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Characterization and expression profiling of glutathione S-transferases in the diamondback moth, Plutella xylostella (L.).

You Y, Xie M, Ren N, Cheng X, Li J, Ma X, Zou M, Vasseur L, Gurr GM, You M - BMC Genomics (2015)

Bottom Line: Delta, Epsilon and Omega GSTs were numerically superior with 5 genes for each of the subclasses.The resulting phylogenetic tree showed that the P. xylostella GSTs were all clustered into Lepidoptera-specific branches.The diversified features and expression patterns of the GSTs are inferred to be associated with the capacity of this species to develop resistance to a wide range of pesticides and biological toxins.

View Article: PubMed Central - PubMed

Affiliation: Institute of Applied Ecology and Research Centre for Biodiversity and Eco-Safety, Fujian Agriculture and Forestry University, Fuzhou, 350002, China. fzyouyc@gmail.com.

ABSTRACT

Background: Glutathione S-transferases (GSTs) are multifunctional detoxification enzymes that play important roles in insects. The completion of several insect genome projects has enabled the identification and characterization of GST genes over recent years. This study presents a genome-wide investigation of the diamondback moth (DBM), Plutella xylostella, a species in which the GSTs are of special importance because this pest is highly resistant to many insecticides.

Results: A total of 22 putative cytosolic GSTs were identified from a published P. xylostella genome and grouped into 6 subclasses (with two unclassified). Delta, Epsilon and Omega GSTs were numerically superior with 5 genes for each of the subclasses. The resulting phylogenetic tree showed that the P. xylostella GSTs were all clustered into Lepidoptera-specific branches. Intron sites and phases as well as GSH binding sites were strongly conserved within each of the subclasses in the GSTs of P. xylostella. Transcriptome-, RNA-seq- and qRT-PCR-based analyses showed that the GST genes were developmental stage- and strain-specifically expressed. Most of the highly expressed genes in insecticide resistant strains were also predominantly expressed in the Malpighian tubules, midgut or epidermis.

Conclusions: To date, this is the most comprehensive study on genome-wide identification, characterization and expression profiling of the GST family in P. xylostella. The diversified features and expression patterns of the GSTs are inferred to be associated with the capacity of this species to develop resistance to a wide range of pesticides and biological toxins. Our findings provide a base for functional research on specific GST genes, a better understanding of the evolution of insecticide resistance, and strategies for more sustainable management of the pest.

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Related in: MedlinePlus

Expression profiling of selected preferentially expressed PxGSTs at larval (A) and adult (B) stages based on qRT-PCR. 1st (L): first instar larva; 2nd (L): second instar larva; 3rd (L): third instar larva; 4th (L): fourth instar larva.
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Fig5: Expression profiling of selected preferentially expressed PxGSTs at larval (A) and adult (B) stages based on qRT-PCR. 1st (L): first instar larva; 2nd (L): second instar larva; 3rd (L): third instar larva; 4th (L): fourth instar larva.

Mentions: Expression profiling with qRT-PCR confirmed that the 22 PxGSTs genes could express at different developmental stages, but exhibited stage-specific patterns. Six genes were predominantly expressed at the larval stage, exhibiting the same patterns based on RPKM value (Figure 4) and qRT-PCR (Figure 5A), which suggests that they might be associated with detoxification of plant defense compounds and insecticides [34,46]. The insect-specific Delta and Epsilon GSTs showed high expression in P. xylostella (Figure 5A), while most of these GSTs had little or no expression in the main detoxification organ (fat body) of domesticated B. mori with little exposure to insecticides for thousands years [28], suggesting that these genes are associated with the evolution of insecticide resistance as proposed in previous reports [34,45]. PxGSTd1, PxGSTe1, PxGSTe5 and PxGSTo3 were highly expressed in the P. xylostella adults (Figure 5B), suggesting that these genes may be involved in odorant processing and/or xenobiotic metabolism [22]. Most of the PxGSTs exhibited low gene expression at the egg stage (Figure 5). Such diversified expression patterns of the PxGSTs imply that GSTs may have multiple functions in P. xylostella, as documented in other insects [34,47,48].Figure 5


Characterization and expression profiling of glutathione S-transferases in the diamondback moth, Plutella xylostella (L.).

You Y, Xie M, Ren N, Cheng X, Li J, Ma X, Zou M, Vasseur L, Gurr GM, You M - BMC Genomics (2015)

Expression profiling of selected preferentially expressed PxGSTs at larval (A) and adult (B) stages based on qRT-PCR. 1st (L): first instar larva; 2nd (L): second instar larva; 3rd (L): third instar larva; 4th (L): fourth instar larva.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4358871&req=5

Fig5: Expression profiling of selected preferentially expressed PxGSTs at larval (A) and adult (B) stages based on qRT-PCR. 1st (L): first instar larva; 2nd (L): second instar larva; 3rd (L): third instar larva; 4th (L): fourth instar larva.
Mentions: Expression profiling with qRT-PCR confirmed that the 22 PxGSTs genes could express at different developmental stages, but exhibited stage-specific patterns. Six genes were predominantly expressed at the larval stage, exhibiting the same patterns based on RPKM value (Figure 4) and qRT-PCR (Figure 5A), which suggests that they might be associated with detoxification of plant defense compounds and insecticides [34,46]. The insect-specific Delta and Epsilon GSTs showed high expression in P. xylostella (Figure 5A), while most of these GSTs had little or no expression in the main detoxification organ (fat body) of domesticated B. mori with little exposure to insecticides for thousands years [28], suggesting that these genes are associated with the evolution of insecticide resistance as proposed in previous reports [34,45]. PxGSTd1, PxGSTe1, PxGSTe5 and PxGSTo3 were highly expressed in the P. xylostella adults (Figure 5B), suggesting that these genes may be involved in odorant processing and/or xenobiotic metabolism [22]. Most of the PxGSTs exhibited low gene expression at the egg stage (Figure 5). Such diversified expression patterns of the PxGSTs imply that GSTs may have multiple functions in P. xylostella, as documented in other insects [34,47,48].Figure 5

Bottom Line: Delta, Epsilon and Omega GSTs were numerically superior with 5 genes for each of the subclasses.The resulting phylogenetic tree showed that the P. xylostella GSTs were all clustered into Lepidoptera-specific branches.The diversified features and expression patterns of the GSTs are inferred to be associated with the capacity of this species to develop resistance to a wide range of pesticides and biological toxins.

View Article: PubMed Central - PubMed

Affiliation: Institute of Applied Ecology and Research Centre for Biodiversity and Eco-Safety, Fujian Agriculture and Forestry University, Fuzhou, 350002, China. fzyouyc@gmail.com.

ABSTRACT

Background: Glutathione S-transferases (GSTs) are multifunctional detoxification enzymes that play important roles in insects. The completion of several insect genome projects has enabled the identification and characterization of GST genes over recent years. This study presents a genome-wide investigation of the diamondback moth (DBM), Plutella xylostella, a species in which the GSTs are of special importance because this pest is highly resistant to many insecticides.

Results: A total of 22 putative cytosolic GSTs were identified from a published P. xylostella genome and grouped into 6 subclasses (with two unclassified). Delta, Epsilon and Omega GSTs were numerically superior with 5 genes for each of the subclasses. The resulting phylogenetic tree showed that the P. xylostella GSTs were all clustered into Lepidoptera-specific branches. Intron sites and phases as well as GSH binding sites were strongly conserved within each of the subclasses in the GSTs of P. xylostella. Transcriptome-, RNA-seq- and qRT-PCR-based analyses showed that the GST genes were developmental stage- and strain-specifically expressed. Most of the highly expressed genes in insecticide resistant strains were also predominantly expressed in the Malpighian tubules, midgut or epidermis.

Conclusions: To date, this is the most comprehensive study on genome-wide identification, characterization and expression profiling of the GST family in P. xylostella. The diversified features and expression patterns of the GSTs are inferred to be associated with the capacity of this species to develop resistance to a wide range of pesticides and biological toxins. Our findings provide a base for functional research on specific GST genes, a better understanding of the evolution of insecticide resistance, and strategies for more sustainable management of the pest.

Show MeSH
Related in: MedlinePlus