Identification of Wild-Type and Comparison of Allelochemical-Induced Expression Profiles of with Its Paralog in .

One possible way to overcome the diversity of toxic plant allelochemicals idiosyncratically distributed among potential host plants is to have more counterdefense genes via gene duplication or fewer gene losses. Cytochrome P450 is the most important gene family responsible for detoxification of the diversity of plant allelochemicals. We have recently reported the identification and cloning of the transposon ()-disrupted non-functional , a duplicated paralog of the xenobiotic-metabolizing P450 from a laboratory colony of . Here we report the identification of the wild-type intact allele of from another colony. This allele encodes a deduced protein of 498 amino acids and has the P450 signature motifs. Quantitative RT-PCR experiments showed that this allele was highly expressed in midgut and fat body and achieved the highest expression level in the developmental stage of 5th and 3rd instar larvae. and were constitutively expressed in low levels but can be differentially and significantly induced by a range of the plant allelochemicals and plant signal molecules, among which xanthotoxin, flavone, and coumarin were the most prominent inducers of both in midgut and fat body, whereas flavone, coumarin, and indole-3-carbinol were the prominent inducers of in midgut and fat body. Moreover, xanthotoxin- and flavone-responsive regulatory elements of were also detected in the promoter region of . Our results enrich the P450 inventory by identifying an allelochemical broadly induced , a paralog of in . Our data also suggest that the / paralogs are a pair of duplicated genes of multigene families and could potentially be involved in the detoxification of plant allelochemicals and adaptation of to its chemical environment.