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Mori T, Rai A, Tsugawa H, Yamada Y, Saito K. A liquid chromatography-mass spectrometry-based metabolomics strategy to explore plant metabolic diversity. Methods Enzymol 2023; 680:247-273. [PMID: 36710013 DOI: 10.1016/bs.mie.2022.08.029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Plants are expert chemists producing millions of metabolites, only a fraction of which are known to date. Plant metabolomics explores the rationale for highly diverse metabolites evolved and synthesized by plants. Over two-thirds of modern medicines are somehow inspired and/or derived from plants, making the identification of phytochemicals a means of discovering new medicines to challenge existing and emerging diseases. This chapter introduces our established liquid chromatography-tandem mass spectrometry-based untargeted metabolomics approach centered around discovering specialized metabolites (so-called secondary metabolites) across broad lineages of nonmodel plant species. Detecting hundreds to thousands of metabolite peaks, including assigning chemical identity, makes metabolomics data generation and analysis a very complex process. Various mass spectrometry techniques are currently being developed to approach the comprehensive metabolome. Among them, untargeted metabolomics can provide new biological insights by simultaneously and unbiasedly measuring and analyzing all detected metabolites. We have provided a hands-on modular account for untargeted plant metabolomics, from preparing plant biological samples to data analysis and processing using ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry. The methods described here offer a foundation and expert opinion on plant metabolome analysis.
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Affiliation(s)
- Tetsuya Mori
- RIKEN Center for Sustainable Resource Science, Kanagawa, Japan.
| | - Amit Rai
- RIKEN Center for Sustainable Resource Science, Kanagawa, Japan; Plant Molecular Science Center, Chiba University, Chiba, Japan
| | - Hiroshi Tsugawa
- RIKEN Center for Sustainable Resource Science, Kanagawa, Japan; RIKEN Center for Integrative Medical Sciences, Kanagawa, Japan; Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, Tokyo, Japan
| | - Yutaka Yamada
- RIKEN Center for Sustainable Resource Science, Kanagawa, Japan
| | - Kazuki Saito
- RIKEN Center for Sustainable Resource Science, Kanagawa, Japan; Plant Molecular Science Center, Chiba University, Chiba, Japan
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Lee SW, Kwon YJ, Baek I, Choi HI, Ahn JW, Kim JB, Kang SY, Kim SH, Jo YD. Mutagenic Effect of Proton Beams Characterized by Phenotypic Analysis and Whole Genome Sequencing in Arabidopsis. FRONTIERS IN PLANT SCIENCE 2021; 12:752108. [PMID: 34777430 PMCID: PMC8581144 DOI: 10.3389/fpls.2021.752108] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Accepted: 10/05/2021] [Indexed: 05/19/2023]
Abstract
Protons may have contributed to the evolution of plants as a major component of cosmic-rays and also have been used for mutagenesis in plants. Although the mutagenic effect of protons has been well-characterized in animals, no comprehensive phenotypic and genomic analyses has been reported in plants. Here, we investigated the phenotypes and whole genome sequences of Arabidopsis M2 lines derived by irradiation with proton beams and gamma-rays, to determine unique characteristics of proton beams in mutagenesis. We found that mutation frequency was dependent on the irradiation doses of both proton beams and gamma-rays. On the basis of the relationship between survival and mutation rates, we hypothesized that there may be a mutation rate threshold for survived individuals after irradiation. There were no significant differences between the total mutation rates in groups derived using proton beam or gamma-ray irradiation at doses that had similar impacts on survival rate. However, proton beam irradiation resulted in a broader mutant phenotype spectrum than gamma-ray irradiation, and proton beams generated more DNA structural variations (SVs) than gamma-rays. The most frequent SV was inversion. Most of the inversion junctions contained sequences with microhomology and were associated with the deletion of only a few nucleotides, which implies that preferential use of microhomology in non-homologous end joining was likely to be responsible for the SVs. These results show that protons, as particles with low linear energy transfer (LET), have unique characteristics in mutagenesis that partially overlap with those of low-LET gamma-rays and high-LET heavy ions in different respects.
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Affiliation(s)
- Sang Woo Lee
- Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup-si, South Korea
- Department of Plant Science and Technology, Chung-Ang University, Anseong, South Korea
| | - Yu-Jeong Kwon
- Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup-si, South Korea
- Department of Horticulture, Chonbuk National University, Jeonju-si, South Korea
| | - Inwoo Baek
- Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup-si, South Korea
| | - Hong-Il Choi
- Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup-si, South Korea
| | - Joon-Woo Ahn
- Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup-si, South Korea
| | - Jin-Baek Kim
- Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup-si, South Korea
| | - Si-Yong Kang
- Department of Horticulture, College of Industrial Sciences, Kongju National University, Yesan-gun, South Korea
| | - Sang Hoon Kim
- Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup-si, South Korea
| | - Yeong Deuk Jo
- Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup-si, South Korea
- *Correspondence: Yeong Deuk Jo,
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Laanen P, Saenen E, Mysara M, Van de Walle J, Van Hees M, Nauts R, Van Nieuwerburgh F, Voorspoels S, Jacobs G, Cuypers A, Horemans N. Changes in DNA Methylation in Arabidopsis thaliana Plants Exposed Over Multiple Generations to Gamma Radiation. FRONTIERS IN PLANT SCIENCE 2021; 12:611783. [PMID: 33868326 PMCID: PMC8044457 DOI: 10.3389/fpls.2021.611783] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Accepted: 03/09/2021] [Indexed: 05/05/2023]
Abstract
Previous studies have found indications that exposure to ionising radiation (IR) results in DNA methylation changes in plants. However, this phenomenon is yet to be studied across multiple generations. Furthermore, the exact role of these changes in the IR-induced plant response is still far from understood. Here, we study the effect of gamma radiation on DNA methylation and its effect across generations in young Arabidopsis plants. A multigenerational set-up was used in which three generations (Parent, generation 1, and generation 2) of 7-day old Arabidopsis thaliana plants were exposed to either of the different radiation treatments (30, 60, 110, or 430 mGy/h) or to natural background radiation (control condition) for 14 days. The parental generation consisted of previously non-exposed plants, whereas generation 1 and generation 2 plants had already received a similar irradiation in the previous one or two generations, respectively. Directly after exposure the entire methylomes were analysed with UPLC-MS/MS to measure whole genome methylation levels. Whole genome bisulfite sequencing was used to identify differentially methylated regions (DMRs), including their methylation context in the three generations and this for three different radiation conditions (control, 30 mGy/h, and 110 mGy/h). Both intra- and intergenerational comparisons of the genes and transposable elements associated with the DMRs were made. Taking the methylation context into account, the highest number of changes were found for cytosines followed directly by guanine (CG methylation), whereas only limited changes in CHG methylation occurred and no changes in CHH methylation were observed. A clear increase in IR-induced DMRs was seen over the three generations that were exposed to the lowest dose rate, where generation 2 had a markedly higher number of DMRs than the previous two generations (Parent and generation 1). Counterintuitively, we did not see significant differences in the plants exposed to the highest dose rate. A large number of DMRs associated with transposable elements were found, the majority of them being hypermethylated, likely leading to more genetic stability. Next to that, a significant number of DMRs were associated with genes (either in their promoter-associated region or gene body). A functional analysis of these genes showed an enrichment for genes related to development as well as various stress responses, including DNA repair, RNA splicing, and (a)biotic stress responses. These observations indicate a role of DNA methylation in the regulation of these genes in response to IR exposure and shows a possible role for epigenetics in plant adaptation to IR over multiple generations.
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Affiliation(s)
- Pol Laanen
- Biosphere Impact Studies, Belgian Nuclear Research Centre (SCK CEN), Mol, Belgium
- Centre for Environmental Research, Hasselt University, Diepenbeek, Belgium
| | - Eline Saenen
- Biosphere Impact Studies, Belgian Nuclear Research Centre (SCK CEN), Mol, Belgium
| | - Mohamed Mysara
- Biosphere Impact Studies, Belgian Nuclear Research Centre (SCK CEN), Mol, Belgium
| | - Jorden Van de Walle
- Biosphere Impact Studies, Belgian Nuclear Research Centre (SCK CEN), Mol, Belgium
- Centre for Environmental Research, Hasselt University, Diepenbeek, Belgium
| | - May Van Hees
- Biosphere Impact Studies, Belgian Nuclear Research Centre (SCK CEN), Mol, Belgium
| | - Robin Nauts
- Biosphere Impact Studies, Belgian Nuclear Research Centre (SCK CEN), Mol, Belgium
| | - Filip Van Nieuwerburgh
- Laboratory of Pharmaceutical Biotechnology, Ghent University, Ghent, Belgium
- NXTGNT, Ghent University, Ghent, Belgium
| | | | - Griet Jacobs
- Vlaamse Instelling voor Technologisch Onderzoek, VITO, Mol, Belgium
| | - Ann Cuypers
- Centre for Environmental Research, Hasselt University, Diepenbeek, Belgium
| | - Nele Horemans
- Biosphere Impact Studies, Belgian Nuclear Research Centre (SCK CEN), Mol, Belgium
- Centre for Environmental Research, Hasselt University, Diepenbeek, Belgium
- *Correspondence: Nele Horemans,
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TRANSPARENT TESTA GLABRA1, a Key Regulator in Plants with Multiple Roles and Multiple Function Mechanisms. Int J Mol Sci 2020; 21:ijms21144881. [PMID: 32664363 PMCID: PMC7402295 DOI: 10.3390/ijms21144881] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 07/06/2020] [Accepted: 07/09/2020] [Indexed: 01/01/2023] Open
Abstract
TRANSPARENT TESTA GLABRA1 (TTG1) is a WD40 repeat protein. The phenotypes caused by loss-of-function of TTG1 were observed about half a century ago, but the TTG1 gene was identified only about twenty years ago. Since then, TTG1 has been found to be a plant-specific regulator with multiple roles and multiple functional mechanisms. TTG1 is involved in the regulation of cell fate determination, secondary metabolisms, accumulation of seed storage reserves, plant responses to biotic and abiotic stresses, and flowering time in plants. In some processes, TTG1 may directly or indirectly regulate the expression of downstream target genes via forming transcription activator complexes with R2R3 MYB and bHLH transcription factors. Whereas in other processes, TTG1 may function alone or interact with other proteins to regulate downstream target genes. On the other hand, the studies on the regulation of TTG1 are very limited. So far, only the B3-domain family transcription factor FUSCA3 (FUS3) has been found to regulate the expression of TTG1, phosphorylation of TTG1 affects its interaction with bHLH transcription factor TT2, and TTG1 proteins can be targeted for degradation by the 26S proteasome. Here, we provide an overview of TTG1, including the identification of TTG1, the functions of TTG1, the possible function mechanisms of TTG1, and the regulation of TTG1. We also proposed potential research directions that may shed new light on the regulation and functional mechanisms of TTG1 in plants.
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Kim SH, Kim YS, Lee HJ, Jo YD, Kim JB, Kang SY. Biological effects of three types of ionizing radiation on creeping bentgrass. Int J Radiat Biol 2019; 95:1295-1300. [DOI: 10.1080/09553002.2019.1619953] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Sang Hoon Kim
- Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup, Korea
| | - Ye-Sol Kim
- Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup, Korea
| | - Hyo-Jeong Lee
- Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup, Korea
| | - Yeong Deuk Jo
- Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup, Korea
| | - Jin-Baek Kim
- Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup, Korea
| | - Si-Yong Kang
- Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup, Korea
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Frequency and Spectrum of Radiation-Induced Mutations Revealed by Whole-Genome Sequencing Analyses of Plants. QUANTUM BEAM SCIENCE 2019. [DOI: 10.3390/qubs3020007] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Mutation breeding and functional genomics studies of mutant populations have made important contributions to plant research involving the application of radiation. The frequency and spectrum of induced mutations have long been regarded as the crucial determinants of the efficiency of the development and use of mutant populations. Systematic studies regarding the mutation frequency and spectrum, including genetic and genomic analyses, have recently resulted in considerable advances. These studies have consistently shown that the mutation frequency and spectrum are affected by diverse factors, including radiation type, linear energy transfer, and radiation dose, as well as the plant tissue type and condition. Moreover, the whole-genome sequencing of mutant individuals based on next-generation sequencing technologies has enabled the genome-wide quantification of mutation frequencies according to DNA mutation types as well as the elucidation of mutation mechanisms based on sequence characteristics. These studies will contribute to the development of a highly efficient and more controlled mutagenesis method relevant for the customized research of plants. We herein review the characteristics of radiation-induced mutations in plants, mainly focusing on recent whole-genome sequencing analyses as well as factors affecting the mutation frequency and spectrum.
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Zhang B, Schrader A. TRANSPARENT TESTA GLABRA 1-Dependent Regulation of Flavonoid Biosynthesis. PLANTS (BASEL, SWITZERLAND) 2017; 6:E65. [PMID: 29261137 PMCID: PMC5750641 DOI: 10.3390/plants6040065] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Revised: 12/02/2017] [Accepted: 12/16/2017] [Indexed: 12/25/2022]
Abstract
The flavonoid composition of various tissues throughout plant development is of biological relevance and particular interest for breeding. Arabidopsis thaliana TRANSPARENT TESTA GLABRA 1 (AtTTG1) is an essential regulator of late structural genes in flavonoid biosynthesis. Here, we provide a review of the regulation of the pathway's core enzymes through AtTTG1-containing R2R3-MYELOBLASTOSIS-basic HELIX-LOOP-HELIX-WD40 repeat (MBW(AtTTG1)) complexes embedded in an evolutionary context. We present a comprehensive collection of A. thalianattg1 mutants and AtTTG1 orthologs. A plethora of MBW(AtTTG1) mechanisms in regulating the five major TTG1-dependent traits is highlighted.
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Affiliation(s)
- Bipei Zhang
- Botanical Institute, University of Cologne, Zuelpicher Str 47B, 50674 Cologne, Germany.
| | - Andrea Schrader
- Botanical Institute, University of Cologne, Zuelpicher Str 47B, 50674 Cologne, Germany.
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Hu W, Li W, Chen J. Recent advances of microbial breeding via heavy-ion mutagenesis at IMP. Lett Appl Microbiol 2017; 65:274-280. [PMID: 28741678 DOI: 10.1111/lam.12780] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Revised: 07/11/2017] [Accepted: 07/17/2017] [Indexed: 12/12/2022]
Abstract
Nowadays, the value of heavy-ion mutagenesis has been accepted as a novel powerful mutagen technique to generate new microbial mutants due to its high linear energy transfer and high relative biological effectiveness. This paper briefly reviews recent progress in developing a more efficient mutagenesis technique for microbial breeding using heavy-ion mutagenesis, and also presents the outline of the beam line for microbial breeding in Heavy Ion Research Facility of Lanzhou. Then, new insights into microbial biotechnology via heavy-ion mutagenesis are also further explored. We hope that our concerns will give deep insight into microbial breeding biotechnology via heavy-ion mutagenesis. We also believe that heavy-ion mutagenesis breeding will greatly contribute to the progress of a comprehensive study industrial strain engineering for bioindustry in the future. SIGNIFICANCE AND IMPACT OF THE STUDY There is currently a great interest in developing rapid and diverse microbial mutation tool for strain modification. Heavy-ion mutagenesis has been proved as a powerful technology for microbial breeding due to its broad spectrum of mutation phenotypes with high efficiency. In order to deeply understand heavy-ion mutagenesis technology, this paper briefly reviews recent progress in microbial breeding using heavy-ion mutagenesis at IMP, and also presents the outline of the beam line for microbial breeding in Heavy Ion Research Facility of Lanzhou (HIRFL) as well as new insights into microbial biotechnology via heavy-ion mutagenesis. Thus, this work can provide the guidelines to promote the development of novel microbial biotechnology cross-linking heavy-ion mutagenesis breeding that could make breeding process more efficiently in the future.
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Affiliation(s)
- W Hu
- Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, China
| | - W Li
- Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, China
| | - J Chen
- Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, China
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Jung IJ, Hwang JE, Han SM, Kim DS, Ahn JW, Choi HI, Kwon SJ, Kang SY, Kim JB. Molecular dissection of the response of the rice Systemic Acquired Resistance Deficient 1 (SARD1) gene to different types of ionizing radiation. Int J Radiat Biol 2017; 93:717-725. [PMID: 28299960 DOI: 10.1080/09553002.2017.1297901] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
PURPOSE Exposure to ionizing radiation induces plant defenses by regulating the expression of response genes. The systemic acquired resistance deficient 1 (SARD1) is a key gene in plant defense response. In this study, the function of Oryza sativa SARD1 (OsSARD1) was investigated after exposure of seeds/plants to ionizing radiation, jasmonic acid (JA) or salicylic acid (SA). MATERIALS AND METHODS Rice seeds exposed to two types of ionizing radiations (gamma ray [GR] and ion beam [IB]) were analyzed by quantitative reverse transcription PCR (qRT-PCR) to identify the genes that are altered in response to ionizing radiation. Then, OsSARD1-overexpressing homozygous Arabidopsis plants were generated to assess the effects of OsSARD1 in the response to irradiation. The phenotypes of these transgenic plants, as well as control plants, were monitored after GR irradiation at doses of 200 and 300 Gray (Gy). RESULTS The OsSARD1 transcript was strongly downregulated after exposure to GR and IB irradiation. Previous phylogenetic analysis showed that the Arabidopsis SARD1 (AtSARD1) protein is closely related to Arabidopsis calmodulin-binding protein 60g (AtCBP60g), which is known to be required for activation of SA biosynthesis. In this study, phylogenetic analysis showed that OsSARD1 was grouped with AtSARD1. The OsSARD1 gene was induced after exposure to SA and JA. The biological phenotype of OsSARD1-overexpressing Arabidopsis plants was examined. OsSARD1-overexpressing plants displayed resistance to GR; in comparison with wild-type plants, the height and weight of OsSARD1-overexpressing plants were significantly greater after GR irradiation. In addition, OsSARD1 protein was abundantly accumulated in the nucleus. CONCLUSIONS The results indicate that OsSARD1 plays an important role in the regulation of the defense responses to GR and IB irradiation and exhibits phytohormone induced expression.
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Affiliation(s)
- In Jung Jung
- a Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute , Jeongeup , Jeollabuk , Republic of Korea
| | - Jung Eun Hwang
- a Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute , Jeongeup , Jeollabuk , Republic of Korea.,b Division of Ecological Conservation, Bureau of Ecological Research , National Institute of Ecology , Seocheon , Republic of Korea
| | - Sung Min Han
- a Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute , Jeongeup , Jeollabuk , Republic of Korea
| | - Dong Sub Kim
- c NJBiopia Co. Ltd , Gwangju , Republic of Korea
| | - Joon-Woo Ahn
- a Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute , Jeongeup , Jeollabuk , Republic of Korea
| | - Hong-Il Choi
- a Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute , Jeongeup , Jeollabuk , Republic of Korea
| | - Soon-Jae Kwon
- a Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute , Jeongeup , Jeollabuk , Republic of Korea
| | - Si-Yong Kang
- a Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute , Jeongeup , Jeollabuk , Republic of Korea
| | - Jin-Baek Kim
- a Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute , Jeongeup , Jeollabuk , Republic of Korea
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Schulz E, Tohge T, Zuther E, Fernie AR, Hincha DK. Flavonoids are determinants of freezing tolerance and cold acclimation in Arabidopsis thaliana. Sci Rep 2016; 6:34027. [PMID: 27658445 PMCID: PMC5034326 DOI: 10.1038/srep34027] [Citation(s) in RCA: 120] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Accepted: 09/06/2016] [Indexed: 12/15/2022] Open
Abstract
In plants from temperate climates such as Arabidopsis thaliana low, non-freezing temperatures lead to increased freezing tolerance in a process termed cold acclimation. This process is accompanied by massive changes in gene expression and in the content of primary metabolites and lipids. In addition, most flavonols and anthocyanins accumulate upon cold exposure, along with most transcripts encoding transcription factors and enzymes of the flavonoid biosynthetic pathway. However, no evidence for a functional role of flavonoids in plant freezing tolerance has been shown. Here, we present a comprehensive analysis using qRT-PCR for transcript, LC-MS for flavonoid and GC-MS for primary metabolite measurements, and an electrolyte leakage assay to determine freezing tolerance of 20 mutant lines in two Arabidopsis accessions that are affected in different steps of the flavonoid biosynthetic pathway. This analysis provides evidence for a functional role of flavonoids in plant cold acclimation. The accumulation of flavonoids in the activation tagging mutant line pap1-D improved, while reduced flavonoid content in different knock-out mutants impaired leaf freezing tolerance. Analysis of the different knock-out mutants suggests redundancy of flavonoid structures, as the lack of flavonols or anthocyanins could be compensated by other compound classes.
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Affiliation(s)
- Elisa Schulz
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, D-14476 Potsdam, Germany
| | - Takayuki Tohge
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, D-14476 Potsdam, Germany
| | - Ellen Zuther
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, D-14476 Potsdam, Germany
| | - Alisdair R. Fernie
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, D-14476 Potsdam, Germany
| | - Dirk K. Hincha
- Max-Planck-Institut für Molekulare Pflanzenphysiologie, Am Mühlenberg 1, D-14476 Potsdam, Germany
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Tohge T, Wendenburg R, Ishihara H, Nakabayashi R, Watanabe M, Sulpice R, Hoefgen R, Takayama H, Saito K, Stitt M, Fernie AR. Characterization of a recently evolved flavonol-phenylacyltransferase gene provides signatures of natural light selection in Brassicaceae. Nat Commun 2016; 7:12399. [PMID: 27545969 PMCID: PMC4996938 DOI: 10.1038/ncomms12399] [Citation(s) in RCA: 123] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Accepted: 06/29/2016] [Indexed: 02/07/2023] Open
Abstract
Incidence of natural light stress renders it important to enhance our understanding of the mechanisms by which plants protect themselves from harmful effects of UV-B irradiation, as this is critical for fitness of land plant species. Here we describe natural variation of a class of phenylacylated-flavonols (saiginols), which accumulate to high levels in floral tissues of Arabidopsis. They were identified in a subset of accessions, especially those deriving from latitudes between 16° and 43° North. Investigation of introgression line populations using metabolic and transcript profiling, combined with genomic sequence analysis, allowed the identification of flavonol-phenylacyltransferase 2 (FPT2) that is responsible for the production of saiginols and conferring greater UV light tolerance in planta. Furthermore, analysis of polymorphism within the FPT duplicated region provides an evolutionary framework of the natural history of this locus in the Brassicaceae.
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Affiliation(s)
- Takayuki Tohge
- Max-Planck-Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany
| | - Regina Wendenburg
- Max-Planck-Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany
| | - Hirofumi Ishihara
- Max-Planck-Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany
| | - Ryo Nakabayashi
- Graduate School of Pharmaceutical Sciences, Chiba University, Inohana 1-8-1 Chuo-ku, Chiba 260-8675, Japan
| | - Mutsumi Watanabe
- Max-Planck-Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany
| | - Ronan Sulpice
- Max-Planck-Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany
| | - Rainer Hoefgen
- Max-Planck-Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany
| | - Hiromitsu Takayama
- Graduate School of Pharmaceutical Sciences, Chiba University, Inohana 1-8-1 Chuo-ku, Chiba 260-8675, Japan
| | - Kazuki Saito
- Graduate School of Pharmaceutical Sciences, Chiba University, Inohana 1-8-1 Chuo-ku, Chiba 260-8675, Japan.,RIKEN Center for Sustainable Resource Science, Suehiro-cho 1-7-22, Yokohama 230-0045, Japan
| | - Mark Stitt
- Max-Planck-Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany
| | - Alisdair R Fernie
- Max-Planck-Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany.,Center of Plant System Biology and Biotechnology, 4000 Plovdiv, Bulgaria
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Zhang L, Qi W, Xu H, Wang L, Jiao Z. Effects of low-energy N(+)-beam implantation on root growth in Arabidopsis seedlings. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2016; 124:111-119. [PMID: 26479682 DOI: 10.1016/j.ecoenv.2015.10.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Revised: 09/16/2015] [Accepted: 10/05/2015] [Indexed: 05/24/2023]
Abstract
The effects of ion implantation on the morphology changes and biological responses of plants are dependent on implantation doses. Previous studies mainly focus on the application of ion-beam technology in genetic mutation. Our knowledge regarding the mechanism underlying the plant growth inhibition induced by ion implantation remains limited. In this study, we explore the responses of root growth to low-energy N(+)-beam implantation using implanted Arabidopsis seeds. Our results showed that the root and root tip length were obviously reduced by implantation with large doses of low-energy N(+) beam. The analysis of confocal images showed that ion implantation reduced the cell viability and cell division activity in root meristem. The production rate of superoxide radical (O2(•-)) and contents of hydrogen peroxide (H2O2) in roots under ion implantation were markedly higher than those of controls. Transcriptional expression analysis of selected genes revealed that Arabidopsis RBOH genes associated with reactive oxygen species (ROS) production were significantly up-regulated in roots in response to ion implantation. The activities of antioxidant enzymes were also induced by ion implantation. Moreover, ROS scavenging obviously enhanced cell viability and cell division in response to ion implantation and alleviated the root growth inhibition of the implanted seedlings. Our results suggest that the overproduction of ROS induced by ion implantation is involved in the inhibitory effect of low-energy ion beam on root growth by affecting the cell viability and cell division of root meristem in Arabidopsis seedlings.
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Affiliation(s)
- Liang Zhang
- College of Life Science, Henan Normal University, Xinxiang 453007, China
| | - Wencai Qi
- College of Life Science, Henan Normal University, Xinxiang 453007, China
| | - Hangbo Xu
- Henan Provincial Key Laboratory of Ion Beam Bio-engineering, Zhengzhou University, Zhengzhou 450052, China
| | - Lin Wang
- Henan Provincial Key Laboratory of Ion Beam Bio-engineering, Zhengzhou University, Zhengzhou 450052, China
| | - Zhen Jiao
- Henan Provincial Key Laboratory of Ion Beam Bio-engineering, Zhengzhou University, Zhengzhou 450052, China.
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Hong MJ, Kim JB, Yoon YH, Kim SH, Ahn JW, Jeong IY, Kang SY, Seo YW, Kim DS. The effects of chronic gamma irradiation on oxidative stress response and the expression of anthocyanin biosynthesis-related genes in wheat (Triticum aestivum). Int J Radiat Biol 2014; 90:1218-28. [DOI: 10.3109/09553002.2014.934930] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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14
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Shi J, Lu W, Sun Y. Comparison of space flight and heavy ion radiation induced genomic/epigenomic mutations in rice (Oryza sativa). LIFE SCIENCES IN SPACE RESEARCH 2014; 1:74-79. [PMID: 26432592 DOI: 10.1016/j.lssr.2014.02.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2013] [Revised: 01/15/2014] [Accepted: 01/23/2014] [Indexed: 06/05/2023]
Abstract
Rice seeds, after space flight and low dose heavy ion radiation treatment were cultured on ground. Leaves of the mature plants were obtained for examination of genomic/epigenomic mutations by using amplified fragment length polymorphism (AFLP) and methylation sensitive amplification polymorphism (MSAP) method, respectively. The mutation sites were identified by fragment recovery and sequencing. The heritability of the mutations was detected in the next generation. Results showed that both space flight and low dose heavy ion radiation can induce significant alterations on rice genome and epigenome (P<0.05). For both genetic and epigenetic assays, while there was no significant difference in mutation rates and their ability to be inherited to the next generation, the site of mutations differed between the space flight and radiation treated groups. More than 50% of the mutation sites were shared by two radiation treated groups, radiated with different LET value and dose, while only about 20% of the mutation sites were shared by space flight group and radiation treated group. Moreover, in space flight group, we found that DNA methylation changes were more prone to occur on CNG sequence than CG sequence. Sequencing results proved that both space flight and heavy ion radiation induced mutations were widely spread on rice genome including coding region and repeated region. Our study described and compared the characters of space flight and low dose heavy ion radiation induced genomic/epigenomic mutations. Our data revealed the mechanisms of application of space environment for mutagenesis and crop breeding. Furthermore, this work implicated that the nature of mutations induced under space flight conditions may involve factors beyond ion radiation.
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Affiliation(s)
- Jinming Shi
- College of Life Science, Northeast Forestry University, Harbin, PR China
| | - Weihong Lu
- Institute of Extreme Environment Nutrition and Protection, School of Food Science and Engineering, Harbin Institute of Technology, Harbin, PR China
| | - Yeqing Sun
- Institute of Environmental Systems Biology, Dalian Maritime University, Dalian, PR China.
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15
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Du Y, Li W, Yu L, Chen G, Liu Q, Luo S, Shu Q, Zhou L. Mutagenic effects of carbon-ion irradiation on dry Arabidopsis thaliana seeds. MUTATION RESEARCH-GENETIC TOXICOLOGY AND ENVIRONMENTAL MUTAGENESIS 2014; 759:28-36. [DOI: 10.1016/j.mrgentox.2013.07.018] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2013] [Revised: 06/07/2013] [Accepted: 07/08/2013] [Indexed: 11/30/2022]
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16
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Yoshihara R, Nozawa S, Hase Y, Narumi I, Hidema J, Sakamoto AN. Mutational effects of γ-rays and carbon ion beams on Arabidopsis seedlings. JOURNAL OF RADIATION RESEARCH 2013; 54:1050-6. [PMID: 23728320 PMCID: PMC3823791 DOI: 10.1093/jrr/rrt074] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
To assess the mutational effects of radiation on vigorously proliferating plant tissue, the mutation spectrum was analyzed with Arabidopsis seedlings using the plasmid-rescue method. Transgenic plants containing the Escherichia coli rpsL gene were irradiated with γ-rays and carbon ion beams (320-MeV (12)C(6+)), and mutations in the rpsL gene were analyzed. Mutant frequency increased significantly following irradiation by γ-rays, but not by 320-MeV (12)C(6+). Mutation spectra showed that both radiations increased the frequency of frameshifts and other mutations, including deletions and insertions, but only γ-rays increased the frequency of total base substitutions. These results suggest that the type of DNA lesions which cause base substitutions were less often induced by 320-MeV (12)C(6+) than by γ-rays in Arabidopsis seedlings. Furthermore, γ-rays never increased the frequencies of G:C to T:A or A:T to C:G transversions, which are caused by oxidized guanine; 320-MeV (12)C(6+), however, produced a slight increase in both transversions. Instead, γ-rays produced a significant increase in the frequency of G:C to A:T transitions. These results suggest that 8-oxoguanine has little effect on mutagenesis in Arabidopsis cells.
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Affiliation(s)
- Ryouhei Yoshihara
- Research Center for Environmental Genomics, Kobe University, 1-1 Rokkodai, Nada, Kobe 657-8501, Japan
| | - Shigeki Nozawa
- Ion Beam Mutagenesis Research Group, Medical and Biotechnological Application Division, Quantum Beam Science Directorate, Japan Atomic Energy Agency, 1233 Watanuki, Takasaki, 370-1292, Japan
| | - Yoshihiro Hase
- Ion Beam Mutagenesis Research Group, Medical and Biotechnological Application Division, Quantum Beam Science Directorate, Japan Atomic Energy Agency, 1233 Watanuki, Takasaki, 370-1292, Japan
| | - Issay Narumi
- Department of Life Sciences, Faculty of Life Sciences, Toyo University, 1-1-1 Izumino, Itakura, 374-0193, Japan
| | - Jun Hidema
- Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
| | - Ayako N. Sakamoto
- Ion Beam Mutagenesis Research Group, Medical and Biotechnological Application Division, Quantum Beam Science Directorate, Japan Atomic Energy Agency, 1233 Watanuki, Takasaki, 370-1292, Japan
- Corresponding author. Ion Beam Mutagenesis Research Group, Medical and Biotechnological Application Division, Quantum Beam Science Directorate, Japan Atomic Energy Agency, 1233 Watanuki, Takasaki, 370-1292, Japan. Tel: +81-27-346-9537; Fax: +81-27-346-9688;
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17
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Saito K, Yonekura-Sakakibara K, Nakabayashi R, Higashi Y, Yamazaki M, Tohge T, Fernie AR. The flavonoid biosynthetic pathway in Arabidopsis: structural and genetic diversity. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2013; 72:21-34. [PMID: 23473981 DOI: 10.1016/j.plaphy.2013.02.001] [Citation(s) in RCA: 466] [Impact Index Per Article: 42.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2012] [Accepted: 02/01/2013] [Indexed: 05/19/2023]
Abstract
Flavonoids are representative plant secondary products. In the model plant Arabidopsis thaliana, at least 54 flavonoid molecules (35 flavonols, 11 anthocyanins and 8 proanthocyanidins) are found. Scaffold structures of flavonoids in Arabidopsis are relatively simple. These include kaempferol, quercetin and isorhamnetin for flavonols, cyanidin for anthocyanins and epicatechin for proanthocyanidins. The chemical diversity of flavonoids increases enormously by tailoring reactions which modify these scaffolds, including glycosylation, methylation and acylation. Genes responsible for the formation of flavonoid aglycone structures and their subsequent modification reactions have been extensively characterized by functional genomic efforts - mostly the integration of transcriptomics and metabolic profiling followed by reverse genetic experimentation. This review describes the state-of-art of flavonoid biosynthetic pathway in Arabidopsis regarding both structural and genetic diversity, focusing on the genes encoding enzymes for the biosynthetic reactions and vacuole translocation.
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Affiliation(s)
- Kazuki Saito
- RIKEN Plant Science Center, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama 230-0045, Japan; Graduate School of Pharmaceutical Sciences, Chiba University, Inohana 1-8-1, Chiba 260-8675, Japan.
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18
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Hirano T, Kazama Y, Ohbu S, Shirakawa Y, Liu Y, Kambara T, Fukunishi N, Abe T. Molecular nature of mutations induced by high-LET irradiation with argon and carbon ions in Arabidopsis thaliana. Mutat Res 2012; 735:19-31. [PMID: 22579628 DOI: 10.1016/j.mrfmmm.2012.04.010] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2011] [Revised: 04/18/2012] [Accepted: 04/27/2012] [Indexed: 10/28/2022]
Abstract
Linear energy transfer (LET) is an important parameter to be considered in heavy-ion mutagenesis. However, in plants, no quantitative data are available on the molecular nature of the mutations induced with high-LET radiation above 101-124keVμm(-1). In this study, we irradiated dry seeds of Arabidopsis thaliana with Ar and C ions with an LET of 290keVμm(-1). We analyzed the DNA alterations caused by the higher-LET radiation. Mutants were identified from the M(2) pools. In total, 14 and 13 mutated genes, including bin2, egy1, gl1, gl2, hy1, hy3-5, ttg1, and var2, were identified in the plants derived from Ar- and C-ions irradiation, respectively. In the mutants from both irradiations, deletion was the most frequent type of mutation; 13 of the 14 mutated genes from the Ar ion-irradiated plants and 11 of the 13 mutated genes from the C ion-irradiated plants harbored deletions. Analysis of junction regions generated by the 2 types of irradiation suggested that alternative non-homologous end-joining was the predominant pathway of repair of break points. Among the deletions, the proportion of large deletions (>100bp) was about 54% for Ar-ion irradiation and about 64% for C-ion irradiation. Both current results and previously reported data revealed that the proportions of the large deletions induced by 290-keVμm(-1) radiations were higher than those of the large deletions induced by lower-LET radiations (6% for 22.5-30.0keVμm(-1) and 27% for 101-124keVμm(-1)). Therefore, the 290keVμm(-1) heavy-ion beams can effectively induce large deletions and will prove useful as novel mutagens for plant breeding and analysis of gene functions, particularly tandemly arrayed genes.
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Affiliation(s)
- Tomonari Hirano
- Nishina Center for Accelerator-Based Science, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
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Kazama Y, Hirano T, Saito H, Liu Y, Ohbu S, Hayashi Y, Abe T. Characterization of highly efficient heavy-ion mutagenesis in Arabidopsis thaliana. BMC PLANT BIOLOGY 2011; 11:161. [PMID: 22085561 PMCID: PMC3261129 DOI: 10.1186/1471-2229-11-161] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2011] [Accepted: 11/15/2011] [Indexed: 05/18/2023]
Abstract
BACKGROUND Heavy-ion mutagenesis is recognised as a powerful technology to generate new mutants, especially in higher plants. Heavy-ion beams show high linear energy transfer (LET) and thus more effectively induce DNA double-strand breaks than other mutagenic techniques. Previously, we determined the most effective heavy-ion LET (LETmax: 30.0 keV μm(-1)) for Arabidopsis mutagenesis by analysing the effect of LET on mutation induction. However, the molecular structure of mutated DNA induced by heavy ions with LETmax remains unclear. Knowledge of the structure of mutated DNA will contribute to the effective exploitation of heavy-ion beam mutagenesis. RESULTS Dry Arabidopsis thaliana seeds were irradiated with carbon (C) ions with LETmax at a dose of 400 Gy and with LET of 22.5 keV μm(-1) at doses of 250 Gy or 450 Gy. The effects on mutation frequency and alteration of DNA structure were compared. To characterise the structure of mutated DNA, we screened the well-characterised mutants elongated hypocotyls (hy) and glabrous (gl) and identified mutated DNA among the resulting mutants by high-resolution melting curve, PCR and sequencing analyses. The mutation frequency induced by C ions with LETmax was two-fold higher than that with 22.5 keV μm(-1) and similar to the mutation frequency previously induced by ethyl methane sulfonate. We identified the structure of 22 mutated DNAs. Over 80% of the mutations caused by C ions with both LETs were base substitutions or deletions/insertions of less than 100 bp. The other mutations involved large rearrangements. CONCLUSIONS The C ions with LETmax showed high mutation efficiency and predominantly induced base substitutions or small deletions/insertions, most of which were null mutations. These small alterations can be determined by single-nucleotide polymorphism (SNP) detection systems. Therefore, C ions with LETmax might be useful as a highly efficient reverse genetic system in conjunction with SNP detection systems, and will be beneficial for forward genetics and plant breeding.
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Affiliation(s)
- Yusuke Kazama
- RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Tomonari Hirano
- RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
- RIKEN Innovation Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Hiroyuki Saito
- RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Yang Liu
- RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Sumie Ohbu
- RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Yoriko Hayashi
- RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Tomoko Abe
- RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
- RIKEN Innovation Center, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
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20
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Kusano M, Tohge T, Fukushima A, Kobayashi M, Hayashi N, Otsuki H, Kondou Y, Goto H, Kawashima M, Matsuda F, Niida R, Matsui M, Saito K, Fernie AR. Metabolomics reveals comprehensive reprogramming involving two independent metabolic responses of Arabidopsis to UV-B light. THE PLANT JOURNAL 2011; 67:354-69. [PMID: 21466600 DOI: 10.1111/j.1365-313x.2011.04599.x] [Citation(s) in RCA: 162] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
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21
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Reinprecht Y, Luk-Labey SY, Yu K, Poysa VW, Rajcan I, Ablett GR, Peter Pauls K. Molecular basis of seed lipoxygenase null traits in soybean line OX948. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2011; 122:1247-64. [PMID: 21243331 DOI: 10.1007/s00122-011-1528-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2010] [Accepted: 12/24/2010] [Indexed: 05/30/2023]
Abstract
The poor stability and off-flavors of soybean oil and protein products can be reduced by eliminating lipoxygenases from soybean seed. Mature seeds of OX948, a lipoxygenase triple null mutant line, do not contain lipoxygenase proteins. The objective of this study was to determine the molecular basis of the seed lipoxygenase null traits in OX948. Comparisons of the sequences for lipoxygenase 1 (Lx1) and lipoxygenase 2 (Lx2) genes in the mutant (OX948) with those in a line with normal lipoxygenase levels (RG10) showed that the mutations in these genes affected a highly conserved group of six histidines necessary for enzymatic activity. The OX948 mutation in Lx1 is a 74 bp deletion in exon 8, which introduces a stop codon that prematurely terminates translation. A single T-A substitution in Lx2 changes histidine H532 (one of the iron-binding ligands essential for L-2 activity) to glutamine. The mutation in the lipoxygenase 3 (Lx3) gene in OX948 is in the promoter region and represents two single base substitutions in a cis-acting AAATAC paired box. All three mutations would result in the loss of lipoxygenase activity in mature seed. The seed lipoxygenase gene mutation-based molecular markers could be used to accelerate and simplify breeding efforts for soybean cultivars with improved flavor.
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Affiliation(s)
- Yarmilla Reinprecht
- Department of Plant Agriculture, University of Guelph, Guelph, ON, N1G 2W1, Canada
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22
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Yoshihara R, Hase Y, Sato R, Takimoto K, Narumi I. Mutational effects of different LET radiations inrpsLtransgenicArabidopsis. Int J Radiat Biol 2010; 86:125-31. [DOI: 10.3109/09553000903336826] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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23
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Tanaka A, Shikazono N, Hase Y. Studies on biological effects of ion beams on lethality, molecular nature of mutation, mutation rate, and spectrum of mutation phenotype for mutation breeding in higher plants. JOURNAL OF RADIATION RESEARCH 2010; 51:223-33. [PMID: 20505261 DOI: 10.1269/jrr.09143] [Citation(s) in RCA: 113] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Recently, heavy ions or ion beams have been used to generate new mutants or varieties, especially in higher plants. It has been found that ion beams show high relative biological effectiveness (RBE) of growth inhibition, lethality, and so on, but the characteristics of ion beams on mutation have not been clearly elucidated. To understand the effect of ion beams on mutation induction, mutation rates were investigated using visible known Arabidopsis mutant phenotypes, indicating that mutation frequencies induced by carbon ions were 20-fold higher than by electrons. In chrysanthemum and carnation, flower-color and flower-form mutants, which are hardly produced by gamma rays or X rays, were induced by ion beams. Novel mutants and their responsible genes, such as UV-B resistant, serrated petals and sepals, anthocyaninless, etc. were induced by ion beams. These results indicated that the characteristics of ion beams for mutation induction are high mutation frequency and broad mutation spectrum and therefore, efficient induction of novel mutants. On the other hand, PCR and sequencing analyses showed that half of all mutants induced by ion beams possessed large DNA alterations, while the rest had point-like mutations. Both mutations induced by ion beams had a common feature that deletion of several bases were predominantly induced. It is plausible that ion beams induce a limited amount of large and irreparable DNA damage, resulting in production of a null mutation that shows a new mutant phenotype.
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Affiliation(s)
- Atsushi Tanaka
- Quantum Beam Science Directorate, Japan Atomic Energy Agency, Takasaki, Gunma, Japan.
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24
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Morita R, Kusaba M, Iida S, Nishio T, Nishimura M. Development of PCR markers to detect the glb1 and Lgc1 mutations for the production of low easy-to-digest protein rice varieties. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2009; 119:125-30. [PMID: 19373444 DOI: 10.1007/s00122-009-1022-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2008] [Accepted: 03/20/2009] [Indexed: 05/05/2023]
Abstract
Limiting the ingestion of protein is the fundamental idea in the diet therapy for patients with chronic renal failure. Two mutations involved in the content of major rice storage proteins useful for developing low easy-to-digest protein rice variety have been isolated. The glb1 mutation causes the deficiency of alpha-globulin, and the Lgc1 mutation reduces the glutelin content. By combining the glb1 and the Lgc1 mutations, it is possible to reduce the easy-to-digest protein content by approximately 50%. The Lgc1 mutation has been shown to be caused by a 3.5-kb deletion between the glutelin structural genes, GluB4 and GluB5, while the molecular basis of glb1 mutation has been less understood. PCR analysis of the glb1 mutation revealed a 62.8-kb deletion, including the structural gene of alpha-globulin. Based on these lines of information, we generated PCR markers that make it possible to detect the glb1 and Lgc1 mutations. Using those PCR markers, we genotyped F(2) plants segregating for the glb1 mutation and the Lgc1 mutation and confirmed the consistency of genotype and phenotype. Because the PCR marker sets can distinguish heterozygotes, they will be very useful in developing new varieties of low easy-to-digest protein rice.
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Affiliation(s)
- Ryouhei Morita
- Institute of Radiation Breeding, National Institute of Agrobiological Sciences, Kamimurata, Hitachi-ohmiya, Japan.
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25
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Morita R, Kusaba M, Iida S, Nishio T, Nishimura M. Knockout of glutelin genes which form a tandem array with a high level of homology in rice by gamma irradiation. Genes Genet Syst 2008; 82:321-7. [PMID: 17895583 DOI: 10.1266/ggs.82.321] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
In the course of evolution, a gene is often duplicated in tandem, resulting in a functional redundancy. The analysis of function of these genes by raising double mutant might be difficult because they are very tightly linked. We described here a mutant of such a tandem duplicated gene. glu1 is a gamma-ray-induced rice mutant, which lacks an acidic subunit of glutelin, a major seed storage protein. We found that glu1 harbors a 129.7-kb deletion involving two highly similar and tandem repeated glutelin genes, GluB5 and GluB4. The deletion eliminated the entire GluB5 and GluB4 gene except half of the first exon of GluB5. GluB5 and GluB4 have the same amino acid sequence in the acidic subunit, suggesting that only the mutation involving both GluB5 and GluB4 results in the lack of the glutelin acidic subunit deleted in glu1. Our finding suggests that gamma-ray can be an effective mutagen to analyze tandem repeated and functionally redundant genes.
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MESH Headings
- DNA, Plant/chemistry
- DNA, Plant/genetics
- DNA, Plant/radiation effects
- Down-Regulation/genetics
- Down-Regulation/radiation effects
- Evolution, Molecular
- Gamma Rays
- Gene Deletion
- Gene Expression Regulation, Plant/radiation effects
- Genes, Plant/genetics
- Genes, Plant/radiation effects
- Glutens/chemistry
- Glutens/genetics
- Glutens/metabolism
- Multigene Family/genetics
- Multigene Family/radiation effects
- Oryza/genetics
- Oryza/metabolism
- Oryza/radiation effects
- Plant Proteins/chemistry
- Plant Proteins/genetics
- Plant Proteins/metabolism
- Plants, Genetically Modified/chemistry
- Plants, Genetically Modified/genetics
- Plants, Genetically Modified/metabolism
- Sequence Analysis, DNA
- Sequence Homology, Nucleic Acid
- Tandem Repeat Sequences/genetics
- Tandem Repeat Sequences/radiation effects
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Affiliation(s)
- Ryouhei Morita
- Institute of Radiation Breeding, National Institute of Agrobiological Sciences, Kamimurata, Hitachi-ohmiya, Japan.
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Bhat RS, Upadhyaya NM, Chaudhury A, Raghavan C, Qiu F, Wang H, Wu J, McNally K, Leung H, Till B, Henikoff S, Comai L. Chemical- and Irradiation-Induced Mutants and TILLING. RICE FUNCTIONAL GENOMICS 2007:148-180. [DOI: 10.1007/0-387-48914-2_8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/19/2023]
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27
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Yang G, Wu L, Chen L, Pei B, Wang Y, Zhan F, Wu Y, Yu Z. Targeted irradiation of shoot apical meristem of Arabidopsis embryos induces long-distance bystander/abscopal effects. Radiat Res 2007; 167:298-305. [PMID: 17316074 DOI: 10.1667/rr0710.1] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2006] [Accepted: 10/05/2006] [Indexed: 11/03/2022]
Abstract
Bystander effects induced by low-dose ionizing radiation have been shown to occur widely in many cell types and may have a significant impact on radiation risk assessment. Although the region of radiation damage is known to be much greater than the initial target volume irradiated, it remains to be seen whether this response is limited to the specific organ irradiated, spans a limited region of the body, or even covers the whole body of the target. To determine whether long-distance bystander/abscopal effects exist in whole organisms and to clarify the problem of intercellular communication, in the present study a specific cell group, the shoot apical meristem in Arabidopsis embryo, was irradiated with a defined number of protons and examined for root development postirradiation. The results showed that after direct damage to the shoot apical meristem from ion traversals, root hair differentiation, primary root elongation and lateral root initiation were all inhibited significantly in postembryonic development, suggesting that radiation-induced long-distance bystander/abscopal responses might exist in the whole organism. To further scrutinize the mechanism(s) underlying these inhibitory effects, a DR5-GUS transgenic Arabidopsis was used. The results showed that accumulation of the reporter GUS gene transcript in irradiated shoot apical meristem embryos decreased in the postembryonic development. Treatment with either 2,4-dichlorophenoxyacetic acid, a synthetic plant auxin, or DMSO, a effective reactive oxygen species (ROS) scavenger, could rescue the reporter GUS enzyme accumulation and the length of primary root in irradiated shoot apical meristem embryos, indicating that ROS or probably the ROS related auxin and auxin-dependent transcription process may be involved in radiation-induced long-distance bystander/abscopal effects.
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Affiliation(s)
- Gen Yang
- Key Laboratory of Ion Beam Bioengineering, Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, People's Republic of China
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28
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Matuo Y, Nishijima S, Hase Y, Sakamoto A, Tanaka A, Shimizu K. Specificity of mutations induced by carbon ions in budding yeast Saccharomyces cerevisiae. Mutat Res 2006; 602:7-13. [PMID: 16949109 DOI: 10.1016/j.mrfmmm.2006.07.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2006] [Revised: 06/27/2006] [Accepted: 07/13/2006] [Indexed: 05/11/2023]
Abstract
To investigate the nature of mutations induced by accelerated ions in eukaryotic cells, the effects of carbon-ion irradiation were compared with those of gamma-ray irradiation in the budding yeast Saccharomyces cerevisiae. The mutational effect and specificity of carbon-ion beams were studied in the URA3 gene of the yeast. Our experiments showed that the carbon ions generated more than 10 times the number of mutations induced by gamma-rays, and that the types of base changes induced by carbon ions include transversions (68.7%), transitions (13.7%) and deletions/insertions (17.6%). The transversions were mainly G:C-->T:A, and all the transitions were G:C-->A:T. In comparison with the surrounding sequence context of mutational base sites, the C residues in the 5'-AC(A/T)-3' sequence were found to be easily changed. Large deletions and duplications were not observed, whereas ion-induced mutations in Arabidopsis thaliana were mainly short deletions and rearrangements. The remarkable feature of yeast mutations induced by carbon ions was that the mutation sites were localized near the linker regions of nucleosomes, whereas mutations induced by gamma-ray irradiation were located uniformly throughout the gene.
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Affiliation(s)
- Youichirou Matuo
- Graduate School of Engineering, Osaka University, Yamada-oka 2-1, Suita, Osaka 565-0871, Japan
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29
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Hase Y, Trung KH, Matsunaga T, Tanaka A. A mutation in the uvi4 gene promotes progression of endo-reduplication and confers increased tolerance towards ultraviolet B light. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2006; 46:317-26. [PMID: 16623893 DOI: 10.1111/j.1365-313x.2006.02696.x] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
We have isolated and characterized a new ultraviolet B (UV-B)-resistant mutant, uvi4 (UV-B-insensitive 4), of Arabidopsis. The fresh weight (FW) of uvi4 plants grown under supplemental UV-B light was more than twice that of the wild-type. No significant difference was found in their ability to repair the UV-B-induced cyclobutane pyrimidine dimers, or in the amount of UV-B absorptive compounds, both of which are well-known factors that contribute to UV sensitivity. Positional cloning revealed that the UVI4 gene encodes a novel basic protein of unknown function. We found that the hypocotyl cells in uvi4 undergo one extra round of endo-reduplication. The uvi4 mutation also promoted the progression of endo-reduplication during leaf development. The UVI4 gene is expressed mainly in actively dividing cells. In the leaves of P(UVI4)::GUS plants, the GUS signal disappeared in basipetal fashion as the leaf developed. The total leaf blade area was not different between uvi4 and the wild-type through leaf development, while the average cell area in the adaxial epidermis was considerably larger in uvi4, suggesting that the uvi4 leaves have fewer but larger epidermal cells. These results suggest that UVI4 is necessary for the maintenance of the mitotic state, and the loss of UVI4 function stimulated endo-reduplication. Tetraploid Arabidopsis was hyper-resistant to UV-B compared to diploid Arabidopsis, suggesting that the enhanced polyploidization is responsible for the increased UV-B tolerance of the uvi4 mutant.
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Affiliation(s)
- Yoshihiro Hase
- Radiation-Applied Biology Division, Japan Atomic Energy Agency, Watanuki 1233, Takasaki, Gunma 370-1292, Japan.
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Naito K, Kusaba M, Shikazono N, Takano T, Tanaka A, Tanisaka T, Nishimura M. Transmissible and nontransmissible mutations induced by irradiating Arabidopsis thaliana pollen with gamma-rays and carbon ions. Genetics 2004; 169:881-9. [PMID: 15371348 PMCID: PMC1449103 DOI: 10.1534/genetics.104.033654] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
An early genetic study showed that most radiation-induced mutations are not transmitted to progeny. In recent molecular studies in plants, mainly M2 plants or their progeny, which contain only transmissible mutations, have been analyzed, but the early results imply that these studies are insufficient as comprehensive descriptions of radiation-induced mutations. To study radiation-induced mutations caused by low-LET gamma-rays and high-LET carbon ions at the molecular level, we used the pollen-irradiation method and the plant Arabidopsis thaliana to study various mutations, including nontransmissible mutations. This analysis revealed that most mutants induced with irradiation with gamma-rays (150-600 Gy) or carbon ions (40-150 Gy) carried extremely large deletions of up to >6 Mbp, the majority of which were not transmitted to progeny. Mutations containing 1- or 4-bp deletions, which were transmitted normally, were also found. Comparison of the deleted regions in the mutants showing various manners of transmission suggests that the nontransmissibility of the large deletions may be due to the deletion of a particular region that contains a gene or genes required for gamete development or viability.
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Affiliation(s)
- Ken Naito
- Institute of Radiation Breeding, National Institute of Agrobiological Sciences, Ohmiya-machi, Naka-gun, Ibaraki 319-2293, Japan
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Kitamura S, Shikazono N, Tanaka A. TRANSPARENT TESTA 19 is involved in the accumulation of both anthocyanins and proanthocyanidins in Arabidopsis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2004; 37:104-14. [PMID: 14675436 DOI: 10.1046/j.1365-313x.2003.01943.x] [Citation(s) in RCA: 311] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Flavonoid compounds such as anthocyanins and proanthocyanidins (PAs; so-called condensed tannins) have a multitude of functions in plants. They must be transported from the site of synthesis in the cytosol to their final destination, the vacuoles. Three models have been proposed for sequestering anthocyanins in vacuoles, but the transport machinery for PAs is poorly understood. Novel Arabidopsis mutants, transparent testa 19 (tt19), which were induced by ion beam irradiation, showed a great reduction of anthocyanin pigments in the vegetative parts as well as brown pigments in the seed coat. The TT19 gene was isolated by chromosome walking and a candidate gene approach, and was shown to be a member of the Arabidopsis glutathione S-transferase (GST) gene family. Heterologous expression of a putative ortholog, petunia anthocyanin 9 (AN9), in tt19 complemented the anthocyanin accumulation but not the brown pigmentation in the seed coat. This suggests that the TT19 gene is required for vacuolar uptake of anthocyanins into vacuoles, but that it has also a function different from that of AN9. The depositional pattern of PA precursors in the mutant was different from that in the wild type. These results indicate that TT19 participates in the PA pathway as well as the anthocyanin pathway of Arabidopsis. As involvement of GST in the PA pathway was previously considered unlikely, the function of TT19 in the PA pathway is also discussed in the context of the putative transporter for PA precursors.
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Affiliation(s)
- Satoshi Kitamura
- Department of Ion-Beam-Applied Biology, Japan Atomic Energy Research Institute, 1233 Watanuki-machi, Takasaki, Gunma 370-1292, Japan.
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Sakamoto A, Lan VTT, Hase Y, Shikazono N, Matsunaga T, Tanaka A. Disruption of the AtREV3 gene causes hypersensitivity to ultraviolet B light and gamma-rays in Arabidopsis: implication of the presence of a translesion synthesis mechanism in plants. THE PLANT CELL 2003; 15:2042-57. [PMID: 12953110 PMCID: PMC181330 DOI: 10.1105/tpc.012369] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
To investigate UV light response mechanisms in higher plants, we isolated a UV light-sensitive mutant, rev3-1, in Arabidopsis. The root growth of rev3-1 was inhibited after UV-B irradiation under both light and dark conditions. We found that chromosome 1 of rev3-1 was broken at a minimum of three points, causing chromosome inversion and translocation. A gene disrupted by this rearrangement encoded the catalytic subunit of DNA polymerase zeta (AtREV3), which is thought to be involved in translesion synthesis. The rev3-1 seedlings also were sensitive to gamma-rays and mitomycin C, which are known to inhibit DNA replication. Incorporation of bromodeoxyuridine after UV-B irradiation was less in rev3-1 than in the wild type. These results indicate that UV light-damaged DNA interrupted DNA replication in the rev3-1 mutant, leading to the inhibition of cell division and root elongation.
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Affiliation(s)
- Ayako Sakamoto
- Department of Ion-Beam-Applied Biology, Japan Atomic Energy Research Institute, Takasaki 370-1292, Japan.
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Shikazono N, Yokota Y, Kitamura S, Suzuki C, Watanabe H, Tano S, Tanaka A. Mutation rate and novel tt mutants of Arabidopsis thaliana induced by carbon ions. Genetics 2003; 163:1449-55. [PMID: 12702688 PMCID: PMC1462525 DOI: 10.1093/genetics/163.4.1449] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Irradiation of Arabidopsis thaliana by carbon ions was carried out to investigate the mutational effect of ion particles in higher plants. Frequencies of embryonic lethals and chlorophyll-deficient mutants were found to be significantly higher after carbon-ion irradiation than after electron irradiation (11-fold and 7.8-fold per unit dose, respectively). To estimate the mutation rate of carbon ions, mutants with no pigments on leaves and stems (tt) and no trichomes on leaves (gl) were isolated at the M2 generation and subjected to analysis. Averaged segregation rate of the backcrossed mutants was 0.25, which suggested that large deletions reducing the viability of the gametophytes were not transmitted, if generated, in most cases. During the isolation of mutants, two new classes of flavonoid mutants (tt18, tt19) were isolated from carbon-ion-mutagenized M2 plants. From PCR and sequence analysis, two of the three tt18 mutant alleles were found to have a small deletion within the LDOX gene and the other was revealed to contain a rearrangement. Using the segregation rates, the mutation rate of carbon ions was estimated to be 17-fold higher than that of electrons. The isolation of novel mutants and the high mutation rate suggest that ion particles can be used as a valuable mutagen for plant genetics.
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Affiliation(s)
- Naoya Shikazono
- Department of Ion Beam Applied Biology, Japan Atomic Energy Research Institute, Takasaki, Gunma 370-1292, Japan.
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Komai F, Shikazono N, Tanaka A. Sexual modification of female spinach seeds (Spinacia oleracea L.) by irradiation with ion particles. PLANT CELL REPORTS 2003; 21:713-717. [PMID: 12789513 DOI: 10.1007/s00299-003-0592-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2002] [Revised: 01/14/2003] [Accepted: 01/15/2003] [Indexed: 05/24/2023]
Abstract
The female seeds of a spinach plant (Spinacia orelacea L.) were exposed to He (12.5 MeV/n) and C (18.3 MeV/n) ions in order to investigate the effects of ion particles on sex expression. He ions did not affect germination rates or flowering at doses up to 50 Gy. C ions did not affect germination rates or flowering at doses up to 15 Gy, but a dose of 25 Gy resulted in many plants with morphological aberrations. When unexposed female plants were grown without cross-fertilization for 10 weeks after sowing, 5.6-14.3% of the plants produced anthers from female flowers. These sex-modified plants could self-pollinate and form seeds, which expressed only female organs. Conversely, gynomonoecious plants were induced from these female seeds by exposure to He ions (5-50 Gy) and C ions (5-25 Gy) without any difference in the rates of flowered progeny. Moreover, andromonoecious plants were induced from female seeds by exposure to He ions at 50 Gy. These results suggest that the sex of a spinach plant is expressed as a flexible phenotype, converging from female to gyno- and andromonoecy after exposure to ion particles.
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Affiliation(s)
- F Komai
- Hokkaido Green-Bio Institute, Naganuma, Hokkaido 069-1317, Japan.
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Tanaka A, Sakamoto A, Ishigaki Y, Nikaido O, Sun G, Hase Y, Shikazono N, Tano S, Watanabe H. An ultraviolet-B-resistant mutant with enhanced DNA repair in Arabidopsis. PLANT PHYSIOLOGY 2002; 129:64-71. [PMID: 12011338 PMCID: PMC155871 DOI: 10.1104/pp.010894] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2001] [Revised: 11/12/2001] [Accepted: 01/25/2002] [Indexed: 05/19/2023]
Abstract
An ultraviolet-B (UV-B)-resistant mutant, uvi1 (UV-B insensitive 1), of Arabidopsis was isolated from 1,280 M(1) seeds that had been exposed to ion beam irradiation. The fresh weight of uvi1 under high-UV-B exposure was more than twice that of the wild type. A root-bending assay indicated that root growth was less inhibited by UV-B exposure in uvi1 than in the wild type. When the seedlings were grown under white light, the UV-B dose required for 50% inhibition was about 6 kJ m(-2) for the wild type and 9 kJ m(-2) for uvi1. When the seedlings were irradiated with UV-B in darkness, the dose required for 50% inhibition was about 1.5 kJ m(-2) for the wild type and 4 kJ m(-2) for uvi1. An enzyme-linked immunosorbent assay showed that the reduction in levels of cyclobutane pyrimidine dimers (CPDs) under white light and of (6-4) photoproducts in darkness occurred faster in uvi1 than in the wild type. These results indicate that uvi1 had increased photoreactivation of CPDs and dark repair of (6-4) photoproducts, leading to strong UV-B resistance. Furthermore, the transcript levels of PHR1 (CPD photolyase gene) were much higher in uvi1 than in the wild type both under white light and after UV-B exposure. Placing the plants in the dark before UV-B exposure decreases the early reduction of CPDs in the wild type but not in uvi1. Our results suggest that UVI1 is a negative regulator of two independent DNA repair systems.
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Affiliation(s)
- Atsushi Tanaka
- Department of Radiation Research for Environment and Resources, Takasaki Radiation Chemistry Research Establishment, Japan Atomic Energy Research Institute, Watanuki-machi 1233, Takasaki, Gunma 370-1292, Japan.
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