Characterization of five CYP4 genes from Asian citrus psyllid and their expression levels in Candidatus Liberibacter asiaticus‐infected and uninfected psyllids

• Published in: Insect molecular biology 2011-12, Vol.20 (6), p.733-744
• Main Authors: Tiwari, S, Gondhalekar, A. D, Mann, R. S, Scharf, M. E, Stelinski, L. L
• Format: Article
• Language: English
• Subjects: Animals; Base Sequence; Candidatus Liberibacter asiaticus; Citrus; cytochrome P-450; Cytochrome P-450 Enzyme System - genetics; Cytochrome P-450 Enzyme System - metabolism; Cytochrome P450; Cytochrome P450 monooxygenase; cytochrome P450 monooxygenases; Diaphorina citri; Female; females; Gene silencing; genes; Genes, Insect; genetic markers; genetic resistance; greening; Hemiptera - enzymology; Hemiptera - genetics; Hemiptera - microbiology; huanglongbing; imagos; Imidacloprid; imidacloprid induction; Imidazoles; Insect Vectors - enzymology; Insect Vectors - genetics; Insect Vectors - microbiology; insecticide resistance; Insecticides; Las infection; Male; males; metabolic detoxification; Metabolism; Molecular Sequence Data; Neonicotinoids; Nitro Compounds; Nymph - enzymology; nymphs; Plant Diseases - microbiology; Psyllidae; Real-Time Polymerase Chain Reaction; Rhizobiaceae - physiology; RNA interference; screening; Sequence Analysis, DNA; Toxins
• ISSN: 0962-1075; 1365-2583
• DOI: 10.1111/j.1365-2583.2011.01103.x

Previously, we reported that Candidatus Liberibacter asiaticus (Las)‐infected Diaphorina citri are characterized by lower levels of cytochrome P450 monooxygenases than uninfected counterparts. In the present study, we investigated expression levels of family 4 cytochrome P450 (CYP4) genes in Las‐infected and uninfected D. citri adults. Five novel CYP4 genes (CYP4C67, CYP4DA1, CYP4C68, CYP4DB1 and CYP4G70) were identified. Four of the five CYP4 genes were expressed at significantly higher levels in uninfected than Las‐infected males, whereas only one was expressed at significantly higher levels in uninfected than Las‐infected females. These results suggest that levels of cytochrome P450 monooxygenases in D. citri may be linked to expression levels of these CYP4 genes. Expression of all five CYP4 genes was induced by exposure of D. citri to imidacloprid, suggesting their possible involvement in metabolism of this toxin. Higher expression of the five CYP4 genes was found in nymphs than adults, which is congruent with previous results indicating higher levels of cytochrome P450 monooxygenases in nymphs than adults. These five CYP4 genes may be promising candidates for RNA‐interference to silence overexpression of genes associated with insecticide resistance in D. citri. These newly identified genes may also serve as DNA‐based screening markers for cytochrome P450‐mediated insecticide resistance in field populations of D. citri.