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Czerniawski P, Piślewska-Bednarek M, Piasecka A, Kułak K, Bednarek P. Loss of MYB34 Transcription Factor Supports the Backward Evolution of Indole Glucosinolate Biosynthesis in a Subclade of the Camelineae Tribe and Releases the Feedback Loop in This Pathway in Arabidopsis. PLANT & CELL PHYSIOLOGY 2023; 64:80-93. [PMID: 36222356 DOI: 10.1093/pcp/pcac142] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Revised: 08/12/2022] [Accepted: 10/11/2022] [Indexed: 06/16/2023]
Abstract
Glucosinolates are specialized defensive metabolites characteristic of the Brassicales order. Among them, aliphatic and indolic glucosinolates (IGs) are usually highly abundant in species from the Brassicaceae family. The exceptions this trend are species representing a subclade of the Camelineae tribe, including Capsella and Camelina genera, which have reduced capacity to produce and metabolize IGs. Our study addresses the contribution of specific glucosinolate-related myeloblastosis (MYB) transcription factors to this unprecedented backward evolution of IG biosynthesis. To this end, we performed phylogenomic and functional studies of respective MYB proteins. The obtained results revealed weakened conservation of glucosinolate-related MYB transcription factors, including loss of functional MYB34 protein, in the investigated species. We showed that the introduction of functional MYB34 from Arabidopsis thaliana partially restores IG biosynthesis in Capsella rubella, indicating that the loss of this transcription factor contributes to the backward evolution of this metabolic pathway. Finally, we performed an analysis of the impact of particular myb mutations on the feedback loop in IG biosynthesis, which drives auxin overproduction, metabolic dysregulation and strong growth retardation caused by mutations in IG biosynthetic genes. This uncovered the unique function of MYB34 among IG-related MYBs in this feedback regulation and consequently in IG conservation in Brassicaceae plants.
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Affiliation(s)
- Paweł Czerniawski
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, Poznań 61-704, Poland
| | - Mariola Piślewska-Bednarek
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, Poznań 61-704, Poland
| | - Anna Piasecka
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, Poznań 61-704, Poland
- Institute of Plant Genetics, Polish Academy of Sciences, Strzeszyńska 34, Poznań 60-479, Poland
| | - Karolina Kułak
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, Poznań 61-704, Poland
- Department of General Botany, Institute of Experimental Biology, Adam Mickiewicz University, Uniwersytetu Poznańskiego 6, Poznań 61-614, Poland
| | - Paweł Bednarek
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, Poznań 61-704, Poland
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Barda O, Levy M. IQD1 Involvement in Hormonal Signaling and General Defense Responses Against Botrytis cinerea. FRONTIERS IN PLANT SCIENCE 2022; 13:845140. [PMID: 35557724 PMCID: PMC9087847 DOI: 10.3389/fpls.2022.845140] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Accepted: 03/15/2022] [Indexed: 06/15/2023]
Abstract
IQ Domain 1 (IQD1) is a novel Arabidopsis thaliana calmodulin-binding protein, which was found to be a positive regulator of glucosinolate (GS) accumulation and plant defense responses against insects. We demonstrate here that the IQD1 overexpressing line (IQD1 OXP ) was also more resistant also to the necrotrophic fungus Botrytis cinerea, whereas an IQD1 knockout line (iqd1-1) was much more sensitive. Furthermore, we showed that IQD1 is up-regulated by jasmonic acid (JA) and downregulated by salicylic acid (SA). A comparison of whole transcriptome expression between iqd1-1 and wild type plants revealed a substantial downregulation of genes involved in plant defense and hormone regulation. Further examination revealed a marked reduction of SA and increases in the levels of ethylene, JA and abscisic acid response genes in the iqd1-1 line. Moreover, quantification of SA, JA, and abscisic acids in IQD1 OXP and iqd1-1 lines relative to the wild type, showed a significant reduction in endogenous JA levels in the knockout line, simultaneously with increased SA levels. Relations between IQD1 OXP and mutants defective in plant-hormone response indicated that IQD1 cannot rescue the absence of NPR1 or impaired SA accumulation in the NahG line. IQD1 cannot rescue ein2 or eto1 mutations connected to the ethylene pathway involved in both defense responses against B. cinerea and in regulating GS accumulation. Furthermore, IQD1cannot rescue the aos, coi1 or jar1mutations, all involved in the defense response against B. cinerea and it depends on JAR1 to control indole glucosinolate accumulation. We also found that in the B. cinerea, which infected the iqd1-1 mutant, the most abundant upregulated group of proteins is involved in the degradation of complex carbohydrates, as correlated with the sensitivity of this mutant. In summary, our results suggest that IQD1 is an important A. thaliana defensive protein against B. cinerea that is integrated into several important pathways, such as those involved in plant defense and hormone responses.
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Accumulation of the Auxin Precursor Indole-3-Acetamide Curtails Growth through the Repression of Ribosome-Biogenesis and Development-Related Transcriptional Networks. Int J Mol Sci 2021; 22:ijms22042040. [PMID: 33670805 PMCID: PMC7923163 DOI: 10.3390/ijms22042040] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 02/16/2021] [Accepted: 02/17/2021] [Indexed: 12/17/2022] Open
Abstract
The major auxin, indole-3-acetic acid (IAA), is associated with a plethora of growth and developmental processes including embryo development, expansion growth, cambial activity, and the induction of lateral root growth. Accumulation of the auxin precursor indole-3-acetamide (IAM) induces stress related processes by stimulating abscisic acid (ABA) biosynthesis. How IAM signaling is controlled is, at present, unclear. Here, we characterize the ami1rooty double mutant, that we initially generated to study the metabolic and phenotypic consequences of a simultaneous genetic blockade of the indole glucosinolate and IAM pathways in Arabidopsisthaliana. Our mass spectrometric analyses of the mutant revealed that the combination of the two mutations is not sufficient to fully prevent the conversion of IAM to IAA. The detected strong accumulation of IAM was, however, recognized to substantially impair seed development. We further show by genome-wide expression studies that the double mutant is broadly affected in its translational capacity, and that a small number of plant growth regulating transcriptional circuits are repressed by the high IAM content in the seed. In accordance with the previously described growth reduction in response to elevated IAM levels, our data support the hypothesis that IAM is a growth repressing counterpart to IAA.
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The dynamic response of the Arabidopsis root metabolome to auxin and ethylene is not predicted by changes in the transcriptome. Sci Rep 2020; 10:679. [PMID: 31959762 PMCID: PMC6971091 DOI: 10.1038/s41598-019-57161-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Accepted: 12/19/2019] [Indexed: 12/27/2022] Open
Abstract
While the effects of phytohormones on plant gene expression have been well characterized, comparatively little is known about how hormones influence metabolite profiles. This study examined the effects of elevated auxin and ethylene on the metabolome of Arabidopsis roots using a high-resolution 24 h time course, conducted in parallel to time-matched transcriptomic analyses. Mass spectrometry using orthogonal UPLC separation strategies (reversed phase and HILIC) in both positive and negative ionization modes was used to maximize identification of metabolites with altered levels. The findings show that the root metabolome responds rapidly to hormone stimulus and that compounds belonging to the same class of metabolites exhibit similar changes. The responses were dominated by changes in phenylpropanoid, glucosinolate, and fatty acid metabolism, although the nature and timing of the response was unique for each hormone. These alterations in the metabolome were not directly predicted by the corresponding transcriptome data, suggesting that post-transcriptional events such as changes in enzyme activity and/or transport processes drove the observed changes in the metabolome. These findings underscore the need to better understand the biochemical mechanisms underlying the temporal reconfiguration of plant metabolism, especially in relation to the hormone-metabolome interface and its subsequent physiological and morphological effects.
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Qian Y, Zhang S, Yao S, Xia J, Li Y, Dai X, Wang W, Jiang X, Liu Y, Li M, Gao L, Xia T. Effects of vitro sucrose on quality components of tea plants (Camellia sinensis) based on transcriptomic and metabolic analysis. BMC PLANT BIOLOGY 2018; 18:121. [PMID: 29914362 PMCID: PMC6007066 DOI: 10.1186/s12870-018-1335-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2018] [Accepted: 05/31/2018] [Indexed: 05/29/2023]
Abstract
BACKGROUND Tea plants [Camellia sinensis (L.) O. Kuntze] can produce one of the three most widely popular non-alcoholic beverages throughout the world. Polyphenols and volatiles are the main functional ingredients determining tea's quality and flavor; however, the biotic or abiotic factors affecting tea polyphenol biosynthesis are unclear. This paper focuses on the molecular mechanisms of sucrose on polyphenol biosynthesis and volatile composition variation in tea plants. RESULTS Metabolic analysis showed that the total content of anthocyanins, catechins, and proanthocyanidins(PAs) increased with sucrose, and they accumulated most significantly after 14 days of treatment. Transcriptomic analysis revealed 8384 and 5571 differentially expressed genes in 2-day and 14-day sucrose-treated tea plants compared with control-treated plants. Most of the structural genes and transcription factors (TFs) involved in polyphenol biosynthesis were significantly up-regulated after 2d. Among these transcripts, the predicted genes encoding glutathione S-transferase (GST), ATP-binding cassette transporters (ABC transporters), and multidrug and toxic compound extrusion transporters (MATE transporters) appeared up regulated. Correspondingly, ultra-performance liquid chromatography-triple quadrupole mass spectrometry (UPLC-QQQ-MS/MS) analysis revealed that the content of non-galloylated catechins and oligomeric PAs decreased in the upper-stem and increased in the lower-stem significantly, especially catechin (C), epicatechin (EC), and their oligomeric PAs. This result suggests that the related flavonoids were transported downward in the stem by transporters. GC/MS data implied that four types of volatile compounds, namely terpene derivatives, aromatic derivatives, lipid derivatives, and others, were accumulated differently after in vitro sucrose treatment. CONCLUSIONS Our data demonstrated that sucrose regulates polyphenol biosynthesis in Camellia sinensis by altering the expression of transcription factor genes and pathway genes. Additionally, sucrose promotes the transport of polyphenols and changes the aroma composition in tea plant.
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Affiliation(s)
- Yumei Qian
- State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, 130 West Changjiang Rd, Hefei, 230036 Anhui China
- School of Biological and Food Engineering, Suzhou University, 49 Middle Bianhe Rd, Suzhou, 234000 Anhui China
| | - Shuxiang Zhang
- School of Life Science, Anhui Agricultural University, 130 West Changjiang Rd, Hefei, 230036 Anhui China
| | - Shengbo Yao
- State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, 130 West Changjiang Rd, Hefei, 230036 Anhui China
| | - Jinxin Xia
- School of Life Science, Anhui Agricultural University, 130 West Changjiang Rd, Hefei, 230036 Anhui China
| | - Yanzhi Li
- State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, 130 West Changjiang Rd, Hefei, 230036 Anhui China
| | - Xinlong Dai
- State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, 130 West Changjiang Rd, Hefei, 230036 Anhui China
| | - Wenzhao Wang
- State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, 130 West Changjiang Rd, Hefei, 230036 Anhui China
| | - Xiaolan Jiang
- State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, 130 West Changjiang Rd, Hefei, 230036 Anhui China
| | - Yajun Liu
- School of Life Science, Anhui Agricultural University, 130 West Changjiang Rd, Hefei, 230036 Anhui China
| | - Mingzhuo Li
- State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, 130 West Changjiang Rd, Hefei, 230036 Anhui China
| | - Liping Gao
- School of Life Science, Anhui Agricultural University, 130 West Changjiang Rd, Hefei, 230036 Anhui China
| | - Tao Xia
- State Key Laboratory of Tea Plant Biology and Utilization, Anhui Agricultural University, 130 West Changjiang Rd, Hefei, 230036 Anhui China
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When Transcriptomics and Metabolomics Work Hand in Hand: A Case Study Characterizing Plant CDF Transcription Factors. High Throughput 2018; 7:ht7010007. [PMID: 29495643 PMCID: PMC5876533 DOI: 10.3390/ht7010007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Revised: 02/21/2018] [Accepted: 02/21/2018] [Indexed: 01/09/2023] Open
Abstract
Over the last three decades, novel “omics” platform technologies for the sequencing of DNA and complementary DNA (cDNA) (RNA-Seq), as well as for the analysis of proteins and metabolites by mass spectrometry, have become more and more available and increasingly found their way into general laboratory life. With this, the ability to generate highly multivariate datasets on the biological systems of choice has increased tremendously. However, the processing and, perhaps even more importantly, the integration of “omics” datasets still remains a bottleneck, although considerable computational and algorithmic advances have been made in recent years. In this mini-review, we use a number of recent “multi-omics” approaches realized in our laboratories as a common theme to discuss possible pitfalls of applying “omics” approaches and to highlight some useful tools for data integration and visualization in the form of an exemplified case study. In the selected example, we used a combination of transcriptomics and metabolomics alongside phenotypic analyses to functionally characterize a small number of Cycling Dof Transcription Factors (CDFs). It has to be remarked that, even though this approach is broadly used, the given workflow is only one of plenty possible ways to characterize target proteins.
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Malka SK, Cheng Y. Possible Interactions between the Biosynthetic Pathways of Indole Glucosinolate and Auxin. FRONTIERS IN PLANT SCIENCE 2017; 8:2131. [PMID: 29312389 PMCID: PMC5735125 DOI: 10.3389/fpls.2017.02131] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Accepted: 11/30/2017] [Indexed: 05/21/2023]
Abstract
Glucosinolates (GLS) are a group of plant secondary metabolites mainly found in Cruciferous plants, share a core structure consisting of a β-thioglucose moiety and a sulfonated oxime, but differ by a variable side chain derived from one of the several amino acids. These compounds are hydrolyzed upon cell damage by thioglucosidase (myrosinase), and the resulting degradation products are toxic to many pathogens and herbivores. Human beings use these compounds as flavor compounds, anti-carcinogens, and bio-pesticides. GLS metabolism is complexly linked to auxin homeostasis. Indole GLS contributes to auxin biosynthesis via metabolic intermediates indole-3-acetaldoxime (IAOx) and indole-3-acetonitrile (IAN). IAOx is proposed to be a metabolic branch point for biosynthesis of indole GLS, IAA, and camalexin. Interruption of metabolic channeling of IAOx into indole GLS leads to high-auxin production in GLS mutants. IAN is also produced as a hydrolyzed product of indole GLS and metabolized to IAA by nitrilases. In this review, we will discuss current knowledge on involvement of GLS in auxin homeostasis.
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Affiliation(s)
- Siva K. Malka
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing, China
| | - Youfa Cheng
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing, China
- School of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
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Lehmann T, Janowitz T, Sánchez-Parra B, Alonso MMP, Trompetter I, Piotrowski M, Pollmann S. Arabidopsis NITRILASE 1 Contributes to the Regulation of Root Growth and Development through Modulation of Auxin Biosynthesis in Seedlings. FRONTIERS IN PLANT SCIENCE 2017. [PMID: 28174581 DOI: 10.3389/fpls.2017.00036.ecollection] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Nitrilases consist of a group of enzymes that catalyze the hydrolysis of organic cyanides. They are found ubiquitously distributed in the plant kingdom. Plant nitrilases are mainly involved in the detoxification of ß-cyanoalanine, a side-product of ethylene biosynthesis. In the model plant Arabidopsis thaliana a second group of Brassicaceae-specific nitrilases (NIT1-3) has been found. This so-called NIT1-subfamily has been associated with the conversion of indole-3-acetonitrile (IAN) into the major plant growth hormone, indole-3-acetic acid (IAA). However, apart of reported functions in defense responses to pathogens and in responses to sulfur depletion, conclusive insight into the general physiological function of the NIT-subfamily nitrilases remains elusive. In this report, we test both the contribution of the indole-3-acetaldoxime (IAOx) pathway to general auxin biosynthesis and the influence of altered nitrilase expression on plant development. Apart of a comprehensive transcriptomics approach to explore the role of the IAOx route in auxin formation, we took a genetic approach to disclose the function of NITRILASE 1 (NIT1) of A. thaliana. We show that NIT1 over-expression (NIT1ox) results in seedlings with shorter primary roots, and an increased number of lateral roots. In addition, NIT1ox plants exhibit drastic changes of both free IAA and IAN levels, which are suggested to be the reason for the observed phenotype. On the other hand, NIT2RNAi knockdown lines, capable of suppressing the expression of all members of the NIT1-subfamily, were generated and characterized to substantiate the above-mentioned findings. Our results demonstrate for the first time that Arabidopsis NIT1 has profound effects on root morphogenesis in early seedling development.
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Affiliation(s)
- Thomas Lehmann
- Lehrstuhl für Pflanzenphysiologie Ruhr-Universität Bochum, Bochum, Germany
| | - Tim Janowitz
- Lehrstuhl für Pflanzenphysiologie Ruhr-Universität Bochum, Bochum, Germany
| | - Beatriz Sánchez-Parra
- Centro de Biotecnología y Genómica de Plantas Universidad Politécnica de Madrid (UPM)-Instituto Nacional de Investigación y Tecnología Agraria y Alimentación (INIA), Pozuelo de Alarcón, Spain
| | - Marta-Marina Pérez Alonso
- Centro de Biotecnología y Genómica de Plantas Universidad Politécnica de Madrid (UPM)-Instituto Nacional de Investigación y Tecnología Agraria y Alimentación (INIA), Pozuelo de Alarcón, Spain
| | - Inga Trompetter
- Lehrstuhl für Pflanzenphysiologie Ruhr-Universität Bochum, Bochum, Germany
| | - Markus Piotrowski
- Lehrstuhl für Pflanzenphysiologie Ruhr-Universität Bochum, Bochum, Germany
| | - Stephan Pollmann
- Lehrstuhl für PflanzenphysiologieRuhr-Universität Bochum, Bochum, Germany; Centro de Biotecnología y Genómica de PlantasUniversidad Politécnica de Madrid (UPM)-Instituto Nacional de Investigación y Tecnología Agraria y Alimentación (INIA), Pozuelo de Alarcón, Spain
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Lehmann T, Janowitz T, Sánchez-Parra B, Alonso MMP, Trompetter I, Piotrowski M, Pollmann S. Arabidopsis NITRILASE 1 Contributes to the Regulation of Root Growth and Development through Modulation of Auxin Biosynthesis in Seedlings. FRONTIERS IN PLANT SCIENCE 2017; 8:36. [PMID: 28174581 PMCID: PMC5258727 DOI: 10.3389/fpls.2017.00036] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Accepted: 01/09/2017] [Indexed: 05/20/2023]
Abstract
Nitrilases consist of a group of enzymes that catalyze the hydrolysis of organic cyanides. They are found ubiquitously distributed in the plant kingdom. Plant nitrilases are mainly involved in the detoxification of ß-cyanoalanine, a side-product of ethylene biosynthesis. In the model plant Arabidopsis thaliana a second group of Brassicaceae-specific nitrilases (NIT1-3) has been found. This so-called NIT1-subfamily has been associated with the conversion of indole-3-acetonitrile (IAN) into the major plant growth hormone, indole-3-acetic acid (IAA). However, apart of reported functions in defense responses to pathogens and in responses to sulfur depletion, conclusive insight into the general physiological function of the NIT-subfamily nitrilases remains elusive. In this report, we test both the contribution of the indole-3-acetaldoxime (IAOx) pathway to general auxin biosynthesis and the influence of altered nitrilase expression on plant development. Apart of a comprehensive transcriptomics approach to explore the role of the IAOx route in auxin formation, we took a genetic approach to disclose the function of NITRILASE 1 (NIT1) of A. thaliana. We show that NIT1 over-expression (NIT1ox) results in seedlings with shorter primary roots, and an increased number of lateral roots. In addition, NIT1ox plants exhibit drastic changes of both free IAA and IAN levels, which are suggested to be the reason for the observed phenotype. On the other hand, NIT2RNAi knockdown lines, capable of suppressing the expression of all members of the NIT1-subfamily, were generated and characterized to substantiate the above-mentioned findings. Our results demonstrate for the first time that Arabidopsis NIT1 has profound effects on root morphogenesis in early seedling development.
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Affiliation(s)
- Thomas Lehmann
- Lehrstuhl für PflanzenphysiologieRuhr-Universität Bochum, Bochum, Germany
| | - Tim Janowitz
- Lehrstuhl für PflanzenphysiologieRuhr-Universität Bochum, Bochum, Germany
| | - Beatriz Sánchez-Parra
- Centro de Biotecnología y Genómica de PlantasUniversidad Politécnica de Madrid (UPM)-Instituto Nacional de Investigación y Tecnología Agraria y Alimentación (INIA), Pozuelo de Alarcón, Spain
| | - Marta-Marina Pérez Alonso
- Centro de Biotecnología y Genómica de PlantasUniversidad Politécnica de Madrid (UPM)-Instituto Nacional de Investigación y Tecnología Agraria y Alimentación (INIA), Pozuelo de Alarcón, Spain
| | - Inga Trompetter
- Lehrstuhl für PflanzenphysiologieRuhr-Universität Bochum, Bochum, Germany
| | - Markus Piotrowski
- Lehrstuhl für PflanzenphysiologieRuhr-Universität Bochum, Bochum, Germany
| | - Stephan Pollmann
- Lehrstuhl für PflanzenphysiologieRuhr-Universität Bochum, Bochum, Germany
- Centro de Biotecnología y Genómica de PlantasUniversidad Politécnica de Madrid (UPM)-Instituto Nacional de Investigación y Tecnología Agraria y Alimentación (INIA), Pozuelo de Alarcón, Spain
- *Correspondence: Stephan Pollmann
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Zheng Z, Guo Y, Novák O, Chen W, Ljung K, Noel JP, Chory J. Local auxin metabolism regulates environment-induced hypocotyl elongation. NATURE PLANTS 2016; 2:16025. [PMID: 27249562 PMCID: PMC4849989 DOI: 10.1038/nplants.2016.25] [Citation(s) in RCA: 88] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Accepted: 02/12/2016] [Indexed: 05/18/2023]
Abstract
A hallmark of plants is their adaptability of size and form in response to widely fluctuating environments. The metabolism and redistribution of the phytohormone auxin play pivotal roles in establishing active auxin gradients and resulting cellular differentiation. In Arabidopsis thaliana, cotyledons and leaves synthesize indole-3-acetic acid (IAA) from tryptophan through indole-3-pyruvic acid (3-IPA) in response to vegetational shade. This newly synthesized auxin moves to the hypocotyl where it induces elongation of hypocotyl cells. Here we show that loss of function of VAS2 (IAA-amido synthetase Gretchen Hagen 3 (GH3).17) leads to increases in free IAA at the expense of IAA-Glu (IAA-glutamate) in the hypocotyl epidermis. This active IAA elicits shade- and high temperature-induced hypocotyl elongation largely independently of 3-IPA-mediated IAA biosynthesis in cotyledons. Our results reveal an unexpected capacity of local auxin metabolism to modulate the homeostasis and spatial distribution of free auxin in specialized organs such as hypocotyls in response to shade and high temperature.
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Affiliation(s)
- Zuyu Zheng
- Howard Hughes Medical Institute and Plant Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, California 92037, USA
| | - Yongxia Guo
- The Jack H. Skirball Center for Chemical Biology and Proteomics, The Salk Institute for Biological Studies, La Jolla, California 92037, USA
| | - Ondřej Novák
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden
- Laboratory of Growth Regulators, Faculty of Science, Palacký University and Institute of Experimental Botany ASCR, Šlechtielů 11, 783 71 Olomouc, Czech Republic
| | - William Chen
- Plant Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, California 92037, USA
| | - Karin Ljung
- Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden
| | - Joseph P. Noel
- Howard Hughes Medical Institute and The Jack H. Skirball Center for Chemical Biology and Proteomics, The Salk Institute for Biological Studies, La Jolla, California 92037, USA, Czech Republic
- Correspondence and requests for materials should be addressed to J.P.N. and J.C. ;
| | - Joanne Chory
- Howard Hughes Medical Institute and Plant Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, California 92037, USA
- Correspondence and requests for materials should be addressed to J.P.N. and J.C. ;
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Auxin and Tryptophan Homeostasis Are Facilitated by the ISS1/VAS1 Aromatic Aminotransferase in Arabidopsis. Genetics 2015; 201:185-99. [PMID: 26163189 DOI: 10.1534/genetics.115.180356] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Accepted: 07/07/2015] [Indexed: 12/20/2022] Open
Abstract
Indole-3-acetic acid (IAA) plays a critical role in regulating numerous aspects of plant growth and development. While there is much genetic support for tryptophan-dependent (Trp-D) IAA synthesis pathways, there is little genetic evidence for tryptophan-independent (Trp-I) IAA synthesis pathways. Using Arabidopsis, we identified two mutant alleles of ISS1 ( I: ndole S: evere S: ensitive) that display indole-dependent IAA overproduction phenotypes including leaf epinasty and adventitious rooting. Stable isotope labeling showed that iss1, but not WT, uses primarily Trp-I IAA synthesis when grown on indole-supplemented medium. In contrast, both iss1 and WT use primarily Trp-D IAA synthesis when grown on unsupplemented medium. iss1 seedlings produce 8-fold higher levels of IAA when grown on indole and surprisingly have a 174-fold increase in Trp. These findings indicate that the iss1 mutant's increase in Trp-I IAA synthesis is due to a loss of Trp catabolism. ISS1 was identified as At1g80360, a predicted aromatic aminotransferase, and in vitro and in vivo analysis confirmed this activity. At1g80360 was previously shown to primarily carry out the conversion of indole-3-pyruvic acid to Trp as an IAA homeostatic mechanism in young seedlings. Our results suggest that in addition to this activity, in more mature plants ISS1 has a role in Trp catabolism and possibly in the metabolism of other aromatic amino acids. We postulate that this loss of Trp catabolism impacts the use of Trp-D and/or Trp-I IAA synthesis pathways.
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Ahrazem O, Rubio-Moraga A, Trapero-Mozos A, Climent MFL, Gómez-Cadenas A, Gómez-Gómez L. Ectopic expression of a stress-inducible glycosyltransferase from saffron enhances salt and oxidative stress tolerance in Arabidopsis while alters anchor root formation. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2015; 234:60-73. [PMID: 25804810 DOI: 10.1016/j.plantsci.2015.02.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Revised: 02/09/2015] [Accepted: 02/11/2015] [Indexed: 05/03/2023]
Abstract
Glycosyltransferases play diverse roles in cellular metabolism by modifying the activities of regulatory metabolites. Three stress-regulated UDP-glucosyltransferase-encoding genes have been isolated from the stigmas of saffron, UGT85U1, UGT85U2 and UGT85V1, which belong to the UGT85 family that includes members associated with stress responses and cell cycle regulation. Arabidopsis constitutively expressing UGT85U1 exhibited and increased anchor root development. No differences were observed in the timing of root emergence, in leaf, stem and flower morphology or flowering time. However, salt and oxidative stress tolerance was enhanced in these plants. Levels of glycosylated compounds were measured in these plants and showed changes in the composition of several indole-derivatives. Moreover, auxin levels in the roots were higher compared to wild type. The expression of several key genes related to root development and auxin homeostasis, including CDKB2.1, CDKB2.2, PIN2, 3 and 4; TIR1, SHR, and CYCD6, were differentially regulated with an increase of expression level of SHR, CYCD6, CDKB2.1 and PIN2. The obtained results showed that UGT85U1 takes part in root growth regulation via auxin signal alteration and the modified expression of cell cycle-related genes, resulting in significantly improved survival during oxidative and salt stress treatments.
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Affiliation(s)
- Oussama Ahrazem
- Instituto Botánico, Departamento de Ciencia y Tecnología Agroforestal y Genética, Facultad de Farmacia, Universidad de Castilla-La Mancha, Campus Universitario s/n, 02071 Albacete, Spain; Fundación Parque Científico y Tecnológico de Albacete, Spain
| | - Angela Rubio-Moraga
- Instituto Botánico, Departamento de Ciencia y Tecnología Agroforestal y Genética, Facultad de Farmacia, Universidad de Castilla-La Mancha, Campus Universitario s/n, 02071 Albacete, Spain
| | - Almudena Trapero-Mozos
- Instituto Botánico, Departamento de Ciencia y Tecnología Agroforestal y Genética, Facultad de Farmacia, Universidad de Castilla-La Mancha, Campus Universitario s/n, 02071 Albacete, Spain
| | | | - Aurelio Gómez-Cadenas
- Universitat Jaume I, Department of Agricultural and Environmental Sciences, 12071 Castelló de la Plana, Spain
| | - Lourdes Gómez-Gómez
- Instituto Botánico, Departamento de Ciencia y Tecnología Agroforestal y Genética, Facultad de Farmacia, Universidad de Castilla-La Mancha, Campus Universitario s/n, 02071 Albacete, Spain.
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13
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Kim JI, Dolan WL, Anderson NA, Chapple C. Indole Glucosinolate Biosynthesis Limits Phenylpropanoid Accumulation in Arabidopsis thaliana. THE PLANT CELL 2015; 27:1529-46. [PMID: 25944103 PMCID: PMC4456644 DOI: 10.1105/tpc.15.00127] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Revised: 03/05/2015] [Accepted: 04/20/2015] [Indexed: 05/17/2023]
Abstract
Plants produce an array of metabolites (including lignin monomers and soluble UV-protective metabolites) from phenylalanine through the phenylpropanoid biosynthetic pathway. A subset of plants, including many related to Arabidopsis thaliana, synthesizes glucosinolates, nitrogen- and sulfur-containing secondary metabolites that serve as components of a plant defense system that deters herbivores and pathogens. Here, we report that the Arabidopsis thaliana reduced epidermal fluorescence5 (ref5-1) mutant, identified in a screen for plants with defects in soluble phenylpropanoid accumulation, has a missense mutation in CYP83B1 and displays defects in glucosinolate biosynthesis and in phenylpropanoid accumulation. CYP79B2 and CYP79B3 are responsible for the production of the CYP83B1 substrate indole-3-acetaldoxime (IAOx), and we found that the phenylpropanoid content of cyp79b2 cyp79b3 and ref5-1 cyp79b2 cyp79b3 plants is increased compared with the wild type. These data suggest that levels of IAOx or a subsequent metabolite negatively influence phenylpropanoid accumulation in ref5 and more importantly that this crosstalk is relevant in the wild type. Additional biochemical and genetic evidence indicates that this inhibition impacts the early steps of the phenylpropanoid biosynthetic pathway and restoration of phenylpropanoid accumulation in a ref5-1 med5a/b triple mutant suggests that the function of the Mediator complex is required for the crosstalk.
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Affiliation(s)
- Jeong Im Kim
- Department of Biochemistry, Purdue University, West Lafayette, Indiana 47907
| | - Whitney L Dolan
- Department of Biochemistry, Purdue University, West Lafayette, Indiana 47907
| | - Nickolas A Anderson
- Department of Biochemistry, Purdue University, West Lafayette, Indiana 47907
| | - Clint Chapple
- Department of Biochemistry, Purdue University, West Lafayette, Indiana 47907
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14
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Maharjan PM, Dilkes BP, Fujioka S, Pěnčík A, Ljung K, Burow M, Halkier BA, Choe S. Arabidopsis gulliver1/SUPERROOT2-7 identifies a metabolic basis for auxin and brassinosteroid synergy. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2014; 80:797-808. [PMID: 25256367 DOI: 10.1111/tpj.12678] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2013] [Revised: 09/09/2014] [Accepted: 09/10/2014] [Indexed: 05/04/2023]
Abstract
Phytohormone homeostasis is essential for proper growth and development of plants. To understand the growth mechanisms mediated by hormonal levels, we isolated a gulliver1 (gul1) mutant that had tall stature in the presence of both brassinazole and the light. The gul1 phenotype depended on functional BR biosynthesis; the genetic introduction of dwarf4, a BR biosynthetic mutation, masked the long hypocotyl phenotype of gul1. Furthermore, BR biosynthesis was dramatically enhanced, such that the level of 22-hydroxy campesterol was 5.8-fold greater in gul1. Molecular cloning revealed that gul1 was a missense mutation, resulting in a glycine to arginine change at amino acid 116 in SUPERROOT2 (CYP83B1), which converts indole acetaldoxime to an S-alkyl thiohydroximate adduct in the indole glucosinolate pathway. Auxin metabolite profiling coupled with quantitative reverse transcription polymerase chain reaction (RT-PCR) analysis of auxin biosynthetic genes revealed that gul1/sur2-7 activated multiple alternative branches of tryptophan-dependent auxin biosynthetic pathways. Furthermore, exogenous treatment of gul1/sur2-7 with BRs caused adventitious roots from hypocotyls, indicative of an increased response to BRs relative to wild-type. Different from severe alleles of sur2, gul1/sur2-7 lacked 'high-auxin' phenotypes that include stunted growth and callus-like disintegration of hypocotyl tissues. The auxin level in gul1/sur2-7 was only 1.6-fold greater than in the wild-type, whereas it was 4.2-fold in a severe allele like sur2-8. Differences in auxin content may account for the range of phenotypes observed among the sur2 alleles. This unusual allele provides long-sought evidence for a synergistic interaction between auxin and BRs in promoting growth in Arabidopsis at the level of their biosynthetic enzymes.
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Affiliation(s)
- Puna M Maharjan
- School of Biological Sciences, College of Natural Sciences, Seoul National University, Seoul, 151-747, Korea
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15
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Grubb CD, Zipp BJ, Kopycki J, Schubert M, Quint M, Lim EK, Bowles DJ, Pedras MSC, Abel S. Comparative analysis of Arabidopsis UGT74 glucosyltransferases reveals a special role of UGT74C1 in glucosinolate biosynthesis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2014; 79:92-105. [PMID: 24779768 DOI: 10.1111/tpj.12541] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Revised: 04/03/2014] [Accepted: 04/23/2014] [Indexed: 05/03/2023]
Abstract
The study of glucosinolates and their regulation has provided a powerful framework for the exploration of fundamental questions about the function, evolution, and ecological significance of plant natural products, but uncertainties about their metabolism remain. Previous work has identified one thiohydroximate S-glucosyltransferase, UGT74B1, with an important role in the core pathway, but also made clear that this enzyme functions redundantly and cannot be the sole UDP-glucose dependent glucosyltransferase (UGT) in glucosinolate synthesis. Here, we present the results of a nearly comprehensive in vitro activity screen of recombinant Arabidopsis Family 1 UGTs, which implicate other members of the UGT74 clade as candidate glucosinolate biosynthetic enzymes. Systematic genetic analysis of this clade indicates that UGT74C1 plays a special role in the synthesis of aliphatic glucosinolates, a conclusion strongly supported by phylogenetic and gene expression analyses. Finally, the ability of UGT74C1 to complement phenotypes and chemotypes of the ugt74b1-2 knockout mutant and to express thiohydroximate UGT activity in planta provides conclusive evidence for UGT74C1 being an accessory enzyme in glucosinolate biosynthesis with a potential function during plant adaptation to environmental challenge.
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Affiliation(s)
- C Douglas Grubb
- Department of Molecular Signal Processing, Leibniz Institute of Plant Biochemistry, Weinberg 3, 06120, Halle, Germany
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16
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Kohli A, Sreenivasulu N, Lakshmanan P, Kumar PP. The phytohormone crosstalk paradigm takes center stage in understanding how plants respond to abiotic stresses. PLANT CELL REPORTS 2013; 32:945-57. [PMID: 23749097 DOI: 10.1007/s00299-013-1461-y] [Citation(s) in RCA: 104] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Revised: 05/18/2013] [Accepted: 05/18/2013] [Indexed: 05/04/2023]
Abstract
The highly coordinated, dynamic nature of growth requires plants to perceive and react to various environmental signals in an interactive manner. Elaborate signaling networks mediate this plasticity in growth and the ability to adapt to changing environmental conditions. The fluctuations of stress-responsive hormones help alter the cellular dynamics and hence play a central role in coordinately regulating the growth responses under stress. Recent experimental data unequivocally demonstrated that interactions among various phytohormones are the rule rather than exception in integrating the diverse input signals and readjusting growth as well as acquiring stress tolerance. The presence of multiple and often redundant signaling intermediates for each phytohormone appears to help in such crosstalk. Furthermore, there are several examples of similar developmental changes occurring in response to distinct abiotic stress signals, which can be explained by the crosstalk in phytohormone signaling. Therefore, in this brief review, we have highlighted the major phytohormone crosstalks with a focus on the response of plants to abiotic stresses. The recent findings have made it increasingly apparent that such crosstalk will also explain the extreme pleiotropic responses elicited by various phytohormones. Indeed, it would not be presumptuous to expect that in the coming years this paradigm will take a central role in explaining developmental regulation.
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Affiliation(s)
- Ajay Kohli
- Genetics and Biotechnology Division, Plant Breeding, International Rice Research Institute, 7777 Manila, Philippines
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17
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Chen YZ, Pang QY, He Y, Zhu N, Branstrom I, Yan XF, Chen S. Proteomics and metabolomics of Arabidopsis responses to perturbation of glucosinolate biosynthesis. MOLECULAR PLANT 2012; 5:1138-50. [PMID: 22498773 DOI: 10.1093/mp/sss034] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
To understand plant molecular networks of glucosinolate metabolism, perturbation of aliphatic glucosinolate biosynthesis was established using inducible RNA interference (RNAi) in Arabidopsis. Two RNAi lines were chosen for examining global protein and metabolite changes using complementary proteomics and metabolomics approaches. Proteins involved in metabolism including photosynthesis and hormone metabolism, protein binding, energy, stress, and defense showed marked responses to glucosinolate perturbation. In parallel, metabolomics revealed major changes in the levels of amino acids, carbohydrates, peptides, and hormones. The metabolomics data were correlated with the proteomics results and revealed intimate molecular connections between cellular pathways/processes and glucosinolate metabolism. This study has provided an unprecedented view of the molecular networks of glucosinolate metabolism and laid a foundation towards rationale glucosinolate engineering for enhanced defense and quality.
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Affiliation(s)
- Ya-zhou Chen
- Department of Biology, Genetics Institute, Plant Molecular and Cellular Biology Program, University of Florida, Gainesville, FL 32610, USA
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18
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Lommen A, Kools HJ. MetAlign 3.0: performance enhancement by efficient use of advances in computer hardware. Metabolomics 2012; 8:719-726. [PMID: 22833710 PMCID: PMC3397215 DOI: 10.1007/s11306-011-0369-1] [Citation(s) in RCA: 143] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2011] [Accepted: 09/25/2011] [Indexed: 11/30/2022]
Abstract
A new, multi-threaded version of the GC-MS and LC-MS data processing software, metAlign, has been developed which is able to utilize multiple cores on one PC. This new version was tested using three different multi-core PCs with different operating systems. The performance of noise reduction, baseline correction and peak-picking was 8-19 fold faster compared to the previous version on a single core machine from 2008. The alignment was 5-10 fold faster. Factors influencing the performance enhancement are discussed. Our observations show that performance scales with the increase in processor core numbers we currently see in consumer PC hardware development.
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Affiliation(s)
- Arjen Lommen
- RIKILT—Institute of Food Safety, Wageningen UR, P.O. Box 230, 6700 AE Wageningen, The Netherlands
| | - Harrie J. Kools
- RIKILT—Institute of Food Safety, Wageningen UR, P.O. Box 230, 6700 AE Wageningen, The Netherlands
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19
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Ginzberg I, Thippeswamy M, Fogelman E, Demirel U, Mweetwa AM, Tokuhisa J, Veilleux RE. Induction of potato steroidal glycoalkaloid biosynthetic pathway by overexpression of cDNA encoding primary metabolism HMG-CoA reductase and squalene synthase. PLANTA 2012; 235:1341-1353. [PMID: 22205426 DOI: 10.1007/s00425-011-1578-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2011] [Accepted: 12/15/2011] [Indexed: 05/31/2023]
Abstract
Potato steroidal glycoalkaloids (SGAs) are toxic secondary metabolites whose total content in tubers must be regulated. SGAs are biosynthesized by the sterol branch of the mevalonic acid/isoprenoid pathway. In a previous study, we showed a correlation between SGA levels and the abundance of transcript coding for HMG-CoA reductase 1 (HMG1) and squalene synthase 1 (SQS1) in potato tissues and potato genotypes varying in SGA content. Here, Solanum tuberosum cv. Desirée (low SGA producer) was transformed with a gene construct containing the coding region of either HMG1 or SQS1 of Solanum chacoense Bitt. clone 8380-1, a high SGA producer. SGA levels in transgenic HMG-plants were either greater than (in eight of 14 plants) or no different from untransformed controls, whereas only four of 12 SQS-transgenics had greater SGA levels than control, as determined by HPLC. Quantitative real-time PCR was used to estimate relative steady-state transcript levels of isoprenoid-, steroid-, and SGA-related genes in leaves of the transgenic plants compared to nontransgenic controls. HMG-transgenic plants exhibited increased transcript accumulation of SQS1, sterol C24-methyltransferase type1 (SMT1), and solanidine glycosyltransferase 2 (SGT2), whereas SQS-transgenic plants, had consistently lower transcript levels of HMG1 and variable SMT1 and SGT2 transcript abundance among different transgenics. HMG-transgenic plants exhibited changes in transcript accumulation for some sterol biosynthetic genes as well. Taken together, the data suggest coordinated regulation of isoprenoid metabolism and SGA secondary metabolism.
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Affiliation(s)
- Idit Ginzberg
- Institute of Plant Sciences, ARO, the Volcani Center, 50250 Bet Dagan, Israel.
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20
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Tognetti VB, Mühlenbock P, Van Breusegem F. Stress homeostasis - the redox and auxin perspective. PLANT, CELL & ENVIRONMENT 2012; 35:321-33. [PMID: 21443606 DOI: 10.1111/j.1365-3040.2011.02324.x] [Citation(s) in RCA: 165] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Under environmental stresses, plant development is adaptively modulated. This modulation is influenced by the steady-state balance (homeostasis) between reactive oxygen species (ROS) and phytohormones. Frequently observed symptoms in plant stress adaptation responses include growth retardation, reduced metabolism and photosynthesis, reallocation of metabolic resources and increased antioxidant activities to maximize plant survival under adverse environmental conditions. In view of stress-induced morphogenetic changes during adaptation, ROS and auxin are the main players in the regulatory networks because both are strongly affected by exposure to environmental cues. However, the mechanisms underlying the crosstalk between ROS and auxin are poorly understood. In this review, we aim at surveying how the integration of environmental stress-related signals is modulated by crosstalk between ROS and auxin regulatory networks.
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21
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Transcription factor WRKY23 assists auxin distribution patterns during Arabidopsis root development through local control on flavonol biosynthesis. Proc Natl Acad Sci U S A 2012; 109:1554-9. [PMID: 22307611 DOI: 10.1073/pnas.1121134109] [Citation(s) in RCA: 138] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Gradients of the plant hormone auxin, which depend on its active intercellular transport, are crucial for the maintenance of root meristematic activity. This directional transport is largely orchestrated by a complex interaction of specific influx and efflux carriers that mediate the auxin flow into and out of cells, respectively. Besides these transport proteins, plant-specific polyphenolic compounds known as flavonols have been shown to act as endogenous regulators of auxin transport. However, only limited information is available on how flavonol synthesis is developmentally regulated. Using reduction-of-function and overexpression approaches in parallel, we demonstrate that the WRKY23 transcription factor is needed for proper root growth and development by stimulating the local biosynthesis of flavonols. The expression of WRKY23 itself is controlled by auxin through the Auxin Response Factor 7 (ARF7) and ARF19 transcriptional response pathway. Our results suggest a model in which WRKY23 is part of a transcriptional feedback loop of auxin on its own transport through local regulation of flavonol biosynthesis.
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Bednarek P, Piślewska-Bednarek M, Ver Loren van Themaat E, Maddula RK, Svatoš A, Schulze-Lefert P. Conservation and clade-specific diversification of pathogen-inducible tryptophan and indole glucosinolate metabolism in Arabidopsis thaliana relatives. THE NEW PHYTOLOGIST 2011; 192:713-26. [PMID: 21793828 DOI: 10.1111/j.1469-8137.2011.03824.x] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
• A hallmark of the innate immune system of plants is the biosynthesis of low-molecular-weight compounds referred to as secondary metabolites. Tryptophan-derived branch pathways contribute to the capacity for chemical defense against microbes in Arabidopsis thaliana. • Here, we investigated phylogenetic patterns of this metabolic pathway in relatives of A. thaliana following inoculation with filamentous fungal pathogens that employ contrasting infection strategies. • The study revealed unexpected phylogenetic conservation of the pathogen-induced indole glucosinolate (IG) metabolic pathway, including a metabolic shift of IG biosynthesis to 4-methoxyindol-3-ylmethylglucosinolate and IG metabolization. By contrast, indole-3-carboxylic acid and camalexin biosyntheses are clade-specific innovations within this metabolic framework. A Capsella rubella accession was found to be devoid of any IG metabolites and to lack orthologs of two A. thaliana genes needed for 4-methoxyindol-3-ylmethylglucosinolate biosynthesis or hydrolysis. However, C. rubella was found to retain the capacity to deposit callose after treatment with the bacterial flagellin-derived epitope flg22 and pre-invasive resistance against a nonadapted powdery mildew fungus. • We conclude that pathogen-inducible IG metabolism in the Brassicaceae is evolutionarily ancient, while other tryptophan-derived branch pathways represent relatively recent manifestations of a plant-pathogen arms race. Moreover, at least one Brassicaceae lineage appears to have evolved IG-independent defense signaling and/or output pathway(s).
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Affiliation(s)
- Paweł Bednarek
- Max Planck Institute for Plant Breeding Research, Department of Plant Microbe Interactions, Köln, Germany.
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23
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Bak S, Beisson F, Bishop G, Hamberger B, Höfer R, Paquette S, Werck-Reichhart D. Cytochromes p450. THE ARABIDOPSIS BOOK 2011; 9:e0144. [PMID: 22303269 PMCID: PMC3268508 DOI: 10.1199/tab.0144] [Citation(s) in RCA: 238] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
There are 244 cytochrome P450 genes (and 28 pseudogenes) in the Arabidopsis genome. P450s thus form one of the largest gene families in plants. Contrary to what was initially thought, this family diversification results in very limited functional redundancy and seems to mirror the complexity of plant metabolism. P450s sometimes share less than 20% identity and catalyze extremely diverse reactions leading to the precursors of structural macromolecules such as lignin, cutin, suberin and sporopollenin, or are involved in biosynthesis or catabolism of all hormone and signaling molecules, of pigments, odorants, flavors, antioxidants, allelochemicals and defense compounds, and in the metabolism of xenobiotics. The mechanisms of gene duplication and diversification are getting better understood and together with co-expression data provide leads to functional characterization.
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Affiliation(s)
- Søren Bak
- Plant Biochemistry Laboratory, Department of Plant Biology and Biotechnology, Faculty of Life Sciences, University of Copenhagen, 40 Thorvaldsensvej, DK-1871 Frederiksberg C, Copenhagen, Denmark
| | - Fred Beisson
- Department of Plant Biology and Environmental Microbiology, CEA/CNRS/Aix-Marseille Université, UMR 6191 Cadarache, F-13108 Saint-Paul-lez-Durance, France
| | - Gerard Bishop
- Division of Biology, Faculty of Natural Sciences, Imperial College London, SW7 2AZ
| | - Björn Hamberger
- Plant Biochemistry Laboratory, Department of Plant Biology and Biotechnology, Faculty of Life Sciences, University of Copenhagen, 40 Thorvaldsensvej, DK-1871 Frederiksberg C, Copenhagen, Denmark
| | - René Höfer
- Institute of Plant Molecular Biology, CNRS UPR 2357, University of Strasbourg, 28 rue Goethe, F-67083 Strasbourg Cedex, France
| | - Suzanne Paquette
- Plant Biochemistry Laboratory, Department of Plant Biology and Biotechnology, Faculty of Life Sciences, University of Copenhagen, 40 Thorvaldsensvej, DK-1871 Frederiksberg C, Copenhagen, Denmark
- Department of Biological Structure, HSB G-514, Box 357420, University of Washington, Seattle, WA, 98195-9420
| | - Danièle Werck-Reichhart
- Institute of Plant Molecular Biology, CNRS UPR 2357, University of Strasbourg, 28 rue Goethe, F-67083 Strasbourg Cedex, France
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Robert-Seilaniantz A, MacLean D, Jikumaru Y, Hill L, Yamaguchi S, Kamiya Y, Jones JDG. The microRNA miR393 re-directs secondary metabolite biosynthesis away from camalexin and towards glucosinolates. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2011; 67:218-31. [PMID: 21457368 DOI: 10.1111/j.1365-313x.2011.04591.x] [Citation(s) in RCA: 142] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
flg22 treatment increases levels of miR393, a microRNA that targets auxin receptors. Over-expression of miR393 renders plants more resistant to biotroph pathogens and more susceptible to necrotroph pathogens. In contrast, over-expression of AFB1, an auxin receptor whose mRNA is partially resistant to miR393 degradation, renders the plant more susceptible to biotroph pathogens. Here we investigate the mechanism by which auxin signalling and miR393 influence plant defence. We show that auxin signalling represses SA levels and signalling. We also show that miR393 represses auxin signalling, preventing it from antagonizing SA signalling. In addition, over-expression of miR393 increases glucosinolate levels and decreases the levels of camalexin. Further studies on pathogen interactions in auxin signalling mutants revealed that ARF1 and ARF9 negatively regulate glucosinolate accumulation, and that ARF9 positively regulates camalexin accumulation. We propose that the action of miR393 on auxin signalling triggers two complementary responses. First, it prevents suppression of SA levels by auxin. Second, it stabilizes ARF1 and ARF9 in inactive complexes. As a result, the plant is able to mount a full SA response and to re-direct metabolic flow toward the most effective anti-microbial compounds for biotroph resistance. We propose that miR393 levels can fine-tune plant defences and prioritize resources.
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25
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Jørgensen K, Morant AV, Morant M, Jensen NB, Olsen CE, Kannangara R, Motawia MS, Møller BL, Bak S. Biosynthesis of the cyanogenic glucosides linamarin and lotaustralin in cassava: isolation, biochemical characterization, and expression pattern of CYP71E7, the oxime-metabolizing cytochrome P450 enzyme. PLANT PHYSIOLOGY 2011; 155:282-92. [PMID: 21045121 PMCID: PMC3075754 DOI: 10.1104/pp.110.164053] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2010] [Accepted: 09/26/2010] [Indexed: 05/18/2023]
Abstract
Cassava (Manihot esculenta) is a eudicotyledonous plant that produces the valine- and isoleucine-derived cyanogenic glucosides linamarin and lotaustralin with the corresponding oximes and cyanohydrins as key intermediates. CYP79 enzymes catalyzing amino acid-to-oxime conversion in cyanogenic glucoside biosynthesis are known from several plants including cassava. The enzyme system converting oxime into cyanohydrin has previously only been identified in the monocotyledonous plant great millet (Sorghum bicolor). Using this great millet CYP71E1 sequence as a query in a Basic Local Alignment Search Tool-p search, a putative functional homolog that exhibited an approximately 50% amino acid sequence identity was found in cassava. The corresponding full-length cDNA clone was obtained from a plasmid library prepared from cassava shoot tips and was assigned CYP71E7. Heterologous expression of CYP71E7 in yeast afforded microsomes converting 2-methylpropanal oxime (valine-derived oxime) and 2-methylbutanal oxime (isoleucine-derived oxime) to the corresponding cyanohydrins, which dissociate into acetone and 2-butanone, respectively, and hydrogen cyanide. The volatile ketones were detected as 2.4-dinitrophenylhydrazone derivatives by liquid chromatography-mass spectrometry. A K(S) of approximately 0.9 μm was determined for 2-methylbutanal oxime based on substrate-binding spectra. CYP71E7 exhibits low specificity for the side chain of the substrate and catalyzes the conversion of aliphatic and aromatic oximes with turnovers of approximately 21, 17, 8, and 1 min(-1) for the oximes derived from valine, isoleucine, tyrosine, and phenylalanine, respectively. A second paralog of CYP71E7 was identified by database searches and showed approximately 90% amino acid sequence identity. In tube in situ polymerase chain reaction showed that in nearly unfolded leaves, the CYP71E7 paralogs are preferentially expressed in specific cells in the endodermis and in most cells in the first cortex cell layer. In fully unfolded leaves, the expression is pronounced in the cortex cell layer just beside the epidermis and in specific cells in the vascular tissue cortex cells. Thus, the transcripts of the CYP71E7 paralogs colocalize with CYP79D1 and CYP79D2. We conclude that CYP71E7 is the oxime-metabolizing enzyme in cyanogenic glucoside biosynthesis in cassava.
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26
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Robert-Seilaniantz A, Grant M, Jones JDG. Hormone crosstalk in plant disease and defense: more than just jasmonate-salicylate antagonism. ANNUAL REVIEW OF PHYTOPATHOLOGY 2011; 49:317-43. [PMID: 21663438 DOI: 10.1146/annurev-phyto-073009-114447] [Citation(s) in RCA: 1041] [Impact Index Per Article: 80.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Until recently, most studies on the role of hormones in plant-pathogen interactions focused on salicylic acid (SA), jasmonic acid (JA), and ethylene (ET). It is now clear that pathogen-induced modulation of signaling via other hormones contributes to virulence. A picture is emerging of complex crosstalk and induced hormonal changes that modulate disease and resistance, with outcomes dependent on pathogen lifestyles and the genetic constitution of the host. Recent progress has revealed intriguing similarities between hormone signaling mechanisms, with gene induction responses often achieved by derepression. Here, we report on recent advances, updating current knowledge on classical defense hormones SA, JA, and ET, and the roles of auxin, abscisic acid (ABA), cytokinins (CKs), and brassinosteroids in molding plant-pathogen interactions. We highlight an emerging theme that positive and negative regulators of these disparate hormone signaling pathways are crucial regulatory targets of hormonal crosstalk in disease and defense.
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Nonhebel H, Yuan Y, Al-Amier H, Pieck M, Akor E, Ahamed A, Cohen JD, Celenza JL, Normanly J. Redirection of tryptophan metabolism in tobacco by ectopic expression of an Arabidopsis indolic glucosinolate biosynthetic gene. PHYTOCHEMISTRY 2011; 72:37-48. [PMID: 21111431 DOI: 10.1016/j.phytochem.2010.10.018] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2010] [Revised: 10/05/2010] [Accepted: 10/25/2010] [Indexed: 05/19/2023]
Abstract
Indole-3-acetaldoxime (IAOx) is a branch point compound of tryptophan (Trp) metabolism in glucosinolate-producing species such as Arabidopsis, serving as a precursor to indole-glucosinolates (IGs), the defense compound camalexin, indole-3-acetonitrile (IAN) and indole-3-acetic acid (IAA). We synthesized [(2)H(5)] and [(13)C(10)(15)N(2)]IAOx and [(13)C(6)], [(2)H(5)] and [2',2'-(2)H(2)]IAN in order to quantify endogenous IAOx and IAN in Arabidopsis and tobacco, a non-IG producing species. We found that side chain-labeled [2',2'-(2)H(2)]IAN overestimated the amount of IAN by 2-fold compared to when [(2)H(5)]IAN was used as internal standard, presumably due to protium-deuterium exchange within the internal standard during extraction of plant tissue. We also determined that [(13)C(1)]IAN underestimated the amount of IAN when the ratio of [(13)C(1)]IAN standard to endogenous IAN was greater than five to one, whereas either [(2)H(5)]IAN or [(13)C(6)]IAN showed a linear relationship with endogenous IAN over a broader range of concentrations. Transgenic tobacco vector control lines did not have detectable levels of IAOx or IAN (limit of detection∼100 pg/gfr.wt), while lines expressing either the IAOx-producing CYP79B2 or CYP79B3 genes from Arabidopsis under CaMV 35S promoter control accumulated IAOx in the range of 1-9 μg/gfr.wt. IAN levels in these lines ranged from 0.6 to 6.7 μg/gfr.wt, and IAA levels were ∼9-14-fold above levels in control lines. An Arabidopsis line expressing the same CYP79B2 overexpression construct accumulated IAOx in two of three lines measured (∼200 and 400 ng/gfr.wt) and accumulated IAN in all three lines. IAN is proposed to be a metabolite of IAOx or an enzymatic breakdown product of IGs induced upon tissue damage. Since tobacco does not produce detectable IGs, the tobacco data are consistent with IAN being a metabolite of IAOx. IAOx and IAN were also examined in the Arabidopsis activation tagged yucca mutant, and no accumulation of IAOx was found above the limits of detection but accumulation of IAN (3-fold above wt) occurred. The latter was surprising in light of recent reports that rule out IAOx and IAN as intermediates in YUCCA-mediated IAA synthesis.
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Affiliation(s)
- Heather Nonhebel
- Molecular and Cellular Biology Group, University of New England, Armidale, New South Wales, Australia.
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Bioinformatic analysis of molecular network of glucosinolate biosynthesis. Comput Biol Chem 2010; 35:10-8. [PMID: 21247808 DOI: 10.1016/j.compbiolchem.2010.12.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2010] [Revised: 11/30/2010] [Accepted: 12/13/2010] [Indexed: 01/01/2023]
Abstract
Glucosinolates constitute a major group of secondary metabolites in Arabidopsis, which play an important role in plant interaction with pathogens and insects. Advances in glucosinolate research have defined the biosynthetic pathways. However, cross-talk and interaction between glucosinolate pathway and other molecular pathways are largely unknown. Here three bioinformatics tools were used to explore novel components and pathway connections in glucosinolate network. Although none of the software tools were prefect to predict glucosinolate genes, combination of results generated by all the tools led to successful prediction of all known glucosinolate genes. This approach was used to predict new genes in glucosinolate network. A total of 330 genes were found with high potential to relate to glucosinolate biosynthesis. Among them 64 genes were selected to construct glucosinolate network because their individual connection to at least one known glucosinolate gene was predicted by all the software tools. Microarray data of candidate gene mutants were used for validation of the results. The mutants of nine genes predicted by glucosinolate seed genes all exhibited changes in the expression of glucosinolate genes. Four of the genes have been well-known to functionally interact with glucosinolate biosynthesis. These results indicate that the approach we took provides a powerful way to reveal new players in glucosinolate networks. Creation of an in silico network of glucosinolate biosynthesis will allow the generation of many testable hypotheses and ultimately enable predictive biology.
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