Iridoid biosynthesis in Chrysomelina larvae: Fat body produces early terpenoid precursors

Burse, Antje; Schmidt, Axel; Frick, Stephanie; Kuhn, Jürgen; Gershenzon, Jonathan; Boland, Wilhelm

doi:10.1016/j.ibmb.2006.11.011

Cited by 34 publications

(60 citation statements)

References 53 publications

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“…Remarkably, it has been implied that the biosynthesis of the similar iridoids in leaf beetles belonging to the Chrysomelidae family is divided between the fat body and a specialized glandular reservoir that also accumulates these defensive secretory compounds (Burse et al, 2007). The fat body expresses the MVA pathway and a geraniol hydroxylase and glucosyltransferase to produce 10-hydroxygeraniol-10-O-b-glucoside.…”

Section: The Possible Roles Of the Plastidic Mep And Cytosolic Mva Pamentioning

confidence: 99%

“…The fat body expresses the MVA pathway and a geraniol hydroxylase and glucosyltransferase to produce 10-hydroxygeraniol-10-O-b-glucoside. This glucoside is then transported to the glandular reservoir where a b-glucosidase releases 10-hydroxygeraniol for enzyme-mediated oxidation and cyclization/isomerization for the formation of toxic iridoids (Burse et al, 2007). In the case of Catharanthus MIA biosynthesis, the identification of a similar pathway step or intermediate in the IPAP cells could be very helpful to completely prove that MEP pathway-derived precursors are transported to the leaf epidermis from the internal phloem parenchyma for the biosynthesis of secologanin (Burlat et al, 2004).…”

Section: The Possible Roles Of the Plastidic Mep And Cytosolic Mva Pamentioning

confidence: 99%

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The Leaf Epidermome ofCatharanthus roseusReveals Its Biochemical Specialization

et al. 2008

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Catharanthus roseus is the sole commercial source of the monoterpenoid indole alkaloids (MIAs), vindoline and catharanthine, components of the commercially important anticancer dimers, vinblastine and vincristine. Carborundum abrasion technique was used to extract leaf epidermis-enriched mRNA, thus sampling the epidermome, or complement, of proteins expressed in the leaf epidermis. Random sequencing of the derived cDNA library established 3655 unique ESTs, composed of 1142 clusters and 2513 singletons. Virtually all known MIA pathway genes were found in this remarkable set of ESTs, while only four known genes were found in the publicly available Catharanthus EST data set. Several novel MIA pathway candidate genes were identified, as demonstrated by the cloning and functional characterization of loganic acid O-methyltransferase involved in secologanin biosynthesis. The pathways for triterpene biosynthesis were also identified, and metabolite analysis showed that oleanane-type triterpenes were localized exclusively to the cuticular wax layer. The pathways for flavonoid and very-longchain fatty acid biosynthesis were also located in this cell type. The results illuminate the biochemical specialization of Catharanthus leaf epidermis for the production of multiple classes of metabolites. The value and versatility of this EST data set for biochemical and biological analysis of leaf epidermal cells is also discussed.

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Section: The Possible Roles Of the Plastidic Mep And Cytosolic Mva Pamentioning

confidence: 99%

Section: The Possible Roles Of the Plastidic Mep And Cytosolic Mva Pamentioning

confidence: 99%

The Leaf Epidermome ofCatharanthus roseusReveals Its Biochemical Specialization

et al. 2008

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“…Each gland consists of several gland cells that are attached to a glandular reservoir whose content is everted when the larvae is disturbed. The defensive secretions of larvae belonging to the subtribe Chrysomelina have been analyzed, and three strategies have been identified that reflect different degrees of specialization during evolution: first, the de novo production of iridoid monoterpenes from terpenoid precursors, providing an autogenous defense that is completely host plant-independent (7,8); second, the biosynthesis of the aromatic compound salicylaldehyde from salicin, a phenolic glucoside taken up from the larval host plant, in a strategy that is fully dependent upon the chemistry of the host plant (9); third, the biosynthesis of esters composed of de novo-synthesized butyric acids with the alcohol moiety of leaf alcohol glucosides retrieved from the plant, representing a strategy partially dependent on the chemistry of the host plant (10).…”

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confidence: 99%

Salicyl Alcohol Oxidase of the Chemical Defense Secretion of Two Chrysomelid Leaf Beetles

Michalski

Mohagheghi

Nimtz

et al. 2008

Journal of Biological Chemistry

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Salicyl alcohol oxidase is an extracellular enzyme that occurs in glandular reservoirs of chrysomelid leaf beetle larvae and catalyzes the formation of salicylaldehyde, a volatile deterrent used by the larvae against predators. Salicyl alcohol is the hydrolysis product of salicin, a plant-derived precursor taken up by the beetle larvae from the leaves of willow and poplar trees. The cDNA encoding salicyl alcohol oxidase from two related species Chrysomela tremulae and Chrysomela populi has been identified, cloned, and expressed in an active form in Escherichia coli. The open reading frame of 623 amino acids begins in both enzymes with an N-terminal signal peptide of 21 amino acids. Sequence comparison has revealed that salicyl alcohol oxidase belongs to the family of glucose-methanol-choline oxidoreductase-like sequences with mostly unknown function. Enzymes of this family share similar overall structure with an essentially identical FAD-binding site but possess different catalytic activities. The data suggest that salicyl alcohol oxidase, essential for the activation of the plant-derived precursor salicin, was originally recruited from an oxidase involved in the autogenous biosynthesis of iridoid monoterpenes and found in related chrysomelid leaf beetle species.

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“…Because HMGR is one of the most regulated enzymes known [64], its regulatory features may also be important for the biosynthesis of iridoids in chrysomelids. Consistently, analyses of different larval tissues from the iridoid synthesizing species Phaedon cochleariae and Gastrophysa viridula revealed high HMGR mRNA levels, high HMGR activity, and accumulation of the iridoid intermediate, 8-hydroxygeraniol-8-O-β-d-glucoside, in the fat body tissue of the iridoid de novo producers [65]. Hence, the fat body -the most prominent tissue in the larvae performing myriad metabolic functions throughout the insects' development [66] -is implicated in de novo production of the glucosidically bound iridoid precursor.…”

Section: Iridoid De Novo Synthesis: Early Stepsmentioning

confidence: 55%

Deciphering the route to cyclic monoterpenes in Chrysomelina leaf beetles: source of new biocatalysts for industrial application?

Burse

Boland

2017

Zeitschrift Für Naturforschung C

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Abstract:The drastic growth of the population on our planet requires the efficient and sustainable use of our natural resources. Enzymes are indispensable tools for a wide range of industries producing food, pharmaceuticals, pesticides, or biofuels. Because insects constitute one of the most species-rich classes of organisms colonizing almost every ecological niche on earth, they have developed extraordinary metabolic abilities to survive in various and sometimes extreme habitats. Despite this metabolic diversity, insect enzymes have only recently generated interest in industrial applications because only a few metabolic pathways have been sufficiently characterized. Here, we address the biosynthetic route to iridoids (cyclic monoterpenes), a group of secondary metabolites used by some members of the leaf beetle subtribe Chrysomelina as defensive compounds against their enemies. The ability to produce iridoids de novo has also convergently evolved in plants. From plant sources, numerous pharmacologically relevant structures have already been described. In addition, in plants, iridoids serve as building blocks for monoterpenoid indole alkaloids with broad therapeutic applications. As the commercial synthesis of iridoidbased drugs often relies on a semisynthetic approach involving biocatalysts, the discovery of enzymes from the insect iridoid route can account for a valuable resource and economic alternative to the previously used enzymes from the metabolism of plants. Hence, this review illustrates the recent discoveries made on the steps of the iridoid pathway in Chrysomelina leaf beetles. The findings are also placed in the context of the studied counterparts in plants and are further discussed regarding their use in technological approaches.

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Iridoid biosynthesis in Chrysomelina larvae: Fat body produces early terpenoid precursors

Cited by 34 publications

References 53 publications

The Leaf Epidermome ofCatharanthus roseusReveals Its Biochemical Specialization

The Leaf Epidermome ofCatharanthus roseusReveals Its Biochemical Specialization

Salicyl Alcohol Oxidase of the Chemical Defense Secretion of Two Chrysomelid Leaf Beetles

Deciphering the route to cyclic monoterpenes in Chrysomelina leaf beetles: source of new biocatalysts for industrial application?

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