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Axelsson, K., Konstanzer, V., Rajarao, G. K., Terenius, O., Seriot, L., Nordenhem, H., . . . Borg-Karlson, A.-K. (2017). Antifeedants Produced by Bacteria Associated with the Gut of the Pine Weevil Hylobius abietis. Microbial Ecology, 74(1), 177-184
Open this publication in new window or tab >>Antifeedants Produced by Bacteria Associated with the Gut of the Pine Weevil Hylobius abietis
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2017 (English)In: Microbial Ecology, ISSN 0095-3628, E-ISSN 1432-184X, Vol. 74, no 1, p. 177-184Article in journal (Refereed) Published
Abstract [en]

The pine weevil, Hylobius abietis, is a severe forest pest insect as it feeds on newly planted conifer seedlings. To identify and develop an antifeedant could be one step towards the protection of seedlings from feeding damage by the pine weevil. With the aim to trace the origin of the antifeedants previously found in feces of the pine weevil, we investigated the culturable bacteria associated with the gut and identified the volatiles they produced. Bacterial isolates were identified by 16S ribosomal RNA gene analysis. The volatile emissions of selected bacteria, cultivated on NB media or on the grated phloem of Scots pine twigs dispersed in water, were collected and analyzed by solid-phase microextraction gas chromatography-mass spectrometry. The bacterial isolates released a variety of compounds, among others 2-methoxyphenol, 2-phenylethanol, 3-methyl-1-butanol, 1-octen-3-ol, 3-octanone, dimethyl disulfide, and dimethyl trisulfide. A strong antifeedant effect was observed by 2-phenylethanol, which could thus be a good candidate for use to protect planted conifer seedlings against feeding damage caused by H. abietis.

Place, publisher, year, edition, pages
SPRINGER, 2017
Keywords
Hylobius abietis, Rahnella, Brevundimonas, 2-Methoxyphenol, 2-Phenylethanol, Antifeedant
National Category
Water Treatment Microbiology
Identifiers
urn:nbn:se:kth:diva-210344 (URN)10.1007/s00248-016-0915-5 (DOI)000403255500017 ()2-s2.0-85009191802 (Scopus ID)
Note

QC 20170704

Available from: 2017-07-04 Created: 2017-07-04 Last updated: 2017-07-04Bibliographically approved
Axelsson, K. (2016). Chemical signals in interactions between Hylobius abietis and associated bacteria. (Doctoral dissertation). Stockholm: Kungliga tekniska högskolan
Open this publication in new window or tab >>Chemical signals in interactions between Hylobius abietis and associated bacteria
2016 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The pine weevil (Hylobius abietis L.) is one of the two topmost economically important insect pests in Swedish conifer forests. The damage increase in areas were the silvicultural practice is to use clear cuttings were the insects gather and breed. During egglaying the female protects her offspring by creating a cave in roots and stumps were she puts her egg and covers it with frass, a mixture of weevil feces and chewed bark. Adult pine weevils have been observed to feed on the other side of the egg laying site and antifeedant substance has been discovered in the feces of the pine weevil. We think it is possible that microorganisms present in the frass contribute with antifeedant/repellent substances. Little is known about the pine weevils associated bacteria community and their symbiotic functions. In this thesis the bacterial community is characterized in gut and frass both from pine weevils in different populations across Europe as well as after a 28 day long diet regime on Scots pine, silver birch or bilberry. Volatile substances produced by isolated bacteria as well as from a consortium of microorganisms were collected with solid phase micro extraction (SPME) and analyzed with GC-MS. The main volatiles were tested against pine weevils using a two-choice test. Wolbachia, Rahnella aquatilis, Serratia and Pseudomonas syringae was commonly associated with the pine weevil. 2-Methoxyphenol, 2-phenylethanol, 3-methyl-1-butanol were found in the headspace from Rahnella aquatilis when grown in substrate containing pine bark. 2-Methoxyphenol and 3-methyl-1-butanol, phenol and methyl salicylate were found in pine feces. Birch and bilberry feces emitted mainly linalool oxides and bilberry emitted also small amounts of 2-phenylethanol.

A second part of the thesis discusses the role of fungi in forest insect interactions and the production of oxygenated monoterpenes as possible antifeedants. Spruce bark beetles (Ips typhographus L.) aggregate with the help of pheromones and with collected forces they kill weakened adult trees as a result of associated fungi growth and larval development. A fungi associated with the bark beetle, Grosmannia europhoides, was shown to produce de novo 2-methyl-3-buten-2-ol, the major component of the spruce bark beetle aggregation pheromone. Chemical defense responses against Endoconidiophora polonica and Heterobasidion parviporum were investigated using four clones of Norway spruce with different susceptibility to Heterobasidion sp. Clone specific differences were found in induced mono-, sesqui and diterpenes. A number of oxygenated monoterpenes which are known antifeedants for the pine weevil were produced in the infested areas.

Place, publisher, year, edition, pages
Stockholm: Kungliga tekniska högskolan, 2016. p. 51
Series
TRITA-CHE-Report, ISSN 1654-1081 ; 21
Keywords
Pine weevil, Hylobius, Rahnella, Pseudomonas, bacteria, fungi, metabolites, 2-methoxyphenol, 2-phenylethanol
National Category
Analytical Chemistry Ecology Microbiology Biochemistry and Molecular Biology Organic Chemistry
Research subject
Chemistry
Identifiers
urn:nbn:se:kth:diva-187817 (URN)978-91-7595-972-6 (ISBN)
Public defence
2016-06-15, F3, Lindstedtvägen 26, Stockholm, 12:00 (English)
Opponent
Supervisors
Funder
Swedish Research Council FormasSwedish Foundation for Strategic Research
Note

QC 20160601

Available from: 2016-05-30 Created: 2016-05-30 Last updated: 2016-06-01Bibliographically approved
Axelsson, K., Zendegi-Shiraz, A., Swedjemark, G., Borg-Karlson, A.-K. & Zhao, T. (2016). Clone specific chemical defense responses in Norway spruce to infestations by two pathogenic fungi. Forest Pathology
Open this publication in new window or tab >>Clone specific chemical defense responses in Norway spruce to infestations by two pathogenic fungi
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2016 (English)In: Forest Pathology, ISSN 1437-4781, E-ISSN 1439-0329Article in journal (Other academic) Submitted
Abstract [en]

Heterobasidion parviporum (Hp) were investigated using four clones of Norway spruce (Picea abies) with different susceptibility to Heterobasidion sp. Eight year old trees were inoculated with Ep and Hp to minimize the variation due to environment. After three weeks the bark tissue at the upper border of the inoculation hole were extracted with hexane and analyzed by GC-MS. Both treatment and clonal differences were found based on induced mono-, sesqui- and diterpenes. In addition, the Hp produced toxin, fomanoxin, was identified in lowest amount in the most Hp susceptible clone. The clonal trees seem to use different defense strategies towards the two fungi. One of the clones was able to induce strong chemical defense against both fungi, one clone induced chemical defense only against Ep and the most susceptible clone exhibited the least capacity to produce an effective defense against Ep and Hp. Two diterpenes were found to be distinctly different between clones with different susceptibilities, which can be used as chemical indication of Norway spruce resistance against fungi.

Place, publisher, year, edition, pages
Wiley-Blackwell, 2016
Keywords
Endoconidiophora polonica, Ceratocystis, Heterobasidion parviporum, Picea abies, clone, induced response, terpenes
National Category
Ecology Organic Chemistry
Identifiers
urn:nbn:se:kth:diva-187876 (URN)
Note

QC 20160531

Available from: 2016-05-30 Created: 2016-05-30 Last updated: 2017-11-30Bibliographically approved
Berasategui, A., Axelsson, K., Nordlander, G., Schmidt, A., Borg-Karlson, A.-K., Gershenzon, J., . . . Kaltenpoth, M. (2016). The Gut microbiota of the pine weevil is similar across Europe and resembles that of other conifer-feeding beetles. Molecular Ecology, 25(16), 4014-4031
Open this publication in new window or tab >>The Gut microbiota of the pine weevil is similar across Europe and resembles that of other conifer-feeding beetles
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2016 (English)In: Molecular Ecology, ISSN 0962-1083, E-ISSN 1365-294X, Vol. 25, no 16, p. 4014-4031Article in journal (Refereed) Published
Abstract [en]

The pine weevil (Hylobius abietis, Coleoptera: Curculionidae) is an important pest of conifer seedlings in Europe. Despite its economic importance, little is known about the composition of its gut microbial community and the role it plays in mediating the weevil's ability to utilize conifers as a food source. Here, we characterized the gut bacterial communities of different populations of H. abietis across Europe and compared them to those of other beetles that occupy similar ecological niches. We demonstrate that the microbial community of H. abietis is similar at higher taxonomic levels (family and genus) across locations in Europe, with Wolbachia as the dominant microbe, followed by Enterobacteria and Firmicutes. Despite this similarity, we observed consistent differences between countries and locations, but not sexes. Our meta-analysis demonstrates that the gut bacterial community of the pine weevil is very similar to that of bark beetles that also exploit conifers as a food source. The Enterobacteriaceae symbionts of both host taxa are especially closely related phylogenetically. Conversely, the microbiota of H. abietis is distinct from that of closely related weevils feeding on non-conifer food sources, suggesting that the microbial community of the pine weevil is determined by the environment and may be relevant to host ecology. Furthermore, several H. abietis-associated members of the Enterobacteriaceae family are known to contain genes involved in terpenoid degradation. As such, we hypothesize that the gut microbial community is important for the utilization of conifer seedlings as a food source, either through the detoxification of plant secondary metabolites or supplementation of essential nutrients.

Place, publisher, year, edition, pages
Wiley-Blackwell, 2016
Keywords
Hylobius abietis, conifer, terpenes, insect symbiosis, bark beetle, microbiota
National Category
Microbiology Ecology
Research subject
Chemistry
Identifiers
urn:nbn:se:kth:diva-187816 (URN)10.1111/mec.13702 (DOI)000381578200017 ()2-s2.0-84981710086 (Scopus ID)
Note

QC 20160530

Available from: 2016-05-30 Created: 2016-05-30 Last updated: 2017-11-30Bibliographically approved
Zhao, T., Axelsson, K., Krokene, P. & Borg-Karlson, A.-K. (2015). Fungal Symbionts of the Spruce Bark Beetle Synthesize the Beetle Aggregation Pheromone 2-Methyl-3-buten-2-ol. Journal of Chemical Ecology
Open this publication in new window or tab >>Fungal Symbionts of the Spruce Bark Beetle Synthesize the Beetle Aggregation Pheromone 2-Methyl-3-buten-2-ol
2015 (English)In: Journal of Chemical Ecology, ISSN 0098-0331, E-ISSN 1573-1561Article in journal (Refereed) Published
Abstract [en]

Tree-killing bark beetles depend on aggregation pheromones to mass-attack their host trees and overwhelm their resistance. The beetles are always associated with phytopathogenic ophiostomatoid fungi that probably assist in breaking down tree resistance, but little is known about if or how much these fungal symbionts contribute to the beetles’ aggregation behavior. In this study, we determined the ability of four major fungal symbionts of the spruce bark beetle Ips typographus to produce beetle aggregation pheromones. The fungi were incubated on Norway spruce Picea abies bark, malt agar, or malt agar amended with 0.5 % 13C glucose. Volatiles present in the headspace of each fungus were analyzed for 7 days after incubation using a SPME autosampler coupled to a GC/MS. Two Grosmannia species (G. penicillata and G. europhioides) produced large amounts of 2-methyl-3-buten-2-ol (MB), the major component in the beetles’ aggregation pheromone blend, when growing on spruce bark or malt agar. Grosmannia europhioides also incorporated 13C glucose into MB, demonstrating that the fungi can synthesize MB de novo using glucose as a carbon source. This is the first clear evidence that fungal symbionts of bark beetles can produce components in the aggregation pheromone blend of their beetle vectors. This provides new insight into the possible ecological roles of fungal symbionts in bark beetle systems and may deepen our understanding of species interactions and coevolution in these important biological systems.

Place, publisher, year, edition, pages
Springer Publishing Company, 2015
Keywords
Bluestain fungi, Plant-insect-microbe interactions, Scolytinae
National Category
Chemical Sciences
Identifiers
urn:nbn:se:kth:diva-175003 (URN)10.1007/s10886-015-0617-3 (DOI)000362333400008 ()2-s2.0-84943200209 (Scopus ID)
Funder
Swedish Research Council Formas, 229-2011-890
Note

QC 20151130

Available from: 2015-11-30 Created: 2015-10-09 Last updated: 2017-12-01Bibliographically approved
Axelsson, K., Konstanzer, V., Kuttuva Rajarao, G., Terenius, O., Seriot, L., Nordenhem, H., . . . Borg-Karlson, A.-K.Antifeedants produced by bacteria associated to the gut of the pine weevil (Hylobius abietis).
Open this publication in new window or tab >>Antifeedants produced by bacteria associated to the gut of the pine weevil (Hylobius abietis)
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(English)Manuscript (preprint) (Other academic)
National Category
Organic Chemistry
Research subject
Chemistry
Identifiers
urn:nbn:se:kth:diva-187874 (URN)
Note

QCR 20150531

Available from: 2016-05-30 Created: 2016-05-30 Last updated: 2016-05-31Bibliographically approved
Axelsson, K., Nilsson, L., Nordlander, G., Borg-Karlson, A.-K. & Terenius, O.Do pine weevil microbiota and corresponding volatiles change due to selective feeding?.
Open this publication in new window or tab >>Do pine weevil microbiota and corresponding volatiles change due to selective feeding?
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(English)Manuscript (preprint) (Other academic)
National Category
Organic Chemistry Ecology
Identifiers
urn:nbn:se:kth:diva-187875 (URN)
Note

QC 20160531

Available from: 2016-05-30 Created: 2016-05-30 Last updated: 2016-06-01Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0003-4970-8352

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