The green peach aphid, Myzus persicae (Sulzer), is one of the most serious pest in cabbage cultivation. Field survey was carried out to know the insecticide resistance levels in five main cabbage cultivation regions (Pyeong-chang, Hong-cheon, Bong-wha, Mu-ju and Je-ju) in 2009~2011. The green peach aphid can resist a wide range of insecticides in five surveyed local populations. Among the nine tested insecticides, four chemicals (methomyl, bifenthrin, pymetrozine and flonicarmid) showed less than 60% mortality in the recommended concentration in most years of local populations. Multi resistant (MR) strain was selected from these populations and modified AChE (MACE: StoF mutation), MtoL mutation in para-type sodium channel, esterase over-expression were observed in almost of all populations including MR strain. Especially, StoF and MtoL mutations were highly correlated with resistance ratio and population based quantitative sequencing results. Therefore, these results suggested that molecular-biology based resistance monitoring can applied resistance management in M. persicae.

The cotton aphid, Aphis gossypii (Glover), is one of the most serious pest in seed potato and various vegetable cultivation. The imidacloprid-resistant strain (IR) was over 300-fold more resistant to imidacloprid compared to a susceptible strain (S) as judged by LC50 values. A highly imidacloprid-resistant local field population (L) was collected from cucumber at Gangwha island in 4th August 2011. Even though neonicotinoid insecticides especially imidacloprid were sprayed six times during June and July, aphid density was too high to be counted. To identify differentially expressed genes in IR or L, comparative transcriptome analyses based on GS-FLX were conducted using total RNAs extracted from IR, L and S strains. Futhermore, to search the resistance associated proteins in IR or L, comparative proteome analyses based on 2DE were conducted using total proteins extracted from IR, L and S strains. Few common candidate genes detected among IR and L such as ABC genes. Comparison of the nucleotide sequence of six nicotinic acetylcholine receptor (nAChR) subunit (alpha 1-5, beta 1) genes from IR, L and S strain revealed a point mutation in the loop D region of the nAChR beta 1 subunit of the IR, causing an arginine to threonine substitution (R81T). These mechanisms also reported in Myzus persicae and this amino acid change confers a vertebrate-like character to the insect nAChR and results in reduced sensitivity to neonicotinoids.

The cotton aphid, Aphis gossypii (Glover), is one of the most serious pest in the cultivation of various vegetables. A highly imidacloprid-resistant field population (CA-L) was collected from cucumber at Gangwha island in 4th August 2011. Even though neonicotinoid insecticides especially imidacloprid were sprayed six times during June and July, aphid density was too high to be counted. IEF and 2DE analyses revealed that general esterase isozyme (pI. 5) in CA-L were dramatically overexpressed and more isozyme spots identified in CA-L compared to susceptible (CA-S) strain. To identify differentially expressed genes in CA-L, comparative transcriptome analyses based on GS-FLX were conducted with total RNA extracted from CA-L, which generated ca. 143 Mb reads. Previously reported, comparative transcriptome analyses performed in imidacloprid resistant (CA-IR) and CA-S. The comparative transcriptome analyses re-investigated after all data sets were combined together. As previously reported, seven ATP-binding cassette (ABC) transporter genes were newly identified in A. gossypii, among which only ABCC9 gene was highly expressed in CA-IR and L. These results suggested that ABCC subfamily associated with imidacloprid resistance in A. gossypii.

After pea aphid Acyrthosiphon pisum genome project, hologenome concept was applied to pea aphid and symbioant such as Buchnera aphidicola. Here we screened symbiotic microorganism in four lab strains (two genetically different insecticide susceptible strains, host plant: cucumber and two different host adopted imiacloprid resistance strains, host plants: cucumber and potato) and four field populations (Jeju, Goryeong, Gimjae and Muju, host plant: potato) of cotton aphid based on GS-FLX pyrosequencing which were conducted with universal primer amplified partial fragments of 16S rRNA from total DNA which was extracted from each strain and population. B. aphidicola occupied over 90% of all identified prokaryotic microorganisms which all tested samples. It’s interesting that the ratio of B. aphidicola occupied over 99% in all of the tested lab strains. However, specific enterobacteriaceae occupied six to seven percents of all field populations which closely related endosymbiont of Glycaspis brimblecombei. That means B. aphidicola occupied only 91~92% of all identified prokaryotic microorganisms. Futhermore, other actinobacteridae and bacillaceae also were detected in field populations. The results obtained for these ratios suggested that there has some interaction between symbioant and environment NOT in imidacloprid resistance.

The cotton aphid, Aphis gossypii (Glover), is one of the most serious pest in seed potato and various vegetable cultivation. The imidacloprid-resistant strain (IR) was over 200-fold more resistant to imidacloprid compared to a susceptible strain (S) as judged by LC50 values. The IR showed cross resistances to other neonicotinoid insecticides. IEF and 2DE analyses revealed that general esterase isozyme patterns in IR were almost identical to those of S. Nevertheless, a significantly overexpressed protein spot was detected in IR. To identify differentially expressed genes in IR, comparative transcriptome analyses based on GS-FLX were conducted using total RNAs extracted from both IR and S strains, which generated ca. 290 Mb reads for each strain. Generally, most nicotinic acetylcholine receptor subunit genes, such as alpha 2 and beta 1, were more transcribed in S than in IR. In contrast, only alpha 5 subunit gene was 1.8 fold more expressed in IR. Seven ATP-binding cassette (ABC) transporter genes were newly identified in A. gossypii, among which only ABCC9 gene was highly expressed in IR. Therefore, this ABCC subfamily, a member of the MRP subfamily which is involved in multi-drug resistance, could be one of the main factors associated with imidacloprid resistance in A. gossypii.