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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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GSH and substrate binding sites of glutathioneS-transferase genes. The short vertical lines represent functionally conserved residues of GST genes among insect species. Red vertical lines represent the GSH binding sites of GSTs (G sites) and blue vertical lines represent the substrate binding sites GSTs (H sites).
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Fig3: GSH and substrate binding sites of glutathioneS-transferase genes. The short vertical lines represent functionally conserved residues of GST genes among insect species. Red vertical lines represent the GSH binding sites of GSTs (G sites) and blue vertical lines represent the substrate binding sites GSTs (H sites).

Mentions: Most of the insect GSTs are composed of a conserved thioredoxin domain containing the GSH binding site (G-site) and a more variable α-helical domain containing the substrate binding site (H-site) [41], and can transfer GSH to a substrate by stabilization of the GSH thiolate [42]. Both G-sites and H-sites among the PxGSTs were analyzed with the NCBI CD-search program, and the results showed that the G-sites appeared fairly conserved while the H-sites were variable among different subclasses (Figure 3, Additional file 6: Table S2). The conserved G-sites indicate their important enzyme functions while the variable H-sites are related to their evolutionary divergence [43]. No G-sites were found for all the genes in Omega GSTs as well as some genes in other subclasses in P. xylostella (Figure 3). Such GSTs (without G-site) may act as intracellular ligand transporters as documented in Nilaparvata lugens and Anopheles cracens [43,44].Figure 3


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)

GSH and substrate binding sites of glutathioneS-transferase genes. The short vertical lines represent functionally conserved residues of GST genes among insect species. Red vertical lines represent the GSH binding sites of GSTs (G sites) and blue vertical lines represent the substrate binding sites GSTs (H sites).
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Fig3: GSH and substrate binding sites of glutathioneS-transferase genes. The short vertical lines represent functionally conserved residues of GST genes among insect species. Red vertical lines represent the GSH binding sites of GSTs (G sites) and blue vertical lines represent the substrate binding sites GSTs (H sites).
Mentions: Most of the insect GSTs are composed of a conserved thioredoxin domain containing the GSH binding site (G-site) and a more variable α-helical domain containing the substrate binding site (H-site) [41], and can transfer GSH to a substrate by stabilization of the GSH thiolate [42]. Both G-sites and H-sites among the PxGSTs were analyzed with the NCBI CD-search program, and the results showed that the G-sites appeared fairly conserved while the H-sites were variable among different subclasses (Figure 3, Additional file 6: Table S2). The conserved G-sites indicate their important enzyme functions while the variable H-sites are related to their evolutionary divergence [43]. No G-sites were found for all the genes in Omega GSTs as well as some genes in other subclasses in P. xylostella (Figure 3). Such GSTs (without G-site) may act as intracellular ligand transporters as documented in Nilaparvata lugens and Anopheles cracens [43,44].Figure 3

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