DOCSLIB.ORG

Dual Role of Tree Florigen Activation Complex Component FD in Photoperiodic Growth Control and Adaptive Response Pathways

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Dual Role of Tree Florigen Activation Complex Component FD in Photoperiodic Growth Control and Adaptive Response Pathways Dual role of tree florigen activation complex component FD in photoperiodic growth control and adaptive response pathways Szymon Tylewicza,1, Hiroyuki Tsujib,1, Pál Miskolczia,1, Anna Petterlea, Abdul Azeeza, Kristoffer Jonssona, Ko Shimamotob,2, and Rishikesh P. Bhaleraoa,c,3 aUmea Plant Science Center, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, S-901 87 Umea, Sweden; bLaboratory of Plant Molecular Genetics, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192, Japan; and cCollege of Science, King Saud University, Riyadh 11362, Saudi Arabia Edited by Ronald R. Sederoff, North Carolina State University, Raleigh, NC, and approved January 27, 2015 (received for review December 9, 2014) A complex consisting of evolutionarily conserved FD, FLOWERING functionality. However, the mechanisms underlying the functional LOCUS T (FT) proteins is a regulator of floral transition. Intriguingly, diversity of the FT complexes and how they can participate in the FT orthologs are also implicated in developmental transitions dis- control of developmental pathways distinct from flowering are not tinct from flowering, such as photoperiodic control of bulbing in well understood because, in contrast to FT, FD or BRC1 (or other onions, potato tuberization, and growth cessation in trees. How- interactors of FT), which provide DNA binding ability to the ever, whether an FT–FD complex participates in these transitions complexes of FT and thus are crucial for the function of these and, if so, its mode of action, are unknown. We identified two complexes, have not been well characterized in pathways distinct closely related FD homologs, FD-like 1 (FDL1)andFD-like 2 (FDL2), from flowering. Thus, the role of complexes of FT and their mode in the model tree hybrid aspen. Using gain of function and RNAi- of action in these pathways remain poorly understood. suppressed FDL1 and FDL2 transgenic plants, we show that FDL1 Cessation of growth before the onset of winter is essential for and FDL2 have distinct functions and a complex consisting of FT and the survival of trees growing in temperate and boreal forests FDL1 mediates in photoperiodic control of seasonal growth. The during subsequent periods of low temperatures (12, 13). Growth downstream target of the FT–FD complex in photoperiodic control cessation is a photoperiodically controlled process (14, 15). In PLANT BIOLOGY “short days” (SDs), when day length falls below the critical of growth is Like AP1 (LAP1), a tree ortholog of the floral meristem threshold allowing growth, elongation growth ceases (14–16). identity gene APETALA1. Intriguingly, FDL1 also participates in the Moreover, the lamina of the last leaf primordia formed before transcriptional control of adaptive response and bud maturation the perception of SDs is aborted, and its stipules develop into pathways, independent of its interaction with FT, presumably via bud scales that enclose the embryonic leaves inside a bud at the interaction with ABSCISIC ACID INSENSITIVE 3 (ABI3) transcription apex (17). Thus, bud set results in termination of the emergence factor, a component of abscisic acid (ABA) signaling. Our data reveal of new leaves. SDs also concomitantly induce transcriptional FD that in contrast to its primary role in flowering, has dual roles in changes resulting in the so-called “adaptive response,” a meta- the photoperiodic control of seasonal growth and stress tolerance in bolic shift toward the accumulation of vegetative proteins and trees. Thus, the functions of FT and FD have diversified during evo- acquisition of cold hardiness that protect the shoot apical mer- lution, and FD homologs have acquired roles that are independent istem and embryonic leaves (18). of their interaction with FT. Significance growth cessation | bud set | seasonal growth | adaptive response | hybrid aspen Perennial plants display seasonal cycles of growth. For exam- ple, in the trees of boreal temperate forests, growth must he evolutionarily conserved protein FLOWERING LOCUS cease prior to the advent of winter and cold hardiness must be TT (FT) plays a key role in the control of flowering in plants acquired to survive extreme low temperature. Growth cessa- (1). Because FT lacks DNA binding activity, its interaction with tion and activation of transcriptional programs underlying – transcription factors, such as FD (2 4) and more recently iden- adaptive responses associated with cold hardiness are photo- tified BRANCHED1 (BRC1) (5), is critical for the formation of periodically controlled. We show that the evolutionarily con- protein complexes to control flowering via transcriptional con- served protein FD implicated in the control of flowering trol of downstream targets [e.g., floral meristem identity genes, mediates photoperiodic control of seasonal growth in trees by transcription factors APETALA1 (AP1)andOsMADS1]. Whereas forming a complex with FLOWERING LOCUS T (FT) protein. FD the FT–FD complex promotes flowering at the shoot apical genes of hybrid aspen display neofunctionalization and, in meristem (4), BRC1 appears to delay floral transition at the ax- contrast to Arabidopsis, have evolved functions that are in- illary meristem (5). These findings indicate that depending upon dependent of their interaction with FT, such as transcriptional its interaction partner, FT-containing complexes can have dis- control of the adaptive response and bud maturation path- tinct roles. The structure of FT–FD complex elucidated in rice ways in trees. has shown that a 14-3-3 protein mediates the interaction between rice FT homolog HEADING DATE 3a (Hd3a) and FD homolog Author contributions: K.S. and R.P.B. designed research; S.T., H.T., P.M., A.P., A.A., and K.J. OsFD1 via the C-terminally located SAP (serine alanine proline) performed research; S.T., H.T., P.M., A.P., A.A., K.J., K.S., and R.P.B. analyzed data; and S.T. and R.P.B. wrote the paper. motif in OsFD1 to generate the active nuclear localized florigen activation complex (3). The authors declare no conflict of interest. Interestingly, FT homologs are also involved in the control of This article is a PNAS Direct Submission. diverse developmental transitions distinct from flowering, such as 1S.T., H.T., and P.M. contributed equally to this work. tuberization in potatoes (6), bulb formation in onions (7), stomatal 2Deceased September 28, 2013. opening (8), and photoperiodic control of seasonal growth in trees 3To whom correspondence should be addressed. Email: [email protected]. – (9 11). These observations suggest that complexes of FT are not This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10. only important to the control of flowering but have a broader 1073/pnas.1423440112/-/DCSupplemental. www.pnas.org/cgi/doi/10.1073/pnas.1423440112 PNAS Early Edition | 1of6 Downloaded by guest on September 25, 2021 Several studies have shown that the tree ortholog of Arabidopsis FT plays an important role in photoperiodic control of growth cessation (9–11). For example, down-regulation of FT2 expres- sion by SDs is a key early event in the induction of growth ces- sation (9). Importantly, functional studies have shown that overexpression of FT2 or its paralog FT1 in hybrid aspen (P. tremula × tremuloides) attenuates SD responses and abolishes growth cessation, whereas suppression of FT expression leads to earlier growth cessation than in WT plants (9–11). The MADS box transcription factor LAP1 (Like-APETALA1), a tree homolog of AP1, has been recently identified as a target of SDs down- stream of FT (19). Like FT, LAP1 overexpression delays SD- mediated growth cessation, whereas its down-regulation causes early growth cessation in SDs (19). These findings clearly dem- onstrate that as in flowering, FT plays a central role in photope- riodic control of seasonal growth in trees. In addition to FT, FD is a key component of the FT–FD complex, given its role in selection of downstream targets by the FT–FD complex. However, in contrast to FT, there are few studies addressing the role of FD other than in flowering (8, 20). Therefore, to improve understanding of the photoperiodic con- trol of seasonal growth, we initiated analysis of FD homologs in the model tree hybrid aspen. Functional analyses in hybrid aspen of the two closely related FD homologs FD-like 1 (FDL1)and A D FD-like 1 (FDL2) show that they have distinct roles. We show that Fig. 1. Bud formation in WT and FDL1oe (lines 3A and 5A) plants. , ,and G represent plants growing in long days (LD). WT plants had ceased growth FDL1 interacts with FT2 to form a complex that mediates in pho- B C E H toperiodic control of seasonal growth. Most previously published and developed buds ( and ), but the FDL1oe plants had not ( and ). – (F and I) FDL1oe plants set buds after 10 wk (W) of SDs. Arrows indicate data suggest that FD functions primarily in a complex with FT (2 4, apical buds. 20). However, we show that FDL1 has additional roles in trees, inde- pendent of its interaction with FT. Thus, the function of the FT–FD complex has diversified during evolution, and FD homologs have stems from differences in their ability to interact with FT or, al- acquired novel roles that are independent of its interaction with FT. ternatively, whether both FDLs can interact with FT but the FDL1–FT complex differs in function from the FDL2–FT com- Results plex. To differentiate between these two possibilities, we used two FDL1 and FDL2 Have Distinct Functions. We cloned full-length approaches. First, we used bimolecular fluorescence complemen- cDNAs for two highly similar FD-like genes, FDL1 and FDL2,from tation (BiFC) (21) to investigate interaction between hybrid aspen hybrid aspen, which encode 168-aa and 302-aa proteins, re- FT and FDL proteins (Fig. S5). BiFC assays indicate that YFP spectively. The larger size of FDL2 is due to an insertion at the C fluorescence is observed only when FT1 or FT2 fused to C-ter- terminus (Fig.
Load more

Recommended publications
  • Florigen Family Chromatin Recruitment, Competition and Target Genes
    bioRxiv preprint doi: https://doi.org/10.1101/2020.02.04.934026; this version posted February 4, 2020. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC-ND 4.0 International license. 1 Florigen family chromatin recruitment, competition and target genes 2 Yang Zhu1, Samantha Klasfeld1, Cheol Woong Jeong1,3†, Run Jin1, Koji Goto4, 3 Nobutoshi Yamaguchi1,2† and Doris Wagner1* 4 1 Department of Biology, University of Pennsylvania, 415 S. University Ave, 5 Philadelphia, PA 19104, USA 6 2 Current address: Science and Technology, Nara Institute of Science and Technology, 7 8916-5 Takayama-cho, Ikoma-shi, Nara 630-0192, Japan 8 3 Current address: LG Economic Research Institute, LG Twin tower, Seoul 07336, 9 Korea 10 4 Research Institute for Biological Sciences, Okayama Prefecture, 7549-1, Kibichuoh- 11 cho, Kaga-gun, Okayama, 716-1241, Japan 12 *Correspondence: [email protected] 13 † equal contribution 14 15 16 1 bioRxiv preprint doi: https://doi.org/10.1101/2020.02.04.934026; this version posted February 4, 2020. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC-ND 4.0 International license. 17 Abstract 18 Plants monitor seasonal cues, such as day-length, to optimize life history traits including 19 onset of reproduction and inflorescence architecture 1-3.
    [Show full text]
  • A Genetic Framework for Regulation and Seasonal Adaptation of Shoot Architecture in Hybrid Aspen
    A genetic framework for regulation and seasonal adaptation of shoot architecture in hybrid aspen Jay P. Mauryaa,b, Pal C. Miskolczia, Sanatkumar Mishraa, Rajesh Kumar Singha, and Rishikesh P. Bhaleraoa,1 aUmeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, SE-901 87 Umeå, Sweden; and bDepartment of Botany, Institute of Science, Banaras Hindu University, Varanasi 221005, Uttar Pradesh, India Edited by Ronald R. Sederoff, North Carolina State University, Raleigh, NC, and approved April 14, 2020 (received for review March 14, 2020) Shoot architecture is critical for optimizing plant adaptation and time–related transcription factor RAV1 has been validated in productivity. In contrast with annuals, branching in perennials branching in trees (17–19). However, information on branching native to temperate and boreal regions must be coordinated with control in perennials is fragmented, and there is a significant gap seasonal growth cycles. How branching is coordinated with in our knowledge of how branching is controlled and integrated seasonal growth is poorly understood. We identified key compo- with seasonal growth cycles in perennial trees (20). Therefore, nents of the genetic network that controls branching and its using functional genetic approaches, we elucidated the genetic regulation by seasonal cues in the model tree hybrid aspen. network that mediates control of branching and its regulation by Our results demonstrate that branching and its control by sea- seasonal cues in the model tree hybrid aspen. These studies re- sonal cues is mediated by mutually antagonistic action of aspen veal the key role played by the mutually antagonistic action of orthologs of the flowering regulators TERMINAL FLOWER 1 LAP1 and TFL1 in mediating control of branching and its re- (TFL1)andAPETALA1 (LIKE APETALA 1/LAP1).
    [Show full text]
  • Florigen Revisited: Proteins of the FT/CETS/PEBP/PKIP/Ybhb Family
    bioRxiv preprint doi: https://doi.org/10.1101/2021.04.16.440192; this version posted April 16, 2021. The copyright holder for this preprint (which was not certified by peer review) is the author/funder. This article is a US Government work. It is not subject to copyright under 17 USC 105 and is also made available for use under a CC0 license. 1 Breakthrough Report 2 3 Florigen revisited: proteins of the FT/CETS/PEBP/PKIP/YbhB family may be the enzymes 4 of small molecule metabolism 5 6 Short title: Florigen-family proteins may be enzymes 7 8 Olga Tsoy1,4 and Arcady Mushegian2,3* 9 10 11 1 Chair of Experimental Bioinformatics, TUM School of Life Sciences Weihenstephan, Technical 12 University of Munich (TUM), 3, Maximus-von-Imhof-Forum, Freising, 85354, Germany 13 14 2 Molecular and Cellular Biology Division, National Science Foundation, 2415 Eisenhower 15 Avenue, Alexandria, Virginia 22314, USA 16 17 3 Clare Hall College, University of Cambridge, Cambridge CB3 9AL, United Kingdom 18 19 4 current address: Chair of Computational Systems Biology, University of Hamburg, 20 Notkestrasse, 9, 22607, Hamburg, Germany 21 22 * corresponding author: [email protected] 23 24 25 26 27 The author responsible for distribution of materials integral to the findings presented in this 28 article in accordance with the policy described in the Instructions for Authors 29 (www.plantcell.org) is Arcady Mushegian ([email protected]). 1 bioRxiv preprint doi: https://doi.org/10.1101/2021.04.16.440192; this version posted April 16, 2021. The copyright holder for this preprint (which was not certified by peer review) is the author/funder.
    [Show full text]
  • Discovery of Flowering Hormone (Florigen) Receptor and Its Crystal Structure
    5 Life Science PF Activity Report 2011 #29 Discovery of Flowering Hormone (Florigen) Receptor and Its Crystal Structure lorigen, a mobile floral induction protein, initiates the flowering process of activating floral identity genes. Many details of the molecular function of florigen remain unclear. In the present study, we found that the rice florigen FHd3a directly interacts with 14-3-3 (GF14) proteins, but not with the transcription factor OsFD1. We further deter- mined the 2.4-Å crystal structure of a tripartite Hd3a-14-3-3-OsFD1 complex [1]. The determined crystal structure offers biological insights into 14-3-3 proteins and how they play a key role in mediating an indirect interaction between Hd3a and OsFD1. Our biochemical, biophysical, and physiological experiments using rice cultured cells and transgenic rice plants revealed that 14-3-3 proteins are intracellular receptors of florigen to activate floral identity genes. Florigen is produced in leaves and transmitted NMR experiments. One consensus sequence among through the phloem to the shoot apex, where it induces the bZIP transcription factors, including OsFD1, that flowering. A number of recent reports have provided reportedly bind FT and its homologs, was found to be evidence that Arabidopsis FT protein (Hd3a in rice) is a R-x-x-(S/T)-A-P-F, which resembles the 14-3-3 protein- key component of florigen [2]. In the shoot apical meri- binding motif R-S-x-(pS/pT)-x-P. The presence of this stem, FT activates floral identity genes such as AP1 sequence in OsFD1 raises the possibility that the inter- transcription and induces flowering by interacting with action between Hd3a and OsFD1 is indirect and is me- Figure 2 the bZIP transcription factor FD, although the details of diated by 14-3-3 proteins.
    [Show full text]
  • Florigen Governs Shoot Regeneration
    Florigen Governs Shoot Regeneration Yaarit Kutsher Agricultural Research Organization Michal Fisler Agricultural Research Organization Adi DORON-FAIGENBOIM Agricultural Research Organization Moshe Reuveni ( [email protected] ) Agricultural Research Organization Research Article Keywords: reproductive stage (owering), protocols of shoot regeneration in plants, tobacco origen mRNA Posted Date: April 30th, 2021 DOI: https://doi.org/10.21203/rs.3.rs-450479/v1 License: This work is licensed under a Creative Commons Attribution 4.0 International License. Read Full License Page 1/16 Abstract It is widely known that during the reproductive stage (owering), plants do not root well. Most protocols of shoot regeneration in plants utilize juvenile tissue. Adding these two realities together encouraged us to study the role of origen in shoot regeneration. Mature tobacco tissue that expresses the endogenous tobacco origen mRNA regenerates poorly, while juvenile tissue that does not express the origen regenerates shoots well. Inhibition of Nitric Oxide (NO) synthesis reduced shoot regeneration as well as promoted owering and increased tobacco origen level. In contrast, the addition of NO (by way of NO donor) to the tissue increased regeneration, delayed owering, reduced tobacco origen mRNA. Ectopic expression of origen genes in tobacco or tomato decreased regeneration capacity signicantly. Overexpression pear PcFT2 gene increased regeneration capacity. During regeneration, origen mRNA was not changed. We conclude that origen presence in mature tobacco leaves reduces roots and shoots regeneration and is the possible reason for the age-related decrease in regeneration capacity. Introduction Plant regeneration by rebuilding new organs (organogenesis) results from new organ formation through dedifferentiation of differentiated plant cells and reorganization of cell division to create new organ meristems and new vascular connection between the explant and the newly regenerating organ 1,2.
    [Show full text]
  • Florigen Coming of Age After 70 Years
    The Plant Cell, Vol. 18, 1783–1789, August 2006, www.plantcell.org ª 2006 American Society of Plant Biologists CURRENT PERSPECTIVE ESSAY Florigen Coming of Age after 70 Years The report that FT mRNA is the long-sought florigen, or at least is universal in plants (at least in closely related species and part of it (Huang et al., 2005), has attracted much attention and different photoperiodic response types). However, despite Downloaded from https://academic.oup.com/plcell/article/18/8/1783/6115260 by guest on 03 October 2021 was ranked the number three breakthrough of 2005 by the numerous attempts to extract florigen and several reports of journal Science (Anonymous, 2005). This exciting discovery has extracts with flower-inducing activity, which all turned out to be brought to center stage one of the major outstanding questions nonreproducible, florigen remained a physiological concept in plant biology: What is the nature of florigen? In this essay, I rather than a chemical entity. As a result, the florigen hypoth- summarize the classical experiments that led to the florigen esis fell into disrepute, and a rival hypothesis, proposing that hypothesis and how molecular-genetic approaches combined flowering would be induced by a specific ratio of known with physiological methods have advanced our understanding hormones and metabolites, gained favor (Bernier, 1988; of florigen. I also discuss the possible universality of florigen and Bernier et al., 1993). some of the remaining questions regarding flowering and other photoperiod-controlled phenomena involving long-distance sig- naling in plants. MOLECULAR-GENETIC STUDIES OF FLOWERING As the physiological-biochemical approaches to flowering had FLORIGEN AS A PHYSIOLOGICAL CONCEPT begun to stagnate, along came molecular genetics with a new approach to the study of flowering.
    [Show full text]
  • Lecture Outline
    The transition from vegetative to reproductive growth Vegetative phase change is required to allow a shoot to be able to produce flowers English Ivy (Hedera helix) A shoot is only competent to flower once it has passed from the juvenile to Adult the adult phase, a transition sometimes marked by gross morphological Juvenile leaf Adult leaf changes Juvenile The vegetative (juvenile to adult) phase transition is controlled by the relative abundance of microRNAs 156 and 172 Acacia koa Reprinted with permission friom Huijscer, P., and Schmid, M. (2011) The control of developmental phase transitions in plants. Development 138: 4117-4129. The nature of the flowering signal was elusive for decades Conversion of meristem vegetative to floral Environmental cues “Florigen” Julius von Sachs Mikhail Chailakhyan (1832-1897) (1901-1991) a.k.a. The “Father of Plant Physiology”. He was the first Proved the existence of a florigenic compound and to propose the existence of a chemical compound demonstrated that it is a small molecule, produced in capable of inducing flowering leaves and translocated to the shoot apex via the produced in leaves of illuminated plants phloem; he named it “florigen” Credits: Romanov, 2012 Russian J Plant Phys 4:443-450; Redrawn from Ayre and Turgeon, 2004 Several physiological pathways regulate flowering These are called ‘enabling pathways’ as they regulate floral competence of the meristem Vernalization Photoperiodic Autonomous GA-dependent pathway pathway pathway Where is florigen? FLOWERING Molecular repressors LOCUS C (FLC) of flowering, also Note: This model called ‘anti-florigenic’ corresponds to signals, maintain the Arabidopsis but many of its modules have vegetative state of counterparts in other the meristem species Vegetative Florigen Flowering Adapted from Reeves, P.H., and Coupland, G.
    [Show full text]
  • Florigen and Anti-Florigen: Flowering Regulation in Horticultural Crops
    Breeding Science 68: 109–118 (2018) doi:10.1270/jsbbs.17084 Review Florigen and anti-florigen: flowering regulation in horticultural crops Yohei Higuchi* Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan Flowering time regulation has significant effects on the agricultural and horticultural industries. Plants respond to changing environments and produce appropriate floral inducers (florigens) or inhibitors (anti-florigens) that determine flowering time. Recent studies have demonstrated that members of two homologous proteins, FLOWERING LOCUS T (FT) and TERMINAL FLOWER 1 (TFL1), act as florigen and anti-florigen, respec- tively. Studies in diverse plant species have revealed universal but diverse roles of the FT/TFL1 gene family in many developmental processes. Recent studies in several crop species have revealed that modification of flow- ering responses, either due to mutations in the florigen/anti-florigen gene itself, or by modulation of the regu- latory pathway, is crucial for crop domestication. The FT/TFL1 gene family could be an important potential breeding target in many crop species. Key Words: anti-florigen, chrysanthemum, florigen, FLOWERING LOCUS T (FT), photoperiod, TERMINAL FLOWER 1 (TFL1). Introduction cies (Corbesier et al. 2007, Lifschitz et al. 2006, Lin et al. 2007, Tamaki et al. 2007). In Arabidopsis, the FT protein is Many plants utilize fluctuations in day-length (photoperiod) induced under flower-inductive long day (LD) photoperiod as the most reliable indicator of seasonal progression to de- in leaves, whereas it forms a complex with a bZIP type tran- termine when to initiate flowering. This phenomenon, called scription factor FD at the shoot apical meristem (SAM) to photoperiodism, enables plants to set seeds at favorable induce floral meristem-identity genes, such as APETALA1 conditions and maximize their chance of survival.
    [Show full text]
  • Florigen Governs Shoot Regeneration
    bioRxiv preprint doi: https://doi.org/10.1101/2021.03.16.435564; this version posted March 17, 2021. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC-ND 4.0 International license. Florigen governs shoot regeneration. From Plant Science Institute ARO Volcani Center, PO Box 6, Bet Dagan 50250, Israel Yaarit Kutsher - [email protected] Michal Fisler - [email protected] Adi Faigenboim - [email protected] Moshe Reuveni – [email protected] - Corresponding author Plant Science Institute, ARO, Volcani Center, 68 Hamakabim Rd, PO Box 15159 Rishon LeZion 7528809, Israel, Tel. 972-3-968-3830 Abstract It is widely known that during the reproductive stage (flowering), plants do not root well. Most protocols of shoot regeneration in plants utilize juvenile tissue. Adding these two realities together encouraged us to studied the role of florigen in shoot regeneration. Mature tobacco tissue that expresses the endogenous tobacco florigen mRNA regenerates poorly, while juvenile tissue that does not express the florigen regenerates shoots well. Inhibition of Nitric Oxide (NO) synthesis reduced shoot regeneration as well as promoted flowering and increased tobacco florigen level. In contrast, the addition of NO (by way of NO donor) to the tissue increased regeneration, delayed flowering, reduced tobacco florigen mRNA. Ectopic expression of florigen genes in tobacco or tomato decreased regeneration capacity significantly. Overexpression pear PcFT2 gene increased regeneration capacity. During regeneration, florigen mRNA was not changed.
    [Show full text]
  • The Flowering Hormone Florigen Accelerates Secondary Cell Wall
    bioRxiv preprint doi: https://doi.org/10.1101/476028; this version posted November 27, 2018. The copyright holder for this preprint (which was not certified by peer review) is the author/funder. All rights reserved. No reuse allowed without permission. 1 The Flowering Hormone Florigen Accelerates Secondary Cell Wall Biogenesis to Harmonize Vascular Maturation with Reproductive Development Akiva Shalit-Kaneh*1, Tamar Eviatar–Ribak*1, Guy Horev*2, Naomi Suss1, Roni Aloni3, Yuval Eshed4, Eliezer Lifschitz 1,5 1Department of Biology, Technion IIT 2Lorey I. Lokey Center for Life Sciences & Engineering, Technion 3 School of Plant Sciences and Food Security, Tel Aviv University, Tel Aviv 69978, Israel 4Department of Plant and Environmental Sciences Weizmann Institute of Science, Rehovot, Israel *Equal contribution 5 Corresponding author [email protected] Developmental Highlights - Florigen accelerates SCWB: A prime case for a long-range regulation of a complete metabolic network by a plant hormone. - The dual acceleration of flowering and vascular maturation by Florigen provides a paradigm for a dynamic regulation of global, independent, developmental programs. - The growth termination functions of florigen and the auto-regulatory mechanism for its production and distribution provide a communication network enveloping the shoot system. - A stable florigen provides a possible mechanism for the quantitative regulation of flowering - Lateral stimulation of xylem differentiation links the phloem-travelling florigen with the annual rings in trunks. - MADS genes are common relay partners in Florigen circuits; vascular maturation in stems and reproductive transition in apical meristems. bioRxiv preprint doi: https://doi.org/10.1101/476028; this version posted November 27, 2018. The copyright holder for this preprint (which was not certified by peer review) is the author/funder.
    [Show full text]
  • Regulation of Tissue Repair in Plants
    COMMENTARY Regulation of tissue repair in plants James B. Reid1 and John J. Ross School of Plant Science, University of Tasmania, Hobart, Tasmania 7001, Australia recent report in PNAS by Asa- gene, one of a family of amino- hina et al. (1) addresses the fas- cyclopropane carboxylic acid synthase A cinating question of tissue repair genes that regulates the rate-limiting in plants. According to recent step in ethylene biosynthesis. suggestions, plants and animals might Jasmonic acid (JA), another plant hor- share cellular mechanisms that allow re- mone, may also play a role (1). JA is generation of tissues after damage (2). a known regulator of plant responses to However, plants and animals differ greatly both biotic and abiotic stresses (10), in their mode of development and their and genes involved in its biosynthesis are ability to respond to damage-inducing en- up-regulated after incision, which is vironmental factors (3). Terrestrial plants shown by microarray and quantitative RT- cannot move their whole body in response PCR analyses (1). One such gene, the to environmental cues, and, because of lipoxygenase gene LOX2, is up-regulated their cell walls, they also lack cellular mo- below the incision in a similar pattern bility within the plant. This means that to RAP2.6L, and application of methyl plants must regenerate damaged tissue jasmonate up-regulates RAP2.6L expres- through cellular regeneration at the point sion. Although studies using the expres- of damage. Traditionally, this regeneration sion of biosynthesis genes to infer was considered to occur by dedifferen- hormone levels need to be treated with tiation of existing mature cells followed by extreme caution (11), it seems that cell division to form callus and differenti- Fig.
    [Show full text]
  • Florigen (II): It Is a Mobile Protein
    Journal of Integrative Plant Biology 2007, 49 (12): 1665–1669 ·Invited Review· Florigen (II): It is a Mobile Protein ∗ ∗ Yuejun Yang1, John Klejnot2, Xuhong Yu2, Xuanming Liu1 and Chentao Lin1,2 (1Bioenergy and Biomaterial Research Center, Hunan University, Changsha 410082, China; 2Department of Molecular, Cell & Developmental Biology, University of California, Los Angeles, CA 90095, USA) Abstract The true identity of florigen – the molecule(s) that migrates from leaves to apical meristem to initiate flowering – was notoriously elusive, having made it almost the “Bigfoot” of plant biology. There was never a lack of drama in the field of florigen study, and florigen researchers have once again experienced such a swing in the last two years. We wrote a minireview last year in this journal (Yu et al. 2006) to excitedly salute, among other discoveries, the notion that the flowering locus T (FT) mRNA might be the molecular form of a florigen. However, this hypothesis was challenged in a little less than two years after its initial proposition, and the original paper proposed that the FT mRNA hypothesis was retracted (Huang et al. 2005; Bohlenius et al. 2007). Interestingly enough, the FT gene previously proposed to encode a florigen was never challenged. Rather, the FT protein, instead of the FT mRNA, is now believed to migrate from leaves to the apical meristem to promote floral initiation. In this update, we will share with our readers some entertaining stories concerning the recent studies of florigen in five different plant species. In addition to the published reports referenced in this update, readers may also refer to our previous minireview and references therein for additional background information (Yu et al.
    [Show full text]