Analysis of expression difference of metabolism genes in Panonychus citri

【Objective】To clarify the relationship among expression level of glutathione S-transferase(GST),Carboxylesterase(CarE),and Catalase(CAT) genes and resistance of P.citri,【Method】Resistance selection was conducted in laboratory and gene expression profiles of GST,CarE,and CAT gene between the resistant strain and susceptible strain were compared using Reads Per kb per Million reads(RPKM) method.【Result】After selection with hexythiazox continuously for 20 generations,a resistant strain was obtained with the resistance ratio(R/S) of 3532.12 compared with the susceptible strain.Analysis results of gene expression difference indicated that 11 GST genes,17 CarE genes and 6 CAT genes were up-regulated,while 14 GST genes,24 CarE genes and 3 CAT genes were down-regulated in resistant strain.Unigene31530[log2 ratio(RS/SS)=1.05],Unigene23121[log2 ratio(RS/SS)=2.05],and Unigene31477 [log2 ratio(RS/SS)=10.04] were the top up-regulated GST gene,CarE gene and CAT gene,respectively.Further gene expression analysis using real-time PCR indicated that there was not significant difference in expression level of Unigene31477 between the resistant strain and susceptible strain.【Conclusion】Judging from gene expression differences between resistant and susceptible strains of P.citri,we concluded that up-regulation of GST,CarE and CAT genes may not play an important role in hexythiazox resistance of P.citri.