scholarly journals Genetic control of branching pattern and floral identity during Petunia inflorescence development

Development ◽  
1998 ◽  
Vol 125 (4) ◽  
pp. 733-742 ◽  
Author(s):  
E. Souer ◽  
A. van der Krol ◽  
D. Kloos ◽  
C. Spelt ◽  
M. Bliek ◽  
...  
Keyword(s):  
In Situ Hybridisation ◽  
Floral Meristem ◽  
Branching Pattern ◽  
Inflorescence Meristem ◽  
Inflorescence Architecture ◽  
Phenotypic Analysis ◽  
Inflorescence Development ◽  
Meristem Identity ◽  
Floral Meristems

A main determinant of inflorescence architecture is the site where floral meristems are initiated. We show that in wild-type Petunia bifurcation of the inflorescence meristem yields two meristems of approximately equal size. One terminates into a floral meristem and the other maintains its inflorescence identity. By random transposon mutagenesis we have generated two mutants in which the architecture of the inflorescence is altered. In the extra petals- (exp) mutant the inflorescence terminates with the formation of a single terminal flower. Phenotypic analysis showed that exp is required for the bifurcation of inflorescence meristems. In contrast, the aberrant leaf and flower- (alf) mutant is affected in the specification of floral meristem identity while the branching pattern of the inflorescence remains unaltered. A weak alf allele was identified that, after bifurcation of the inflorescence meristem, yields a ‘floral’ meristem with partial inflorescence characteristics. By analysing independent transposon dTph1 insertion alleles we show that the alf locus encodes the Petunia FLORICAULA/LEAFY homolog. In situ hybridisation shows that alf is expressed in the floral meristem and also in the vegetative meristem. Differences and similarities between these Petunia mutants and mutations affecting inflorescence architecture in other species will be discussed.

scholarly journals The SINGLE FLOWER (SFL) gene encodes a MYB transcription factor that regulates the number of flowers produced by the inflorescence of chickpea

2020 ◽  
Author(s):  
Cristina Caballo ◽  
Ana Berbel ◽  
Raul Ortega ◽  
Juan Gil ◽  
Teresa Millán ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Myb Transcription Factor ◽  
Legume Species ◽  
Inflorescence Architecture ◽  
Key Points ◽  
Meristem Identity ◽  
Single Flower ◽  
Gene Regulatory ◽  
Floral Meristems

SUMMARYresearch conducted & rationaleLegume species usually have compound inflorescences, where flowers appear in secondary inflorescences (I2), at lateral positions of the primary inflorescence (I1), in contrast to simple inflorescences, as in Arabidopsis, where flowers are formed in the primary inflorescence stem. The number of flowers per I2, characteristic of each legume species, determines inflorescence diversity, and the number of pods produced, which can affect yield. Gene Regulatory Network that controls the activity of I2 meristems, and therefore the number of flowers per secondary inflorescence is mostly unknown, as well as how specific are factors controlling this trait and whether they share this function in other meristems.methodsChickpea produces one flower per I2 but single flower (sfl) mutants produce two (double-pod phenotype). By mapping the sfl-d mutation and identification and analysis of a second mutant allele we have isolated SFL. We used scanning electron microscopy to study the effect of sfl mutations on inflorescence ontogeny and in situ hybridization to study the expression of SFL and of meristem identity genes in the developing chickpea inflorescence.key resultWe show that the SFL gene corresponds to CaRAX1/2a, encoding a MYB transcription factor. Our results show that CaRAX1/2a / SFL is specifically expressed in the I2 meristem, possibly activated by CaVEGETATIVE1.main conclusion & key points for discussionOur findings reveal that SFL plays a central role in the control of chickpea inflorescence architecture, specifically acting in the I2 meristem to control the time length for which it is active, and therefore determining the number of floral meristems that it can produce.

The indeterminate floral apex1 gene regulates meristem determinacy and identity in the maize inflorescence

Development ◽  
2002 ◽  
Vol 129 (11) ◽  
pp. 2629-2638 ◽  
Author(s):  
Debbie Laudencia-Chingcuanco ◽  
Sarah Hake
Keyword(s):  
Double Mutant ◽  
Floral Meristem ◽  
Marker Genes ◽  
Integrated Process ◽  
Inflorescence Meristem ◽  
Mutant Analysis ◽  
Lateral Organs ◽  
Meristem Identity ◽  
Mutant Phenotypes ◽  
Floral Meristems

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.

The ULTRAPETALA gene controls shoot and floral meristem size in Arabidopsis

Development ◽  
2001 ◽  
Vol 128 (8) ◽  
pp. 1323-1333 ◽  
Author(s):  
J.C. Fletcher
Keyword(s):  
Signal Transduction Pathway ◽  
Floral Meristem ◽  
Transduction Pathway ◽  
Wild Type ◽  
Inflorescence Meristem ◽  
Genetic Studies ◽  
Meristem Cell ◽  
Meristem Size ◽  
Cell Accumulation ◽  
Floral Meristems

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.

scholarly journals PROLIFERATING INFLORESCENCE MERISTEM, a MADS-Box Gene That Regulates Floral Meristem Identity in Pea

2002 ◽  
Vol 129 (3) ◽  
pp. 1150-1159 ◽  
Author(s):  
Scott A. Taylor ◽  
Julie M.I. Hofer ◽  
Ian C. Murfet ◽  
John D. Sollinger ◽  
Susan R. Singer ◽  
...  
Keyword(s):  
Floral Meristem ◽  
Mads Box ◽  
Inflorescence Meristem ◽  
Floral Meristem Identity ◽  
Meristem Identity ◽  
Mads Box Gene

Growth temperature affects inflorescence architecture in Arabidopsis thaliana

Botany ◽  
2013 ◽  
Vol 91 (9) ◽  
pp. 642-651 ◽  
Author(s):  
Marlène Antoun ◽  
François Ouellet
Keyword(s):  
Arabidopsis Thaliana ◽  
Growth Temperature ◽  
Effect Of Temperature ◽  
Maximum Height ◽  
Temperature Dependent ◽  
Phenotypic Analysis ◽  
Inflorescence Development ◽  
Extensive Analysis ◽  
Adverse Environmental Conditions ◽  
Floral Meristems

Plants adjust their growth and development to ensure survival under adverse environmental conditions. Nonoptimal growth temperatures can have a major impact on biomass and crop yield. A detailed phenotypic analysis (number and length of rosette and cauline branches, flowers, and buds) in Arabidopsis thaliana revealed that growth temperatures below (12 and 17 °C) and above (27 and 32 °C) the control 22 °C affect branching and flowering. The elongation of internodes on the main stem and of primary branches at cauline leaves is reduced at lower temperatures and increased at higher temperatures. Similar results are observed in plants treated before or after bolting. Our data therefore indicate that plants that have transitioned to the reproductive stage before treatment are slightly less affected by temperature variations than plants that are in their vegetative stage. Our results also suggest that plants need to reach a maximum height (internodes length) before they begin forming floral meristems and that this “maximum height” is dependent on the growth temperature. Plants grown at 17 °C show a slightly reduced branching, while those at 27 °C show increased branching. This suggests that apical dominance is a temperature-dependent phenomenon. This is, to our knowledge, the first extensive analysis of the effect of temperature on Arabidopsis inflorescence development.

scholarly journals The CLV3 Homolog in Setaria viridis Selectively Controls Inflorescence Meristem Size

2021 ◽  
Vol 12 ◽  
Author(s):  
Chuanmei Zhu ◽  
Lei Liu ◽  
Olivia Crowell ◽  
Hui Zhao ◽  
Thomas P. Brutnell ◽  
...  
Keyword(s):  
Bioinformatic Analysis ◽  
Peptide Ligands ◽  
Setaria Viridis ◽  
Inflorescence Meristem ◽  
Inflorescence Development ◽  
Knock Out ◽  
Meristem Size ◽  
Cle Peptides ◽  
Vegetative Traits ◽  
Floral Meristems

The CLAVATA pathway controls meristem size during inflorescence development in both eudicots and grasses, and is initiated by peptide ligands encoded by CLV3/ESR-related (CLE) genes. While CLV3 controls all shoot meristems in Arabidopsis, evidence from cereal grasses indicates that different meristem types are regulated by different CLE peptides. The rice peptide FON2 primarily controls the size of the floral meristem, whereas the orthologous peptides CLE7 and CLE14 in maize have their most dramatic effects on inflorescence and branch meristems, hinting at diversification among CLE responses in the grasses. Setaria viridis is more closely related to maize than to rice, so can be used to test whether the maize CLE network can be generalized to all members of subfamily Panicoideae. We used CRISPR-Cas9 in S. viridis to knock out the SvFON2 gene, the closest homolog to CLV3 and FON2. Svfon2 mutants developed larger inflorescence meristems, as in maize, but had normal floral meristems, unlike Osfon2, suggesting a panicoid-specific CLE network. Vegetative traits such as plant height, tiller number and leaf number were not significantly different between mutant and wild type plants, but time to heading was shorter in the mutants. In situ hybridization showed strong expression of Svfon2 in the inflorescence and branch meristems, consistent with the mutant phenotype. Using bioinformatic analysis, we predicted the co-expression network of SvFON2 and its signaling components, which included genes known to control inflorescence architecture in maize as well as genes of unknown function. The similarity between SvFON2 function in Setaria and maize suggests that its developmental specialization in inflorescence meristem control may be shared among panicoid grasses.

Inflorescence development in two tomato species

2007 ◽  
Vol 85 (1) ◽  
pp. 111-118 ◽  
Author(s):  
N. Welty ◽  
C. Radovich ◽  
T. Meulia ◽  
E. van der Knaap
Keyword(s):  
Floral Development ◽  
Inflorescence Meristem ◽  
Inflorescence Architecture ◽  
Crop Species ◽  
Inflorescence Development ◽  
Solanum Lycopersicum L ◽  
Tomato Species ◽  
Flower And Fruit Development ◽  
Determinate Growth ◽  
Regular Manner

The inflorescence of tomato has been characterized as either a cyme or raceme. Cymose inflorescences are determinate, whereas racemose inflorescences are indeterminate. In this study, we addressed the discrepancy in inflorescence architecture by analyzing the morphology of a wild relative of tomato Solanum pimpinellifolium L. and four domesticated Solanum lycopersicum L. lines. Careful observation of developing inflorescences of both species showed a bifurcation of the meristem into a determinate floral and an indeterminate inflorescence meristem. Interestingly, higher fruit carpel number was associated with delayed floral development, which might give the impression of determinate growth in some of the lines. Nevertheless, our results demonstrated that tomato inflorescences are indeterminate in nature regardless of the line studied. Floral buds were formed concomitantly with the development of the inflorescence meristem and not on the flanks of the peduncle, a characteristic of racemose growth. Thus, tomato inflorescences should be classified as a cyme with the note that the inflorescence meristem does not terminate into a flower and, in fact, maintains indeterminacy. In addition, S. pimpinellifolium produced many more flowers in a highly regular manner when compared with the cultivated types. This demonstrated the usefulness of wild relatives of tomato as a tool to further understand flower and fruit development in this crop species.

scholarly journals EgLFY, the Eucalyptus grandis homolog of the Arabidopsis gene LEAFY is expressed in reproductive and vegetative tissues

2004 ◽  
Vol 16 (2) ◽  
pp. 105-114 ◽  
Author(s):  
Marcelo Carnier Dornelas ◽  
Weber A. Neves do Amaral ◽  
Adriana Pinheiro Martinelli Rodriguez
Keyword(s):  
Transgenic Arabidopsis ◽  
Eucalyptus Grandis ◽  
Floral Meristem ◽  
Flower Initiation ◽  
Coding Region ◽  
Vegetative Tissues ◽  
Adult Trees ◽  
Meristem Identity ◽  
Meristem Identity Gene

The EgLFY gene cloned from Eucalyptus grandis has sequence homology to the floral meristem identity gene LEAFY (LFY) from Arabidopsis and FLORICAULA (FLO) from Antirrhinum. EgLFY is preferentially expressed in the developing eucalypt floral organs in a pattern similar to that described previously for the Arabidopsis LFY. In situ hybridization experiments have shown that EgLFY is strongly expressed in the early floral meristem and then successively in the primordia of sepals, petals, stamens and carpels. It is also expressed in the leaf primordia of adult trees. The expression of the EgLFY coding region under control of the Arabidopsis LFY promoter could complement strong lfy mutations in transgenic Arabidopsis plants. These data suggest that EgLFY plays a similar role to LFY in flower development and that the basic mechanisms involved in flower initiation and development in Eucalyptus may be similar to those occurring in Arabidopsis.

Separation of shoot and floral identity in Arabidopsis

Development ◽  
1999 ◽  
Vol 126 (6) ◽  
pp. 1109-1120 ◽  
Author(s):  
O.J. Ratcliffe ◽  
D.J. Bradley ◽  
E.S. Coen
Keyword(s):  
Shoot Apex ◽  
Floral Meristem ◽  
Floral Meristem Identity ◽  
Terminal Flower ◽  
Terminal Flower 1 ◽  
Type Pattern ◽  
Meristem Identity ◽  
Floral Meristems ◽  
Arabidopsis Plant ◽  
Meristem Identity Gene

The overall morphology of an Arabidopsis plant depends on the behaviour of its meristems. Meristems derived from the shoot apex can develop into either shoots or flowers. The distinction between these alternative fates requires separation between the function of floral meristem identity genes and the function of an antagonistic group of genes, which includes TERMINAL FLOWER 1. We show that the activities of these genes are restricted to separate domains of the shoot apex by different mechanisms. Meristem identity genes, such as LEAFY, APETALA 1 and CAULIFLOWER, prevent TERMINAL FLOWER 1 transcription in floral meristems on the apex periphery. TERMINAL FLOWER 1, in turn, can inhibit the activity of meristem identity genes at the centre of the shoot apex in two ways; first by delaying their upregulation, and second, by preventing the meristem from responding to LEAFY or APETALA 1. We suggest that the wild-type pattern of TERMINAL FLOWER 1 and floral meristem identity gene expression depends on the relative timing of their upregulation.

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