Cloning And Character Of Expression Analysis Of The ABCC2 Genes In Plutella Xylostella

The resistance of field population of Plutella xylostella to seven insecticides in three production areas of vegetables (Nianyuxu Town of Yueyang City; Canggang Town of Changde City; Shatou Town of Yiyang City) in Northern Hunan was determined through leaf-dip method under experimental conditions. The results showed that the P.xylostella have an extremely high level of resistance to beta-cypermethrin (RR= 257.13-fold); have high level of resistance to abamectin and indoxacarb (RR= 135.15-fold and RR=103.08-flod); have moderate level of resistance to chlorfenapyr and emamectin benzoate; remain a relatively high level of sensitivity to chlorantraniliprole and bacillus thuringiensis (Bt). Therefore, the prevention of Plutella xylostella shall focus on the alternative use of chlorfenapyr, emamectin, chlorantraniliprole and bacillus thuringiensis, and stop using beta-cypermethrin, so as to delay the generation and development of resistance to insecticides.ABCC2 played an important role in transporting endogenous and exogenous toxicants in the body of insects.In this study,The full-length cDNA of the ABCC2 (ATP-binding cassette,sub-family C,member 2) from the diamondback moth (Plutella xylostella) was amplified,cloned, sequenced and analyzed by using transcription polymerase chain reaction (RT-PCR) method and rapid amplification of cDNA ends (RACE) method.The sequence was 4260 bp (GenBank accession:KM103521), containinga 5'-UTR of 132, a 3'-UTR of 84 bp and a full open reading frame (ORF) of 4044bp. The amino acid sequence deduced from the sequence was 1347 amino acids.he deduced amino acids sequence showed that there were 9 transmembrane domains, the signal peptide was not be found. With the typical ABC transporter family structure marshalling sequence of TMD1-NBD1-TMD2-NBD2.It contained ABC transporters highly conservative motif of Walker A, Walker, B and ABC signature.The results show that the expression abundance of ABCC2 gene in P. xylostella is significantly varied among different growing stages.The expression abundance at the larval stage keeps increasing and adult P. xylostella has the highest expression abundance on gene ABCC2 and its expression abundance is 4.27-fold of the 3th instar,2.20-fold of the 4th instar, and 9.98-fold of the pupa stage. In addition, the gene ABCC2 in P. xylostella at the 4th instar has the highest expression abundance in the mid-gut, which is 4.51-fold of malpighian tubule, 9.12-fold of the fat body and 16.88-fold of the testis. The expression abundance in the head and integument is the lowest. The expression quantity on ABCC2 gene in P. xylostella at the larval stage has a positive correlation with the lethal concentration of the pesticide. And the expression abundance in Indoxacarb resistant strain is 6.7-fold of that in sensitive strain. It demonstrates that the over-expression on ABCC2 in P. xylostella is probably related to its resistance to drugs.