Insect-Induced Conifer Defense. White Pine Weevil and Methyl Jasmonate Induce Traumatic Resinosis, de Novo Formed Volatile Emissions, and Accumulation of Terpenoid Synthase and Putative Octadecanoid Pathway Transcripts in Sitka Spruce

Miller, Barbara; Madilao, Lufiani L.; Ralph, Steven; Bohlmann, Jörg

doi:10.1104/pp.104.050187

Cited by 252 publications

(335 citation statements)

References 36 publications

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“…To the best of our knowledge, diterpenoids with a hydroxyl group at carbon-13 have not been found in previous analyses of Norway spruce resin or the resin of other spruce species (30,31). Whether their apparent absence is due to enzymatic or non-enzymatic dehydration in planta or to their sensitivity to dehydration ex planta in the process of resin extraction and analysis is not known and will be difficult to resolve.…”

Section: Discussionmentioning

confidence: 91%

The Primary Diterpene Synthase Products of Picea abies Levopimaradiene/Abietadiene Synthase (PaLAS) Are Epimers of a Thermally Unstable Diterpenol

Keeling

Madilao

Zerbe

et al. 2011

Journal of Biological Chemistry

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The levopimaradiene/abietadiene synthase from Norway spruce (Picea abies; PaLAS) has previously been reported to produce a mixture of four diterpene hydrocarbons when incubated with geranylgeranyl diphosphate as the substrate: levopimaradiene, abietadiene, neoabietadiene, and palustradiene. However, variability in the assay products observed by GC-MS of this and orthologous conifer diterpene synthases over the past 15 years suggested that these diterpenes may not be the initial enzyme assay products but are rather the products of dehydration of an unstable alcohol. We have identified epimers of the thermally unstable allylic tertiary alcohol 13-hydroxy-8(14)-abietene as the products of PaLAS. The identification of these compounds, not previously described in conifers, as the initial products of PaLAS has considerable implications for our understanding of the complexity of the biosynthetic pathway of the structurally diverse diterpene resin acids of conifer defense.

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Section: Discussionmentioning

confidence: 91%

The Primary Diterpene Synthase Products of Picea abies Levopimaradiene/Abietadiene Synthase (PaLAS) Are Epimers of a Thermally Unstable Diterpenol

Keeling

Madilao

Zerbe

et al. 2011

Journal of Biological Chemistry

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“…These results agree with a role of DRAs in constitutive conifer defense. Previous studies with Sitka spruce showed that MJ treatment mimics insect attack on trees (14). In loblolly pine, transcripts hybridizing with PtAO and PtLAS were increased in stem bark and xylem upon MJ treatment as part of the induced resin terpenoid defense (Fig.…”

Section: De Novo Diterpenoid Formation In Metabolically Engineered Yementioning

confidence: 96%

“…Organic solvents were then completely evaporated under N 2 , and dried compounds were dissolved in 50 l of diethyl ether. Diterpenoids were analyzed by GC-MS by using a 6890 GC-MSD system (70 eV, Agilent Technologies, Palo Alto, CA) with a DB1 capillary column (0.25 mm ϫ 0.25 m ϫ 30 m, J & W Scientific, Folsom, CA) (14). Injections of 2-l samples were splitless at 220°C with a column flow of 1 ml of He͞min.…”

Section: Constructs For P450 Expression In Yeastmentioning

confidence: 99%

Loblolly pine abietadienol/abietadienal oxidase PtAO (CYP720B1) is a multifunctional, multisubstrate cytochrome P450 monooxygenase

Arimura

Lau

et al. 2005

Proc. Natl. Acad. Sci. U.S.A.

171

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conifer defense ͉ gibberellic acid ͉ diterpene resin acids ͉ conifer genomics ͉ plant secondary metabolism D iterpene resin acids (DRAs) (Fig. 1A) are important defense compounds of conifers against potential herbivores and pathogens, such as bark beetles and their associated fungi (1-3). DRAs are formed and sequestered as major components of complex oleoresin blends in resin ducts, resin blisters, or resin cells in stems, needles, and roots of most conifers. Biosynthesis of DRAs involves formation of geranylgeranyl diphosphate (GGDP), cyclization of GGDP to a series of diterpene olefins by activity of diterpene synthases (diTPSs), and three subsequent oxidations at carbon 18 (Fig. 1B). A small family of singleproduct or multiproduct diTPSs of DRA biosynthesis has recently been cloned and characterized (4-6). Studies with grand fir (Abies grandis) and lodgepole pine (Pinus contorta) tissue extracts showed that stepwise oxidation of the diterpene olefin abietadiene (1a) to abietic acid (1d) can be achieved by membrane-bound cytochrome P450 monooxygenase (P450) and soluble aldehyde dehydrogenase enzyme activities (Fig. 1B) (7, 8). The general pathway scheme of oxidation of abietadiene to abietic acid in conifer secondary metabolism resembles that of oxidation of ent-kaurene to ent-kaurenoic acid in the biosynthesis of gibberellin phytohormones (9-11). A multifunctional P450 responsible for the three-step oxidation of ent-kaurene to kaurenoic acid has previously been identified by using genetic approaches in Arabidopsis thaliana (10-11). Similarly, a multifunctional P450 also catalyzes the subsequent three-step oxidation from kaurenoic acid to GA 12 in Arabidopsis (12). Cloning and identification of P450s of DRA secondary metabolism have been hampered by difficulties in purifying the corresponding enzymes and by lack of suitable forward genetic tools for conifers. However, large collections of ESTs for loblolly pine (Pinus taeda, Pt) (13) can enable gene discovery and biochemical identification of candidate P450 cDNAs of terpenoid secondary metabolism in conifers. Here, we describe cloning and functional characterization of abietadienol͞abietadienal oxidase (PtAO, CYP720B1), a P450 enzyme that is unusual in that it catalyzes an array of consecutive oxidations of multiple diterpene alcohol and aldehyde intermediates in DRA biosynthesis in loblolly pine. The methyl jasmonate (MJ)-inducible PtAO can account for much of the oxidative diversification of diterpenoid natural product defense compounds in loblolly pine. Materials and MethodsMaterials. Seedlings of loblolly pine and Sitka spruce (Picea sitchensis) were grown to 2-year-old trees as described in ref. 14. Yeast strain YPH499 (MATa, ura3-52, lys2-801, ade2-101, trp1-⌬63, his3-⌬200, and leu2-⌬1) and yeast dual expression vectors (pESC-Leu and pESC-His) were from Stratagene. Diterpenoid substrates were prepared from the corresponding DRAs (Helix Biotech, Surrey, BC, Canada) as described in Supporting Materials and Methods, which is published as supporting informat...

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“…These defenses consist of resin exudation that pitches out or delays attacking adults, and allelochemicals, particularly monoterpenes, that repel or kill the adults, prevent egg hatch, and inhibit or kill their symbionts (18)(19)(20). Monoterpenes occur at relatively low concentrations in constitutive (preattack) phloem, but are rapidly biosynthesized at the point of attack and accumulate to toxic levels within a few days (21)(22)(23). Bark beetles can overwhelm these barriers through pheromone-mediated mass attacks, in which large numbers of both sexes land on selected trees and tunnel into their tissues.…”

mentioning

confidence: 99%

Temperature-driven range expansion of an irruptive insect heightened by weakly coevolved plant defenses

Raffa¹,

Powell²,

Townsend

2012

Proc. Natl. Acad. Sci. U.S.A.

185

202

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Warming climate has increased access of native bark beetles to high-elevation pines that historically received only intermittent exposure to these tree-killing herbivores. Here we show that a dominant, relatively naïve, high-elevation species, whitebark pine, has inferior defenses against mountain pine beetle compared with its historical lower-elevation host, lodgepole pine. Lodgepole pines respond by exuding more resin and accumulating higher concentrations of toxic monoterpenes than whitebark pine, where they co-occur. Furthermore, the chemical composition of whitebark pine appears less able to inhibit the pheromonal communication beetles use to jointly overcome tree defenses. Despite whitebark pine's inferior defenses, beetles were more likely to attack their historical host in mixed stands. This finding suggests there has been insufficient sustained contact for beetles to alter their complex behavioral mechanisms driving host preference. In no-choice assays, however, beetles readily entered and tunneled in both hosts equally, and in stands containing less lodgepole pine, attacks on whitebark pines increased. High-elevation trees in pure stands may thus be particularly vulnerable to temperature-driven range expansions. Predators and competitors were more attracted to volatiles from herbivores attacking their historical host, further increasing risk in less coevolved systems. Our results suggest cold temperatures provided a sufficient barrier against herbivores for high-elevation trees to allocate resources to other physiological processes besides defense. Changing climate may reduce the viability of that evolutionary strategy, and the life histories of high-elevation trees seem unlikely to foster rapid counter adaptation. Consequences extend from reduced food supplies for endangered grizzly bears to altered landscape and hydrological processes.climate change | coevolution | disturbance | plant-insect interactions | forest insects

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Insect-Induced Conifer Defense. White Pine Weevil and Methyl Jasmonate Induce Traumatic Resinosis, de Novo Formed Volatile Emissions, and Accumulation of Terpenoid Synthase and Putative Octadecanoid Pathway Transcripts in Sitka Spruce

Cited by 252 publications

References 36 publications

The Primary Diterpene Synthase Products of Picea abies Levopimaradiene/Abietadiene Synthase (PaLAS) Are Epimers of a Thermally Unstable Diterpenol

The Primary Diterpene Synthase Products of Picea abies Levopimaradiene/Abietadiene Synthase (PaLAS) Are Epimers of a Thermally Unstable Diterpenol

Loblolly pine abietadienol/abietadienal oxidase PtAO (CYP720B1) is a multifunctional, multisubstrate cytochrome P450 monooxygenase

Temperature-driven range expansion of an irruptive insect heightened by weakly coevolved plant defenses

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