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Characterization of midgut trypsinogen‐like cDNA and enzymatic activity in Plutella xylostella parasitized by Cotesia vestalis or Diadegma semiclausum
Author(s) -
Shi Min,
Huang Fang,
Chen YaFeng,
Meng XiangFeng,
Chen XueXin
Publication year - 2009
Publication title -
archives of insect biochemistry and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.576
H-Index - 66
eISSN - 1520-6327
pISSN - 0739-4462
DOI - 10.1002/arch.20249
Subject(s) - biology , plutella , midgut , complementary dna , digestive enzyme , parasitoid , rapid amplification of cdna ends , biochemistry , microbiology and biotechnology , peptide sequence , open reading frame , botany , enzyme , lipase , gene , larva
Protein digestion in insects is a result of the action of a complex of proteinases present in the midgut. In this report we describe the cloning and sequencing of a trypsin cDNA from larvae of the lepidopteran herbivore Plutella xylostella . We investigated the expression of this gene and enzymatic activity of its translation product with N ‐a‐benzoyl‐l‐arginine p ‐nitroanilide (BA p NA) as substrate in P. xylostella larvae that were either unparasitized or parasitized by Cotesia vestalis or Diadegma semiclausum parasitoids. The full cDNA sequence consisted of an open reading frame (ORF) encoding 273 amino acid residues including 23 residues of a signal peptide, and the predicted mature trypsinogen‐like enzyme had a molecular mass of 26.5 kDa. The amino acid sequence of this trypsinogen‐like enzyme protein and phylogenetic relationship with other published trypsin enzyme proteins suggested that it may be a new proteinase in the trypsin protein family. Parasitism of D. semiclausum did not significantly change the mRNA transcript level or BA p NAase activity in host larvae. By contrast, parasitization by C. vestalis induced higher transcript levels coupled with a higher level of BA p NAase activity. The BA p NAase activity in the midgut of nonparasitized or parasitized P. xylostella larvae increased to a maximum level at pH 12, and the parasitism by both C. vestalis and D. semiclausum increased sensitivity of the enzyme to pH values ranging from 2 to 9.5. These parasitoid‐induced changes may represent host manipulation by the developing parasitoid larva. Arch. Insect Biochem. Physiol. 2008. © 2008 Wiley‐Liss, Inc.