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N. Mimida J. Li C. Zhang S. Moriya Y. Moriya-Tanaka H. Iwanami C. Honda H. Oshino K. Takagishi A. Suzuki S. Komori M. Wada 《Biologia Plantarum》2012,56(3):465-472
Rosaceae is a large family, however, our understanding of its phylogeny is based largely on morphological observations. To understand the relationship between subfamilies Rosoideae, Amygdaloideae, Maloideae and Spiraeoideae at a molecular level, we isolated and compared the plant phosphatidyl ethanolamine-binding protein-like genes TERMINAL FLOWER1 (TFL1)-like and CENTRORADIALIS (CEN)-like, which are involved in the control of shoot meristem identity and flowering time. A comparison of gene structures and phylogenetic tree analyses by the Neighbor-Joining method showed that each of the two TFL1-like (MdTFL1-1 and MdTFL1-2) and CEN-like genes (MdCENa and MdCENb) in Maloideae were classified into two distinct clades. The TFL1-like and CEN-like genes of Gillenia in Spiraeoideae belonged to monophyletic Maloideae groups, suggesting that Gillenia and Maloideae have a common near ancestor. However, the Gillenia TFL1-like gene does not contain the insertion sequence of the third intron that is found in MdTFL1-2-like genes of the members of Maloideae such as apple, Korean whitebeam, quince, and Siberian mountain ash. Therefore, after the Maloideae ancestor genome became polyploid through hybridization between Gillenia-like species or genome doubling, an insertion sequence of the third intron of MdTFL1-2-like genes was generated. 相似文献
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The architecture of a flower is tightly linked to the way a plant pollinates, making it one of the most physiologically and
ecologically important traits of angiosperms. Floral organ development is proposed to be governed by the activity of three
different classes of organ identity genes (the ABC model), and the expression of those genes are regulated by a number of
meristem identity genes. Here we use a transgenetic strategy to elucidate the role of one floral meristem identify gene,LEAFY (LFY), in the evolution of floral organogenesis of a self pollinatorIdahoa scapigera and a obligatory out-crosserLeavenworthia crassa in the mustard family, Brassicaceae. By introducing theLFY genes from these two types of pollination habit into the genetic model speciesArabidopsis thaliana, we provide evidence that changes inLFY influenced flower architecture probably by controlling the downstream organ identity genes. 相似文献
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Meristems may be determinate or indeterminate. In maize, the indeterminate inflorescence meristem produces three types of determinate meristems: spikelet pair, spikelet and floral meristems. These meristems are defined by their position and their products. We have discovered a gene in maize, indeterminate floral apex1 (ifa1) that regulates meristem determinacy. The defect found in ifa1 mutants is specific to meristems and does not affect lateral organs. In ifa1 mutants, the determinate meristems become less determinate. The spikelet pair meristem initiates more than a pair of spikelets and the spikelet meristem initiates more than the normal two flowers. The floral meristem initiates all organs correctly, but the ovule primordium, the terminal product of the floral meristem, enlarges and proliferates, expressing both meristem and ovule marker genes. A role for ifa1 in meristem identity in addition to meristem determinacy was revealed by double mutant analysis. In zea agamous1 (zag1) ifa1 double mutants, the female floral meristem converts to a branch meristem whereas the male floral meristem converts to a spikelet meristem. In indeterminate spikelet1 (ids1) ifa1 double mutants, female spikelet meristems convert to branch meristems and male spikelet meristems convert to spikelet pair meristems. The double mutant phenotypes suggest that the specification of meristems in the maize inflorescence involves distinct steps in an integrated process. 相似文献
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S J Liljegren C Gustafson-Brown A Pinyopich G S Ditta M F Yanofsky 《The Plant cell》1999,11(6):1007-1018
Upon floral induction, the primary shoot meristem of an Arabidopsis plant begins to produce flower meristems rather than leaf primordia on its flanks. Assignment of floral fate to lateral meristems is primarily due to the cooperative activity of the flower meristem identity genes LEAFY (LFY), APETALA1 (AP1), and CAULIFLOWER. We present evidence here that AP1 expression in lateral meristems is activated by at least two independent pathways, one of which is regulated by LFY. In lfy mutants, the onset of AP1 expression is delayed, indicating that LFY is formally a positive regulator of AP1. We have found that AP1, in turn, can positively regulate LFY, because LFY is expressed prematurely in the converted floral meristems of plants constitutively expressing AP1. Shoot meristems maintain an identity distinct from that of flower meristems, in part through the action of genes such as TERMINAL FLOWER1 (TFL1), which bars AP1 and LFY expression from the influorescence shoot meristem. We show here that this negative regulation can be mutual because TFL1 expression is downregulated in plants constitutively expressing AP1. Therefore, the normally sharp phase transition between the production of leaves with associated shoots and formation of the flowers, which occurs upon floral induction, is promoted by positive feedback interactions between LFY and AP1, together with negative interactions of these two genes with TFL1. 相似文献
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The SEP4 gene of Arabidopsis thaliana functions in floral organ and meristem identity 总被引:19,自引:0,他引:19
The ABC model of flower organ identity is widely recognized as providing a framework for understanding the specification of flower organs in diverse plant species. Recent studies in Arabidopsis thaliana have shown that three closely related MADS-box genes, SEPALLATA1 (SEP1), SEP2 and SEP3, are required to specify petals, stamens, and carpels because these organs are converted into sepals in sep1 sep2 sep3 triple mutants. Additional studies indicate that the SEP proteins form multimeric complexes with the products of the B and C organ identity genes. Here, we characterize the SEP4 gene, which shares extensive sequence similarity to and an overlapping expression pattern with the other SEP genes. Although sep4 single mutants display a phenotype similar to that of wild-type plants, we find that floral organs are converted into leaf-like organs in sep1 sep2 sep3 sep4 quadruple mutants, indicating the involvement of all four SEP genes in the development of sepals. We also find that SEP4 contributes to the development of petals, stamens, and carpels in addition to sepals and that it plays an important role in meristem identity. These and other data demonstrate that the SEP genes play central roles in flower meristem identity and organ identity. 相似文献
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Taylor SA Hofer JM Murfet IC Sollinger JD Singer SR Knox MR Ellis TH 《Plant physiology》2002,129(3):1150-1159
SQUAMOSA and APETALA1 are floral meristem identity genes from snapdragon (Antirrhinum majus) and Arabidopsis, respectively. Here, we characterize the floral meristem identity mutation proliferating inflorescence meristem (pim) from pea (Pisum sativum) and show that it corresponds to a defect in the PEAM4 gene, a homolog of SQUAMOSA and APETALA1. The PEAM4 coding region was deleted in the pim-1 allele, and this deletion cosegregated with the pim-1 mutant phenotype. The pim-2 allele carried a nucleotide substitution at a predicted 5' splice site that resulted in mis-splicing of pim-2 mRNA. PCR products corresponding to unspliced and exon-skipped mRNA species were observed. The pim-1 and pim-2 mutations delayed floral meristem specification and altered floral morphology significantly but had no observable effect on vegetative development. These floral-specific mutant phenotypes and the restriction of PIM gene expression to flowers contrast with other known floral meristem genes in pea that additionally affect vegetative development. The identification of PIM provides an opportunity to compare pathways to flowering in species with different inflorescence architectures. 相似文献
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Background and Aims
The family of MADS box genes is involved in a number of processes besides controlling floral development. In addition to supplying homeotic functions defined by the ABC model, they influence flowering time and transformation of vegetative meristem into inflorescence meristem, and have functions in roots and leaves. Three Gerbera hybrida At-SOC1-like genes (Gh-SOC1–Gh-SOC3) were identified among gerbera expressed sequence tags.Methods
Evolutionary relationships between SOC1-like genes from gerbera and other plants were studied by phylogenetic analysis. The function of the gerbera gene Gh-SOC1 in gerbera floral development was studied using expression analysis, protein–protein interaction assays and reverse genetics. Transgenic gerbera lines over-expressing or downregulated for Gh-SOC1 were obtained using Agrobacterium transformation and investigated for their floral phenotype.Key Results
Phylogenetic analysis revealed that the closest paralogues of At-SOC1 are Gh-SOC2 and Gh-SOC3. Gh-SOC1 is a more distantly related paralogue, grouping together with a number of other At-SOC1 paralogues from arabidopsis and other plant species. Gh-SOC1 is inflorescence abundant and no expression was seen in vegetative parts of the plant. Ectopic expression of Gh-SOC1 did not promote flowering, but disturbed the development of floral organs. The epidermal cells of ray flower petals appeared shorter and their shape was altered. The colour of ray flower petals differed from that of the wild-type petals by being darker red on the adaxial side and greenish on the abaxial surface. Several protein–protein interactions with other gerbera MADS domain proteins were identified.Conclusions
The At-SOC1 paralogue in gerbera shows a floral abundant expression pattern. A late petal expression might indicate a role in the final stages of flower development. Over-expression of Gh-SOC1 led to partial loss of floral identity, but did not affect flowering time. Lines where Gh-SOC1 was downregulated did not show a phenotype. Several gerbera MADS domain proteins interacted with Gh-SOC1. 相似文献12.
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Arabidopsis thaliana (L.) Heynh. has been used as a model system to investigate the regulatory genes that control and coordinate the determination, differentiation and morphogenesis of the floral meristem and floral organs. We show here that benzylaminopurine (BAP), a cytokinin, influences flower development inArabidopsis and induces partial phenocopies of known floral homeotic mutants. Application of BAP to wild-type inflorescences at three developmental stages results in: (i) increase in floral organ number; (ii) formation of abnormal floral organs and (iii) induction of secondary floral buds in the axils of sepals. These abnormalities resemble the phenotypes of mutants,clv1 (increase in organ number),ap1,ap2,ap3 (abnormal floral organs) andap1 (secondary floral buds in the axils of first-whorl organs). In addition, BAP induces secondary floral buds in the axils of perianth members ofapt2-6, ap3-1 andag mutants, and accentuates the phenotype of theapt2-1 mutant to resemble theapt2-6 mutant. These observations suggest that exogenous BAP suppresses the normal functioning of the genes for floral meristem identity and thereby affects flower development and the later stages of floral organ differentiation.Abbreviations BAP
N6-benzylaminopurine
- CK
cytokinin 相似文献
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Fletcher JC 《Development (Cambridge, England)》2001,128(8):1323-1333
The regulation of proper shoot and floral meristem size during plant development is mediated by a complex interaction of stem cell promoting and restricting factors. The phenotypic effects of mutations in the ULTRAPETALA gene, which is required to control shoot and floral meristem cell accumulation in Arabidopsis thaliana, are described. ultrapetala flowers contain more floral organs and whorls than wild-type plants, phenotypes that correlate with an increase in floral meristem size preceding organ initiation. ultrapetala plants also produce more floral meristems than wild-type plants, correlating with an increase in inflorescence meristem size without visible fasciation. Expression analysis indicates that ULTRAPETALA controls meristem cell accumulation partly by limiting the domain of CLAVATA1 expression. Genetic studies show that ULTRAPETALA acts independently of ERA1, but has overlapping functions with PERIANTHIA and the CLAVATA signal transduction pathway in controlling shoot and floral meristem size and meristem determinacy. Thus ULTRAPETALA defines a novel locus that restricts meristem cell accumulation in Arabidopsis shoot and floral meristems. 相似文献
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Floral transition should be strictly regulated because it is one of the most critical developmental processes in plants. Arabidopsis terminal flower 2 (tfl2) mutants show an early-flowering phenotype that is relatively insensitive to photoperiod, as well as several other pleiotropic phenotypes. We found that the early flowering of tfl2 is caused mainly by ectopic expression of the FLOWERING LOCUS T (FT) gene, a floral pathway integrator. Molecular cloning of TFL2 showed that it encodes a protein with homology to heterochromatin protein 1 (HP1) of animals and Swi6 of fission yeast. TFL2 protein localizes in subnuclear foci and expression of the TFL2 gene complemented yeast swi6(-) mutants. These results suggested that TFL2 might function as an HP1 in Arabidopsis: Gene expression analyses using DNA microarrays, however, did not show an increase in the expression of heterochromatin genes in tfl2 mutants but instead showed the upregulation of the floral homeotic genes APETALA3, PISTILLATA, AGAMOUS and SEPALLATA3. The pleiotropic phenotype of the tfl2 mutant could reflect the fact that TFL2 represses the expression of multiple genes. Our results demonstrate that despite its homology to HP1, TFL2 is involved in the repression of specific euchromatin genes and not heterochromatin genes in Arabidopsis. 相似文献
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A sucrose: sucrose 1-fructosyltransferase (1-SST) gene and cDNA (Lp 1-SST) from perennial ryegrass (Lolium perenne) were isolated. The Lp 1-SST gene was fully sequenced and shown to contain three exons and two introns. Nucleotide sequence analysis of the 4824 bp Lp 1-SST genomic sequence revealed 1618 bp of 5' UTR and an open reading frame of 1962 bp encoding a protein of 653 amino acids. Lp 1-SST is 95% identical to the tall fescue 1-SST and contains plant fructosyltransferase functional domains. Lp 1-SST corresponds to a single copy gene in perennial ryegrass, and is expressed in young leaf bases and mature leaf sheaths. The recombinant Lp 1-SST protein from corresponding cDNA expression in Pichia pastoris showed 1-SST activity. 相似文献
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Separation of AG function in floral meristem determinacy from that in reproductive organ identity by expressing antisense AG RNA 总被引:15,自引:0,他引:15
The Arabidopsis floral homeotic gene AGAMOUS (AG) is a regulator of early flower development. The ag mutant phenotypes suggest that AG has two functions in flower development: (1) specifying the identity of stamens and carpels, and (2) controlling floral meristem determinacy. To dissect these two AG functions, we have generated transgenic Arabidopsis plants carrying an antisense AG construct. We found that all of the transgenic plants produced abnormal flowers, which can be classified into three types. Type I transgenic flowers are phenocopies of the ag-1 mutant flowers, with both floral meristem indeterminacy and floral organ conversion; type II flowers are indeterminate and have partial conversion of the reproductive organs; and type III flowers have normal stamens and carpels, but still have an indeterminate floral meristem inside the fourth whorl of fused carpels. The existence of type III flowers indicates that AG function can be perturbed to affect only floral meristem determinacy, but not floral organ identity. Furthermore, the fact that floral meristem determinacy is affected in all transformants, but floral organ identity only in a subset of them, suggests that the former may required a higher level of AG activity than the latter. This hypothesis is supported by the levels of AG'mRNA detected in different transformants with different frequencies of distinct types of abnormal antisense AG transgenic flowers. Finally, since AG inhibits the expression of another floral regulatory gene AP1, we examined AP1 expression in antisense AG flowers, and found that AP1 is expressed at a relatively high level in the center of type II flowers, but very little or below detectable levels in the inner whorls of type III flowers. These results provide further insights into the interaction of AG and AP1 and how such an interaction may control both organ identity and floral meristem determinacy. 相似文献