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Terpene synthases and their contribution to herbivore-induced volatile emission in western balsam poplar (Populus trichocarpa).

Irmisch S, Jiang Y, Chen F, Gershenzon J, Köllner TG - BMC Plant Biol. (2014)

Bottom Line: Gypsy moth-feeding on individual leaves of P. trichocarpa trees resulted in induced volatile emission from damaged leaves, but not from undamaged adjacent leaves.Our data indicate that the formation of herbivore-induced volatile terpenes in P. trichocarpa is mainly regulated by transcript accumulation of multiple TPS genes and is likely mediated by jasmonates.The specific local emission of volatiles from herbivore-damaged leaves might help herbivore enemies to find their hosts or prey in the tree canopy.

View Article: PubMed Central - PubMed

Affiliation: Max Planck Institute for Chemical Ecology, Hans-Knöll-Strasse 8, Jena, Germany. koellner@ice.mpg.de.

ABSTRACT

Background: As a response to caterpillar feeding, poplar releases a complex mixture of volatiles which comprises several classes of compounds. Poplar volatiles have been reported to function as signals in plant-insect interactions and intra- and inter-plant communication. Although the volatile blend is dominated by mono- and sesquiterpenes, there is much to be learned about their formation in poplar.

Results: Here we report the terpene synthase (TPS) gene family of western balsam poplar (Populus trichocarpa) consisting of 38 members. Eleven TPS genes (PtTPS5-15) could be isolated from gypsy moth (Lymantria dispar)-damaged P. trichocarpa leaves and heterologous expression in Escherichia coli revealed TPS activity for ten of the encoded enzymes. Analysis of TPS transcript abundance in herbivore-damaged leaves and undamaged control leaves showed that seven of the genes, PtTPS6, PtTPS7, PtTPS9, PtTPS10, PtTPS12, PtTPS13 and PtTPS15, were significantly upregulated after herbivory. Gypsy moth-feeding on individual leaves of P. trichocarpa trees resulted in induced volatile emission from damaged leaves, but not from undamaged adjacent leaves. Moreover, the concentration of jasmonic acid and its isoleucine conjugates as well as PtTPS6 gene expression were exclusively increased in the damaged leaves, suggesting that no systemic induction occurred within the tree.

Conclusions: Our data indicate that the formation of herbivore-induced volatile terpenes in P. trichocarpa is mainly regulated by transcript accumulation of multiple TPS genes and is likely mediated by jasmonates. The specific local emission of volatiles from herbivore-damaged leaves might help herbivore enemies to find their hosts or prey in the tree canopy.

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GC-MS analysis of sesquiterpenes(A),monoterpenes and diterpenes(B)produced by recombinant PtTPS5,PtTPS6,PtTPS7,PtTPS9,PtTPS10,PtTPS11,PtTPS12,PtTPS13 and PtTPS15. The enzymes were expressed in E. coli, extracted, partially purified, and incubated with the substrates FPP, GPP and GGPP. Products were collected with a solid-phase microextraction (SPME) fiber and analyzed by GC-MS. 1, elemol; 2, β-eudesmol*; 3, unidentified sesquiterpene alcohol; 4, (E)-β-caryophyllene*; 5, α-humulene*; 6, β-elemene*; 7, eremophilene; 8, α-selinene*; 9, unidentified sesquiterpene; 10, γ-curcumene*; 11, nerolidol*; 12, (E)-β-ocimene*; 13, myrcene*; 14, limonene*; 15, terpinolene*; 16, linalool*; 17, sabinene*; 18, 1,8-cineole*; 19, terpineol*; 20, geranyllinalool*; cont., contamination. Compounds marked with * were identified using authentic standards.
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Fig2: GC-MS analysis of sesquiterpenes(A),monoterpenes and diterpenes(B)produced by recombinant PtTPS5,PtTPS6,PtTPS7,PtTPS9,PtTPS10,PtTPS11,PtTPS12,PtTPS13 and PtTPS15. The enzymes were expressed in E. coli, extracted, partially purified, and incubated with the substrates FPP, GPP and GGPP. Products were collected with a solid-phase microextraction (SPME) fiber and analyzed by GC-MS. 1, elemol; 2, β-eudesmol*; 3, unidentified sesquiterpene alcohol; 4, (E)-β-caryophyllene*; 5, α-humulene*; 6, β-elemene*; 7, eremophilene; 8, α-selinene*; 9, unidentified sesquiterpene; 10, γ-curcumene*; 11, nerolidol*; 12, (E)-β-ocimene*; 13, myrcene*; 14, limonene*; 15, terpinolene*; 16, linalool*; 17, sabinene*; 18, 1,8-cineole*; 19, terpineol*; 20, geranyllinalool*; cont., contamination. Compounds marked with * were identified using authentic standards.

Mentions: All putative MTS (PtTPS6, PtTPS12, PtTPS13 and PtTPS15) accepted GPP as substrate and produced monoterpenes (Figure 2B). PtTPS6 formed (E)-β-ocimene as the major product with minor amounts of (Z)-β-ocimene. A similar narrow product specificity could also be observed for PtTPS15, which produced only linalool, and PtTPS12 which formed linalool and trace amounts of β-phellandrene, (E)-β-ocimene and α-terpinolene. However, PtTPS13 made five monoterpenes including α-pinene, β-pinene, sabinene, 1,8-cineole and α-terpineol. The incubation of PtTPS6 and PtTPS13 with FPP revealed no product formation. In contrast, PtTPS12 showed a broad sesquiterpene product spectrum and produced at least 25 different sesquiterpenes with γ-curcumene being the major one, and PtTPS15 was able to convert FPP to nerolidol (Figure 2A).Figure 2


Terpene synthases and their contribution to herbivore-induced volatile emission in western balsam poplar (Populus trichocarpa).

Irmisch S, Jiang Y, Chen F, Gershenzon J, Köllner TG - BMC Plant Biol. (2014)

GC-MS analysis of sesquiterpenes(A),monoterpenes and diterpenes(B)produced by recombinant PtTPS5,PtTPS6,PtTPS7,PtTPS9,PtTPS10,PtTPS11,PtTPS12,PtTPS13 and PtTPS15. The enzymes were expressed in E. coli, extracted, partially purified, and incubated with the substrates FPP, GPP and GGPP. Products were collected with a solid-phase microextraction (SPME) fiber and analyzed by GC-MS. 1, elemol; 2, β-eudesmol*; 3, unidentified sesquiterpene alcohol; 4, (E)-β-caryophyllene*; 5, α-humulene*; 6, β-elemene*; 7, eremophilene; 8, α-selinene*; 9, unidentified sesquiterpene; 10, γ-curcumene*; 11, nerolidol*; 12, (E)-β-ocimene*; 13, myrcene*; 14, limonene*; 15, terpinolene*; 16, linalool*; 17, sabinene*; 18, 1,8-cineole*; 19, terpineol*; 20, geranyllinalool*; cont., contamination. Compounds marked with * were identified using authentic standards.
© Copyright Policy - open-access
Related In: Results  -  Collection

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Fig2: GC-MS analysis of sesquiterpenes(A),monoterpenes and diterpenes(B)produced by recombinant PtTPS5,PtTPS6,PtTPS7,PtTPS9,PtTPS10,PtTPS11,PtTPS12,PtTPS13 and PtTPS15. The enzymes were expressed in E. coli, extracted, partially purified, and incubated with the substrates FPP, GPP and GGPP. Products were collected with a solid-phase microextraction (SPME) fiber and analyzed by GC-MS. 1, elemol; 2, β-eudesmol*; 3, unidentified sesquiterpene alcohol; 4, (E)-β-caryophyllene*; 5, α-humulene*; 6, β-elemene*; 7, eremophilene; 8, α-selinene*; 9, unidentified sesquiterpene; 10, γ-curcumene*; 11, nerolidol*; 12, (E)-β-ocimene*; 13, myrcene*; 14, limonene*; 15, terpinolene*; 16, linalool*; 17, sabinene*; 18, 1,8-cineole*; 19, terpineol*; 20, geranyllinalool*; cont., contamination. Compounds marked with * were identified using authentic standards.
Mentions: All putative MTS (PtTPS6, PtTPS12, PtTPS13 and PtTPS15) accepted GPP as substrate and produced monoterpenes (Figure 2B). PtTPS6 formed (E)-β-ocimene as the major product with minor amounts of (Z)-β-ocimene. A similar narrow product specificity could also be observed for PtTPS15, which produced only linalool, and PtTPS12 which formed linalool and trace amounts of β-phellandrene, (E)-β-ocimene and α-terpinolene. However, PtTPS13 made five monoterpenes including α-pinene, β-pinene, sabinene, 1,8-cineole and α-terpineol. The incubation of PtTPS6 and PtTPS13 with FPP revealed no product formation. In contrast, PtTPS12 showed a broad sesquiterpene product spectrum and produced at least 25 different sesquiterpenes with γ-curcumene being the major one, and PtTPS15 was able to convert FPP to nerolidol (Figure 2A).Figure 2

Bottom Line: Gypsy moth-feeding on individual leaves of P. trichocarpa trees resulted in induced volatile emission from damaged leaves, but not from undamaged adjacent leaves.Our data indicate that the formation of herbivore-induced volatile terpenes in P. trichocarpa is mainly regulated by transcript accumulation of multiple TPS genes and is likely mediated by jasmonates.The specific local emission of volatiles from herbivore-damaged leaves might help herbivore enemies to find their hosts or prey in the tree canopy.

View Article: PubMed Central - PubMed

Affiliation: Max Planck Institute for Chemical Ecology, Hans-Knöll-Strasse 8, Jena, Germany. koellner@ice.mpg.de.

ABSTRACT

Background: As a response to caterpillar feeding, poplar releases a complex mixture of volatiles which comprises several classes of compounds. Poplar volatiles have been reported to function as signals in plant-insect interactions and intra- and inter-plant communication. Although the volatile blend is dominated by mono- and sesquiterpenes, there is much to be learned about their formation in poplar.

Results: Here we report the terpene synthase (TPS) gene family of western balsam poplar (Populus trichocarpa) consisting of 38 members. Eleven TPS genes (PtTPS5-15) could be isolated from gypsy moth (Lymantria dispar)-damaged P. trichocarpa leaves and heterologous expression in Escherichia coli revealed TPS activity for ten of the encoded enzymes. Analysis of TPS transcript abundance in herbivore-damaged leaves and undamaged control leaves showed that seven of the genes, PtTPS6, PtTPS7, PtTPS9, PtTPS10, PtTPS12, PtTPS13 and PtTPS15, were significantly upregulated after herbivory. Gypsy moth-feeding on individual leaves of P. trichocarpa trees resulted in induced volatile emission from damaged leaves, but not from undamaged adjacent leaves. Moreover, the concentration of jasmonic acid and its isoleucine conjugates as well as PtTPS6 gene expression were exclusively increased in the damaged leaves, suggesting that no systemic induction occurred within the tree.

Conclusions: Our data indicate that the formation of herbivore-induced volatile terpenes in P. trichocarpa is mainly regulated by transcript accumulation of multiple TPS genes and is likely mediated by jasmonates. The specific local emission of volatiles from herbivore-damaged leaves might help herbivore enemies to find their hosts or prey in the tree canopy.

Show MeSH
Related in: MedlinePlus