1
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Maple R, Zhu P, Hepworth J, Wang JW, Dean C. Flowering time: From physiology, through genetics to mechanism. PLANT PHYSIOLOGY 2024; 195:190-212. [PMID: 38417841 PMCID: PMC11060688 DOI: 10.1093/plphys/kiae109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Revised: 01/12/2024] [Accepted: 02/12/2024] [Indexed: 03/01/2024]
Abstract
Plant species have evolved different requirements for environmental/endogenous cues to induce flowering. Originally, these varying requirements were thought to reflect the action of different molecular mechanisms. Thinking changed when genetic and molecular analysis in Arabidopsis thaliana revealed that a network of environmental and endogenous signaling input pathways converge to regulate a common set of "floral pathway integrators." Variation in the predominance of the different input pathways within a network can generate the diversity of requirements observed in different species. Many genes identified by flowering time mutants were found to encode general developmental and gene regulators, with their targets having a specific flowering function. Studies of natural variation in flowering were more successful at identifying genes acting as nodes in the network central to adaptation and domestication. Attention has now turned to mechanistic dissection of flowering time gene function and how that has changed during adaptation. This will inform breeding strategies for climate-proof crops and help define which genes act as critical flowering nodes in many other species.
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Affiliation(s)
- Robert Maple
- Department of Cell and Developmental Biology, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK
| | - Pan Zhu
- Department of Cell and Developmental Biology, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK
| | - Jo Hepworth
- Department of Biosciences, Durham University, Stockton Road, Durham, DH1 3LE, UK
| | - Jia-Wei Wang
- National Key Laboratory of Plant Molecular Genetics (NKLPMG), CAS Center for Excellence in Molecular Plant Sciences (CEMPS), Institute of Plant Physiology and Ecology (SIPPE), Chinese Academy of Sciences (CAS), Shanghai 200032, China
- School of Life Science and Technology, Shanghai Tech University, Shanghai 201210, China
- New Cornerstone Science Laboratory, Shanghai 200032, China
| | - Caroline Dean
- Department of Cell and Developmental Biology, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK
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2
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Rehman S, Bahadur S, Xia W. An overview of floral regulatory genes in annual and perennial plants. Gene 2023; 885:147699. [PMID: 37567454 DOI: 10.1016/j.gene.2023.147699] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 07/31/2023] [Accepted: 08/08/2023] [Indexed: 08/13/2023]
Abstract
The floral initiation in angiosperms is a complex process influenced by endogenous and exogenous signals. With this approach, we aim to provide a comprehensive review to integrate this complex floral regulatory process and summarize the regulatory genes and their functions in annuals and perennials. Seven primary paths leading to flowering have been discovered in Arabidopsis under several growth condition that include; photoperiod, ambient temperature, vernalization, gibberellins, autonomous, aging and carbohydrates. These pathways involve a series of interlinked signaling pathways that respond to both internal and external signals, such as light, temperature, hormones, and developmental cues, to coordinate the expression of genes that are involved in flower development. Among them, the photoperiodic pathway was the most important and conserved as some of the fundamental loci and mechanisms are shared even by closely related plant species. The activation of floral regulatory genes such as FLC, FT, LFY, and SOC1 that determine floral meristem identity and the transition to the flowering stage result from the merging of these pathways. Recent studies confirmed that alternative splicing, antisense RNA and epigenetic modification play crucial roles by regulating the expression of genes related to blooming. In this review, we documented recent progress in the floral transition time in annuals and perennials, with emphasis on the specific regulatory mechanisms along with the application of various molecular approaches including overexpression studies, RNA interference and Virus-induced flowering. Furthermore, the similarities and differences between annual and perennial flowering will aid significant contributions to the field by elucidating the mechanisms of perennial plant development and floral initiation regulation.
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Affiliation(s)
- Shazia Rehman
- Sanya Nanfan Research Institution, Hainan University, Haikou 572025, China; College of Tropical Crops, Hainan University, Haikou 570228, China
| | - Saraj Bahadur
- College of Forestry, Hainan University, Haikou 570228 China
| | - Wei Xia
- Sanya Nanfan Research Institution, Hainan University, Haikou 572025, China; College of Tropical Crops, Hainan University, Haikou 570228, China.
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3
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Zhu P, Schon M, Questa J, Nodine M, Dean C. Causal role of a promoter polymorphism in natural variation of the Arabidopsis floral repressor gene FLC. Curr Biol 2023; 33:4381-4391.e3. [PMID: 37729909 DOI: 10.1016/j.cub.2023.08.079] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 07/06/2023] [Accepted: 08/25/2023] [Indexed: 09/22/2023]
Abstract
Noncoding polymorphism frequently associates with phenotypic variation, but causation and mechanism are rarely established. Noncoding single-nucleotide polymorphisms (SNPs) characterize the major haplotypes of the Arabidopsis thaliana floral repressor gene FLOWERING LOCUS C (FLC). This noncoding polymorphism generates a range of FLC expression levels, determining the requirement for and the response to winter cold. The major adaptive determinant of these FLC haplotypes was shown to be the autumnal levels of FLC expression. Here, we investigate how noncoding SNPs influence FLC transcriptional output. We identify an upstream transcription start site (uTSS) cluster at FLC, whose usage is increased by an A variant at the promoter SNP-230. This variant is present in relatively few Arabidopsis accessions, with the majority containing G at this site. We demonstrate a causal role for the A variant at -230 in reduced FLC transcriptional output. The G variant upregulates FLC expression redundantly with the major transcriptional activator FRIGIDA (FRI). We demonstrate an additive interaction of SNP-230 with an intronic SNP+259, which also differentially influences uTSS usage. Combinatorial interactions between noncoding SNPs and transcriptional activators thus generate quantitative variation in FLC transcription that has facilitated the adaptation of Arabidopsis accessions to distinct climates.
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Affiliation(s)
- Pan Zhu
- John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK
| | - Michael Schon
- Laboratory of Molecular Biology, Wageningen University, Wageningen 6708 PB, the Netherlands; Gregor Mendel Institute, Vienna Biocenter, Vienna 1030, Austria
| | - Julia Questa
- John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK
| | - Michael Nodine
- Laboratory of Molecular Biology, Wageningen University, Wageningen 6708 PB, the Netherlands; Gregor Mendel Institute, Vienna Biocenter, Vienna 1030, Austria
| | - Caroline Dean
- John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK.
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4
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Mitsui Y, Yokoyama H, Nakaegawa W, Tanaka K, Komatsu K, Koizuka N, Okuzaki A, Matsumoto T, Takahara M, Tabei Y. Epistatic interactions among multiple copies of FLC genes with naturally occurring insertions correlate with flowering time variation in radish. AOB PLANTS 2023; 15:plac066. [PMID: 36751367 PMCID: PMC9893874 DOI: 10.1093/aobpla/plac066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Accepted: 01/26/2023] [Indexed: 06/18/2023]
Abstract
Brassicaceae crops, which underwent whole-genome triplication during their evolution, have multiple copies of flowering-related genes. Interactions among multiple gene copies may be involved in flowering time regulation; however, this mechanism is poorly understood. In this study, we performed comprehensive, high-throughput RNA sequencing analysis to identify candidate genes involved in the extremely late-bolting (LB) trait in radish. Then, we examined the regulatory roles and interactions of radish FLOWERING LOCUS C (RsFLC) paralogs, the main flowering repressor candidates. Seven flowering integrator genes, five vernalization genes, nine photoperiodic/circadian clock genes and eight genes from other flowering pathways were differentially expressed in the early-bolting (EB) cultivar 'Aokubinagafuto' and LB radish cultivar 'Tokinashi' under different vernalization conditions. In the LB cultivar, RsFLC1 and RsFLC2 expression levels were maintained after 40 days of cold exposure. Bolting time was significantly correlated with the expression rates of RsFLC1 and RsFLC2. Using the EB × LB F2 population, we performed association analyses of genotypes with or without 1910- and 1627-bp insertions in the first introns of RsFLC1 and RsFLC2, respectively. The insertion alleles prevented the repression of their respective FLC genes under cold conditions. Interestingly, genotypes homozygous for RsFLC2 insertion alleles maintained high RsFLC1 and RsFLC3 expression levels under cold conditions, and two-way analysis of variance revealed that RsFLC1 and RsFLC3 expression was influenced by the RsFLC2 genotype. Our results indicate that insertions in the first introns of RsFLC1 and RsFLC2 contribute to the late-flowering trait in radish via different mechanisms. The RsFLC2 insertion allele conferred a strong delay in bolting by inhibiting the repression of all three RsFLC genes, suggesting that radish flowering time is determined by epistatic interactions among multiple FLC gene copies.
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Affiliation(s)
| | - Hinano Yokoyama
- Faculty of Agriculture, Tokyo University of Agriculture, 1737 Atsugi, Kanagawa 243-0034, Japan
| | - Wataru Nakaegawa
- Faculty of Agriculture, Tokyo University of Agriculture, 1737 Atsugi, Kanagawa 243-0034, Japan
| | - Keisuke Tanaka
- NODAI Genome Research Center, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya-ku, Tokyo 156-8502, Japan
| | - Kenji Komatsu
- Faculty of Agriculture, Tokyo University of Agriculture, 1737 Atsugi, Kanagawa 243-0034, Japan
| | - Nobuya Koizuka
- College of Agriculture, Tamagawa University, 6-1-1 Tamagawa Gakuen, Machida, Tokyo 194-8610, Japan
| | - Ayako Okuzaki
- College of Agriculture, Tamagawa University, 6-1-1 Tamagawa Gakuen, Machida, Tokyo 194-8610, Japan
| | - Takashi Matsumoto
- Faculty of Applied Biology, Tokyo University of Agriculture, 1-1-1 Sakuragaoka, Setagaya-ku, Tokyo 156-8502, Japan
| | - Manabu Takahara
- Institute of Agrobiological Sciences, National Agriculture and Food Research Organization, Tsukuba, Ibaraki, 305-8634, Japan
| | - Yutaka Tabei
- Faculty of Food and Nutritional Sciences, Toyo University, 1-1-1 Izumino, Itakura-machi, Ora-gun, Gunma 374-0193, Japan
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5
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Tudor EH, Jones DM, He Z, Bancroft I, Trick M, Wells R, Irwin JA, Dean C. QTL-seq identifies BnaFT.A02 and BnaFLC.A02 as candidates for variation in vernalization requirement and response in winter oilseed rape (Brassica napus). PLANT BIOTECHNOLOGY JOURNAL 2020; 18:2466-2481. [PMID: 32452611 PMCID: PMC7680531 DOI: 10.1111/pbi.13421] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 03/10/2020] [Accepted: 05/11/2020] [Indexed: 05/05/2023]
Abstract
Winter, spring and biennial varieties of Brassica napus that vary in vernalization requirement are grown for vegetable and oil production. Here, we show that the obligate or facultative nature of the vernalization requirement in European winter oilseed rape is determined by allelic variation at a 10 Mbp region on chromosome A02. This region includes orthologues of the key floral regulators FLOWERING LOCUS C (BnaFLC.A02) and FLOWERING LOCUS T (BnaFT.A02). Polymorphism at BnaFLC.A02 and BnaFT.A02, mostly in cis-regulatory regions, results in distinct gene expression dynamics in response to vernalization treatment. Our data suggest allelic variation at BnaFT.A02 is associated with flowering time in the absence of vernalization, while variation at BnaFLC.A02 is associated with flowering time under vernalizing conditions. We hypothesize selection for BnaFLC.A02 and BnaFT.A02 gene expression variation has facilitated the generation of European winter oilseed rape varieties that are adapted to different winter climates. This knowledge will allow for the selection of alleles of flowering time regulators that alter the vernalization requirement of oilseed rape, informing the generation of new varieties with adapted flowering times and improved yields.
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Affiliation(s)
| | | | - Zhesi He
- Department of BiologyUniversity of YorkYorkUK
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6
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Hepworth J, Antoniou-Kourounioti RL, Berggren K, Selga C, Tudor EH, Yates B, Cox D, Collier Harris BR, Irwin JA, Howard M, Säll T, Holm S, Dean C. Natural variation in autumn expression is the major adaptive determinant distinguishing Arabidopsis FLC haplotypes. eLife 2020; 9:57671. [PMID: 32902380 PMCID: PMC7518893 DOI: 10.7554/elife.57671] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Accepted: 09/08/2020] [Indexed: 12/27/2022] Open
Abstract
In Arabidopsis thaliana, winter is registered during vernalization through the temperature-dependent repression and epigenetic silencing of floral repressor FLOWERING LOCUS C (FLC). Natural Arabidopsis accessions show considerable variation in vernalization. However, which aspect of the FLC repression mechanism is most important for adaptation to different environments is unclear. By analysing FLC dynamics in natural variants and mutants throughout winter in three field sites, we find that autumnal FLC expression, rather than epigenetic silencing, is the major variable conferred by the distinct Arabidopsis FLChaplotypes. This variation influences flowering responses of Arabidopsis accessions resulting in an interplay between promotion and delay of flowering in different climates to balance survival and, through a post-vernalization effect, reproductive output. These data reveal how expression variation through non-coding cis variation at FLC has enabled Arabidopsis accessions to adapt to different climatic conditions and year-on-year fluctuations.
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Affiliation(s)
- Jo Hepworth
- Cell and Developmental Biology, John Innes Centre, Norwich, United Kingdom
| | | | - Kristina Berggren
- Department of Natural Sciences, Mid Sweden University, Sundsvall, Sweden
| | - Catja Selga
- Department of Biology, Lund University, Lund, Sweden
| | - Eleri H Tudor
- Crop Genetics, John Innes Centre, Norwich, United Kingdom
| | - Bryony Yates
- Cell and Developmental Biology, John Innes Centre, Norwich, United Kingdom
| | - Deborah Cox
- Cell and Developmental Biology, John Innes Centre, Norwich, United Kingdom
| | | | - Judith A Irwin
- Crop Genetics, John Innes Centre, Norwich, United Kingdom
| | - Martin Howard
- Computational and Systems Biology, John Innes Centre, Norwich, United Kingdom
| | - Torbjörn Säll
- Department of Biology, Lund University, Lund, Sweden
| | - Svante Holm
- Department of Natural Sciences, Mid Sweden University, Sundsvall, Sweden
| | - Caroline Dean
- Cell and Developmental Biology, John Innes Centre, Norwich, United Kingdom
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7
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Quesneville H. Twenty years of transposable element analysis in the Arabidopsis thaliana genome. Mob DNA 2020; 11:28. [PMID: 32742313 PMCID: PMC7385966 DOI: 10.1186/s13100-020-00223-x] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Accepted: 07/16/2020] [Indexed: 11/10/2022] Open
Abstract
Transposable elements (TEs) are mobile repetitive DNA sequences shown to be major drivers of genome evolution. As the first plant to have its genome sequenced and analyzed at the genomic scale, Arabidopsis thaliana has largely contributed to our TE knowledge. The present report describes 20 years of accumulated TE knowledge gained through the study of the Arabidopsis genome and covers the known TE families, their relative abundance, and their genomic distribution. It presents our knowledge of the different TE family activities, mobility, population and long-term evolutionary dynamics. Finally, the role of TE as substrates for new genes and their impact on gene expression is illustrated through a few selected demonstrative cases. Promising future directions for TE studies in this species conclude the review.
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8
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Miryeganeh M. Synchronization of senescence and desynchronization of flowering in Arabidopsis thaliana. AOB PLANTS 2020; 12:plaa018. [PMID: 32577195 PMCID: PMC7299267 DOI: 10.1093/aobpla/plaa018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/18/2020] [Accepted: 05/04/2020] [Indexed: 06/11/2023]
Abstract
In a recent publication, we proposed that adjusting lifespan in order to synchronize senescence is important for timing of reproduction, and we quantified the synchrony of reproductive timing relative to germination timing. Here, in a second sequential seeding experiment (SSE), the germination timing of Arabidopsis thaliana accessions was manipulated and plants were then grown under two different temperature regimes. Life stage traits of plants in each temperature regime were analysed and it was evaluated whether the cohorts were grouped according to age and/or environmental conditions. While flowering-related traits showed desynchrony among cohorts, striking synchrony in the timing of senescence among cohorts for each group was found. A quantitative trait locus (QTL) analysis using a genotyped population of 'Cvi/Ler' recombinant inbred lines (RILs) was then conducted. Novel and known loci were assigned to flowering and senescence timing. However, senescence synchrony resulted in low variation in senescence time and weak QTL detection for flowering termination. Overlapping flowering and senescence genes with loci affecting either of those traits were found and suggest a potential interdependency of reproductive traits.
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Affiliation(s)
- Matin Miryeganeh
- Center for Ecological Research, Kyoto University, Hirano, Otsu, Japan
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9
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Golicz AA, Steinfort U, Arya H, Singh MB, Bhalla PL. Analysis of the quinoa genome reveals conservation and divergence of the flowering pathways. Funct Integr Genomics 2020; 20:245-258. [PMID: 31515641 PMCID: PMC7018680 DOI: 10.1007/s10142-019-00711-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Revised: 07/19/2019] [Accepted: 08/14/2019] [Indexed: 01/09/2023]
Abstract
Quinoa (Chenopodium quinoa Willd.) is a grain crop grown in the Andes renowned as a highly nutritious plant exhibiting tolerance to abiotic stress such as drought, cold and high salinity. Quinoa grows across a range of latitudes corresponding to differing day lengths, suggesting regional adaptations of flowering regulation. Improved understanding and subsequent modification of the flowering process, including flowering time, ensuring high yields, is one of the key factors behind expansion of cultivation zones and goals of the crop improvement programs worldwide. However, our understanding of the molecular basis of flower initiation and development in quinoa is limited. Here, we use a computational approach to perform genome-wide identification and analysis of 611 orthologues of the Arabidopsis thaliana flowering genes. Conservation of the genes belonging to the photoperiod, gibberellin and autonomous pathways was observed, while orthologues of the key genes found in the vernalisation pathway (FRI, FLC) were absent from the quinoa genome. Our analysis indicated that on average each Arabidopsis flowering gene has two orthologous copies in quinoa. Several genes including orthologues of MIF1, FT and TSF were identified as homologue-rich genes in quinoa. We also identified 459 quinoa-specific genes uniquely expressed in the flower and/or meristem, with no known orthologues in other species. The genes identified provide a resource and framework for further studies of flowering in quinoa and related species. It will serve as valuable resource for plant biologists, crop physiologists and breeders to facilitate further research and establishment of modern breeding programs for quinoa.
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Affiliation(s)
- Agnieszka A Golicz
- Plant Molecular Biology and Biotechnology Laboratory, Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Parkville, Melbourne, VIC, Australia.
| | - Ursula Steinfort
- Facultad de Agronomía e Ingeniería Forestal, Pontificia Universidad Católica de Chile, Santiago, Chile.
| | - Hina Arya
- Plant Molecular Biology and Biotechnology Laboratory, Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Parkville, Melbourne, VIC, Australia
| | - Mohan B Singh
- Plant Molecular Biology and Biotechnology Laboratory, Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Parkville, Melbourne, VIC, Australia
| | - Prem L Bhalla
- Plant Molecular Biology and Biotechnology Laboratory, Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Parkville, Melbourne, VIC, Australia
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10
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Gaudinier A, Blackman BK. Evolutionary processes from the perspective of flowering time diversity. THE NEW PHYTOLOGIST 2020; 225:1883-1898. [PMID: 31536639 DOI: 10.1111/nph.16205] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Accepted: 08/30/2019] [Indexed: 05/18/2023]
Abstract
Although it is well appreciated that genetic studies of flowering time regulation have led to fundamental advances in the fields of molecular and developmental biology, the ways in which genetic studies of flowering time diversity have enriched the field of evolutionary biology have received less attention despite often being equally profound. Because flowering time is a complex, environmentally responsive trait that has critical impacts on plant fitness, crop yield, and reproductive isolation, research into the genetic architecture and molecular basis of its evolution continues to yield novel insights into our understanding of domestication, adaptation, and speciation. For instance, recent studies of flowering time variation have reconstructed how, when, and where polygenic evolution of phenotypic plasticity proceeded from standing variation and de novo mutations; shown how antagonistic pleiotropy and temporally varying selection maintain polymorphisms in natural populations; and provided important case studies of how assortative mating can evolve and facilitate speciation with gene flow. In addition, functional studies have built detailed regulatory networks for this trait in diverse taxa, leading to new knowledge about how and why developmental pathways are rewired and elaborated through evolutionary time.
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Affiliation(s)
- Allison Gaudinier
- Department of Plant and Microbial Biology, University of California, Berkeley, CA, 94720, USA
| | - Benjamin K Blackman
- Department of Plant and Microbial Biology, University of California, Berkeley, CA, 94720, USA
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11
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Hyun Y, Vincent C, Tilmes V, Bergonzi S, Kiefer C, Richter R, Martinez-Gallegos R, Severing E, Coupland G. A regulatory circuit conferring varied flowering response to cold in annual and perennial plants. Science 2019; 363:409-412. [PMID: 30679374 DOI: 10.1126/science.aau8197] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Accepted: 12/19/2018] [Indexed: 12/23/2022]
Abstract
The reproductive strategies of plants are highly variable. Short-lived annuals flower abundantly soon after germination, whereas longer-lived perennials postpone and spatially restrict flowering. We used CRISPR/Cas9 and interspecies gene transfer to understand divergence in reproductive patterns between annual and perennial crucifers. We show that in perennial Arabis alpina, flowering in response to winter cold depends on the floral integrator SQUAMOSA PROMOTER BINDING PROTEIN-LIKE 15 (SPL15), whose activity is limited to older shoots and branches during cold exposure. In annuals, this regulatory system is conserved, but cold-induced flowering occurs in young shoots, without requirement for SPL15, through the photoperiodic pathway when plants return to warm. By reconstructing the annual response in perennials, we conclude that characteristic patterns of reproduction in annuals and perennials are conferred through variation in dependency on distinct flowering pathways acting in parallel.
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Affiliation(s)
- Youbong Hyun
- Max Planck Institute for Plant Breeding Research, Carl-von-Linne-Weg 10, D50829, Germany
| | - Coral Vincent
- Max Planck Institute for Plant Breeding Research, Carl-von-Linne-Weg 10, D50829, Germany
| | - Vicky Tilmes
- Max Planck Institute for Plant Breeding Research, Carl-von-Linne-Weg 10, D50829, Germany
| | - Sara Bergonzi
- Max Planck Institute for Plant Breeding Research, Carl-von-Linne-Weg 10, D50829, Germany
| | - Christiane Kiefer
- Max Planck Institute for Plant Breeding Research, Carl-von-Linne-Weg 10, D50829, Germany
| | - René Richter
- Max Planck Institute for Plant Breeding Research, Carl-von-Linne-Weg 10, D50829, Germany
| | | | - Edouard Severing
- Max Planck Institute for Plant Breeding Research, Carl-von-Linne-Weg 10, D50829, Germany
| | - George Coupland
- Max Planck Institute for Plant Breeding Research, Carl-von-Linne-Weg 10, D50829, Germany.
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12
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Bao S, Hua C, Huang G, Cheng P, Gong X, Shen L, Yu H. Molecular Basis of Natural Variation in Photoperiodic Flowering Responses. Dev Cell 2019; 50:90-101.e3. [PMID: 31178399 DOI: 10.1016/j.devcel.2019.05.018] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Revised: 02/11/2019] [Accepted: 05/06/2019] [Indexed: 12/21/2022]
Abstract
Plants exhibit different flowering behaviors in response to variable photoperiods across a wide geographical range. Here, we identify MYC3, a bHLH transcription factor, and its cis-element form the long-sought regulatory module responsible for cis-regulatory changes at the florigen gene FLOWERING LOCUS T (FT) that mediate natural variation in photoperiodic flowering responses in Arabidopsis. MYC3 is stabilized by DELLAs in the gibberellin pathway to suppress FT through binding the ACGGAT motif and antagonizing CONSTANS (CO) activation. Changing photoperiods modulate the relative abundance of MYC3 and CO, thus determining either of them as the predominant regulator for FT expression under different day lengths. Cis-regulatory changes in the MYC3 binding site at FT are associated with natural variation in day-length requirement for flowering in Arabidopsis accessions. Our findings reveal that environmental and developmental signals converge at MYC3 suppression of FT, an elementary event underlying natural variation in photoperiodic flowering responses.
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Affiliation(s)
- Shengjie Bao
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore 117543, Singapore
| | - Changmei Hua
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore 117543, Singapore
| | - Gengqing Huang
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore 117543, Singapore; Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan 430079, China
| | - Peng Cheng
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore 117543, Singapore
| | - Ximing Gong
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore 117543, Singapore
| | - Lisha Shen
- Temasek Life Sciences Laboratory, National University of Singapore, Singapore 117604, Singapore
| | - Hao Yu
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore 117543, Singapore; Temasek Life Sciences Laboratory, National University of Singapore, Singapore 117604, Singapore.
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13
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Abuyusuf M, Nath UK, Kim HT, Islam MR, Park JI, Nou IS. Molecular markers based on sequence variation in BoFLC1.C9 for characterizing early- and late-flowering cabbage genotypes. BMC Genet 2019; 20:42. [PMID: 31029104 PMCID: PMC6487051 DOI: 10.1186/s12863-019-0740-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Accepted: 03/18/2019] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Cabbage (Brassica oleracea var. capitata) is popular worldwide for consumption as a leafy vegetable. Premature flowering is triggered by low temperature, and deteriorates quality of cabbage as vegetable. In general, growers prefer late-flowering varieties to assure good quality compact head. Here, we report BoFLC1.C9 as a gene with clear sequence variation between cabbage lines with different flowering times, and proposed as molecular marker to characterize early- and late-flowering cabbage lines. RESULTS We identified sequence variation of 67 bp insertions in intron 2, which were contributed in flowering time variation between two inbred lines through rapid down-regulation of the BoFLC1.C9 gene in early-flowering line compared to late-flowering one upon vernalization. One set of primer 'F7R7' proposed as marker, of which was explained with 83 and 80% of flowering time variation in 141 F2 individuals and 20 commercial lines, respectively. CONCLUSIONS This F7R7 marker could be used as genetic tools to characterize flowering time variation and to select as well to develop early- and late-flowering cabbage cultivars.
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Affiliation(s)
- Md Abuyusuf
- Department of Horticulture, Sunchon National University, 255 Jungang-ro, Suncheon, Jeonnam, 57922, Republic of Korea.,Department of Agronomy, Patuakhali Science and Technology University, Patuakhali, 8602, Bangladesh
| | - Ujjal Kumar Nath
- Department of Horticulture, Sunchon National University, 255 Jungang-ro, Suncheon, Jeonnam, 57922, Republic of Korea.,Department of Genetics and Plant Breeding, Bangladesh Agricultural University, Mymensingh, 2202, Bangladesh
| | - Hoy-Taek Kim
- Department of Horticulture, Sunchon National University, 255 Jungang-ro, Suncheon, Jeonnam, 57922, Republic of Korea.,University-Industry Cooperation Foundation, Sunchon National University, 255 Jungang-ro, Suncheon, Jeonnam, 57922, Republic of Korea
| | - Md Rafiqul Islam
- Department of Horticulture, Sunchon National University, 255 Jungang-ro, Suncheon, Jeonnam, 57922, Republic of Korea
| | - Jong-In Park
- Department of Horticulture, Sunchon National University, 255 Jungang-ro, Suncheon, Jeonnam, 57922, Republic of Korea.
| | - Ill-Sup Nou
- Department of Horticulture, Sunchon National University, 255 Jungang-ro, Suncheon, Jeonnam, 57922, Republic of Korea.
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14
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Nibau C, Gallemí M, Dadarou D, Doonan JH, Cavallari N. Thermo-Sensitive Alternative Splicing of FLOWERING LOCUS M Is Modulated by Cyclin-Dependent Kinase G2. FRONTIERS IN PLANT SCIENCE 2019; 10:1680. [PMID: 32038671 PMCID: PMC6987439 DOI: 10.3389/fpls.2019.01680] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 11/29/2019] [Indexed: 05/05/2023]
Abstract
The ability to sense environmental temperature and to coordinate growth and development accordingly, is critical to the reproductive success of plants. Flowering time is regulated at the level of gene expression by a complex network of factors that integrate environmental and developmental cues. One of the main players, involved in modulating flowering time in response to changes in ambient temperature is FLOWERING LOCUS M (FLM). FLM transcripts can undergo extensive alternative splicing producing multiple variants, of which FLM-β and FLM-δ are the most representative. While FLM-β codes for the flowering repressor FLM protein, translation of FLM-δ has the opposite effect on flowering. Here we show that the cyclin-dependent kinase G2 (CDKG2), together with its cognate cyclin, CYCLYN L1 (CYCL1) affects the alternative splicing of FLM, balancing the levels of FLM-β and FLM-δ across the ambient temperature range. In the absence of the CDKG2/CYCL1 complex, FLM-β expression is reduced while FLM-δ is increased in a temperature dependent manner and these changes are associated with an early flowering phenotype in the cdkg2 mutant lines. In addition, we found that transcript variants retaining the full FLM intron 1 are sequestered in the cell nucleus. Strikingly, FLM intron 1 splicing is also regulated by CDKG2/CYCL1. Our results provide evidence that temperature and CDKs regulate the alternative splicing of FLM, contributing to flowering time definition.
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Affiliation(s)
- Candida Nibau
- Institute of Biological, Environmental, and Rural Sciences, Aberystwyth University, Aberystwyth, United Kingdom
- *Correspondence: Nicola Cavallari, ; Candida Nibau,
| | - Marçal Gallemí
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Despoina Dadarou
- Institute of Biological, Environmental, and Rural Sciences, Aberystwyth University, Aberystwyth, United Kingdom
| | - John H. Doonan
- Institute of Biological, Environmental, and Rural Sciences, Aberystwyth University, Aberystwyth, United Kingdom
| | - Nicola Cavallari
- Institute of Science and Technology Austria, Klosterneuburg, Austria
- Max F. Perutz Laboratories, Medical University of Vienna, Vienna, Austria
- *Correspondence: Nicola Cavallari, ; Candida Nibau,
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15
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van Hulten MHA, Paulo MJ, Kruijer W, Blankestijn-De Vries H, Kemperman B, Becker FFM, Yang J, Lauss K, Stam ME, van Eeuwijk FA, Keurentjes JJB. Assessment of heterosis in two Arabidopsis thaliana common-reference mapping populations. PLoS One 2018; 13:e0205564. [PMID: 30312352 PMCID: PMC6185836 DOI: 10.1371/journal.pone.0205564] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Accepted: 09/27/2018] [Indexed: 12/01/2022] Open
Abstract
Hybrid vigour, or heterosis, has been of tremendous importance in agriculture for the improvement of both crops and livestock. Notwithstanding large efforts to study the phenomenon of heterosis in the last decades, the identification of common molecular mechanisms underlying hybrid vigour remain rare. Here, we conducted a systematic survey of the degree of heterosis in Arabidopsis thaliana hybrids. For this purpose, two overlapping Arabidopsis hybrid populations were generated by crossing a large collection of naturally occurring accessions to two common reference lines. In these Arabidopsis hybrid populations the range of heterosis for several developmental and yield related traits was examined, and the relationship between them was studied. The traits under study were projected leaf area at 17 days after sowing, flowering time, height of the main inflorescence, number of side branches from the main stem or from the rosette base, total seed yield, seed weight, seed size and the estimated number of seeds per plant. Predominantly positive heterosis was observed for leaf area and height of the main inflorescence, whereas mainly negative heterosis was observed for rosette branching. For the other traits both positive and negative heterosis was observed in roughly equal amounts. For flowering time and seed size only low levels of heterosis were detected. In general the observed heterosis levels were highly trait specific. Furthermore, no correlation was observed between heterosis levels and the genetic distance between the parental lines. Since all selected lines were a part of the Arabidopsis genome wide association (GWA) mapping panel, a genetic mapping approach was applied to identify possible regions harbouring genetic factors causal for heterosis, with separate calculations for additive and dominance effects. Our study showed that the genetic mechanisms underlying heterosis were highly trait specific in our hybrid populations and greatly depended on the genetic background, confirming the elusive character of heterosis.
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Affiliation(s)
| | - Maria-Joāo Paulo
- Biometris, Wageningen University and Research, Wageningen, The Netherlands
| | - Willem Kruijer
- Biometris, Wageningen University and Research, Wageningen, The Netherlands
| | | | - Brend Kemperman
- Laboratory of Genetics, Wageningen University and Research, Wageningen, the Netherlands
| | - Frank F. M. Becker
- Laboratory of Genetics, Wageningen University and Research, Wageningen, the Netherlands
| | - Jiaming Yang
- Laboratory of Genetics, Wageningen University and Research, Wageningen, the Netherlands
| | - Kathrin Lauss
- Plant Development & (Epi)Genetics, Faculty of Science, Swammerdam Institute for Life Sciences, Universiteit van Amsterdam, Amsterdam, The Netherlands
| | - Maike E. Stam
- Plant Development & (Epi)Genetics, Faculty of Science, Swammerdam Institute for Life Sciences, Universiteit van Amsterdam, Amsterdam, The Netherlands
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16
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Sahebi M, Hanafi MM, van Wijnen AJ, Rice D, Rafii MY, Azizi P, Osman M, Taheri S, Bakar MFA, Isa MNM, Noor YM. Contribution of transposable elements in the plant's genome. Gene 2018; 665:155-166. [PMID: 29684486 DOI: 10.1016/j.gene.2018.04.050] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Revised: 04/04/2018] [Accepted: 04/18/2018] [Indexed: 12/26/2022]
Abstract
Plants maintain extensive growth flexibility under different environmental conditions, allowing them to continuously and rapidly adapt to alterations in their environment. A large portion of many plant genomes consists of transposable elements (TEs) that create new genetic variations within plant species. Different types of mutations may be created by TEs in plants. Many TEs can avoid the host's defense mechanisms and survive alterations in transposition activity, internal sequence and target site. Thus, plant genomes are expected to utilize a variety of mechanisms to tolerate TEs that are near or within genes. TEs affect the expression of not only nearby genes but also unlinked inserted genes. TEs can create new promoters, leading to novel expression patterns or alternative coding regions to generate alternate transcripts in plant species. TEs can also provide novel cis-acting regulatory elements that act as enhancers or inserts within original enhancers that are required for transcription. Thus, the regulation of plant gene expression is strongly managed by the insertion of TEs into nearby genes. TEs can also lead to chromatin modifications and thereby affect gene expression in plants. TEs are able to generate new genes and modify existing gene structures by duplicating, mobilizing and recombining gene fragments. They can also facilitate cellular functions by sharing their transposase-coding regions. Hence, TE insertions can not only act as simple mutagens but can also alter the elementary functions of the plant genome. Here, we review recent discoveries concerning the contribution of TEs to gene expression in plant genomes and discuss the different mechanisms by which TEs can affect plant gene expression and reduce host defense mechanisms.
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Affiliation(s)
- Mahbod Sahebi
- Laboratory of Climate-Smart Food Crop Production, Institute of Tropical Agriculture and Food Security, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia.
| | - Mohamed M Hanafi
- Laboratory of Climate-Smart Food Crop Production, Institute of Tropical Agriculture and Food Security, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia; Laboratory of Plantation Science and Technology, Institute of Plantation Studies, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia; Department of Land Management, Faculty of Agriculture, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia.
| | | | - David Rice
- Department of Molecular Biology & Biotecnology, University of Sheffield, United Kingdom
| | - M Y Rafii
- Laboratory of Climate-Smart Food Crop Production, Institute of Tropical Agriculture and Food Security, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia
| | - Parisa Azizi
- Department of Crop Science, Faculty of Agriculture, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia
| | - Mohamad Osman
- Department of Crop Science, Faculty of Agriculture, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia
| | - Sima Taheri
- Department of Crop Science, Faculty of Agriculture, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia
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17
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Bloomer RH, Dean C. Fine-tuning timing: natural variation informs the mechanistic basis of the switch to flowering in Arabidopsis thaliana. JOURNAL OF EXPERIMENTAL BOTANY 2017; 68:5439-5452. [PMID: 28992087 DOI: 10.1093/jxb/erx270] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The evolution of diverse life history strategies has allowed Arabidopsis thaliana to adapt to worldwide locations, spanning a range of latitudinal and environmental conditions. Arabidopsis thaliana accessions are either vernalization-requiring winter annuals or rapid cyclers, with extensive natural variation in vernalization requirement and response. Genetic and molecular analysis of this variation has enhanced our understanding of the mechanisms involved in life history determination, with translation to both natural and crop systems in the Brassicaceae and beyond.
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Affiliation(s)
- R H Bloomer
- John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK
| | - C Dean
- John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK
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18
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Schwartz CJ, Lee J, Amasino R. Variation in shade-induced flowering in Arabidopsis thaliana results from FLOWERING LOCUS T allelic variation. PLoS One 2017; 12:e0187768. [PMID: 29117199 PMCID: PMC5695581 DOI: 10.1371/journal.pone.0187768] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Accepted: 10/25/2017] [Indexed: 11/25/2022] Open
Abstract
Plants have evolved developmental mechanisms to ensure reproduction when in sub-optimal local environments. The shade-avoidance syndrome is one such mechanism that causes plants to elongate and accelerate flowering. Plants sense shade via the decreased red:far-red (R:FR) ratio that occurs in shade. We explored natural variation in flowering behavior caused by a decrease in the R:FR ratio of Arabidopsis thaliana accessions. A survey of accessions revealed that most exhibit a vigorous rapid-flowering response in a FR-enriched environment. However, a subset of accessions appeared to be compromised in the accelerated-flowering component of the shade-avoidance response. The genetic basis of the muted response to FR enrichment was studied in three accessions (Fl-1, Hau-0, and Mir-0). For all three accessions, the reduced FR flowering-time effect mapped to the FLOWERING LOCUS T (FT) region, and the FT alleles from these accessions are expressed at a lower level in FR-enriched light compared to alleles from accessions that respond robustly to FR enrichment. In the Mir-0 accession, a second genomic region, which includes CONSTANTS (CO), also influenced flowering in FR-enriched conditions. We have demonstrated that variation in the degree of precocious flowering in shaded conditions (low R:FR ratio) results from allelic variation at FT.
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Affiliation(s)
- C. J. Schwartz
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- * E-mail: (CS); (RA)
| | - Joohyun Lee
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Richard Amasino
- Department of Biochemistry, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
- * E-mail: (CS); (RA)
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19
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Seidl MF, Thomma BPHJ. Transposable Elements Direct The Coevolution between Plants and Microbes. Trends Genet 2017; 33:842-851. [PMID: 28800915 DOI: 10.1016/j.tig.2017.07.003] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 06/24/2017] [Accepted: 07/14/2017] [Indexed: 12/31/2022]
Abstract
Transposable elements are powerful drivers of genome evolution in many eukaryotes. Although they are mostly considered as 'selfish' genetic elements, increasing evidence suggests that they contribute to genetic variability; particularly under stress conditions. Over the past few years, the role of transposable elements during host-microbe interactions has been recognised. It has been proposed that many pathogenic microbes have evolved a 'two-speed' genome with regions that show increased variability and that are enriched in transposable elements and pathogenicity-related genes. Plants similarly display structured genomes with transposable-element-rich regions that mediate accelerated evolution. Immune receptor genes typically reside in such regions. Various mechanisms have recently been identified through which transposable elements contribute to the coevolution between plants and their associated microbes.
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Affiliation(s)
- Michael F Seidl
- Laboratory of Phytopathology, Wageningen University and Research, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands; Both authors contributed equally.
| | - Bart P H J Thomma
- Laboratory of Phytopathology, Wageningen University and Research, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands; Both authors contributed equally.
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20
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Abstract
Our understanding of the detailed molecular mechanisms underpinning adaptation is still poor. One example for which mechanistic understanding of regulation has converged with studies of life history variation is Arabidopsis thaliana FLOWERING LOCUS C (FLC). FLC determines the need for plants to overwinter and their ability to respond to prolonged cold in a process termed vernalization. This review highlights how molecular analysis of vernalization pathways has revealed important insight into antisense-mediated chromatin silencing mechanisms that regulate FLC. In turn, such insight has enabled molecular dissection of the diversity in vernalization across natural populations of A. thaliana. Changes in both cotranscriptional regulation and epigenetic silencing of FLC are caused by noncoding polymorphisms at FLC. The FLC locus is therefore providing important concepts for how noncoding transcription and chromatin regulation influence gene expression and how these mechanisms can vary to underpin adaptation in natural populations.
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Affiliation(s)
- Charles Whittaker
- John Innes Centre, Norwich Research Park, Norwich NR4 7UH, United Kingdom;
| | - Caroline Dean
- John Innes Centre, Norwich Research Park, Norwich NR4 7UH, United Kingdom;
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21
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Taylor JL, Massiah A, Kennedy S, Hong Y, Jackson SD. FLC expression is down-regulated by cold treatment in Diplotaxis tenuifolia (wild rocket), but flowering time is unaffected. JOURNAL OF PLANT PHYSIOLOGY 2017; 214:7-15. [PMID: 28419907 PMCID: PMC5477103 DOI: 10.1016/j.jplph.2017.03.015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Revised: 03/22/2017] [Accepted: 03/24/2017] [Indexed: 05/07/2023]
Abstract
Wild rocket (Diplotaxis tenuifolia) has become a very popular salad leaf due to its peppery taste. It is part of the Brassicaceae family and thus has a high level of homology at the DNA level to other Brassica species including Arabidopsis thaliana. The vernalization and photoperiodic requirements of wild rocket have not been reported to date. Photoperiodic experiments described here demonstrate that rocket is a facultative long day plant. To investigate the vernalization requirement, both seed and young plants were given vernalization treatments at 4°C for different lengths of time. A rocket homologue of FLOWERING LOCUS C (DtFLC) was isolated and shown to functionally complement the Arabidopsis FRI+flc3 null mutant. Whilst the expression of DtFLC was significantly reduced after just one week of cold treatment, cold treatments of two to eight weeks had no significant effect on bolting time of wild rocket indicating that rocket does not have a vernalization requirement. These findings illustrate that important fundamental differences can exist between model and crop plant species, such as in this case where down-regulation of DtFLC expression does not enable earlier flowering in wild rocket as it does in Arabidopsis and many other Brassica species.
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Affiliation(s)
- Jemma L Taylor
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, UK
| | - Andrea Massiah
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, UK
| | - Sue Kennedy
- Elsoms Seeds Ltd, Pinchbeck Road, Spalding PE11 1QG, UK
| | - Yiguo Hong
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, UK; Research Centre for Plant RNA Signaling, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou 310036, China
| | - Stephen D Jackson
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, UK.
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22
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Blair L, Auge G, Donohue K. Effect of FLOWERING LOCUS C on seed germination depends on dormancy. FUNCTIONAL PLANT BIOLOGY : FPB 2017; 44:493-506. [PMID: 32480582 DOI: 10.1071/fp16368] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Accepted: 12/28/2016] [Indexed: 05/11/2023]
Abstract
FLOWERING LOCUS C (FLC) has a major regulatory role in the timing of flowering in Arabidopsis thaliana (L.) Heynh. and has more recently been shown to influence germination. Here, we investigated the conditions under which FLC influences germination, and demonstrated that its effect depends on the level of primary and secondary dormancy and the temperature of seed imbibition. We tested the germination response of genotypes with different degrees of FLC activity over the course of after-ripening and after secondary dormancy induction by hot stratification. Genotypes with high FLC-activity showed higher germination; this response was greatest when seeds exhibited primary dormancy or were induced into secondary dormancy by hot stratification. In this study, which used less dormant seeds, the effect of FLC was more evident at 22°C, the less permissive germination temperature, than at 10°C, in contrast to prior published results that used more dormant seeds. Thus, because effects of FLC variation depend on dormancy, and because the range of temperature that permits germination also depends on dormancy, the temperature at which FLC affects germination can also vary with dormancy. Finally, we document that the effect of FLC can depend on FRIGIDA and that FRIGIDA itself appears to influence germination. Thus, pleiotropy between germination and flowering pathways in A. thaliana extends beyond FLC and involves other genes in the FLC genetic pathway.
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Affiliation(s)
- Logan Blair
- Duke University, Department of Biology, Box 90338, Durham, NC 27708, USA
| | - Gabriela Auge
- Duke University, Department of Biology, Box 90338, Durham, NC 27708, USA
| | - Kathleen Donohue
- Duke University, Department of Biology, Box 90338, Durham, NC 27708, USA
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23
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Blackman BK. Changing Responses to Changing Seasons: Natural Variation in the Plasticity of Flowering Time. PLANT PHYSIOLOGY 2017; 173:16-26. [PMID: 27872243 PMCID: PMC5210766 DOI: 10.1104/pp.16.01683] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Accepted: 11/20/2016] [Indexed: 05/19/2023]
Abstract
The mechanisms by which the environment regulates flowering time have evolved as crops and wild populations have adapted to diverse climates, and the specific variants involved are increasingly known.
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Affiliation(s)
- Benjamin K Blackman
- Department of Plant and Microbial Biology, University of California, Berkeley, California 94720
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24
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Ågren J, Oakley CG, Lundemo S, Schemske DW. Adaptive divergence in flowering time among natural populations of
Arabidopsis thaliana
: Estimates of selection and QTL mapping. Evolution 2016; 71:550-564. [DOI: 10.1111/evo.13126] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Revised: 10/27/2016] [Accepted: 10/31/2016] [Indexed: 01/18/2023]
Affiliation(s)
- Jon Ågren
- Department of Plant Ecology and Evolution, Evolutionary Biology Centre Uppsala University Norbyvägen 18 D SE‐752 36 Uppsala Sweden
| | | | - Sverre Lundemo
- Department of Plant Ecology and Evolution, Evolutionary Biology Centre Uppsala University Norbyvägen 18 D SE‐752 36 Uppsala Sweden
- WWF Norway Postboks 6784, St. Olavs Plass 0130 Oslo Norway
| | - Douglas W. Schemske
- Department of Plant Biology and W. K. Kellogg Biological Station Michigan State University East Lansing Michigan 48824
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25
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Negi P, Rai AN, Suprasanna P. Moving through the Stressed Genome: Emerging Regulatory Roles for Transposons in Plant Stress Response. FRONTIERS IN PLANT SCIENCE 2016; 7:1448. [PMID: 27777577 PMCID: PMC5056178 DOI: 10.3389/fpls.2016.01448] [Citation(s) in RCA: 81] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2016] [Accepted: 09/12/2016] [Indexed: 05/02/2023]
Abstract
The recognition of a positive correlation between organism genome size with its transposable element (TE) content, represents a key discovery of the field of genome biology. Considerable evidence accumulated since then suggests the involvement of TEs in genome structure, evolution and function. The global genome reorganization brought about by transposon activity might play an adaptive/regulatory role in the host response to environmental challenges, reminiscent of McClintock's original 'Controlling Element' hypothesis. This regulatory aspect of TEs is also garnering support in light of the recent evidences, which project TEs as "distributed genomic control modules." According to this view, TEs are capable of actively reprogramming host genes circuits and ultimately fine-tuning the host response to specific environmental stimuli. Moreover, the stress-induced changes in epigenetic status of TE activity may allow TEs to propagate their stress responsive elements to host genes; the resulting genome fluidity can permit phenotypic plasticity and adaptation to stress. Given their predominating presence in the plant genomes, nested organization in the genic regions and potential regulatory role in stress response, TEs hold unexplored potential for crop improvement programs. This review intends to present the current information about the roles played by TEs in plant genome organization, evolution, and function and highlight the regulatory mechanisms in plant stress responses. We will also briefly discuss the connection between TE activity, host epigenetic response and phenotypic plasticity as a critical link for traversing the translational bridge from a purely basic study of TEs, to the applied field of stress adaptation and crop improvement.
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Affiliation(s)
| | | | - Penna Suprasanna
- Plant Stress Physiology and Biotechnology Section, Nuclear Agriculture and Biotechnology Division, Bhabha Atomic Research CentreTrombay, India
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26
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Irwin JA, Soumpourou E, Lister C, Ligthart JD, Kennedy S, Dean C. Nucleotide polymorphism affecting FLC expression underpins heading date variation in horticultural brassicas. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2016; 87:597-605. [PMID: 27232938 PMCID: PMC5053238 DOI: 10.1111/tpj.13221] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Revised: 04/20/2016] [Accepted: 05/17/2016] [Indexed: 05/03/2023]
Abstract
Variation in flowering time and response to overwintering has been exploited to breed brassica vegetables that can be harvested year-round. Our knowledge of flowering time control now enables the investigation of the molecular basis of this important variation. Here, we show that a major determinant of heading date variation in Brassica oleracea is from variation in vernalization response through allelic variation at FLOWERING LOCUS C.C2 (BoFLC4). We characterize two alleles of BoFLC.C2 that are both functional and confer a requirement for vernalization, but they show distinct expression dynamics in response to cold. Complementation experiments in Arabidopsis thaliana revealed that the allelic variation results from cis polymorphism at BoFLC.C2, which quantitatively influences the degree of cold-induced epigenetic silencing. This results in one allelic variant conferring consistently later heading under both glasshouse and field conditions through reduced environmental sensitivity. Our results suggest that breeding of brassica varieties for commercially valuable variation in heading date has been achieved through the selection of cis polymorphism at FLC, similar to that underpinning natural variation in A. thaliana. This understanding will allow for the selection of alleles with distinct sensitivities to cold and robust heading dates under variable climatic conditions, and will facilitate the breeding of varieties more resistant to climate change.
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Affiliation(s)
- Judith A Irwin
- John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK
| | | | - Clare Lister
- John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK
| | | | - Sue Kennedy
- Elsoms Seeds Ltd, Pinchbeck Road, Spalding, PE11 1QG, UK
| | - Caroline Dean
- John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK.
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27
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Sanchez-Bermejo E, Balasubramanian S. Natural variation involving deletion alleles of FRIGIDA modulate temperature-sensitive flowering responses in Arabidopsis thaliana. PLANT, CELL & ENVIRONMENT 2016; 39:1353-65. [PMID: 26662639 DOI: 10.1111/pce.12690] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Revised: 11/28/2015] [Accepted: 11/29/2015] [Indexed: 05/12/2023]
Abstract
Ambient temperature is one of the major environmental factors that modulate plant growth and development. There is extensive natural genetic variation in thermal responses of plants exemplified by the variation exhibited by the accessions of Arabidopsis thaliana. In this work we have studied the enhanced temperature response in hypocotyl elongation and flowering shown by the Tsu-0 accession in long days. Genetic mapping in the Col-0 × Tsu-0 recombinant inbred line (RIL) population identified several QTLs for thermal response including three major effect loci encompassing candidate genes FRIGIDA (FRI), FLOWERING LOCUS C (FLC) and FLOWERING LOCUS T (FT). We confirm and validate these QTLs. We show that the Tsu-0 FRI allele, which is the same as FRI-Ler is associated with late flowering but only at lower temperatures in long days. Using transgenic lines and accessions, we show that the FRI-Ler allele confers temperature-sensitive late flowering confirming a role for FRI in photoperiod-dependent thermal response. Through quantitative complementation with heterogeneous inbred families, we further show that cis-regulatory variation at FT contributes to the observed hypersensitivity of Tsu-0 to ambient temperature. Overall our results suggest that multiple loci that interact epistatically govern photoperiod-dependent thermal responses of A. thaliana.
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28
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Finnegan EJ. Time-dependent stabilization of the +1 nucleosome is an early step in the transition to stable cold-induced repression of FLC. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2015; 84:875-885. [PMID: 26437570 DOI: 10.1111/tpj.13044] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Revised: 09/08/2015] [Accepted: 09/24/2015] [Indexed: 06/05/2023]
Abstract
In vernalized Arabidopsis, the extent of FLC repression and promotion of flowering are correlated with the length of winter (low temperature exposure), but how plants measure the duration of winter is unknown. Repression of FLC occurs in two phases: establishment and maintenance. This study investigates the early events in the transition between establishment and maintenance of repression. Initial repression was rapid but transient; within 24 h of being placed at low temperatures FLC transcription was reduced by 40% and repression was complete after 5 days in the cold. The extent to which repression was maintained depended on the length of the cold treatment. Occupancy of the +1 nucleosome in FLC chromatin increased in a time-dependent manner over a 4-week low temperature treatment concomitant with decreased histone acetylation and increased trimethylation of histone H3 lysine 27 (H3K27me3). Mutant analyses showed that increased nucleosome occupancy occurred independent of histone deacetylation and increased H3K27me3, suggesting that it is an early step in the switch between transient and stable repression. Both altered histone composition and deacetylation contributed to increased nucleosome occupancy. The time-dependency of the steps required for the switch between transient and stable repression suggests that the duration of winter is measured by the chromatin state at FLC. A chromatin-based switch is consistent with finding that each FLC allele in a cell undergoes this transition independently.
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Affiliation(s)
- E Jean Finnegan
- CSIRO, Agriculture, GPO Box 1600, Canberra, ACT, 2601, Australia
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Modulation of Ambient Temperature-Dependent Flowering in Arabidopsis thaliana by Natural Variation of FLOWERING LOCUS M. PLoS Genet 2015; 11:e1005588. [PMID: 26492483 PMCID: PMC4619661 DOI: 10.1371/journal.pgen.1005588] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Accepted: 09/16/2015] [Indexed: 12/27/2022] Open
Abstract
Plants integrate seasonal cues such as temperature and day length to optimally adjust their flowering time to the environment. Compared to the control of flowering before and after winter by the vernalization and day length pathways, mechanisms that delay or promote flowering during a transient cool or warm period, especially during spring, are less well understood. Due to global warming, understanding this ambient temperature pathway has gained increasing importance. In Arabidopsis thaliana, FLOWERING LOCUS M (FLM) is a critical flowering regulator of the ambient temperature pathway. FLM is alternatively spliced in a temperature-dependent manner and the two predominant splice variants, FLM-ß and FLM-δ, can repress and activate flowering in the genetic background of the A. thaliana reference accession Columbia-0. The relevance of this regulatory mechanism for the environmental adaptation across the entire range of the species is, however, unknown. Here, we identify insertion polymorphisms in the first intron of FLM as causative for accelerated flowering in many natural A. thaliana accessions, especially in cool (15°C) temperatures. We present evidence for a potential adaptive role of this structural variation and link it specifically to changes in the abundance of FLM-ß. Our results may allow predicting flowering in response to ambient temperatures in the Brassicaceae.
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Sasaki E, Zhang P, Atwell S, Meng D, Nordborg M. "Missing" G x E Variation Controls Flowering Time in Arabidopsis thaliana. PLoS Genet 2015; 11:e1005597. [PMID: 26473359 PMCID: PMC4608753 DOI: 10.1371/journal.pgen.1005597] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 09/18/2015] [Indexed: 11/18/2022] Open
Abstract
Understanding how genetic variation interacts with the environment is essential for understanding adaptation. In particular, the life cycle of plants is tightly coordinated with local environmental signals through complex interactions with the genetic variation (G x E). The mechanistic basis for G x E is almost completely unknown. We collected flowering time data for 173 natural inbred lines of Arabidopsis thaliana from Sweden under two growth temperatures (10°C and 16°C), and observed massive G x E variation. To identify the genetic polymorphisms underlying this variation, we conducted genome-wide scans using both SNPs and local variance components. The SNP-based scan identified several variants that had common effects in both environments, but found no trace of G x E effects, whereas the scan using local variance components found both. Furthermore, the G x E effects appears to be concentrated in a small fraction of the genome (0.5%). Our conclusion is that G x E effects in this study are mostly due to large numbers of allele or haplotypes at a small number of loci, many of which correspond to previously identified flowering time genes.
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Affiliation(s)
- Eriko Sasaki
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna Biocenter (VBC), Vienna, Austria
| | - Pei Zhang
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna Biocenter (VBC), Vienna, Austria
- Molecular and Computational Biology, University of Southern California, Los Angeles, California, United States of America
| | - Susanna Atwell
- Molecular and Computational Biology, University of Southern California, Los Angeles, California, United States of America
| | - Dazhe Meng
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna Biocenter (VBC), Vienna, Austria
- Molecular and Computational Biology, University of Southern California, Los Angeles, California, United States of America
| | - Magnus Nordborg
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna Biocenter (VBC), Vienna, Austria
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31
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Lazaro A, Mouriz A, Piñeiro M, Jarillo JA. Red Light-Mediated Degradation of CONSTANS by the E3 Ubiquitin Ligase HOS1 Regulates Photoperiodic Flowering in Arabidopsis. THE PLANT CELL 2015; 27:2437-54. [PMID: 26373454 PMCID: PMC4815090 DOI: 10.1105/tpc.15.00529] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2015] [Revised: 08/12/2015] [Accepted: 08/22/2015] [Indexed: 05/18/2023]
Abstract
The regulation of CONSTANS (CO) gene expression is crucial to accurately measure changes in daylength, which influences flowering time in Arabidopsis thaliana. CO expression is under both transcriptional and posttranslational control mechanisms. We previously showed that the E3 ubiquitin ligase HIGH EXPRESSION OF OSMOTICALLY RESPONSIVE GENES1 (HOS1) physically interacts with CO in Arabidopsis. This interaction is required to precisely modulate the timing of CO accumulation and, consequently, to maintain low levels of FLOWERING LOCUS T expression during the first part of the day. The data presented here demonstrate that HOS1 is involved in the red light-mediated degradation of CO that takes place in the early stages of the daylight period. Our results show that phytochrome B (phyB) is able to regulate flowering time, acting in the phloem companion cells, as previously described for CO and HOS1. Moreover, we reveal that phyB physically interacts with HOS1 and CO, indicating that the three proteins may be present in a complex in planta that is required to coordinate a correct photoperiodic response in Arabidopsis.
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Affiliation(s)
- Ana Lazaro
- Centro de Biotecnología y Genómica de Plantas, INIA-UPM, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, 28223 Madrid, Spain
| | - Alfonso Mouriz
- Centro de Biotecnología y Genómica de Plantas, INIA-UPM, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, 28223 Madrid, Spain
| | - Manuel Piñeiro
- Centro de Biotecnología y Genómica de Plantas, INIA-UPM, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, 28223 Madrid, Spain
| | - José A Jarillo
- Centro de Biotecnología y Genómica de Plantas, INIA-UPM, Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria, 28223 Madrid, Spain
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Hepworth J, Dean C. Flowering Locus C's Lessons: Conserved Chromatin Switches Underpinning Developmental Timing and Adaptation. PLANT PHYSIOLOGY 2015; 168:1237-45. [PMID: 26149571 PMCID: PMC4528751 DOI: 10.1104/pp.15.00496] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Accepted: 07/03/2015] [Indexed: 05/18/2023]
Abstract
Analysis of how seasonal cues influence the timing of the floral transition has revealed many important principles for how epigenetic regulation can integrate a variety of environmental cues with developmental signals. The study of the pathways that necessitate overwintering in plants and their ability to respond to prolonged cold (the vernalization requirement and response pathways) has elaborated different chromatin regulatory pathways and the involvement of noncoding RNAs. The major target of these vernalization pathways in Arabidopsis (Arabidopsis thaliana) is Flowering Locus C (FLC). A relatively simple picture of FLC regulation is emerging of a few core complexes and mechanisms that antagonize each other's actions. This balance provides a fine degree of control that has nevertheless permitted evolution of a wide range of natural variation in vernalization in Arabidopsis. Similar simple routes of adaptation may underlie life history variation between species.
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Affiliation(s)
- Jo Hepworth
- John Innes Centre, Norwich Research Park, Norwich NR4 7UH, United Kingdom
| | - Caroline Dean
- John Innes Centre, Norwich Research Park, Norwich NR4 7UH, United Kingdom
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Berry S, Dean C. Environmental perception and epigenetic memory: mechanistic insight through FLC. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2015; 83:133-48. [PMID: 25929799 PMCID: PMC4691321 DOI: 10.1111/tpj.12869] [Citation(s) in RCA: 151] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Revised: 04/13/2015] [Accepted: 04/20/2015] [Indexed: 05/18/2023]
Abstract
Chromatin plays a central role in orchestrating gene regulation at the transcriptional level. However, our understanding of how chromatin states are altered in response to environmental and developmental cues, and then maintained epigenetically over many cell divisions, remains poor. The floral repressor gene FLOWERING LOCUS C (FLC) in Arabidopsis thaliana is a useful system to address these questions. FLC is transcriptionally repressed during exposure to cold temperatures, allowing studies of how environmental conditions alter expression states at the chromatin level. FLC repression is also epigenetically maintained during subsequent development in warm conditions, so that exposure to cold may be remembered. This memory depends on molecular complexes that are highly conserved among eukaryotes, making FLC not only interesting as a paradigm for understanding biological decision-making in plants, but also an important system for elucidating chromatin-based gene regulation more generally. In this review, we summarize our understanding of how cold temperature induces a switch in the FLC chromatin state, and how this state is epigenetically remembered. We also discuss how the epigenetic state of FLC is reprogrammed in the seed to ensure a requirement for cold exposure in the next generation.
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Affiliation(s)
- Scott Berry
- John Innes Centre, Norwich Research ParkNorwich, NR4 7UH, UK
| | - Caroline Dean
- John Innes Centre, Norwich Research ParkNorwich, NR4 7UH, UK
- * For correspondence (e-mail )
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Investigating the Association between Flowering Time and Defense in the Arabidopsis thaliana-Fusarium oxysporum Interaction. PLoS One 2015; 10:e0127699. [PMID: 26034991 PMCID: PMC4452756 DOI: 10.1371/journal.pone.0127699] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Accepted: 04/17/2015] [Indexed: 12/21/2022] Open
Abstract
Plants respond to pathogens either by investing more resources into immunity which is costly to development, or by accelerating reproductive processes such as flowering time to ensure reproduction occurs before the plant succumbs to disease. In this study we explored the link between flowering time and pathogen defense using the interaction between Arabidopsis thaliana and the root infecting fungal pathogen Fusarium oxysporum. We report that F. oxysporum infection accelerates flowering time and regulates transcription of a number of floral integrator genes, including FLOWERING LOCUS C (FLC), FLOWERING LOCUS T (FT) and GIGANTEA (GI). Furthermore, we observed a positive correlation between late flowering and resistance to F. oxysporum in A. thaliana natural ecotypes. Late-flowering gi and autonomous pathway mutants also exhibited enhanced resistance to F. oxysporum, supporting the association between flowering time and defense. However, epistasis analysis showed that accelerating flowering time by deletion of FLC in fve-3 or fpa-7 mutants did not alter disease resistance, suggesting that the effect of autonomous pathway on disease resistance occurs independently from flowering time. Indeed, RNA-seq analyses suggest that fve-3 mediated resistance to F. oxysporum is most likely a result of altered defense-associated gene transcription. Together, our results indicate that the association between flowering time and pathogen defense is complex and can involve both pleiotropic and direct effects.
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35
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Rodríguez-Leal D, León-Martínez G, Abad-Vivero U, Vielle-Calzada JP. Natural variation in epigenetic pathways affects the specification of female gamete precursors in Arabidopsis. THE PLANT CELL 2015; 27:1034-45. [PMID: 25829442 PMCID: PMC4558685 DOI: 10.1105/tpc.114.133009] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Revised: 01/23/2015] [Accepted: 03/01/2015] [Indexed: 05/03/2023]
Abstract
In angiosperms, the transition to the female gametophytic phase relies on the specification of premeiotic gamete precursors from sporophytic cells in the ovule. In Arabidopsis thaliana, a single diploid cell is specified as the premeiotic female gamete precursor. Here, we show that ecotypes of Arabidopsis exhibit differences in megasporogenesis leading to phenotypes reminiscent of defects in dominant mutations that epigenetically affect the specification of female gamete precursors. Intraspecific hybridization and polyploidy exacerbate these defects, which segregate quantitatively in F2 populations derived from ecotypic hybrids, suggesting that multiple loci control cell specification at the onset of female meiosis. This variation in cell differentiation is influenced by the activity of ARGONAUTE9 (AGO9) and RNA-DEPENDENT RNA POLYMERASE6 (RDR6), two genes involved in epigenetic silencing that control the specification of female gamete precursors. The pattern of transcriptional regulation and localization of AGO9 varies among ecotypes, and abnormal gamete precursors in ovules defective for RDR6 share identity with ectopic gamete precursors found in selected ecotypes. Our results indicate that differences in the epigenetic control of cell specification lead to natural phenotypic variation during megasporogenesis. We propose that this mechanism could be implicated in the emergence and evolution of the reproductive alternatives that prevail in flowering plants.
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Affiliation(s)
- Daniel Rodríguez-Leal
- Grupo de Desarrollo Reproductivo y Apomixis, Laboratorio Nacional de Genómica para la Biodiversidad y Departamento de Ingeniería Genética de Plantas, Cinvestav Irapuato CP36821 Guanajuato, Mexico
| | - Gloria León-Martínez
- Centro Interdisciplinario de Investigación para el Desarrollo Integral Regional del Instituto Politécnico Nacional, Unidad Michoacán, CP 59510 Jiquilpan, Mexico
| | - Ursula Abad-Vivero
- Grupo de Desarrollo Reproductivo y Apomixis, Laboratorio Nacional de Genómica para la Biodiversidad y Departamento de Ingeniería Genética de Plantas, Cinvestav Irapuato CP36821 Guanajuato, Mexico
| | - Jean-Philippe Vielle-Calzada
- Grupo de Desarrollo Reproductivo y Apomixis, Laboratorio Nacional de Genómica para la Biodiversidad y Departamento de Ingeniería Genética de Plantas, Cinvestav Irapuato CP36821 Guanajuato, Mexico
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36
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Simpson S, Edwards J, Emes RD, Cobb MA, Mongan NP, Rutland CS. A predictive model for canine dilated cardiomyopathy-a meta-analysis of Doberman Pinscher data. PeerJ 2015; 3:e842. [PMID: 25834770 PMCID: PMC4380154 DOI: 10.7717/peerj.842] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Accepted: 02/27/2015] [Indexed: 11/20/2022] Open
Abstract
Dilated cardiomyopathy is a prevalent and often fatal disease in humans and dogs. Indeed dilated cardiomyopathy is the third most common form of cardiac disease in humans, reported to affect approximately 36 individuals per 100,000 individuals. In dogs, dilated cardiomyopathy is the second most common cardiac disease and is most prevalent in the Irish Wolfhound, Doberman Pinscher and Newfoundland breeds. Dilated cardiomyopathy is characterised by ventricular chamber enlargement and systolic dysfunction which often leads to congestive heart failure. Although multiple human loci have been implicated in the pathogenesis of dilated cardiomyopathy, the identified variants are typically associated with rare monogenic forms of dilated cardiomyopathy. The potential for multigenic interactions contributing to human dilated cardiomyopathy remains poorly understood. Consistent with this, several known human dilated cardiomyopathy loci have been excluded as common causes of canine dilated cardiomyopathy, although canine dilated cardiomyopathy resembles the human disease functionally. This suggests additional genetic factors contribute to the dilated cardiomyopathy phenotype.This study represents a meta-analysis of available canine dilated cardiomyopathy genetic datasets with the goal of determining potential multigenic interactions relating the sex chromosome genotype (XX vs. XY) with known dilated cardiomyopathy associated loci on chromosome 5 and the PDK4 gene in the incidence and progression of dilated cardiomyopathy. The results show an interaction between known canine dilated cardiomyopathy loci and an unknown X-linked locus. Our study is the first to test a multigenic contribution to dilated cardiomyopathy and suggest a genetic basis for the known sex-disparity in dilated cardiomyopathy outcomes.
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Affiliation(s)
- Siobhan Simpson
- School of Veterinary Medicine and Science, Sutton Bonington Campus, University of Nottingham , Leicestershire , UK
| | - Jennifer Edwards
- School of Veterinary Medicine and Science, Sutton Bonington Campus, University of Nottingham , Leicestershire , UK
| | - Richard D Emes
- School of Veterinary Medicine and Science, Sutton Bonington Campus, University of Nottingham , Leicestershire , UK ; Advanced Data Analysis Centre, Sutton Bonington Campus, University of Nottingham , Leicestershire , UK
| | - Malcolm A Cobb
- School of Veterinary Medicine and Science, Sutton Bonington Campus, University of Nottingham , Leicestershire , UK
| | - Nigel P Mongan
- School of Veterinary Medicine and Science, Sutton Bonington Campus, University of Nottingham , Leicestershire , UK ; Department of Pharmacology, Weill Cornell Medical College , New York, NY , USA
| | - Catrin S Rutland
- School of Veterinary Medicine and Science, Sutton Bonington Campus, University of Nottingham , Leicestershire , UK
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37
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Helliwell CA, Anderssen RS, Robertson M, Finnegan EJ. How is FLC repression initiated by cold? TRENDS IN PLANT SCIENCE 2015; 20:76-82. [PMID: 25600480 DOI: 10.1016/j.tplants.2014.12.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Revised: 11/21/2014] [Accepted: 12/16/2014] [Indexed: 05/07/2023]
Abstract
Vernalization is the promotion of flowering in response to prolonged exposure to low temperatures. In Arabidopsis, FLOWERING LOCUS C (FLC), a suppressor of flowering, is repressed by low temperatures but the mechanism leading to the initial decrease in FLC transcription remains a mystery. No mutants that block the repression of FLC at low temperatures have been identified to date. If the failure to identify such a mutant is assumed to imply that no such mutant exists, then it follows that the first response to the drop in temperature is physical, not genetic. In this Opinion article we propose that the drop in temperature first causes a simple change in the topology of the chromatin polymer, which in turn initiates the repression of FLC transcription.
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Affiliation(s)
- Chris A Helliwell
- Commonwealth Scientific and Industrial Research Organisation (CSIRO), Agriculture, Canberra ACT, Australia
| | | | - Masumi Robertson
- Commonwealth Scientific and Industrial Research Organisation (CSIRO), Agriculture, Canberra ACT, Australia
| | - E Jean Finnegan
- Commonwealth Scientific and Industrial Research Organisation (CSIRO), Agriculture, Canberra ACT, Australia.
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38
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Golembeski GS, Imaizumi T. Photoperiodic Regulation of Florigen Function in Arabidopsis thaliana. THE ARABIDOPSIS BOOK 2015; 13:e0178. [PMID: 26157354 PMCID: PMC4489636 DOI: 10.1199/tab.0178] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
One mechanism through which flowering in response to seasonal change is brought about is by sensing the fluctuation in day-length; the photoperiod. Flowering induction occurs through the production of the florigenic protein FLOWERING LOCUS T (FT) and its movement from the phloem companion cells in the leaf vasculature into the shoot apex, where meristematic reprogramming occurs. FT activation in response to photoperiod condition is accomplished largely through the activity of the transcription factor CONSTANS (CO). Regulation of CO expression and protein stability, as well as the timing of other components via the circadian clock, is a critical mechanism by which plants are able to respond to photoperiod to initiate the floral transition. Modulation of FT expression in response to external and internal stimuli via components of the flowering network is crucial to mediate a fluid flowering response to a variety of environmental parameters. In addition, the regulated movement of FT protein from the phloem to the shoot apex, and interactions that determine floral meristem cell fate, constitute novel mechanisms through which photoperiodic information is translated into flowering time.
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Affiliation(s)
- Greg S. Golembeski
- University of Washington, Department of Biology, Seattle, WA, 98195-1800
| | - Takato Imaizumi
- University of Washington, Department of Biology, Seattle, WA, 98195-1800
- Address correspondence to
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39
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Suter L, Rüegg M, Zemp N, Hennig L, Widmer A. Gene regulatory variation mediates flowering responses to vernalization along an altitudinal gradient in Arabidopsis. PLANT PHYSIOLOGY 2014; 166:1928-42. [PMID: 25339407 PMCID: PMC4256870 DOI: 10.1104/pp.114.247346] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Steep environmental gradients provide ideal settings for studies of potentially adaptive phenotypic and genetic variation in plants. The accurate timing of flowering is crucial for reproductive success and is regulated by several pathways, including the vernalization pathway. Among the numerous genes known to enable flowering in response to vernalization, the most prominent is FLOWERING LOCUS C (FLC). FLC and other genes of the vernalization pathway vary extensively among natural populations and are thus candidates for the adaptation of flowering time to environmental gradients such as altitude. We used 15 natural Arabidopsis (Arabidopsis thaliana) genotypes originating from an altitudinal gradient (800-2,700 m above sea level) in the Swiss Alps to test whether flowering time correlated with altitude under different vernalization scenarios. Additionally, we measured the expression of 12 genes of the vernalization pathway and its downstream targets. Flowering time correlated with altitude in a nonlinear manner for vernalized plants. Flowering time could be explained by the expression and regulation of the vernalization pathway, most notably by AGAMOUS LIKE19 (AGL19), FLOWERING LOCUS T (FT), and FLC. The expression of AGL19, FT, and VERNALIZATION INSENSITIVE3 was associated with altitude, and the regulation of MADS AFFECTING FLOWERING2 (MAF2) and MAF3 differed between low- and high-altitude genotypes. In conclusion, we found clinal variation across an altitudinal gradient both in flowering time and the expression and regulation of genes in the flowering time control network, often independent of FLC, suggesting that the timing of flowering may contribute to altitudinal adaptation.
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Affiliation(s)
- Léonie Suter
- Eidgenössisch Technische Hochschule Zürich, Institute of Integrative Biology, 8092 Zurich, Switzerland (L.S., M.R., N.Z., A.W.); andDepartment of Plant Biology, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, SE-75007 Uppsala, Sweden (L.H.)
| | - Marlene Rüegg
- Eidgenössisch Technische Hochschule Zürich, Institute of Integrative Biology, 8092 Zurich, Switzerland (L.S., M.R., N.Z., A.W.); andDepartment of Plant Biology, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, SE-75007 Uppsala, Sweden (L.H.)
| | - Niklaus Zemp
- Eidgenössisch Technische Hochschule Zürich, Institute of Integrative Biology, 8092 Zurich, Switzerland (L.S., M.R., N.Z., A.W.); andDepartment of Plant Biology, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, SE-75007 Uppsala, Sweden (L.H.)
| | - Lars Hennig
- Eidgenössisch Technische Hochschule Zürich, Institute of Integrative Biology, 8092 Zurich, Switzerland (L.S., M.R., N.Z., A.W.); andDepartment of Plant Biology, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, SE-75007 Uppsala, Sweden (L.H.)
| | - Alex Widmer
- Eidgenössisch Technische Hochschule Zürich, Institute of Integrative Biology, 8092 Zurich, Switzerland (L.S., M.R., N.Z., A.W.); andDepartment of Plant Biology, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, SE-75007 Uppsala, Sweden (L.H.)
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40
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Dittmar EL, Oakley CG, Ågren J, Schemske DW. Flowering time QTL in natural populations ofArabidopsis thalianaand implications for their adaptive value. Mol Ecol 2014; 23:4291-303. [DOI: 10.1111/mec.12857] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2014] [Accepted: 06/27/2014] [Indexed: 01/31/2023]
Affiliation(s)
- Emily L. Dittmar
- Department of Plant Biology and W. K. Kellogg Biological Station; Michigan State University; East Lansing MI 48824 USA
| | | | - Jon Ågren
- Department of Plant Ecology and Evolution; Evolutionary Biology Centre; Uppsala University; Norbyvägen 18 D SE-752 36 Uppsala Sweden
| | - Douglas W. Schemske
- Department of Plant Biology and W. K. Kellogg Biological Station; Michigan State University; East Lansing MI 48824 USA
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Liu L, Adrian J, Pankin A, Hu J, Dong X, von Korff M, Turck F. Induced and natural variation of promoter length modulates the photoperiodic response of FLOWERING LOCUS T. Nat Commun 2014; 5:4558. [PMID: 25087553 PMCID: PMC4143923 DOI: 10.1038/ncomms5558] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Accepted: 06/30/2014] [Indexed: 12/15/2022] Open
Abstract
FLOWERING LOCUS T (FT) regulates the floral transition in many plant species by integrating environmental seasonal signals and internal cues. Here we show that two interdependent regulatory regions are necessary and sufficient to convey photoperiod responsiveness to FT. While a minimal distance between the regulatory regions is required to fully suppress FT expression under short days, increased distance reduces promoter response to long days. Natural variation at FT creating promoter length differences is widespread, correlates with longitudinal and latitudinal clines and affects a promoter region physically interacting with both photoperiod control regions. Three major FT promoter variants correlate with differences in FT allele usage in F1 hybrids. We propose that FT variation in cis could be adaptive by conferring differences in FT transcriptional control ultimately translating to increased fitness. Gene expression at FLOWERING LOCUS T controls floral transition in many plants and is regulated by both environmental signals and internal cues. Liu et al. show that the distance between two regulatory sequences in the FT promoter varies with geographical location and determines responsiveness to photoperiod.
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Affiliation(s)
- Liangyu Liu
- 1] Max Planck Institute for Plant Breeding Research, Department of Plant Developmental Biology, Carl von Linne Weg 10, 50829 Cologne, Germany [2] Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Kunming, Yunnan 650223, China [3] University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jessika Adrian
- 1] Max Planck Institute for Plant Breeding Research, Department of Plant Developmental Biology, Carl von Linne Weg 10, 50829 Cologne, Germany [2]
| | - Artem Pankin
- Max Planck Institute for Plant Breeding Research, Department of Plant Developmental Biology, Carl von Linne Weg 10, 50829 Cologne, Germany
| | - Jinyong Hu
- Max Planck Institute for Plant Breeding Research, Department of Plant Breeding and Genetics, Carl von Linne Weg 10, 50829 Cologne, Germany
| | - Xue Dong
- Max Planck Institute for Plant Breeding Research, Department of Plant Developmental Biology, Carl von Linne Weg 10, 50829 Cologne, Germany
| | - Maria von Korff
- 1] Max Planck Institute for Plant Breeding Research, Department of Plant Developmental Biology, Carl von Linne Weg 10, 50829 Cologne, Germany [2] Institute of Plant Genetics, Heinrich-Heine-University, Cluster of Excellence on Plant Sciences "From Complex Traits towards Synthetic Modules", 40225 Düsseldorf, Germany
| | - Franziska Turck
- Max Planck Institute for Plant Breeding Research, Department of Plant Developmental Biology, Carl von Linne Weg 10, 50829 Cologne, Germany
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Budde KB, Heuertz M, Hernández-Serrano A, Pausas JG, Vendramin GG, Verdú M, González-Martínez SC. In situ genetic association for serotiny, a fire-related trait, in Mediterranean maritime pine (Pinus pinaster). THE NEW PHYTOLOGIST 2014; 201:230-241. [PMID: 24015853 DOI: 10.1111/nph.12483] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Accepted: 07/28/2013] [Indexed: 05/28/2023]
Abstract
Wildfire is a major ecological driver of plant evolution. Understanding the genetic basis of plant adaptation to wildfire is crucial, because impending climate change will involve fire regime changes worldwide. We studied the molecular genetic basis of serotiny, a fire-related trait, in Mediterranean maritime pine using association genetics. A single nucleotide polymorphism (SNP) set was used to identify genotype : phenotype associations in situ in an unstructured natural population of maritime pine (eastern Iberian Peninsula) under a mixed-effects model framework. RR-BLUP was used to build predictive models for serotiny in this region. Model prediction power outside the focal region was tested using independent range-wide serotiny data. Seventeen SNPs were potentially associated with serotiny, explaining approximately 29% of the trait phenotypic variation in the eastern Iberian Peninsula. Similar prediction power was found for nearby geographical regions from the same maternal lineage, but not for other genetic lineages. Association genetics for ecologically relevant traits evaluated in situ is an attractive approach for forest trees provided that traits are under strong genetic control and populations are unstructured, with large phenotypic variability. This will help to extend the research focus to ecological keystone non-model species in their natural environments, where polymorphisms acquired their adaptive value.
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Affiliation(s)
- Katharina B Budde
- Department of Forest Ecology and Genetics, INIA Forest Research Centre, 28040, Madrid, Spain
| | - Myriam Heuertz
- Department of Forest Ecology and Genetics, INIA Forest Research Centre, 28040, Madrid, Spain
| | - Ana Hernández-Serrano
- Centro de Investigaciones sobre Desertificación (CIDE-CSIC/UV/GV), 46113, Moncada, Valencia, Spain
| | - Juli G Pausas
- Centro de Investigaciones sobre Desertificación (CIDE-CSIC/UV/GV), 46113, Moncada, Valencia, Spain
| | - Giovanni G Vendramin
- Plant Genetics Institute, National Research Council, 50019, Sesto Fiorentino, Florence, Italy
| | - Miguel Verdú
- Centro de Investigaciones sobre Desertificación (CIDE-CSIC/UV/GV), 46113, Moncada, Valencia, Spain
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43
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Kim DH, Sung S. Genetic and epigenetic mechanisms underlying vernalization. THE ARABIDOPSIS BOOK 2014; 12:e0171. [PMID: 24653667 PMCID: PMC3952384 DOI: 10.1199/tab.0171] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Plants have evolved a number of monitoring systems to sense their surroundings and to coordinate their growth and development accordingly. Vernalization is one example, in which flowering is promoted after plants have been exposed to a long-term cold temperature (i.e. winter). Vernalization results in the repression of floral repressor genes that inhibit the floral transition in many plant species. Here, we describe recent advances in our understanding of the vernalization-mediated promotion of flowering in Arabidopsis and other flowering plants. In Arabidopsis, the vernalization response includes the recruitment of chromatin-modifying complexes to floral repressors and thus results in the enrichment of repressive histone marks that ensure the stable repression of floral repressor genes. Changes in histone modifications at floral repressor loci are stably maintained after cold exposure, establishing the competence to flower the following spring. We also discuss similarities and differences in regulatory circuits in vernalization responses among Arabidopsis and other plants.
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Affiliation(s)
- Dong-Hwan Kim
- Department of Molecular Biosciences and Institute for Cellular and Molecular Biology, University of Texas, Austin, Texas 78712
| | - Sibum Sung
- Department of Molecular Biosciences and Institute for Cellular and Molecular Biology, University of Texas, Austin, Texas 78712
- Address correspondence to
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44
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Abstract
It is increasingly important to improve our understanding of the genetic basis of local adaptation because of its relevance to climate change, crop and animal production, and conservation of genetic resources. Phenotypic patterns that are generated by spatially varying selection have long been observed, and both genetic mapping and field experiments provided initial insights into the genetic architecture of adaptive traits. Genomic tools are now allowing genome-wide studies, and recent theoretical advances can help to design research strategies that combine genomics and field experiments to examine the genetics of local adaptation. These advances are also allowing research in non-model species, the adaptation patterns of which may differ from those of traditional model species.
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45
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Putterill J, Zhang L, Yeoh CC, Balcerowicz M, Jaudal M, Gasic EV. FT genes and regulation of flowering in the legume Medicago truncatula. FUNCTIONAL PLANT BIOLOGY : FPB 2013; 40:1199-1207. [PMID: 32481188 DOI: 10.1071/fp13087] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Accepted: 05/25/2013] [Indexed: 05/04/2023]
Abstract
Flowering time is an important contributor to plant productivity and yield. Plants integrate flowering signals from a range of different internal and external cues in order to flower and set seed under optimal conditions. Networks of genes controlling flowering time have been uncovered in the flowering models Arabidopsis, wheat, barley and rice. Investigations have revealed important commonalities such as FT genes that promote flowering in all of these plants, as well as regulators that are unique to some of them. FT genes also have functions beyond floral promotion, including acting as floral repressors and having a complex role in woody polycarpic plants such as vines and trees. However, much less is known overall about flowering control in other important groups of plants such as the legumes. This review discusses recent efforts to uncover flowering-time regulators using candidate gene approaches or forward screens for spring early flowering mutants in the legume Medicago truncatula. The results highlight the importance of a Medicago FT gene, FTa1, in flowering-time control. However, the mechanisms by which FTa1 is regulated by environmental signals such as long days (photoperiod) and vernalisation (winter cold) appear to differ from Arabidopsis.
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Affiliation(s)
- Joanna Putterill
- Flowering Lab, School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand
| | - Lulu Zhang
- Flowering Lab, School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand
| | - Chin Chin Yeoh
- Flowering Lab, School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand
| | - Martin Balcerowicz
- Flowering Lab, School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand
| | - Mauren Jaudal
- Flowering Lab, School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland, New Zealand
| | - Erika Varkonyi Gasic
- The New Zealand Institute for Plant and Food Research Limited (Plant and Food Research) Mt Albert, Private Bag 92169, Auckland Mail Centre, Auckland 1142, New Zealand
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46
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Turck F, Coupland G. Natural variation in epigenetic gene regulation and its effects on plant developmental traits. Evolution 2013; 68:620-31. [PMID: 24117443 DOI: 10.1111/evo.12286] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Accepted: 09/30/2013] [Indexed: 01/02/2023]
Abstract
In plants, epigenetic variation contributes to phenotypic differences in developmental traits. At the mechanistic level, this variation is conferred by DNA methylation and histone modifications. We describe several examples in which changes in gene expression caused by variation in DNA methylation lead to alterations in plant development. In these examples, the presence of repeated sequences or transposons within the promoters of the affected genes are associated with DNA methylation and gene inactivation. Small interfering RNAs expressed from these sequences recruit DNA methylation to the gene. Some of these methylated alleles are unstable giving rise to revertant sectors during mitosis and to progeny in which the methylated state is lost. However, others are stable for many generations and persist through speciation. These examples indicate that although DNA methylation influences gene expression, this is frequently dependent on classical changes to DNA sequence such as transposon insertions. By contrast, forms of histone methylation cause repression of gene expression that is stably inherited through mitosis but that can also be erased over time or during meiosis. A striking example involves the induction of flowering by exposure to low winter temperatures in Arabidopsis thaliana and its relatives. Histone methylation participates in repression of expression of an inhibitor of flowering during cold. In annual, semelparous species such as A. thaliana, this histone methylation is stably inherited through mitosis after return from cold to warm temperatures allowing the plant to flower continuously during spring and summer until it senesces. However, in perennial, iteroparous relatives the histone modification rapidly disappears when temperatures rise, allowing expression of the floral inhibitor to increase and limiting flowering to a short interval. In this case, epigenetic histone modifications control a key adaptive trait, and their pattern changes rapidly during evolution associated with life-history strategy. We discuss these examples of epigenetic developmental traits with emphasis on the underlying mechanisms, their stability, and adaptive value.
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Affiliation(s)
- Franziska Turck
- Max Planck Institute for Plant Breeding Research, Carl von Linne Weg 10, D-50829, Cologne, Germany.
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Huang X, Ding J, Effgen S, Turck F, Koornneef M. Multiple loci and genetic interactions involving flowering time genes regulate stem branching among natural variants of Arabidopsis. THE NEW PHYTOLOGIST 2013; 199:843-57. [PMID: 23668187 DOI: 10.1111/nph.12306] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Accepted: 04/04/2013] [Indexed: 05/02/2023]
Abstract
Shoot branching is a major determinant of plant architecture. Genetic variants for reduced stem branching in the axils of cauline leaves of Arabidopsis were found in some natural accessions and also at low frequency in the progeny of multiparent crosses. Detailed genetic analysis using segregating populations derived from backcrosses with the parental lines and bulked segregant analysis was used to identify the allelic variation controlling reduced stem branching. Eight quantitative trait loci (QTLs) contributing to natural variation for reduced stem branching were identified (REDUCED STEM BRANCHING 1-8 (RSB1-8)). Genetic analysis showed that RSB6 and RSB7, corresponding to flowering time genes FLOWERING LOCUS C (FLC) and FRIGIDA (FRI), epistatically regulate stem branching. Furthermore, FLOWERING LOCUS T (FT), which corresponds to RSB8 as demonstrated by fine-mapping, transgenic complementation and expression analysis, caused pleiotropic effects not only on flowering time, but, in the specific background of active FRI and FLC alleles, also on the RSB trait. The consequence of allelic variation only expressed in late-flowering genotypes revealed novel and thus far unsuspected roles of several genes well characterized for their roles in flowering time control.
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Affiliation(s)
- Xueqing Huang
- State Key Laboratory of Genetic Engineering, Institute of Plant Biology, School of Life Sciences, Fudan University, Shanghai, China
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Seedat N, Dinsdale A, Ong EK, Gendall AR. Acceleration of flowering in Arabidopsis thaliana by Cape Verde Islands alleles of FLOWERING H is dependent on the floral promoter FD. JOURNAL OF EXPERIMENTAL BOTANY 2013; 64:2767-2778. [PMID: 23667042 PMCID: PMC3697943 DOI: 10.1093/jxb/ert120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Flowering time in the model plant Arabidopsis thaliana is regulated by both external environmental signals and internal developmental pathways. Natural variation at the FLOWERING H (FLH) locus has previously been described, with alleles present in the Cape Verde Islands accession causing early flowering, particularly after vernalization. The mechanism of FLH-induced early flowering is not understood. Here, the integration of FLH activity into the known flowering time pathways is described using molecular and genetic approaches. The identification of molecular markers that co-segregated with the FLH locus allowed the generation of multiple combinations of FLH alleles with mutations in flowering time genes in different flowering pathways. Combining an early flowering FLH allele with mutations in vernalization pathway genes that regulate FLC expression revealed that FLH appears to act in parallel to FLC. Surprisingly, the early flowering allele of FLH requires the floral integrator FD, but not FT, to accelerate flowering. This suggests a model in which some alleles of FLH are able to affect the FD-dependent activity of the floral activator complex.
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Affiliation(s)
- Noorina Seedat
- Department of Botany, La Trobe University, Bundoora, Victoria, 3086Australia
- AgriBio, Centre for AgriBiosciences, 5 Ring Road, Bundoora, Victoria, 3086, Australia
| | - Adrian Dinsdale
- Department of Botany, La Trobe University, Bundoora, Victoria, 3086Australia
| | - Eng Kok Ong
- Department of Botany, La Trobe University, Bundoora, Victoria, 3086Australia
| | - Anthony Richard Gendall
- Department of Botany, La Trobe University, Bundoora, Victoria, 3086Australia
- AgriBio, Centre for AgriBiosciences, 5 Ring Road, Bundoora, Victoria, 3086, Australia
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49
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Preston JC, Sandve SR. Adaptation to seasonality and the winter freeze. FRONTIERS IN PLANT SCIENCE 2013; 4:167. [PMID: 23761798 PMCID: PMC3669742 DOI: 10.3389/fpls.2013.00167] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Accepted: 05/13/2013] [Indexed: 05/20/2023]
Abstract
Flowering plants initially diversified during the Mesozoic era at least 140 million years ago in regions of the world where temperate seasonal environments were not encountered. Since then several cooling events resulted in the contraction of warm and wet environments and the establishment of novel temperate zones in both hemispheres. In response, less than half of modern angiosperm families have members that evolved specific adaptations to cold seasonal climates, including cold acclimation, freezing tolerance, endodormancy, and vernalization responsiveness. Despite compelling evidence for multiple independent origins, the level of genetic constraint on the evolution of adaptations to seasonal cold is not well understood. However, the recent increase in molecular genetic studies examining the response of model and crop species to seasonal cold offers new insight into the evolutionary lability of these traits. This insight has major implications for our understanding of complex trait evolution, and the potential role of local adaptation in response to past and future climate change. In this review, we discuss the biochemical, morphological, and developmental basis of adaptations to seasonal cold, and synthesize recent literature on the genetic basis of these traits in a phylogenomic context. We find evidence for multiple genetic links between distinct physiological responses to cold, possibly reinforcing the coordinated expression of these traits. Furthermore, repeated recruitment of the same or similar ancestral pathways suggests that land plants might be somewhat pre-adapted to dealing with temperature stress, perhaps making inducible cold traits relatively easy to evolve.
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Affiliation(s)
- Jill C. Preston
- Department of Plant Biology, University of VermontBurlington, VT, USA
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50
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Quilot-Turion B, Leppälä J, Leinonen PH, Waldmann P, Savolainen O, Kuittinen H. Genetic changes in flowering and morphology in response to adaptation to a high-latitude environment in Arabidopsis lyrata. ANNALS OF BOTANY 2013; 111:957-68. [PMID: 23519836 PMCID: PMC3631339 DOI: 10.1093/aob/mct055] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2012] [Accepted: 01/29/2013] [Indexed: 05/08/2023]
Abstract
BACKGROUND AND AIMS The adaptive plastic reactions of plant populations to changing climatic factors, such as winter temperatures and photoperiod, have changed during range shifts after the last glaciation. Timing of flowering is an adaptive trait regulated by environmental cues. Its genetics has been intensively studied in annual plants, but in perennials it is currently not well characterized. This study examined the genetic basis of differentiation in flowering time, morphology, and their plastic responses to vernalization in two locally adapted populations of the perennial Arabidopsis lyrata: (1) to determine whether the two populations differ in their vernalization responses for flowering phenology and morphology; and (2) to determine the genomic areas governing differentiation and vernalization responses. METHODS Two A. lyrata populations, from central Europe and Scandinavia, were grown in growth-chamber conditions with and without cold treatment. A QTL analysis was performed to find genomic regions that interact with vernalization. KEY RESULTS The population from central Europe flowered more rapidly and invested more in inflorescence growth than the population from alpine Scandinavia, especially after vernalization. The alpine population had consistently a low number of inflorescences and few flowers, suggesting strong constraints due to a short growing season, but instead had longer leaves and higher leaf rosettes. QTL mapping in the F2 population revealed genomic regions governing differentiation in flowering time and morphology and, in some cases, the allelic effects from the two populations on a trait were influenced by vernalization (QTL × vernalization interactions). CONCLUSIONS The results indicate that many potentially adaptive genetic changes have occurred during colonization; the two populations have diverged in their plastic responses to vernalization in traits closely connected to fitness through changes in many genomic areas.
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