scholarly journals Host-Tree Monoterpenes and Biosynthesis of Aggregation Pheromones in the Bark BeetleIps paraconfusus

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
John A. Byers ◽  
Göran Birgersson
Keyword(s):  
Aggregation Pheromone ◽  
Pinus Ponderosa ◽  
Bark Beetles ◽  
De Novo ◽  
Host Tree ◽  
Ips Paraconfusus ◽  
Pheromone Biosynthesis ◽  
Host Plant Selection ◽  
Aggregation Pheromones ◽  
Host Trees

A paradigm developed in the 1970s thatIpsbark beetles biosynthesize their aggregation pheromone components ipsenol and ipsdienol by hydroxylating myrcene, a host tree monoterpene. Similarly, hostα-pinene was hydroxylated to a third pheromone componentcis-verbenol. In 1990, however, we reported that amounts of ipsenol and ipsdienol produced by maleIps paraconfusus(Coleoptera: Scolytinae) feeding in five host pine species were nearly the same, even though no detectable myrcene precursor was detected in one of these pines (Pinus sabiniana). Subsequent research showed ipsenol and ipsdienol are also biosynthesized from smaller precursors such as acetate and mevalonate, and thisde novopathway is the major one, while host tree myrcene conversion by the beetle is the minor one. We report concentrations of myrcene,α-pinene and other major monoterpenes in five pine hosts (Pinus ponderosa,P. lambertiana,P. jeffreyi,P. sabiniana, andP. contorta) ofI. paraconfusus. A scheme for biosynthesis of ipsdienol and ipsenol from myrcene and possible metabolites such as ipsenone is presented. Mass spectra and quantities of ipsenone are reported and its possible role in biosynthesis of aggregation pheromone. Coevolution of bark beetles and host trees is discussed in relation to pheromone biosynthesis, host plant selection/suitability, and plant resistance.

BIOSYNTHESIS OF CONIFEROPHAGOUS BARK BEETLE PHEROMONES AND CONIFER ISOPRENOIDS: EVOLUTIONARY PERSPECTIVE AND SYNTHESIS

2000 ◽  
Vol 132 (6) ◽  
pp. 697-753 ◽  
Author(s):  
Steven J. Seybold ◽  
Jörg Bohlmann ◽  
Kenneth F. Raffa
Keyword(s):  
Bark Beetles ◽  
De Novo ◽  
Scientific Paper ◽  
Pheromone Biosynthesis ◽  
Aggregation Pheromones ◽  
Transcriptional Level ◽  
Geranyl Diphosphate ◽  
Biochemical Systems ◽  
Vertebrate Model ◽  
Monoterpene Biosynthesis

AbstractIn this overview we compare the significance and evolutionary history of two interacting biological systems, the conifer-feeding bark beetles (Coleoptera: Scolytidae) and their host conifers (Gymnospermae: Coniferales and Taxales). Isoprenoid natural products play key roles in the aggregation of the bark beetles and in the defence of the conifers. Our approach is to couple the most recent advances in the biochemical and molecular literature on these systems with ecological and behavioral data to compare monoterpenoid pheromone biosynthesis in scolytids with monoterpene biosynthesis in conifers. This synthesis reveals and evaluates the evolutionary redundancy occurring in the biochemical systems of the insect and host. Although host monoterpenes may be utilized directly or as derivatives in aggregation by scolytids, oxygenated monoterpenes that are behaviorally active for scolytids have been rarely identified from their coniferous hosts. De novo monoterpenoid biosynthesis in the Scolytidae, a process that is likely to be rare among metazoans, is substantially different from monoterpene biosynthesis in the conifers. The pathways appear to be shared only at the late-stage reactions that follow the formation of isopentenyl diphosphate. Little is known of the regulation of monoterpene biosynthesis in conifers, but scolytids positively regulate monoterpenoid biosynthesis using a sesquiterpenoid hormone, juvenile hormone, which does not occur in conifers. Little is known of the subcellular site of synthesis of monoterpenoids in scolytids, but conifer monoterpene biosynthesis is compartmentalized in the plastids, which do not occur in scolytid cells. In addition to bark beetles and conifers, the vertebrate model presents one of the few systems in which isoprenoid synthesis has been studied enough to provide a meaningful comparison. Possible unique features of monoterpenoid pheromone biosynthesis in scolytids relative to isoprenoid biosynthesis in vertebrates include the following: (1) a monoterpenoid end product; (2) a hypothetically scolytid-specific prenyl transferase (= geranyl diphosphate synthase) that catalyzes the condensation of two five-carbon (C5) units, but does not catalyze additional condensation reactions with the C5 monomelic unit; (3) a scolytid-specific monoterpene (myrcene) synthase; and (4) a scolytid-specific, transcriptional-level sesquiterpenoid isoprenoid regulatory mechanism. Features 2 and 3 may be shared with conifers. This review also updates the 1985 landmark scientific paper by John Borden by listing the references and species of coniferophagous Scolytidae for which aggregation pheromones have been identified since 1985.

scholarly journals De novo formation of an aggregation pheromone precursor by an isoprenyl diphosphate synthase-related terpene synthase in the harlequin bug

2018 ◽  
Vol 115 (37) ◽  
pp. E8634-E8641 ◽  
Author(s):  
Jason Lancaster ◽  
Ashot Khrimian ◽  
Sharon Young ◽  
Bryan Lehner ◽  
Katrin Luck ◽  
...  
Keyword(s):  
Aggregation Pheromone ◽  
De Novo ◽  
Pheromone Biosynthesis ◽  
Terpene Synthase ◽  
Aggregation Pheromones ◽  
Limited Information ◽  
Terpene Biosynthesis ◽  
Intraspecific Interactions ◽  
Unknown Compound ◽  
Isoprenyl Diphosphate

Insects use a diverse array of specialized terpene metabolites as pheromones in intraspecific interactions. In contrast to plants and microbes, which employ enzymes called terpene synthases (TPSs) to synthesize terpene metabolites, limited information from few species is available about the enzymatic mechanisms underlying terpene pheromone biosynthesis in insects. Several stink bugs (Hemiptera: Pentatomidae), among them severe agricultural pests, release 15-carbon sesquiterpenes with a bisabolene skeleton as sex or aggregation pheromones. The harlequin bug, Murgantia histrionica, a specialist pest of crucifers, uses two stereoisomers of 10,11-epoxy-1-bisabolen-3-ol as a male-released aggregation pheromone called murgantiol. We show that MhTPS (MhIDS-1), an enzyme unrelated to plant and microbial TPSs but with similarity to trans-isoprenyl diphosphate synthases (IDS) of the core terpene biosynthetic pathway, catalyzes the formation of (1S,6S,7R)-1,10-bisaboladien-1-ol (sesquipiperitol) as a terpene intermediate in murgantiol biosynthesis. Sesquipiperitol, a so-far-unknown compound in animals, also occurs in plants, indicating convergent evolution in the biosynthesis of this sesquiterpene. RNAi-mediated knockdown of MhTPS mRNA confirmed the role of MhTPS in murgantiol biosynthesis. MhTPS expression is highly specific to tissues lining the cuticle of the abdominal sternites of mature males. Phylogenetic analysis suggests that MhTPS is derived from a trans-IDS progenitor and diverged from bona fide trans-IDS proteins including MhIDS-2, which functions as an (E,E)-farnesyl diphosphate (FPP) synthase. Structure-guided mutagenesis revealed several residues critical to MhTPS and MhFPPS activity. The emergence of an IDS-like protein with TPS activity in M. histrionica demonstrates that de novo terpene biosynthesis evolved in the Hemiptera in an adaptation for intraspecific communication.

scholarly journals Bark Beetles,Pityogenes bidentatus, Orienting to Aggregation Pheromone Avoid Conifer Monoterpene Odors When Flying but Not When Walking

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
John A. Byers
Keyword(s):  
Picea Abies ◽  
Pinus Sylvestris ◽  
Aggregation Pheromone ◽  
Bark Beetles ◽  
Slow Rotation ◽  
Scotch Pine ◽  
Release Rates ◽  
Host Trees ◽  
Pheromone Components ◽  
Males And Females

Previous studies and data presented here suggest that odors from healthy host Scotch pine (Pinus sylvestris) and nonhost Norway spruce (Picea abies), as well as major monoterpenes of these trees at natural release rates, significantly reduce the attraction of flying bark beetles,Pityogenes bidentatus, of both sexes to their aggregation pheromone components grandisol andcis-verbenol in the field, as tested by slow rotation of trap pairs. In contrast,P. bidentatusmales and females walking in an open-arena olfactometer in the laboratory did not avoid monoterpene vapors at release rates spanning several orders of magnitude in combination with aggregation pheromone. The bark beetle may avoid monoterpenes when flying as a mechanism for avoiding nonhost species, vigorous and thus unsuitable host trees, as well as harmful resinous areas of hosts. Inhibition of this flight avoidance response in beetles after landing would allow them to initiate, or to find and enter, gallery holes with high monoterpene vapor concentrations in order to feed and reproduce.

scholarly journals Monoterpenyl esters in juvenile mountain pine beetle and sex-specific release of the aggregation pheromone trans-verbenol

2018 ◽  
Vol 115 (14) ◽  
pp. 3652-3657 ◽  
Author(s):  
Christine C. Chiu ◽  
Christopher I. Keeling ◽  
Joerg Bohlmann
Keyword(s):  
Aggregation Pheromone ◽  
Mountain Pine Beetle ◽  
Host Tree ◽  
Response To Treatment ◽  
Pheromone Biosynthesis ◽  
Specific System ◽  
New Host ◽  
Adult Females ◽  
Mountain Pine ◽  
Pine Beetle

A recent outbreak of mountain pine beetle (MPB) has spread over more than 25 million hectares of pine forests in western North America, affecting pine species of sensitive boreal and mountain ecosystems. During initial host colonization, female MPB produce and release the aggregation pheromone trans-verbenol to coordinate a mass attack of individual trees. trans-Verbenol is formed by hydroxylation of α-pinene, a monoterpene of the pine oleoresin defense. It is thought that adult females produce and immediately release trans-verbenol when encountering α-pinene on a new host tree. Here, we show that both sexes of MPB accumulate the monoterpenyl esters verbenyl oleate and verbenyl palmitate during their development in the brood tree. Verbenyl oleate and verbenyl palmitate were retained in adult female MPB until the time of emergence from brood trees, but were depleted in males. Adult females released trans-verbenol in response to treatment with juvenile hormone III (JHIII). While both sexes produced verbenyl esters when exposed to α-pinene, only females responded to JHIII with release of trans-verbenol. Accumulation of verbenyl esters at earlier life stages may allow adult females to release the aggregation pheromone trans-verbenol upon landing on a new host tree, independent of access to α-pinene. Formation of verbenyl esters may be part of a general detoxification system to overcome host monoterpene defenses in both sexes, from which a specialized and female-specific system of pheromone biosynthesis and release may have evolved.

scholarly journals Bark beetles locate fungal symbionts by detecting volatile fungal metabolites of host tree resin monoterpenes

2021 ◽  
Author(s):  
Dinesh Kandasamy ◽  
Rashaduz Zaman ◽  
Yoko Nakamura ◽  
Tao Zhao ◽  
Henrik Hartmann ◽  
...  
Keyword(s):  
Bark Beetles ◽  
De Novo ◽  
Host Tree ◽  
Bornyl Acetate ◽  
Conifer Forest ◽  
Mature Trees ◽  
Breeding Sites ◽  
Spruce Bark ◽  
Short Period

Outbreaks of bark beetles have decimated millions of hectares of conifer forest worldwide in recent years. The ability of these tiny 3-6 mm long insects to kill mature trees over a short period has been ascribed to two factors: (1) mass attacks on the host tree to overcome tree defenses and (2) the presence of fungal symbionts that support successful beetle development in the tree. While the role of pheromones in coordinating mass attacks has been well studied, the role of chemical communication in maintaining the fungal symbiosis is poorly understood. We previously demonstrated that Eurasian spruce bark beetles (Ips typographus) can recognize beneficial fungal symbionts of the genera Grosmannia, Endoconidiophora and Ophiostoma by their de novo synthesized volatile compounds. We hypothesized that the fungal symbionts of the bark beetles might metabolize spruce resin monoterpenes of the beetle host tree, Norway spruce (Picea abies), and that the volatile products could be used as cues by beetles for locating breeding sites with beneficial symbionts. Grosmannia penicillata and other fungal symbionts altered the profile of spruce bark volatiles by converting the major monoterpenes to oxygenated derivatives. Bornyl acetate was metabolized to camphor, and α- and β-pinene to trans-4-thujanol and other oxygenated products. Extensive electrophysiological measurements showed that bark beetles possess olfactory sensory neurons that are selective for these oxygenated symbiont metabolites. Compounds such as camphor and trans-4-thujanol attracted beetles at specific doses in olfactory experiments and stimulated the response of female beetles to a mixture of pheromones. Finally, the fungal symbiont was found to stimulate bark beetle tunneling on diets. Collectively, our results show that oxygenated metabolites of conifer monoterpenes produced by fungal symbionts are used by bark beetles as cues to find these essential microbial symbionts. The oxygenated metabolites may aid beetles in assessing the presence of the fungus, the defense status of the host tree and the density of conspecifics at potential feeding and breeding sites.

Endocrine regulation of de novo aggregation pheromone biosynthesis in the pine engraver, Ips pini (Say) (Coleoptera: Scolytidae)

1998 ◽  
Vol 28 (9) ◽  
pp. 705-715 ◽  
Author(s):  
Julie A. Tillman ◽  
Glenn L. Holbrook ◽  
Paul L. Dallara ◽  
Coby Schal ◽  
David L. Wood ◽  
...  
Keyword(s):  
Aggregation Pheromone ◽  
De Novo ◽  
Ips Pini ◽  
Pheromone Biosynthesis ◽  
Endocrine Regulation ◽  
Pine Engraver

SURVIVAL AND DEVELOPMENT OF IPS PARACONFUSUS LANIER (COLEOPTERA: SCOLYTIDAE) REARED AXENICALLY AND WITH TREE-PATHOGENIC FUNGI VECTORED BY COHABITING DENDROCTONUS SPECIES

1992 ◽  
Vol 124 (6) ◽  
pp. 1157-1167 ◽  
Author(s):  
J.W. Fox ◽  
D.L. Wood ◽  
R.P. Akers ◽  
J.R. Parmeter
Keyword(s):  
Pinus Ponderosa ◽  
Ponderosa Pine ◽  
Bark Beetles ◽  
Pathogenic Fungi ◽  
Developmental Rate ◽  
Ips Paraconfusus ◽  
Dendroctonus Brevicomis ◽  
Survival And Development ◽  
New Association ◽  
Leptographium Terebrantis

AbstractSurvival and development of Ips paraconfusus Lanier larvae reared individually in intact Pinus ponderosa Laws. phloem without associated fungi and dietary supplements was demonstrated. Survival was reduced.in intact ponderosa pine phloem previously occupied by other larvae or by bluestaining fungi [i.e. Ophiostoma ips (Rumb.) vectored by I. paraconfusus, O. minus (Hedge.) H. & P. Syd. vectored by Dendroctonus brevicomis LeConte, O. clavigerum (Robins.-Jeff. & Davids.) vectored by D. ponderosae Hopkins, and Leptographium terebrantis Barras & Perry vectored by D. valens LeConte] compared with those reared without fungi or symbiotic yeasts. The highest proportion of larvae initiating tunnels and surviving to adult was observed for untreated eggs, and the lowest proportion occurred in the L. terebrantis treatment. Size was reduced and developmental rate was slower for larvae reared without fungi compared with larvae reared with associated fungi.Tunnels excavated by first- and second-instar larvae reared without associated fungi were longer than those excavated by larvae reared with associated fungi. The most frequent larval turnabouts occurred with larvae reared axenically and reared with Ips yeast and O. ips. The fewest occurred with larvae reared with Ips egg niche plugs and from untreated eggs. Females reared free of any fungi or with Penicillium or Aspergillus did not oviposit in surface-sterilized ponderosa pine logs. Naturally eclosed females from ponderosa pine logs in which they developed, laid eggs in these sterilized logs. Potential for a new association among bark beetles and fungi is discussed.

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