title: Overexpression of Tyrosine hydroxylase and Dopa decarboxylase associated with pupal melanization in Spodoptera exigua.
abstract: Melanism has been found in a wide range of species, but the molecular mechanisms involved remain largely elusive. In this study, we studied the molecular mechanisms of the pupal melanism in Spodoptera exigua. The full length cDNA sequences of tyrosine hydroxylase (TH) and dopa decarboxylase (DDC), two key enzymes in the biosynthesis pathway of melanin, were cloned, and their temporal expression patterns in the integument were compared during the larval-pupal metamorphosis process of the S. exigua wild type (SEW) and melanic mutant (SEM) strains. No amino acid change in the protein sequence of TH and DDC was found between the two strains. Both DDC and TH were significantly over-expressed in the integument of the SEM strain at late-prepupa and 0 h pupa, respectively, compared with those of the SEW strain. Feeding 5(th) instar larvae of SEM with diets incorporated with 1 mg/g of the DDC inhibitor L-α-Methyl-DOPA and 0.75 mg/g of the TH inhibitor 3-iodo-tyrosine (3-IT) resulted in 20% pupae with partially-rescued phenotype and 68.2% of pupae with partially- or fully-rescued phenotype, respectively. These results indicate that overexpressions of TH and DDC are involved in the pupal melanization of S. exigua.
authors.affiliation: 1] Department of Pesticide Science, College of Plant Science &Technology, Huazhong Agricultural University, Wuhan, 430070, China [2] Department of Entomology and BIO5 Institute, University of Arizona, Tucson, AZ 85721, USA [3] Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, Institute of Insect Resources, Huazhong Agricultural University, Wuhan, 430070, China.
authors.forename: Sisi
authors.initials: S
authors.lastname: Liu
authors.affiliation: 1] Department of Pesticide Science, College of Plant Science &Technology, Huazhong Agricultural University, Wuhan, 430070, China [2] Hubei Insect Resources Utilization and Sustainable Pest Management Key Laboratory, Institute of Insect Resources, Huazhong Agricultural University, Wuhan, 430070, China.
authors.forename: Mo
authors.initials: M
authors.lastname: Wang
authors.affiliation: 1] Department of Entomology and BIO5 Institute, University of Arizona, Tucson, AZ 85721, USA [2] State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China.
authors.forename: Xianchun
authors.initials: X
authors.lastname: Li
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D018076:DNA, Complementary / Q000235:genetics / Q000378:metabolism; D004296:Dopa Decarboxylase / Q000235:genetics* / Q000378:metabolism; D015870:Gene Expression; D008543:Melanins / Q000378:metabolism*; D008969:Molecular Sequence Data; D009154:Mutation; D010641:Phenotype; D010802:Phylogeny; D010858:Pigmentation; D011485:Protein Binding; D011679:Pupa; D018411:Spodoptera / Q000235:genetics* / Q000378:metabolism*; D014446:Tyrosine 3-Monooxygenase / Q000235:genetics* / Q000378:metabolism
chemical_list: D018076:DNA, Complementary; D008543:Melanins; D014446:Tyrosine 3-Monooxygenase; D004296:Dopa Decarboxylase