Abstract
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
.