title: Xenobiotic metabolism of plant secondary compounds in the English grain aphid, Sitobion avenae (F.) (Hemiptera: Aphididae).
abstract: Plant secondary compounds have been documented to be deleterious to insects and other herbivores in diverse ways. In this study, the effect of catechol (phenolics), gramine (alkaloid) and L-ornithine-HCI (non-protein amino acid) on the activities of xenobiotic metabolizing enzymes in English grain aphid, Sitobion avenae, was evaluated. Phase I enzymes investigated in this study included carboxylesterase (CarE), and oxidoreductase, whereas Phase II enzymes were represented by glutathione S-transferase (GST). In general, CarE and GST activities in S. avenae were positively correlated with the concentration of plant secondary compounds in artificial diets. Oxidoreductase activity, however, displayed a different profile. Specifically, peroxidase (POD) and polyphenol oxidase (PPO) activities in S. avenae were positively correlated with concentrations of dietary catechol and gramine, respectively, whereas catalase (CAT) activity was significantly suppressed by the higher concentration of catechol, gramine and L-ornithine-HCl. These combined results suggest that CarE and GST in S. avenae are key enzymes to breakdown a broad spectrum of plant secondary compounds, whereas oxidoreductase, including PPO and POD, degrades specific groups of plant secondary compounds.
authors.affiliation: College of Natural Resources and Environment, South China Agricultural University, Guangzhou 510642, Guangdong Province, PR China.
authors.forename: Maoxin
authors.initials: M
authors.lastname: Zhang
authors.affiliation: College of Agronomy and Biotechnology, China Agricultural University, Beijing 10094, PR China.
authors.forename: Tingting
authors.initials: T
authors.lastname: Fang
authors.affiliation: College of Agronomy and Biotechnology, China Agricultural University, Beijing 10094, PR China.
authors.forename: Guilin
authors.initials: G
authors.lastname: Pu
authors.affiliation: College of Agronomy and Biotechnology, China Agricultural University, Beijing 10094, PR China.
authors.forename: Xiaoqin
authors.initials: X
authors.lastname: Sun
authors.affiliation: Department of Entomology, S-225 Agricultural Science Center N, University of Kentucky, Lexington, KY 40546-0091, USA. Electronic address: xuguozhou@uky.edu.
authors.forename: Xuguo
authors.initials: X
authors.lastname: Zhou
authors.affiliation: College of Agronomy and Biotechnology, China Agricultural University, Beijing 10094, PR China. Electronic address: caiqn@cau.edu.cn.
authors.forename: Qingnian
authors.initials: Q
authors.lastname: Cai
mesh_terms: D000470:Alkaloids / Q000378:metabolism; D000818:Animals; D001042:Aphids / Q000201:enzymology*; D043182:Carboxylesterase / Q000378:metabolism; D002374:Catalase / Q000378:metabolism; D004156:Catechol Oxidase / Q000378:metabolism; D002396:Catechols / Q000378:metabolism; D005982:Glutathione Transferase / Q000378:metabolism; D026121:Indole Alkaloids; D019476:Insect Proteins / Q000378:metabolism*; D009952:Ornithine / Q000378:metabolism; D009195:Peroxidase / Q000378:metabolism; D010944:Plants / Q000378:metabolism; D015262:Xenobiotics / Q000378:metabolism*
chemical_list: D000470:Alkaloids; D002396:Catechols; D026121:Indole Alkaloids; D019476:Insect Proteins; D015262:Xenobiotics; D009952:Ornithine; D004156:Catechol Oxidase; D002374:Catalase; D009195:Peroxidase; D005982:Glutathione Transferase; D043182:Carboxylesterase; C007884:gramine; C034221:catechol
keywords: Phase I and II detoxification enzymes; Plant defense; Secondary plant compounds; Sitobion avenae; Xenobiotic metabolism