title: Identification and characterisation of multiple glutathione S-transferase genes from the diamondback moth, Plutella xylostella.
abstract: BACKGROUND
  The diamondback moth (DBM), Plutella xylostella, is one of the most harmful insect pests on crucifer crops worldwide. In this study, 19 cDNAs encoding glutathione S-transferases (GSTs) were identified from the genomic and transcriptomic database for DBM (KONAGAbase) and further characterized.
  
  
  RESULTS
  Phylogenetic analysis showed that the 19 GSTs were classified into six different cytosolic classes, including four in delta, six in epsilon, three in omega, two in sigma, one in theta and one in zeta. Two GSTs were unclassified. RT-PCR analysis revealed that most GST genes were expressed in all developmental stages, with higher expression in the larval stages. Six DBM GSTs were expressed at the highest levels in the midgut tissue. Twelve purified recombinant GSTs showed varied enzymatic properties towards 1-chloro-2,4-dinitrobenzene and glutathione, whereas rPxGSTo2, rPxGSTz1 and rPxGSTu2 had no activity. Real-time quantitative PCR revealed that expression levels of the 19 DBM GST genes were varied and changed after exposure to acephate, indoxacarb, beta-cypermethrin and spinosad. PxGSTd3 was significantly overexpressed, while PxGSTe3 and PxGSTs2 were significantly downregulated by all four insecticide exposures.
  
  
  CONCLUSIONS
  The changes in DBM GST gene expression levels exposed to different insecticides indicate that they may play individual roles in tolerance to insecticides and xenobiotics.
authors.affiliation: Key Laboratory of Plant Protection Resources and Pest Management, Ministry of Education, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi, China.
authors.forename: Xi'en
authors.initials: X
authors.lastname: Chen
authors.forename: Ya-lin
authors.initials: YL
authors.lastname: Zhang
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics / Q000378:metabolism; D005982:Glutathione Transferase / Q000235:genetics* / Q000378:metabolism; D019476:Insect Proteins / Q000235:genetics* / Q000378:metabolism; D007306:Insecticides / Q000494:pharmacology*; D007814:Larva / Q000737:chemistry / Q000187:drug effects / Q000201:enzymology / Q000235:genetics; D008969:Molecular Sequence Data; D009036:Moths / Q000737:chemistry / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics*; D010063:Ovum / Q000737:chemistry / Q000187:drug effects / Q000201:enzymology; D010802:Phylogeny; D011679:Pupa / Q000737:chemistry / Q000187:drug effects / Q000201:enzymology / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D016415:Sequence Alignment
chemical_list: D018076:DNA, Complementary; D019476:Insect Proteins; D007306:Insecticides; D012333:RNA, Messenger; D005982:Glutathione Transferase
keywords: Escherichia coli expression; GSTs; Plutella xylostella; gene expression; insecticides