Floral Transformation Research Articles

PHOTOLYASE/BLUE LIGHT RECEPTOR2 regulates chrysanthemum flowering by compensating for gibberellin perception.

The gibberellins (GAs) receptor GA INSENSITIVE DWARF1 (GID1) plays a central role in GA signal perception and transduction. The typical photoperiodic plant chrysanthemum (Chrysanthemum morifolium) only flowers when grown in short-day photoperiods. In addition, chrysanthemum flowering is also controlled by the aging pathway, but whether and how GAs participate in photoperiod- and age-dependent regulation of flowering remain unknown. Here, we demonstrate that photoperiod affects CmGID1B expression in response to GAs and developmental age. Moreover, we identified PHOTOLYASE/BLUE LIGHT RECEPTOR2, an atypical photocleavage synthase, as a CRYPTOCHROME-INTERACTING bHLH1 interactor with which it forms a complex in response to short days to activate CmGID1B transcription. Knocking down CmGID1B raised endogenous bioactive GA contents and GA signal perception, in turn modulating the expression of the aging-related genes MicroRNA156 and SQUAMOSA PROMOTER BINDING PROTEIN-LIKE3. We propose that exposure to short days accelerates the juvenile-to-adult transition by increasing endogenous GA contents and response to GAs, leading to entry into floral transformation.

Transcriptional Regulation of Female and Male Flower Bud Initiation and Development in Pecan (Carya illinoensis)

Pecan (Carya illinoensis) nuts are delicious and rich in unsaturated fatty acids, which are beneficial for human health. Their yield is closely related to several factors, such as the ratio of female and male flowers. We sampled and paraffin-sectioned female and male flower buds for one year and determined the stages of initial flower bud differentiation, floral primordium formation, and pistil and stamen primordium formation. We then performed transcriptome sequencing on these stages. Our data analysis suggested that FLOWERING LOCUS T (FT) and SUPPRESSOR OF OVEREXPRESSION OF CONSTANS 1 play a role in flower bud differentiation. J3 was highly expressed in the early stage of female flower buds and may play a role in regulating flower bud differentiation and flowering time. Genes such as NF-YA1 and STM were expressed during male flower bud development. NF-YA1 belongs to the NF-Y transcription factor family and may initiate downstream events leading to floral transformation. STM promoted the transformation of leaf buds to flower buds. AP2 may have been involved in the establishment of floral meristem characteristics and the determination of floral organ characteristics. Our results lay a foundation for the control and subsequent regulation of female and male flower bud differentiation and yield improvement.

Phenylethanoid glycosides in Xiaoer Chiqiao Qingre Granules and its metabolic transformation in vitro and in vivo

To clarify the metabolic transformation mechanism of phenylethanoid glycosides in Xiaoer Chiqiao Qingre Granules in vivo, this study extracted and separated the phenylethanoid glycosides in Xiaoer Chiqiao Qingre Granules. Based on UPLC-Q-TOF-MS/MS technology, the retention time and primary and secondary mass spectrometry information were analyzed by UNIFI software, and 11 phenylethanoid glycosides in Xiaoer Chiqiao Qingre Granules were preliminarily identified. Sixty-nine metabolites related to phenylethanoid glycosides were identified from the plasma samples of juvenile rats after administration of Xiaoer Chiqiao Qingre Granules. In addition, this study simulated the transformation system of intestinal flora in children, and discussed the metabolic effects of intestinal flora on the representative components forsythoside A, forsythoside E, and salidroside of phenylethanoid glycosides. The model of gastrointestinal heat retention in children with food accumulation was established to study the differential metabolites of phenylethanoid glycosides. Through the comparative analysis of the representative components absorbed in blood and the intestinal floral transformation products, it was found that the main metabolic pathways of phenylethanoid glycosides were dehydrogenation, oxidation, acetylation, sulfation, and glucuronidation. The findings of this study revealed the transformation law of phenylethanoid glycosides in the gastrointestinal tract. Through the preliminary discussion of the pharmacological mechanism, this study provides references for further clarifying the pharmacodynamic material basis of Xiaoer Chiqiao Qingre Granules and exploring the pediatric Chinese medicine compound.

Characterization and expression analysis of the SPL gene family during floral development and abiotic stress in pecan (Carya illinoinensis).

SQUAMOSA promoter binding protein-like (SPL) genes are a type of plant-specific transcription factors that play crucial roles in the regulation of phase transition, floral transformation, fruit development, and various stresses. Although SPLs have been characterized in several model species, no systematic analysis has been studied in pecans, an important woody oil tree species. In this study, a total of 32 SPL genes (CiSPLs) were identified in the pecan genome. After conducting phylogenetic analysis of the conserved SBP proteins from Arabidopsis, rice, and poplar, the CiSPLs were separated into eight subgroups. The CiSPL genes within the same subgroup contained very similar exon-intron structures and conserved motifs. Nine segmentally duplicated gene pairs in the pecan genome and 16 collinear gene pairs between the CiSPL and AtSPL genes were identified. Cis-element analysis showed that CiSPL genes may regulate plant meristem differentiation and seed development, participate in various biological processes, and respond to plant hormones and environmental stresses. Therefore, we focused our study on the expression profiles of CiSPL genes during flower and fruit development. Most of the CiSPL genes were predominantly expressed in buds and/or female flowers. Additionally, quantitative real time PCR (qRT-PCR) analyses confirmed that CiSPL genes showed distinct spatiotemporal expression patterns in response to drought and salt treatments. The study provides foundation for the further exploration of the function and evolution of SPL genes in pecan.

Agrobacterium-mediated In-planta transformation of bread wheat (Triticum aestivum L.)

Agrobacterium-mediated in-planta transformation method allows efficient plant transformation without tissue culture. In the present study, a tissue culture independent protocol for floral transformation in bread wheat was developed. Three bread wheat genotypes namely, HD 2967, HD 3086 and Bobwhite were used for floral transformation. At pre-anthesis stage, clipped florets were sprayed with inoculation medium containing Agrobacterium tumefaciens strain EHA 105 culture harboring binary vector pCAMBIA1301-p35S:hptII-p35S:gus and allowed to grow till maturity. Positive transformants were confirmed through antibiotic selection, PCR analysis and southern blotting. The method led to generation of transformation events in Bobwhite and HD 2967 wheat genotypes. The transformation efficiency of T1 transgenic plants was higher in Bobwhite as compared to HD 2967. Floral spray method of transformation developed in the present study is efficient for development of transgenic wheat and can be used for improvement of wheat using transgenic approach.

Genome-Wide Identification and Expression Analysis of MIKC-Type MADS-Box Gene Family in Punica granatum L.

MADS-box is a critical transcription factor regulating the development of floral organs and plays essential roles in the growth and development of floral transformation, flower meristem determination, the development of male and female gametophytes, and fruit development. In this study, 36 MIKC-type MADS-box genes were identified in the ‘Taishanhong’ pomegranate genome. By utilizing phylogenetic analysis, 36 genes were divided into 14 subfamilies. Bioinformatics methods were used to analyze the gene structure, conserved motifs, cis-acting elements, and the protein interaction networks of the MIKC-type MADS-box family members in pomegranate, and their expressions pattern in different tissues of pomegranate were analyzed. Tissue-specific expression analysis revealed that the E-class genes (PgMADS03, PgMADS21, and PgMADS27) were highly expressed in floral tissues, while PgMADS29 was not expressed in all tissues, indicating that the functions of the E-class genes were differentiated. PgMADS15 of the C/D-class was the key gene in the development network of pomegranate flower organs, suggesting that PgMADS15 might play an essential role in the peel and inner seed coat development of pomegranate. The results in this study will provide a reference for the classification, cloning, and functional research of pomegranate MADS-box genes.

Reproductive Strategy of Aegiceras corniculatum L. (Blanco.) - A Mangrove Species, in MNP&S, Gujarat, India

Mangroves occur in the tropical and subtropical inter-tidal regions of the world. Owing to their locations, they are expected to have a reproductive strategy which can facilitate generalized pollination. The present work has examined the floral biology, breeding system, pollinator resource and their efficiency, and the reproductive strategy of Aegiceras corniculatum L. (Blanco) at three islands (three populations) in Marine National Park and Sanstuary (MNP&S), Gulf of Kachchh, Gujarat, India. The temporal relations in the floral processes such as anther dehiscence, stigma receptivity and nectar secretion were studied and the results were juxtaposed to have comprehensive view. The floral life is very long (21 days) and the pace of floral transformation varies with the floral process. Significant diurnal variations in the stigma receptivity and nectar secretions influence the pollinators’ availability during different periods of the day. All the three breeding systems are present indicating occurrence of autogamy. However, strong protandry reduces its possibility to a significant level. Further, the asynchrony in the flowering processes at inflorescence level and the foraging behavior of pollinators increase the possibility of geitonogamy. The reproductive strategy of the plant is inclined towards cross pollination with keeping some possibility of self-pollination.

Analysis of the Impact of Climatic Conditions on Floral Transformation in Hydrangea macrophylla ‘Leuchtfeuer’

Hydrangea macrophylla is a horticultural plant of considerable commercial interest that has been widely studied with the aim to more effectively control the different stages of its development during production. However, although floral transformation is a key factor underlying the commercial quality of the product, it remains difficult to control despite these efforts. The floral transformation sequence consists of three successive phases: floral induction (B1), floral evocation (B2), and floral organogenesis (B3). The first is a phase of vegetative organogenesis without elongation leading to the formation of a bud composed of eight phytomer primordia under inductive climatic conditions. This work shows that climatic conditions favorable to floral transformation must be continuously applied without interruption throughout phase B1 to ensure the formation of the floral bud in Hydrangea macrophylla ‘Leuchtfeuer’. In the opposite case, floral transformation is stopped and vegetative growth begins once again.

The Sterol Methyltransferases SMT1, SMT2, and SMT3 Influence Arabidopsis Development through Nonbrassinosteroid Products

Plant sterols are structural components of cell membranes that provide rigidity, permeability, and regional identity to membranes. Sterols are also the precursors to the brassinosteroid signaling molecules. Evidence is accumulating that specific sterols have roles in pattern formation during development. COTYLEDON VASCULAR PATTERNING1 (CVP1) encodes C-24 STEROL METHYLTRANSFERASE2 (SMT2), one of three SMTs in Arabidopsis (Arabidopsis thaliana). SMT2 and SMT3, which also encodes a C-24 SMT, catalyze the reaction that distinguishes the synthesis of structural sterols from signaling brassinosteroid derivatives and are highly regulated. The deficiency of SMT2 in the cvp1 mutant results in moderate developmental defects, including aberrant cotyledon vein patterning, serrated floral organs, and reduced stature, but plants are viable, suggesting that SMT3 activity can substitute for the loss of SMT2. To test the distinct developmental roles of SMT2 and SMT3, we identified a transcript null smt3 mutant. Although smt3 single mutants appear wild type, cvp1 smt3 double mutants show enhanced defects relative to cvp1 mutants, such as discontinuous cotyledon vein pattern, and produce novel phenotypes, including defective root growth, loss of apical dominance, sterility, and homeotic floral transformations. These phenotypes are correlated with major alterations in the profiles of specific sterols but without significant alterations to brassinosteroid profiles. The alterations to sterol profiles in cvp1 mutants affect auxin response, demonstrated by weak auxin insensitivity, enhanced axr1 auxin resistance, ectopically expressed DR5:beta-glucuronidase in developing embryos, and defective response to auxin-inhibited PIN2-green fluorescent protein endocytosis. We discuss the developmental roles of sterols implied by these results.

Morphogenetic analysis of the phenotypic variability of the architectural unit of Hydrangea macrophylla

• Hydrangea macrophylla is a ligneous plant that has attracted the attention of many plant breeders and agronomists for the purpose of enhancing its phenotypic plasticity. However, this plasticity was always exploited empirically.• Can this plasticity be assessed by a more scientific approach? In this work, the phenotypic variation is analysed via a description of the different development sequences of the plant and by exposing the plant to different contrasted environments.• The architectural unit consists of two morphogenetic units: the Vegetative Unit (VU) and the Vegetative and Floral Unit (VFU). They result in four successive development sequences: an organogenetic phase accompanied by continuous growth (sequence A), floral transformation (sequence B), dormancy (sequence C) and flower bloom (sequence D). Under the effect of environmental factors, the formation of the mixed terminal bud (sequence B) provides a considerable source of spatial variability, whereas the absence or presence of dormancy (sequence C) is responsible for a source of temporal variation.• The in-depth description of the architectural unit with its morphological components and the characterisation of the four development sequences provide a necessary scientific basis to identify environmental effects on plant development and for the integrated use of its plasticity.

Evidence for stable transformation of wheat by floral dip in Agrobacterium tumefaciens

Hexaploid wheat, one of the world’s most important staple crops, remains a challenge for genetic transformation. We are developing a floral transformation protocol for wheat that does not require tissue culture. This paper presents three transformants in the hard red germplasm line Crocus that have been characterized thoroughly at the molecular level over three to six generations. Wheat spikes at the early boot stage, i.e. the early, mid or late uninucleate microspore stages, were immersed in an infiltration medium of strain C58C1 harboring pDs(Hyg)35S, or strain AGL1 harboring pBECKSred. pDs(Hyg)35S contains the NPTII and hph selectable markers, and transformants were detected using paromomycin spray at the whole plant level, NPTII ELISAs, or selection on medium with hygromycin. Strain AGL1, harboring pBECKSred, which contains the maize anthocyanin regulators, Lc and C1, and the NPTII gene, was also used to produce a Crocus transformant. T1 and T2 seeds with red embryos were selected; T1 and T2 plants were screened by sequential tests for paromomycin resistance and NPTII ELISAs. The transformants were low copy number and showed Mendelian segregation in the T2. Stable transmission of the transgenes over several generations has been demonstrated using Southern analysis. Gene expression in advanced progeny was shown using Reverse Transcriptase-PCR and ELISA assays for NPTII protein expression. This protocol has the potential to reduce the time and expense required for wheat transformation.Electronic supplementary materialThe online version of this article (doi:10.1007/s00299-009-0696-0) contains supplementary material, which is available to authorized users.

In Silico and Deletion Analysis of Upstream Promoter Fragment of S-Adenosyl Homocysteine Hydrolase (SAHH1) Gene of Arabidopsis Leads to the Identification of a Fragment Capable of Driving Gene Expression in Developing Seeds and Anthers

S-adenosyl homocysteine hydrolase (SAHH) is a key enzyme in methylation metabolism of eukaryotes. A 1585 by fragment upstream to ATG of SAHH1 gene, was fused with a promoter-less β-Glucuronidase (GUS) gene and mobilized into Arabidopsis by Agrobacterium-mediated floral transformation to generate transgenic Arabidopsis. This fragment was found to drive constitutive expression of GUS in T2 progeny of transgenic Arabidopsis. In silico analysis of the promoter region of SAHH1 suggested the presence of several cis-regulatory motifs including seed-specific motifs as well as anther-specific motifs in the 376 by (upstream to TSS of SAHH1) promoter fragment. Based on the partial deletion analysis carried out in the promoter region of SAHH1 (At4gl3940) this 376 by promoter fragment was found to be capable of driving GUS expression in developing seeds and in some anthers/micros pores.

An Evolutionary Basis for Pollination Ecology

In the introduction and chapter 2 the incentives and way of reasoning are given for the description of an evolutionary basis of pollination ecology. Starting from the until recently rather anecdotical character of the study of pollination ecology as a whole, and in the absence of large-scale correlations of flowerecologically important character states with angiosperm and insect phylogeny (in the sense of Hennig, 1966), an attempt is made to derive directed evolutionary lines (transformation series) of floral character states. Because the fossil record of flowers is very restricted and the study of angiosperm phylogeny in the sense of Hennig (1966) is only at its very beginning, the only possibilities to achieve this, can be based on the comparatively well-known fossil history of insects and insect phylogeny, the least anecdotically compiled survey of insect visits to flowers, whether resulting in pollination or not, by Knuth (1898a and 1899) as far as it concerns the central European area (most thoroughly known area concerning insect fauna and angiosperm flora), and the fossil record of extant angiosperm taxa. The insect visits to flowers are correlated with the pollination-ecologically important floral character states as they are found in Hegi (1906-1931; 1963, etc.; 1966, etc.) and Knuth (1898a and 1899) by statistical analyses on an extensive data base. These analyses, based on a geographically restricted area, are correlated with the evolution of insect-feeding (and corresponding morphology) based on insect phylogeny and fossil record. These correlations require two presuppositions: “horizontal” uniformitarianism (Recent insect behaviour and physiology in taxa of lower rank are supposed to be rather constant over the world); and ”vertical” uniformitarianism (as it is used in historical geology). The results of these correlations form a series of functionally and stratigraphically/phylogenetically directed floral transformation series, dated by the fossil record of insects. The transformation series are compared w

Assessment of an apparent relationship between availability of soluble carbohydrates and reduced nitrogen during floral initiation in tobacco.

Daily relative accumulation rate of soluble carbohydrates (RARS) and reduced nitrogen (RARN) in the shoot, as estimates of source strength, were compared with daily relative growth rates (RGR) of the shoot, as an estimate of sink demand, during floral transformation in apical meristems of tobacco (Nicotiana tabacum 'NC 2326') grown at day/night temperatures of 18/14, 22/18, 26/22, 30/26, and 34/30 C. Source strength was assumed to exceed sink demand for either carbohydrates or nitrogen when the ratio of RARS/RGR or RARN/RGR was greater than unity, and sink demand was assumed to exceed source strength when the ratio was less than unity. Time of floral initiation, which was delayed up to 21 days with increases in temperature over the experimental range, was associated with intervals in which source strength of either carbohydrate or nitrogen exceeded sink demand, while sink demand for the other exceeded source strength. Floral initiation was not observed during intervals in which source strengths of both carbohydrates and nitrogen were greater than or less than sink demand. These results indicate that floral initiation is responsive to an imbalance in the relative availabilities of carbohydrate and nitrogen.

Plant evolution dances to a different beat

Land plants have origination rates comparable to those of some animal groups, but the driving forces for evolution of plants differ. Floral transformations have been due to gradual replacement and piecemeal, not mass extinction. Plant “geoevents”; have not been synchronous with epochal animal originations/ extinctions and hence may not be attributable to the same causes. Initiation of new plant forms probably results primarily from intrinsic genetic factors. Plant taxa are much less subject to extrinsic factors than are comparable animal groups. Plants evolve related forms adapted to very different environments; hybridity and polyploidy produce variants with different qualities in some organs. Mosaic evolution is thus characteristic of plants. Heterochrony has probably permitted rapid shifts in timing of ontogeny to produce new life‐forms. Vegetative reproduction and persistence, indeterminate growth, potential long dormancy of propagules, comparative freedom from demands of population size, and comparati...

Induced floral transformations in barley

Five types of floral transformations, viz. four carpels, five stamens, two stamens, leafy floret and grooved ovary with one stamen transformed to rudimentary ovary fitting in the groove, vs. the normal with three stamens, one carpel and two lodicules, were induced in N 164 barley and each was controlled by a single recessive gene designated as mo, fs, lf and go, respectively. These transformations imply an interpretation of both phylogeny and ontogeny of flower. Also, these may become of great interest in understanding the process of differentiation.

Floral Initiation, Development, and Associated Phenomena of Dianthus caryophyllus L. Part I - Effect of Photoperiod1

Abstract Dianthus caryophyllus L., a quantitative long day plant, was used for studies of the effect of photoperiod on the different stages of plant development. The anatomical structure of the vegetative shoot apex and the changes during floral transformation are described. These stages were not affected by the various photoperiod lengths, i.e., 9, 13, and 18 hr. The developmental cycle of D. caryophyllus may be divided into 3 stages: vegetative, floral initiation, and floral development. The influence of photoperiod on the duration of each of the 3 stages was different. The length of the vegetative stage was inversely related to the length of the photoperiod (the longer the photoperiod, the shorter the vegetative stage). Daylength had no effect on the period of floral initiation, but did affect the period of floral development (i.e., the longer the photoperiod, the longer the developmental stage). The rate of stem elongation under all treatments increased exponentially until the floral initiation state, and then the plants grown under photoperiods of 13 hr or longer elongated significantly faster than those under the 9-hr photoperiod. After flower initiation was completed, the rate of stem elongation suddenly increased linearly until the flower opened. In contrast to the vegetative shoot, the rate of stem elongation of flowering plants was completely independent of photoperiod, and the rate was the same in the 9, 13, and 18 hr photoperiods.