutations in the EMBRYONIC FLOWER genes (EMF1 and EMF2) cause Arabidopsis to flower directly, bypassing vegetative shoot growth. This phenotype suggests that the EMF genes play a major role in repression of the reproductive program. Positional cloning of EMF2 revealed that it encodes a zinc finger protein similar to FERTILIZATION-INDEPENDENT SEED2 and VERNALIZATION2 of Arabidopsis. These genes are characterized as structural homologs of Suppressor of zeste 12 [Su(z)12], a novel Polycomb group gene currently identified in Drosophila. In situ hybridization studies have demonstrated that EMF2 RNA is found in developing embryos, in both the vegetative and the reproductive shoot meristems, and in lateral organ primordia. Transgenic suppression of EMF2 produced a spectrum of early-flowering phenotypes, including emf2 mutant-like phenotype. This result confirms the role of EMF2 in phase transitions by repressing reproductive development.  相似文献   

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In a screen for MADS box genes which activate and/or repress flowering in rice, we identified a gene encoding a MADS domain protein (OsSOC1) related to the Arabidopsis gene AtSOC1. AtSOC1 and OsSOC1 show a 97% amino acid similarity in their MADS domain. The rice gene contains a large first intron of 27.6 kb compared to the 1 kb intron in Arabidopsis. OsSOC1 is located on top of the short arm of chromosome 3, tightly linked to the heading date locus, Hd9. OsSOC1 is expressed in vegetative tissues, and expression is elevated at the time of floral initiation, 40-50 days after sowing, and remains uniformly high thereafter, similar to the expression pattern of AtSOC1. The constitutive expression of OsSOC1 in Arabidopsis results in early flowering, suggesting that the rice gene is a functional equivalent of AtSOC1. We were not able to identify FLC-like sequences in the rice genome; however, we show that ectopic expression of the Arabidopsis FLC delays flowering in rice, and the up-regulation of OsSOC1 at the onset of flowering initiation is delayed in the AtFLC transgenic lines. The reciprocal recognition and flowering time effects of genes introduced into either Arabidopsis or rice suggest that some components of the flowering pathways may be shared. This points to a potential application in the manipulation of flowering time in cereals using well characterized Arabidopsis genes.  相似文献   

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The diversity of plant architectural form is largely determined by the extent and duration of axillary meristem (AM) derived lateral growth. The orthologous basic helix-loop-helix (bHLH) proteins maize BARREN STALK1 (BA1) and rice LAX PANICLE1 (LAX1) are essential for the formation of AMs during vegetative development and all lateral structures during inflorescence development, but whether BA1/LAX1 co-orthologs exist outside of the grass family is unclear. Here, we present Bayesian phylogenetic evidence of a well-supported BA1/LAX1 clade comprised monocots and eudicots, estimating an origin for the lineage at least near the base of flowering plants. Genomic analyses in Arabidopsis, papaya, medicago, rice, sorghum, and maize indicate that BA1/LAX1 genes reside in syntenic regions, although there has also been a complex pattern of gene duplication and loss during the diversification of the angiosperm clade. BA1/LAX1 mRNA expression coincided with the initiation of leaves and associated AMs in the vegetative meristems of broccoli, medicago, and papaya implicating a role for the lineage in the formation of AMs in eudicots as well as monocots. Expression on the adaxial surface of lateral inflorescence structures was conserved in all sampled flowering plants, whereas mRNA expression in leaves of Arabidopsis, broccoli, and papaya also links BA1/LAX1 co-orthologs with roles in regulating leaf development, possibly as a downstream target of auxin regulating genes. Together these data point to roles for BA1/LAX1 genes during AM formation, leaf, and inflorescence development in diverse flowering plants and lend support to the hypothesis that the same genetic mechanisms regulate the development of different AM types.  相似文献   

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Park YD  Jang HS  Kim SY  Ko SK  Lyou YJ  Lee DY  Paik YK  Yang JM 《Proteomics》2006,6(4):1362-1370
Recently, we reported altered protein expression in primary cultured fibroblasts from atopic dermatitis (AD) patients. As a sequential study, we conducted proteomic analysis of primary keratinocytes derived from AD patients to further identify AD-related proteins. Three pH ranges, 4-7, 6-9, and 7-11, were used to profile the altered protein expression in AD. We obtained 46 candidate spots from the 2-D gel image analysis: 18 proteins were up-regulated and 27 proteins were down-regulated. Among the several important candidate proteins, NCC27 showed the same profile of a defect in PTM in both AD-derived keratinocytes and fibroblasts. On the basis of current and previous reports, real-time PCR was performed on select candidate genes to compare RNA and protein expression levels in AD-derived keratinocytes and fibroblasts. Our results provide new clues to aid in understanding the mechanism of atopic alterations in keratinocytes and suggest new AD-associated proteins that are important in AD pathogenesis.  相似文献   

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The genes controlling the timing of the transition from vegetative to reproductive growth are likely candidates for regulators of genes initiating floral development. We have investigated the interaction of one particular gene controlling flowering time, FCA, with the meristem identity-genes TERMINAL FLOWER 1 (TFL1), APETALA 1 (AP1) and LEAFY (LFY) and the floral repression gene EMBRYONIC FLOWER 1 (EMF1). Double mutant combinations were generated and the phenotypes characterized. The influence of strong and intermediate fca mutant alleles on the phenotype conferred by a 35S-LFY transgene was also analysed. The results support a model where FCA function promotes flowering in multiple pathways, one leading to activation of LFY and AP1, and another acting in parallel with LFY and AP1. Only the latter pathway is predicted to be non-functional in the intermediate fca-4 allele. The results are also consistent with AP1 and TFL1 negatively regulating FCA function. Combination of Columbia fca and emf1 mutant alleles confirmed that FCA is required for the early flowering of emf1. EMF1 and FCA are therefore likely to operate in different floral pathways.  相似文献   

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The seed maturation programme occurs only during the late phase of embryo development, and repression of the maturation genes is pivotal for seedling development. However, mechanisms that repress the expression of this programme in vegetative tissues are not well understood. A genetic screen was performed for mutants that express maturation genes in leaves. Here, it is shown that mutations affecting SDG8 (SET DOMAIN GROUP 8), a putative histone methyltransferase, cause ectopic expression of a subset of maturation genes in leaves. Further, to investigate the relationship between SDG8 and the Polycomb Group (PcG) proteins, which are known to repress many developmentally important genes including seed maturation genes, double mutants were made and formation of somatic embryos was observed on mutant seedlings with mutations in both SDG8 and EMF2 (EMBRYONIC FLOWER 2). Analysis of histone methylation status at the chromatin sites of a number of maturation loci revealed a synergistic effect of emf2 and sdg8 on the deposition of the active histone mark which is the trimethylation of Lys4 on histone 3 (H3K4me3). This is consistent with high expression of these genes and formation of somatic embryos in the emf2 sdg8 double mutants. Interestingly, a double mutant of sdg8 and vrn2 (vernalization2), a paralogue of EMF2, grew and developed normally to maturity. These observations demonstrate a functional cooperative interplay between SDG8 and an EMF2-containing PcG complex in maintaining vegetative cell identity by repressing seed genes to promote seedling development. The work also indicates the functional specificities of PcG complexes in Arabidopsis.  相似文献   

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The timing of flowering   总被引:2,自引:0,他引:2  
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To understand the genetic regulation of vegetative to reproductive transition in higher plants, further characterization of the Arabidopsis mutant embryonic flower1, emf1, was conducted. Using three flowering symptoms, we showed that emf1 mutants could only grow reproductive and not rosette shoots under five different growth conditions. The mutant embryos did not produce the typical tunica–corpus shoot apical structures at the heart-, torpedo-, and mature stages. The divergent shoot apical development during mutant and wild-type embryogenesis indicated that the wild-type EMF1 gene was expressed in early embryogenesis. Mutations in the EMF1 gene affected the embryonic shoot apical development and caused the germinating embryo and regenerating callus to grow inflorescence, instead of rosette, shoots. Our results support the hypothesis that the EMF1 gene regulates the switch between vegetative and reproductive growth in Arabidopsis.  相似文献   

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