Biosynthesis of glucosinolates – gene discovery and beyond
TL;DR: Major breakthroughs include the ability to produce glucosinolates in Nicotiana benthamiana, the finding that specific glucos inolates play a key role in Arabidopsis innate immune response, and a better understanding of the link between primary sulfur metabolism and glucosInolate biosynthesis.
About: This article is published in Trends in Plant Science.The article was published on 2010-05-01. It has received 740 citations till now. The article focuses on the topics: Glucosinolate.
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TL;DR: Important new components of jasmonate signalling including its receptor were identified, providing deeper insight into the role ofJASMONATE signalling pathways in stress responses and development.
1,868 citations
University of Évry Val d'Essonne1, Crops Research Institute2, Agriculture and Agri-Food Canada3, J. Craig Venter Institute4, Fujian Agriculture and Forestry University5, Plant Genome Mapping Laboratory6, University of Giessen7, French Alternative Energies and Atomic Energy Commission8, Institut national de la recherche agronomique9, National Research Council10, Australian Centre for Plant Functional Genomics11, University of Cologne12, Purdue University13, University of California, Berkeley14, University of British Columbia15, Fondation Jean Dausset Centre d'Etude du Polymorphisme Humain16, Huazhong Agricultural University17, Hunan Agricultural University18, Chungnam National University19, University of Arizona20, University of York21, University of Missouri22, Southern Cross University23, University of Western Australia24, Centre national de la recherche scientifique25
TL;DR: The polyploid genome of Brassica napus, which originated from a recent combination of two distinct genomes approximately 7500 years ago and gave rise to the crops of rape oilseed, is sequenced.
Abstract: Oilseed rape (Brassica napus L.) was formed ~7500 years ago by hybridization between B. rapa and B. oleracea, followed by chromosome doubling, a process known as allopolyploidy. Together with more ancient polyploidizations, this conferred an aggregate 72× genome multiplication since the origin of angiosperms and high gene content. We examined the B. napus genome and the consequences of its recent duplication. The constituent An and Cn subgenomes are engaged in subtle structural, functional, and epigenetic cross-talk, with abundant homeologous exchanges. Incipient gene loss and expression divergence have begun. Selection in B. napus oilseed types has accelerated the loss of glucosinolate genes, while preserving expansion of oil biosynthesis genes. These processes provide insights into allopolyploid evolution and its relationship with crop domestication and improvement.
1,743 citations
TL;DR: This review focuses on the animal studies demonstrating the beneficial effects of glucosinolates and isothiocyanates in models of carcinogenesis, and cardiovascular and neurological diseases, as well as on the intervention studies of their safety, pharmacokinetics, and efficacy in humans.
500 citations
TL;DR: The probable existence of structure-specific GSL catabolism in intact plants suggests that biochemical evolution of GSLs has more complex implications than the mere liberation of a different hydrolysis product upon tissue disruption.
415 citations
Cites background or methods from "Biosynthesis of glucosinolates – ge..."
...The chain elongated homologues are produced by addition of acetate to the corresponding a-keto acid followed by isomerization and reduction (Ettlinger and Kjær, 1968; Sawada et al., 2009; Sønderby et al., 2010), analogous to, e....
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...The biosynthesis of GSLs includes a number of common steps responsible for formation of the core structure, as well as a number of diverse steps responsible for side chain and other diversification, and has recently been reviewed (Halkier and Gershenzon, 2006; Sønderby et al., 2010)....
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...…by addition of acetate to the corresponding a-keto acid followed by isomerization and reduction (Ettlinger and Kjær, 1968; Sawada et al., 2009; Sønderby et al., 2010), analogous to, e.g. the steps from oxaloacetate to a-ketoglutarate in the citric acid cycle and similar steps in Leu…...
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TL;DR: A triple mutant of MYC2, MYC3, and MYC4 transcription factors is devoid of glucosinolates and more sensitive to attack by a generalist insect, underlines the importance of GS in shaping plant interactions with adapted and nonadapted herbivores.
Abstract: Arabidopsis thaliana plants fend off insect attack by constitutive and inducible production of toxic metabolites, such as glucosinolates (GSs). A triple mutant lacking MYC2, MYC3, and MYC4, three basic helix-loop-helix transcription factors that are known to additively control jasmonate-related defense responses, was shown to have a highly reduced expression of GS biosynthesis genes. The myc2 myc3 myc4 (myc234) triple mutant was almost completely devoid of GS and was extremely susceptible to the generalist herbivore Spodoptera littoralis. On the contrary, the specialist Pieris brassicae was unaffected by the presence of GS and preferred to feed on wild-type plants. In addition, lack of GS in myc234 drastically modified S. littoralis feeding behavior. Surprisingly, the expression of MYB factors known to regulate GS biosynthesis genes was not altered in myc234, suggesting that MYC2/MYC3/MYC4 are necessary for direct transcriptional activation of GS biosynthesis genes. To support this, chromatin immunoprecipitation analysis showed that MYC2 binds directly to the promoter of several GS biosynthesis genes in vivo. Furthermore, yeast two-hybrid and pull-down experiments indicated that MYC2/MYC3/MYC4 interact directly with GS-related MYBs. This specific MYC–MYB interaction plays a crucial role in the regulation of defense secondary metabolite production and underlines the importance of GS in shaping plant interactions with adapted and nonadapted herbivores.
412 citations
Cites background or methods from "Biosynthesis of glucosinolates – ge..."
...GSs are not distributed uniformly in A. thaliana leaves and accumulate to higher levels in leaf margins and veins (Shroff et al., 2008; Sønderby et al., 2010a)....
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...The figure is adapted from Sønderby et al. (2010b) and Yatusevich et al. (2010). plants with the generalist S. littoralis and the specialist P. brassicae....
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...MYB28, MYB29, and MYB76 act in concert in a complex interaction module to control aliphatic-GS genes (Hirai et al., 2007; Gigolashvili et al., 2008; Sønderby et al., 2010a), whereas MYB34, MYB51, and MYB122 control indole-GS genes (Gigolashvili et al., 2007a)....
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...These factors play a role in leaf GS distribution, and it was postulated that they regulate a specific GS transport from the vein to the leaf edge (Sønderby et al., 2010a)....
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...In recent years, most genes involved in Arabidopsis thaliana GS biosynthesis have been identified and are involved in amino acid chain elongation, core GS structure biosynthesis, sulfate assimilation pathway, and secondary modifications (Sønderby et al., 2010b)....
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References
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TL;DR: This review addresses the complex array of glucosinolates, the precursors of isothiocyanates, present in sixteen families of dicotyledonous angiosperms including a large number of edible species including Brassica vegetables.
2,679 citations
TL;DR: Glucosinolates are sulfur-rich, anionic natural products that upon hydrolysis by endogenous thioglucosidases called myrosinases produce several different products that function as cancer-preventing agents, biopesticides, and flavor compounds.
Abstract: Glucosinolates are sulfur-rich, anionic natural products that upon hydrolysis by endogenous thioglucosidases called myrosinases produce several different products (e.g., isothiocyanates, thiocyanates, and nitriles). The hydrolysis products have many different biological activities, e.g., as defense compounds and attractants. For humans these compounds function as cancer-preventing agents, biopesticides, and flavor compounds. Since the completion of the Arabidopsis genome, glucosinolate research has made significant progress, resulting in near-complete elucidation of the core biosynthetic pathway, identification of the first regulators of the pathway, metabolic engineering of specific glucosinolate profiles to study function, as well as identification of evolutionary links to related pathways. Although much has been learned in recent years, much more awaits discovery before we fully understand how and why plants synthesize glucosinolates. This may enable us to more fully exploit the potential of these compounds in agriculture and medicine.
1,955 citations
TL;DR: This review surveys the occurrence, analysis, and properties of glucosinolates and derived compounds in plants and products intended for humans and animal consumption and places particular emphasis on members of the Brassica family.
Abstract: This review surveys the occurrence, analysis, and properties of glucosinolates and derived compounds in plants and products intended for humans and animal consumption. The paper, which includes references published in 1981, is also intended to compliment existing reviews on the chemistry of these sulfur‐containing natural products. Particular emphasis is placed upon members of the Brassica family because of their importance as vegetables, condiments, oilseeds, and animal feedingstuffs. Since much of the work considered here relates to glucosinolate decomposition products, biochemical information concerning the nature, occurrence, and properties of the glucosinolate‐degrading enzyme, myrosinase, is considered in Section III. The methods available for the chemical analysis of glucosinolates and their various breakdown products are discussed critically. Factors affecting the glucosinolate content of plants and plant products arc outlined in Section VII. Particular emphasis is placed upon the effect of proces...
1,269 citations
TL;DR: It is shown that well-studied plant metabolites, previously identified as important in avoiding damage by herbivores, are also required as a component of the plant defense response against microbial pathogens.
Abstract: The perception of pathogen or microbe-associated molecular pattern molecules by plants triggers a basal defense response analogous to animal innate immunity and is defined partly by the deposition of the glucan polymer callose at the cell wall at the site of pathogen contact. Transcriptional and metabolic profiling in Arabidopsis mutants, coupled with the monitoring of pathogen-triggered callose deposition, have identified major roles in pathogen response for the plant hormone ethylene and the secondary metabolite 4-methoxy-indol-3-ylmethylglucosinolate. Two genes, PEN2 and PEN3, are also necessary for resistance to pathogens and are required for both callose deposition and glucosinolate activation, suggesting that the pathogen-triggered callose response is required for resistance to microbial pathogens. Our study shows that well-studied plant metabolites, previously identified as important in avoiding damage by herbivores, are also required as a component of the plant defense response against microbial pathogens.
995 citations
TL;DR: It is proposed that reiterated enzymatic cycles, controlling the generation of toxic molecules and their detoxification, enable the recruitment of glucosinolates in defense responses.
Abstract: Selection pressure exerted by insects and microorganisms shapes the diversity of plant secondary metabolites. We identified a metabolic pathway for glucosinolates, known insect deterrents, that differs from the pathway activated by chewing insects. This pathway is active in living plant cells, may contribute to glucosinolate turnover, and has been recruited for broad-spectrum antifungal defense responses. The Arabidopsis CYP81F2 gene encodes a P450 monooxygenase that is essential for the pathogen-induced accumulation of 4-methoxyindol-3-ylmethylglucosinolate, which in turn is activated by the atypical PEN2 myrosinase (a type of beta-thioglucoside glucohydrolase) for antifungal defense. We propose that reiterated enzymatic cycles, controlling the generation of toxic molecules and their detoxification, enable the recruitment of glucosinolates in defense responses.
876 citations