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Soulhat C, Wehbi H, Fierlej Y, Berquin P, Girin T, Hilson P, Bouchabké-Coussa O. Fast-track transformation and genome editing in Brachypodium distachyon. Plant Methods 2023; 19:31. [PMID: 36991448 PMCID: PMC10053978 DOI: 10.1186/s13007-023-01005-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Accepted: 03/09/2023] [Indexed: 06/19/2023]
Abstract
BACKGROUND Even for easy-to-transform species or genotypes, the creation of transgenic or edited plant lines remains a significant bottleneck. Thus, any technical advance that accelerates the regeneration and transformation process is welcome. So far, methods to produce Brachypodium distachyon (Bd) transgenics span at least 14 weeks from the start of tissue culture to the recovery of regenerated plantlets. RESULTS We have previously shown that embryogenic somatic tissues grow in the scutellum of immature zygotic Bd embryos within 3 days of in vitro induction with exogenous auxin and that the development of secondary embryos can be initiated immediately thereafter. Here, we further demonstrate that such pluripotent reactive tissues can be genetically transformed with Agrobacterium tumefaciens right after the onset of somatic embryogenesis. In brief, immature zygotic embryos are induced for callogenesis for one week, co-cultured with Agrobacterium for three days, then incubated on callogenesis selective medium for three weeks, and finally transferred on selective regeneration medium for up to three weeks to obtain plantlets ready for rooting. This 7-to-8-week procedure requires only three subcultures. Its validation includes the molecular and phenotype characterization of Bd lines carrying transgenic cassettes and novel CRISPR/Cas9-generated mutations in two independent loci coding for nitrate reductase enzymes (BdNR1 and BdNR2). CONCLUSIONS With a short callogenesis stage and streamlined in vitro regeneration following co-cultivation with Agrobacterium, transgenic and edited T0 Bd plantlets can be produced in about 8 weeks, a gain of one to two months compared to previously published methods, with no reduction in transformation efficiency and at lower costs.
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Affiliation(s)
- Camille Soulhat
- Université Paris-Saclay, INRAE, AgroParisTech, Institut Jean-Pierre Bourgin (IJPB), 78000, Versailles, France
| | - Houssein Wehbi
- Université Paris-Saclay, INRAE, AgroParisTech, Institut Jean-Pierre Bourgin (IJPB), 78000, Versailles, France
| | - Yannick Fierlej
- Université Paris-Saclay, INRAE, AgroParisTech, Institut Jean-Pierre Bourgin (IJPB), 78000, Versailles, France
| | - Patrick Berquin
- Université Paris-Saclay, INRAE, AgroParisTech, Institut Jean-Pierre Bourgin (IJPB), 78000, Versailles, France
| | - Thomas Girin
- Université Paris-Saclay, INRAE, AgroParisTech, Institut Jean-Pierre Bourgin (IJPB), 78000, Versailles, France
| | - Pierre Hilson
- Université Paris-Saclay, INRAE, AgroParisTech, Institut Jean-Pierre Bourgin (IJPB), 78000, Versailles, France
| | - Oumaya Bouchabké-Coussa
- Université Paris-Saclay, INRAE, AgroParisTech, Institut Jean-Pierre Bourgin (IJPB), 78000, Versailles, France.
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Agapit C, Gigon A, Girin T, Leitao L, Blouin M. Split-root system optimization based on the survival, growth and development of the model Poaceae Brachypodium distachyon. Physiol Plant 2020; 168:227-236. [PMID: 30950064 DOI: 10.1111/ppl.12971] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Revised: 03/21/2019] [Accepted: 03/29/2019] [Indexed: 05/09/2023]
Abstract
Split-root system has been developed to better understand plant response to environmental factors, by exposing two separate parts of a single root system to heterogeneous situations. Surprisingly, there is no study attempting to maximize plant survival, growth and root system structure through a statistically sound comparison of different experimental protocols. Here, we aim at optimizing split-root systems on the model plant for Poaceae and cereals Brachypodium distachyon in terms of plant survival, number of roots and their equal distribution between the two compartments. We tested the effect of hydroponic or soil as growing media, with or without change of media at the transplantation step. The partial or total cutting of roots and/or shoots was also tested in different treatments as it could have an influence on plant access to energy and water and consequently on survival, growth and root development. Growing plants in soil before and after transplantation in split-root system was the best condition to get the highest survival rate, number of coleoptile node axile roots and growth. Cutting the whole root system was the best option to have a high root biomass and length at the end of the experiment. However, cutting shoots was detrimental for plant growth, especially in terms of root biomass production. In well-watered conditions, a plant submitted to a transfer in a split-root system is thus mainly lacking energy to produce new roots thanks to photosynthesis or adaptive autophagy, not water or nutrients.
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Affiliation(s)
- Corinne Agapit
- Institute of Ecology and Environmental Sciences of Paris (UMR 7618), UPEC, Créteil, France
| | - Agnès Gigon
- Institute of Ecology and Environmental Sciences of Paris (UMR 7618), UPEC, Créteil, France
| | - Thomas Girin
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, 78000 Versailles, France
| | - Luis Leitao
- Institute of Ecology and Environmental Sciences of Paris (UMR 7618), UPEC, Créteil, France
| | - Manuel Blouin
- Agroécologie, AgroSup Dijon CNRS, INRA, Université Bourgogne Franche-Comté, Dijon, France
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David LC, Girin T, Fleurisson E, Phommabouth E, Mahfoudhi A, Citerne S, Berquin P, Daniel-Vedele F, Krapp A, Ferrario-Méry S. Developmental and physiological responses of Brachypodium distachyon to fluctuating nitrogen availability. Sci Rep 2019; 9:3824. [PMID: 30846873 PMCID: PMC6405861 DOI: 10.1038/s41598-019-40569-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Accepted: 02/12/2019] [Indexed: 02/03/2023] Open
Abstract
The Nitrogen Use Efficiency (NUE) of grain cereals depends on nitrate (NO3-) uptake from the soil, translocation to the aerial parts, nitrogen (N) assimilation and remobilization to the grains. Brachypodium distachyon has been proposed as a model species to identify the molecular players and mechanisms that affects these processes, for the improvement of temperate C3 cereals. We report on the developmental, physiological and grain-characteristic responses of the Bd21-3 accession of Brachypodium to variations in NO3- availability. As previously described in wheat and barley, we show that vegetative growth, shoot/root ratio, tiller formation, spike development, tissue NO3- and N contents, grain number per plant, grain yield and grain N content are sensitive to pre- and/or post-anthesis NO3- supply. We subsequently described constitutive and NO3--inducible components of both High and Low Affinity Transport Systems (HATS and LATS) for root NO3- uptake, and BdNRT2/3 candidate genes potentially involved in the HATS. Taken together, our data validate Brachypodium Bd21-3 as a model to decipher cereal N nutrition. Apparent specificities such as high grain N content, strong post-anthesis NO3- uptake and efficient constitutive HATS, further identify Brachypodium as a direct source of knowledge for crop improvement.
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Affiliation(s)
- L C David
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, 78000, Versailles, France
| | - T Girin
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, 78000, Versailles, France.
| | - E Fleurisson
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, 78000, Versailles, France
| | - E Phommabouth
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, 78000, Versailles, France
| | - A Mahfoudhi
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, 78000, Versailles, France
| | - S Citerne
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, 78000, Versailles, France
| | - P Berquin
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, 78000, Versailles, France
| | - F Daniel-Vedele
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, 78000, Versailles, France
| | - A Krapp
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, 78000, Versailles, France
| | - S Ferrario-Méry
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, 78000, Versailles, France
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Girin T, David LC, Chardin C, Sibout R, Krapp A, Ferrario-Méry S, Daniel-Vedele F. Brachypodium: a promising hub between model species and cereals. J Exp Bot 2014; 65:5683-96. [PMID: 25262566 DOI: 10.1093/jxb/eru376] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Brachypodium distachyon was proposed as a model species for genetics and molecular genomics in cereals less than 10 years ago. It is now established as a standard for research on C3 cereals on a variety of topics, due to its close phylogenetic relationship with Triticeae crops such as wheat and barley, and to its simple genome, its minimal growth requirement, and its short life cycle. In this review, we first highlight the tools and resources for Brachypodium that are currently being developed and made available by the international community. We subsequently describe how this species has been used for comparative genomic studies together with cereal crops, before illustrating major research fields in which Brachypodium has been successfully used as a model: cell wall synthesis, plant-pathogen interactions, root architecture, and seed development. Finally, we discuss the usefulness of research on Brachypodium in order to improve nitrogen use efficiency in cereals, with the aim of reducing the amount of applied fertilizer while increasing the grain yield. Several paths are considered, namely an improvement of either nitrogen remobilization from the vegetative organs, nitrate uptake from the soil, or nitrate assimilation by the plant. Altogether, these examples position the research on Brachypodium as at an intermediate stage between basic research, carried out mainly in Arabidopsis, and applied research carried out on wheat and barley, enabling a complementarity of the studies and reciprocal benefits.
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Affiliation(s)
- Thomas Girin
- Institut National de la Recherche Agronomique (INRA), UMR1318, Institut Jean-Pierre Bourgin, Saclay Plant Sciences, RD10, F-78000 Versailles, France AgroParisTech, Institut Jean-Pierre Bourgin, RD10, F-78000 Versailles, France
| | - Laure C David
- Institut National de la Recherche Agronomique (INRA), UMR1318, Institut Jean-Pierre Bourgin, Saclay Plant Sciences, RD10, F-78000 Versailles, France AgroParisTech, Institut Jean-Pierre Bourgin, RD10, F-78000 Versailles, France
| | - Camille Chardin
- Institut National de la Recherche Agronomique (INRA), UMR1318, Institut Jean-Pierre Bourgin, Saclay Plant Sciences, RD10, F-78000 Versailles, France AgroParisTech, Institut Jean-Pierre Bourgin, RD10, F-78000 Versailles, France
| | - Richard Sibout
- Institut National de la Recherche Agronomique (INRA), UMR1318, Institut Jean-Pierre Bourgin, Saclay Plant Sciences, RD10, F-78000 Versailles, France AgroParisTech, Institut Jean-Pierre Bourgin, RD10, F-78000 Versailles, France
| | - Anne Krapp
- Institut National de la Recherche Agronomique (INRA), UMR1318, Institut Jean-Pierre Bourgin, Saclay Plant Sciences, RD10, F-78000 Versailles, France AgroParisTech, Institut Jean-Pierre Bourgin, RD10, F-78000 Versailles, France
| | - Sylvie Ferrario-Méry
- Institut National de la Recherche Agronomique (INRA), UMR1318, Institut Jean-Pierre Bourgin, Saclay Plant Sciences, RD10, F-78000 Versailles, France AgroParisTech, Institut Jean-Pierre Bourgin, RD10, F-78000 Versailles, France
| | - Françoise Daniel-Vedele
- Institut National de la Recherche Agronomique (INRA), UMR1318, Institut Jean-Pierre Bourgin, Saclay Plant Sciences, RD10, F-78000 Versailles, France AgroParisTech, Institut Jean-Pierre Bourgin, RD10, F-78000 Versailles, France
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Chardin C, Girin T, Roudier F, Meyer C, Krapp A. The plant RWP-RK transcription factors: key regulators of nitrogen responses and of gametophyte development. J Exp Bot 2014; 65:5577-87. [PMID: 24987011 DOI: 10.1093/jxb/eru261] [Citation(s) in RCA: 102] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
The plant specific RWP-RK family of transcription factors, initially identified in legumes and Chlamydomonas, are found in all vascular plants, green algae, and slime molds. These proteins possess a characteristic RWP-RK motif, which mediates DNA binding. Based on phylogenetic and domain analyses, we classified the RWP-RK proteins of six different species in two subfamilies: the NIN-like proteins (NLPs), which carry an additional PB1 domain at their C-terminus, and the RWP-RK domain proteins (RKDs), which are divided into three subgroups. Although, the functional analysis of this family is still in its infancy, several RWP-RK proteins have a key role in regulating responses to nitrogen availability. The nodulation-specific NIN proteins are involved in nodule organogenesis and rhizobial infection under nitrogen starvation conditions. Arabidopsis NLP7 in particular is a major player in the primary nitrate response. Several RKDs act as transcription factors involved in egg cell specification and differentiation or gametogenesis in algae, the latter modulated by nitrogen availability. Further studies are required to extend the general picture of the functional role of these exciting transcription factors.
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Affiliation(s)
- Camille Chardin
- Institut National de la Recherche Agronomique (INRA), UMR1318, Institut Jean-Pierre Bourgin, Saclay Plant Sciences, RD10, F-78000 Versailles, France AgroParisTech, Institut Jean-Pierre Bourgin, RD10, F-78000 Versailles, France
| | - Thomas Girin
- Institut National de la Recherche Agronomique (INRA), UMR1318, Institut Jean-Pierre Bourgin, Saclay Plant Sciences, RD10, F-78000 Versailles, France AgroParisTech, Institut Jean-Pierre Bourgin, RD10, F-78000 Versailles, France
| | - François Roudier
- Institut de Biologie de l'Ecole Normale Supérieure, Centre National de la Recherche Scientifique (CNRS) UMR8197, Institut National de la Santé et de la Recherche Médicale (INSERM) U1024, Paris, France
| | - Christian Meyer
- Institut National de la Recherche Agronomique (INRA), UMR1318, Institut Jean-Pierre Bourgin, Saclay Plant Sciences, RD10, F-78000 Versailles, France AgroParisTech, Institut Jean-Pierre Bourgin, RD10, F-78000 Versailles, France
| | - Anne Krapp
- Institut National de la Recherche Agronomique (INRA), UMR1318, Institut Jean-Pierre Bourgin, Saclay Plant Sciences, RD10, F-78000 Versailles, France AgroParisTech, Institut Jean-Pierre Bourgin, RD10, F-78000 Versailles, France
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6
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Krapp A, David LC, Chardin C, Girin T, Marmagne A, Leprince AS, Chaillou S, Ferrario-Méry S, Meyer C, Daniel-Vedele F. Nitrate transport and signalling in Arabidopsis. J Exp Bot 2014; 65:789-98. [PMID: 24532451 DOI: 10.1093/jxb/eru001] [Citation(s) in RCA: 247] [Impact Index Per Article: 24.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Plants have developed adaptive responses allowing them to cope with nitrogen (N) fluctuation in the soil and maintain growth despite changes in external N availability. Nitrate is the most important N form in temperate soils. Nitrate uptake by roots and its transport at the whole-plant level involves a large panoply of transporters and impacts plant performance. Four families of nitrate-transporting proteins have been identified so far: nitrate transporter 1/peptide transporter family (NPF), nitrate transporter 2 family (NRT2), the chloride channel family (CLC), and slow anion channel-associated homologues (SLAC/SLAH). Nitrate transporters are also involved in the sensing of nitrate. It is now well established that plants are able to sense external nitrate availability, and hence that nitrate also acts as a signal molecule that regulates many aspects of plant intake, metabolism, and gene expression. This review will focus on a global picture of the nitrate transporters so far identified and the recent advances in the molecular knowledge of the so-called primary nitrate response, the rapid regulation of gene expression in response to nitrate. The recent discovery of the NIN-like proteins as master regulators for nitrate signalling has led to a new understanding of the regulation cascade.
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Affiliation(s)
- Anne Krapp
- Institut National de la Recherche Agronomique (INRA), UMR1318, Institut Jean-Pierre Bourgin, Saclay Plant Sciences, RD10, F-78000 Versailles, France
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Girin T, Paicu T, Stephenson P, Fuentes S, Körner E, O’Brien M, Sorefan K, Wood TA, Balanzá V, Ferrándiz C, Smyth DR, Østergaard L. INDEHISCENT and SPATULA interact to specify carpel and valve margin tissue and thus promote seed dispersal in Arabidopsis. Plant Cell 2011; 23:3641-53. [PMID: 21990939 PMCID: PMC3229140 DOI: 10.1105/tpc.111.090944] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2011] [Revised: 09/16/2011] [Accepted: 09/23/2011] [Indexed: 05/18/2023]
Abstract
Structural organization of organs in multicellular organisms occurs through intricate patterning mechanisms that often involve complex interactions between transcription factors in regulatory networks. For example, INDEHISCENT (IND), a basic helix-loop-helix (bHLH) transcription factor, specifies formation of the narrow stripes of valve margin tissue, where Arabidopsis thaliana fruits open on maturity. Another bHLH transcription factor, SPATULA (SPT), is required for reproductive tissue development from carpel margins in the Arabidopsis gynoecium before fertilization. Previous studies have therefore assigned the function of SPT to early gynoecium stages and IND to later fruit stages of reproductive development. Here we report that these two transcription factors interact genetically and via protein-protein contact to mediate both gynoecium development and fruit opening. We show that IND directly and positively regulates the expression of SPT, and that spt mutants have partial defects in valve margin formation. Careful analysis of ind mutant gynoecia revealed slight defects in apical tissue formation, and combining mutations in IND and SPT dramatically enhanced both single-mutant phenotypes. Our data show that SPT and IND at least partially mediate their joint functions in gynoecium and fruit development by controlling auxin distribution and suggest that this occurs through cooperative binding to regulatory sequences in downstream target genes.
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Affiliation(s)
- Thomas Girin
- Department of Crop Genetics, John Innes Centre, Norwich Research Park, Norwich, Norfolk NR4 7UH, United Kingdom
| | - Teodora Paicu
- School of Biological Sciences, Monash University, Melbourne, Victoria 3800, Australia
| | - Pauline Stephenson
- Department of Crop Genetics, John Innes Centre, Norwich Research Park, Norwich, Norfolk NR4 7UH, United Kingdom
| | - Sara Fuentes
- Department of Crop Genetics, John Innes Centre, Norwich Research Park, Norwich, Norfolk NR4 7UH, United Kingdom
| | - Evelyn Körner
- Department of Crop Genetics, John Innes Centre, Norwich Research Park, Norwich, Norfolk NR4 7UH, United Kingdom
| | - Martin O’Brien
- School of Biological Sciences, Monash University, Melbourne, Victoria 3800, Australia
| | - Karim Sorefan
- Department of Crop Genetics, John Innes Centre, Norwich Research Park, Norwich, Norfolk NR4 7UH, United Kingdom
| | - Thomas A. Wood
- Department of Crop Genetics, John Innes Centre, Norwich Research Park, Norwich, Norfolk NR4 7UH, United Kingdom
| | - Vicente Balanzá
- Instituto de Biología Molecular y Celular de Plantas, Consejo Superior de Investigaciones Científicas–Universidad Politécnica de Valencia, 46022 Valencia, Spain
| | - Cristina Ferrándiz
- Instituto de Biología Molecular y Celular de Plantas, Consejo Superior de Investigaciones Científicas–Universidad Politécnica de Valencia, 46022 Valencia, Spain
| | - David R. Smyth
- School of Biological Sciences, Monash University, Melbourne, Victoria 3800, Australia
| | - Lars Østergaard
- Department of Crop Genetics, John Innes Centre, Norwich Research Park, Norwich, Norfolk NR4 7UH, United Kingdom
- Address correspondence to
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Arnaud N, Girin T, Sorefan K, Fuentes S, Wood TA, Lawrenson T, Sablowski R, Østergaard L. Gibberellins control fruit patterning in Arabidopsis thaliana. Genes Dev 2010; 24:2127-32. [PMID: 20889713 DOI: 10.1101/gad.593410] [Citation(s) in RCA: 149] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The Arabidopsis basic helix-loop-helix (bHLH) proteins INDEHISCENT (IND) and ALCATRAZ (ALC) specify tissues required for fruit opening that have major roles in seed dispersal and plant domestication. Here, we show that synthesis of the phytohormone gibberellin is a direct and necessary target of IND, and that ALC interacts directly with DELLA repressors, which antagonize ALC function but are destabilized by gibberellin. Thus, the gibberellin/DELLA pathway has a key role in patterning the Arabidopsis fruit, and the interaction between DELLA and bHLH proteins, previously shown to connect gibberellin and light responses, is a versatile regulatory module also used in tissue patterning.
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Affiliation(s)
- Nicolas Arnaud
- Cell and Developmental Biology Department, John Innes Centre, Norwich, NR4 7UH, United Kingdom
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Girin T, Stephenson P, Goldsack CMP, Kempin SA, Perez A, Pires N, Sparrow PA, Wood TA, Yanofsky MF, Østergaard L. Brassicaceae INDEHISCENT genes specify valve margin cell fate and repress replum formation. Plant J 2010; 63:329-338. [PMID: 20444234 DOI: 10.1111/j.1365-313x.2010.04244.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Members of the Brassicaceae family, including Arabidopsis thaliana and oilseed rape (Brassica napus), produce dry fruits that open upon maturity along a specialised tissue called the valve margin. Proper development of the valve margin in Arabidopsis is dependent on the INDEHISCENT (IND) gene, the role of which in genetic and hormonal regulation has been thoroughly characterised. Here we perform phylogenetic comparison of IND genes in Arabidopsis and Brassica to identify conserved regulatory sequences that are responsible for specific expression at the valve margin. In addition we have taken a comparative development approach to demonstrate that the BraA.IND.a and BolC.IND.a genes from B. rapa and B. oleracea share identical function with Arabidopsis IND since ethyl methanesulphonate (EMS) mutant alleles and silenced transgenic lines have valve margin defects. Furthermore we show that the degree of these defects can be fine-tuned for crop improvement. Wild-type Arabidopsis produces an outer replum composed of about six cell files at the medial region of the fruits, whereas Brassica fruits lack this tissue. A strong loss-of-function braA.ind.a mutant gained outer replum tissue in addition to its defect in valve margin development. An enlargement of replum size was also observed in the Arabidopsis ind mutant suggesting a general role of Brassicaceae IND genes in preventing valve margin cells from adopting replum identity.
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Affiliation(s)
- Thomas Girin
- Department of Crop Genetics, John Innes Centre, Colney Lane, Norwich NR4 7UH, UK
| | - Pauline Stephenson
- Department of Crop Genetics, John Innes Centre, Colney Lane, Norwich NR4 7UH, UK
| | | | - Sherry A Kempin
- Section of Cell and Developmental Biology, University of California at San Diego, La Jolla, CA 92093-0116, USA
| | - Amandine Perez
- Department of Crop Genetics, John Innes Centre, Colney Lane, Norwich NR4 7UH, UK
| | - Nuno Pires
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford OX1 3RB, UK
| | - Penelope A Sparrow
- Department of Crop Genetics, John Innes Centre, Colney Lane, Norwich NR4 7UH, UK
| | - Thomas A Wood
- Department of Crop Genetics, John Innes Centre, Colney Lane, Norwich NR4 7UH, UK
| | - Martin F Yanofsky
- Section of Cell and Developmental Biology, University of California at San Diego, La Jolla, CA 92093-0116, USA
| | - Lars Østergaard
- Department of Crop Genetics, John Innes Centre, Colney Lane, Norwich NR4 7UH, UK
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Girin T, El-Kafafi ES, Widiez T, Erban A, Hubberten HM, Kopka J, Hoefgen R, Gojon A, Lepetit M. Identification of Arabidopsis mutants impaired in the systemic regulation of root nitrate uptake by the nitrogen status of the plant. Plant Physiol 2010; 153:1250-60. [PMID: 20448103 PMCID: PMC2899898 DOI: 10.1104/pp.110.157354] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2010] [Accepted: 05/04/2010] [Indexed: 05/18/2023]
Abstract
Nitrate uptake by the roots is under systemic feedback repression by high nitrogen (N) status of the whole plant. The NRT2.1 gene, which encodes a NO(3)(-) transporter involved in high-affinity root uptake, is a major target of this N signaling mechanism. Using transgenic Arabidopsis (Arabidopsis thaliana) plants expressing the pNRT2.1::LUC reporter gene (NL line), we performed a genetic screen to isolate mutants altered in the NRT2.1 response to high N provision. Three hni (for high nitrogen insensitive) mutants belonging to three genetic loci and related to single and recessive mutations were selected. Compared to NL plants, these mutants display reduced down-regulation of both NRT2.1 expression and high-affinity NO(3)(-) influx under repressive conditions. Split-root experiments demonstrated that this is associated with an almost complete suppression of systemic repression of pNRT2.1 activity by high N status of the whole plant. Other mechanisms related to N and carbon nutrition regulating NRT2.1 or involved in the control of root SO(4)(-) uptake by the plant sulfur status are not or are slightly affected. The hni mutations did not lead to significant changes in total N and NO(3)(-) contents of the tissues, indicating that hni mutants are more likely regulatory mutants rather than assimilatory mutants. Nevertheless, hni mutations induce changes in amino acid, organic acid, and sugars pools, suggesting a possible role of these metabolites in the control of NO(3)(-) uptake by the plant N status. Altogether, our data indicate that the three hni mutants define a new class of N signaling mutants specifically impaired in the systemic feedback repression of root NO(3)(-) uptake.
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Stephenson P, Baker D, Girin T, Perez A, Amoah S, King GJ, Østergaard L. A rich TILLING resource for studying gene function in Brassica rapa. BMC Plant Biol 2010; 10:62. [PMID: 20380715 PMCID: PMC2923536 DOI: 10.1186/1471-2229-10-62] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2009] [Accepted: 04/09/2010] [Indexed: 05/19/2023]
Abstract
BACKGROUND The Brassicaceae family includes the model plant Arabidopsis thaliana as well as a number of agronomically important species such as oilseed crops (in particular Brassica napus, B. juncea and B. rapa) and vegetables (eg. B. rapa and B. oleracea). Separated by only 10-20 million years, Brassica species and Arabidopsis thaliana are closely related, and it is expected that knowledge obtained relating to Arabidopsis growth and development can be translated into Brassicas for crop improvement. Moreover, certain aspects of plant development are sufficiently different between Brassica and Arabidopsis to warrant studies to be carried out directly in the crop species. However, mutating individual genes in the amphidiploid Brassicas such as B. napus and B. juncea may, on the other hand, not give rise to expected phenotypes as the genomes of these species can contain up to six orthologues per single-copy Arabidopsis gene. In order to elucidate and possibly exploit the function of redundant genes for oilseed rape crop improvement, it may therefore be more efficient to study the effects in one of the diploid Brassica species such as B. rapa. Moreover, the ongoing sequencing of the B. rapa genome makes this species a highly attractive model for Brassica research and genetic resource development. RESULTS Seeds from the diploid Brassica A genome species, B. rapa were treated with ethyl methane sulfonate (EMS) to produce a TILLING (Targeting Induced Local Lesions In Genomes) population for reverse genetics studies. We used the B. rapa genotype, R-o-18, which has a similar developmental ontogeny to an oilseed rape crop. Hence this resource is expected to be well suited for studying traits with relevance to yield and quality of oilseed rape. DNA was isolated from a total of 9,216 M2 plants and pooled to form the basis of the TILLING platform. Analysis of six genes revealed a high level of mutations with a density of about one per 60 kb. This analysis also demonstrated that screening a 1 kb amplicon in just one third of the population (3072 M2 plants) will provide an average of 68 mutations and a 97% probability of obtaining a stop-codon mutation resulting in a truncated protein. We furthermore calculated that each plant contains on average approximately 10,000 mutations and due to the large number of plants, it is predicted that mutations in approximately half of the GC base pairs in the genome exist within this population. CONCLUSIONS We have developed the first EMS TILLING resource in the diploid Brassica species, B. rapa. The mutation density in this population is approximately 1 per 60 kb, which makes it the most densely mutated diploid organism for which a TILLING population has been published. This resource is publicly available through the RevGenUK reverse genetics platform http://revgenuk.jic.ac.uk.
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Affiliation(s)
| | - David Baker
- John Innes Genome Laboratory, John Innes Centre, Norwich, NR4 7UH, UK
| | - Thomas Girin
- Department of Crop Genetics, John Innes Centre, Norwich, NR4 7UH, UK
| | - Amandine Perez
- Department of Crop Genetics, John Innes Centre, Norwich, NR4 7UH, UK
| | - Stephen Amoah
- Plant Science Department, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, UK
| | - Graham J King
- Plant Science Department, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, UK
| | - Lars Østergaard
- Department of Crop Genetics, John Innes Centre, Norwich, NR4 7UH, UK
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Abstract
The diversity of shape in life is astounding, and this is particularly vivid when the varied forms observed in our fruit bowls are examined. How some of the tissues of the Arabidopsis fruit are moulded is starting to be understood, revealing how plants may sculpt plant form by modulating the degree of meristematic properties. In this fruit the KNOX I and BLH meristem identity genes promote medial tissue proliferation by maintaining these tissues in a 'quasi-meristematic' fate. The action of these genes is opposed by ASYMMETRIC LEAVES activity that promotes valve formation together with JAGGED/FILAMENTOUS FLOWER and FRUITFULL activities. This is reminiscent of the function of these genes in the shoot apical meristem and in leaf development. In this review, the aim is to present the medial tissues of the Arabidopsis fruit as a modified meristem and extrapolate our knowledge from other plant organs to fruit development.
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Affiliation(s)
- Thomas Girin
- Crop Genetics Department, John Innes Centre, Norwich, UK
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Girin T, Lejay L, Wirth J, Widiez T, Palenchar PM, Nazoa P, Touraine B, Gojon A, Lepetit M. Identification of a 150 bp cis-acting element of the AtNRT2.1 promoter involved in the regulation of gene expression by the N and C status of the plant. Plant Cell Environ 2007; 30:1366-80. [PMID: 17897408 DOI: 10.1111/j.1365-3040.2007.01712.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
The Arabidopsis thaliana AtNRT2.1 gene, which encodes a NO(3)(-) transporter involved in high-affinity uptake by the roots, is a molecular target of several mechanisms responsible for the regulation of root NO(3)(-) acquisition by the N status of the plant. All levels of AtNRT2.1 expression (promoter activity, transcript level, protein accumulation, transport activity) are coordinately up-regulated in the presence of NO(3)(-), and repressed by downstream N metabolites. Transgenic plants expressing the GUS reporter gene under the control of upstream sequences of AtNRT2.1 have been studied to identify elements targeted by these two regulatory mechanisms. A 150 bp sequence located upstream of the TATA box that is required for both stimulation by NO(3)(-) and repression by N metabolites of the promoter has been identified. This sequence is able to confer these two regulations to a minimal promoter. Split-root experiments indicate that the stimulation of the chimaeric promoter by NO(3)(-) occurs only at the local level, whereas its repression by N metabolites is mediated by a systemic signal spread to the whole plant. The activity of the cis-acting 150 bp element is also regulated by sucrose supply to the roots, suggesting a possible interaction between N and C signalling within this short region. Accordingly, multiple motifs potentially involved in regulations by N and/or C status are identified within this sequence by bioinformatic approaches. This is the first report of such a cis-acting element in higher plants.
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Affiliation(s)
- Thomas Girin
- UMR 5004, Institut National de la Recherché Agronomique (INRA)--Centre National de la Recherche Scientifique (CNRS)-Sup Agro-UM2, Institut de Biologie Intégrative des Plantes, 2 Place Viala, Montpellier, F-34060 France
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14
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Gissot L, Polge C, Jossier M, Girin T, Bouly JP, Kreis M, Thomas M. AKINbetagamma contributes to SnRK1 heterotrimeric complexes and interacts with two proteins implicated in plant pathogen resistance through its KIS/GBD sequence. Plant Physiol 2006; 142:931-44. [PMID: 17028154 PMCID: PMC1630761 DOI: 10.1104/pp.106.087718] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
The sucrose nonfermenting-1 protein kinase (SNF1)/AMP-activated protein kinase subfamily plays a central role in metabolic responses to nutritional and environmental stresses. In yeast (Saccharomyces cerevisiae) and mammals, the beta- and gamma-noncatalytic subunits are implicated in substrate specificity and subcellular localization, respectively, and regulation of the kinase activity. The atypical betagamma-subunit has been previously described in maize (Zea mays), presenting at its N-terminal end a sequence related to the KIS (kinase interacting sequence) domain specific to the beta-subunits (Lumbreras et al., 2001). The existence of two components, SNF1-related protein kinase (SnRK1) complexes containing the betagamma-subunit and one SnRK1 kinase, had been proposed. In this work, we show that, despite its unusual features, the Arabidopsis (Arabidopsis thaliana) homolog AKINbetagamma clearly interacts with AKINbeta-subunits in vitro and in vivo, suggesting its involvement in heterotrimeric complexes located in both cytoplasm and nucleus. Unexpectedly, a transcriptional analysis of AKINbetagamma gene expression highlighted the implication of alternative splicing mechanisms in the regulation of AKINbetagamma expression. A two-hybrid screen performed with AKINbetagamma as bait, together with in planta bimolecular fluorescence complementation experiments, suggests the existence of interactions in the cytosol between AKINbetagamma and two leucine-rich repeats related to pathogen resistance proteins. Interestingly, this interaction occurs through the truncated KIS domain that corresponds exactly to a GBD (glycogen-binding domain) recently described in mammals and yeast. A phylogenetic study suggests that AKINbetagamma-related proteins are restricted to the plant kingdom. Altogether, these data suggest the existence of plant-specific SnRK1 trimeric complexes putatively involved in a plant-specific function such as plant-pathogen interactions.
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Affiliation(s)
- Lionel Gissot
- Institut de Biotechnologie des Plantes, Unité Mixte de Recherche Centre National de la Recherche Scientifique 8618, Université Paris-Sud, F-91405 Orsay cedex, France
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Remans T, Nacry P, Pervent M, Girin T, Tillard P, Lepetit M, Gojon A. A central role for the nitrate transporter NRT2.1 in the integrated morphological and physiological responses of the root system to nitrogen limitation in Arabidopsis. Plant Physiol 2006; 140:909-21. [PMID: 16415211 PMCID: PMC1400583 DOI: 10.1104/pp.105.075721] [Citation(s) in RCA: 229] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Up-regulation of the high-affinity transport system (HATS) for NO(3)(-) and stimulation of lateral root (LR) growth are two important adaptive responses of the root system to nitrogen limitation. Up-regulation of the NO(3)(-) HATS by nitrogen starvation is suppressed in the atnrt2.1-1 mutant of Arabidopsis (Arabidopsis thaliana), deleted for both NRT2.1 and NRT2.2 nitrate transporter genes. We then used this mutant to determine whether lack of HATS stimulation affected the response of the root system architecture (RSA) to low NO(3)(-) availability. In Wassilewskija (Ws) wild-type plants, transfer from high to low NO(3)(-) medium resulted in contrasting responses of RSA, depending on the level of nitrogen limitation. Moderate nitrogen limitation (transfer from 10 mm to 1 or 0.5 mm NO(3)(-)) mostly led to an increase in the number of visible laterals, while severe nitrogen stress (transfer from 10 mm to 0.1 or 0.05 mm NO(3)(-)) promoted mean LR length. The RSA response of the atnrt2.1-1 mutant to low NO(3)(-) was markedly different. After transfer from 10 to 0.5 mm NO(3)(-), the stimulated appearance of LRs was abolished in atnrt2.1-1 plants, whereas the increase in mean LR length was much more pronounced than in Ws. These modifications of RSA mimicked those of Ws plants subjected to severe nitrogen stress and could be fully explained by the lowered NO(3)(-) uptake measured in the mutant. This suggests that the uptake rate of NO(3)(-), rather than its external concentration, is the key factor triggering the observed changes in RSA. However, the mutation of NRT2.1 was also found to inhibit initiation of LR primordia in plants subjected to nitrogen limitation independently of the rate of NO(3)(-) uptake by the whole root system and even of the presence of added NO(3)(-) in the external medium. This indicates a direct stimulatory role for NRT2.1 in this particular step of LR development. Thus, it is concluded that NRT2.1 has a key dual function in coordinating root development with external NO(3)(-) availability, both indirectly through its role as a major NO(3)(-) uptake system that determines the nitrogen uptake-dependent RSA responses, and directly through a specific action on LR initiation under nitrogen-limited conditions.
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Affiliation(s)
- Tony Remans
- Laboratoire de Biochimie and Physiologie Moléculaire des Plantes, Unité Mixte de Recherche, Centre National de la Recherche Scientifique, Ecole Nationale Supérieure Agronomique, Université Monpellier II, France
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