title: Phenoloxidase and its zymogen are required for the larval-pupal transition in Bactrocera dorsalis (Diptera: Tephritidae).
abstract: Phenoloxidases (POs) play a key role in melanin production, are involved in invertebrate immune mechanisms, and are considered important enzymes in the insect development process. In the present study, we report the developmental stage and tissue-specific expression patterns of BdPPO1 and PO activity from Bactrocera dorsalis. The results showed that the activity of PO and its zymogen expression were closely related to the development of B. dorsalis during the larval-pupal transition, particularly in the integument. Additionally, biochemical characterization showed that PO from different developmental stages and tissues all had maximum activity at pH 7.5 and 37°C. After feeding a metal ion-containing artificial diet, the activity of PO and expression of BdPPO1 were significantly increased, indicating that PO was a metalloprotein and it could be activated by Zn2+, Mg2+, Ca2+, and Cu2+. The functional analysis showed that the expression of BdPPO1 could be regulated by 20-hydroxyecdysone (20E) after injection. Furthermore, injection of the double-stranded RNA of BdPPO1 into the 3rd instar larvae significantly reduced mRNA levels after 24 h and 48 h, and resulted in a lower pupation rate and abnormal phenotype. These results expand the understanding of the important role of PO and its zymogen in the growth of B. dorsalis.
authors.affiliation: Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing 400716, PR China.
authors.forename: Ping-Ping
authors.initials: PP
authors.lastname: Bai
authors.affiliation: Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing 400716, PR China.
authors.forename: Yi-Fei
authors.initials: YF
authors.lastname: Xie
authors.affiliation: Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing 400716, PR China.
authors.forename: Guang-Mao
authors.initials: GM
authors.lastname: Shen
authors.affiliation: Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing 400716, PR China.
authors.forename: Dan-Dan
authors.initials: DD
authors.lastname: Wei
authors.affiliation: Key Laboratory of Entomology and Pest Control Engineering, College of Plant Protection, Southwest University, Chongqing 400716, PR China. Electronic address: jjwang7008@yahoo.com.
authors.forename: Jin-Jun
authors.initials: JJ
authors.lastname: Wang
mesh_terms: D000818:Animals; D004156:Catechol Oxidase / Q000235:genetics* / Q000378:metabolism; D004792:Enzyme Precursors / Q000235:genetics* / Q000378:metabolism; D005786:Gene Expression Regulation; D019476:Insect Proteins / Q000235:genetics* / Q000378:metabolism; D007814:Larva / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D018978:Molting; D014442:Monophenol Monooxygenase / Q000235:genetics* / Q000378:metabolism; D011679:Pupa / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D034622:RNA Interference; D033621:Tephritidae / Q000201:enzymology / Q000235:genetics* / Q000254:growth & development* / Q000378:metabolism
chemical_list: D004792:Enzyme Precursors; D019476:Insect Proteins; C038451:pro-phenoloxidase; D004156:Catechol Oxidase; D014442:Monophenol Monooxygenase
keywords: Bactrocera dorsalis; Metal ions; Phenoloxidase; Prophenoloxidase; RNA interference