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Persistence and transgenerational effect of plant-mediated RNAi in aphids.

Coleman AD, Wouters RH, Mugford ST, Hogenhout SA - J. Exp. Bot. (2014)

Bottom Line: Moreover, gene expression levels returned to wild-type levels within ~6 d after removal of the aphids from the transgenic plants, indicating that a continuous supply of dsRNA is required to maintain the RNAi effect.Target genes were also down-regulated in nymphs born from mothers exposed to dsRNA-producing transgenic plants, and the RNAi effect lasted twice as long (12-14 d) in these nymphs.In a field setting, a reduction of the aphid reproduction by 40-60% would dramatically decrease aphid population growth, contributing to a substantial reduction in agricultural losses.

View Article: PubMed Central - PubMed

Affiliation: Department of Cell and Developmental Biology, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK.

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Aphid population growth is reduced by 40–60% on dsRack1, dsMpPInt02, and dsMpC002 transgenic A. thaliana. Aphid populations were established on dsRack1-, dsMpPInt02-, dsMpC002-, or dsGFP-expressing A. thaliana over 4 weeks. The mean total aphid population ±SEM from three biological replicates with n=4 per replicate is plotted for each time point, together with an exponential curve fitted to the data (GenStat). Curves plotted were: dsGFP, A=0.37(t)4.05; dsMpPInt02, A=1+0.76(t)3.16; dsRack1, A=1+0.35(t)3.76; dsMpC002, A=1+0.77(t)2.83 where A=total population and t=time in weeks. An asterisk with a corresponding P-value (to three decimal places) indicates a significant difference in treatments at 2, 3, or 4 weeks compared with dsGFP (Student’s t-test, n=4, P<0.05).
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Figure 4: Aphid population growth is reduced by 40–60% on dsRack1, dsMpPInt02, and dsMpC002 transgenic A. thaliana. Aphid populations were established on dsRack1-, dsMpPInt02-, dsMpC002-, or dsGFP-expressing A. thaliana over 4 weeks. The mean total aphid population ±SEM from three biological replicates with n=4 per replicate is plotted for each time point, together with an exponential curve fitted to the data (GenStat). Curves plotted were: dsGFP, A=0.37(t)4.05; dsMpPInt02, A=1+0.76(t)3.16; dsRack1, A=1+0.35(t)3.76; dsMpC002, A=1+0.77(t)2.83 where A=total population and t=time in weeks. An asterisk with a corresponding P-value (to three decimal places) indicates a significant difference in treatments at 2, 3, or 4 weeks compared with dsGFP (Student’s t-test, n=4, P<0.05).

Mentions: It was previously shown that plant-mediated RNAi of Rack1, MpPIntO2, and MpC002 resulted in decreased aphid fecundity by ~10–20% at 16 d (Pitino et al., 2011; Pitino and Hogenhout, 2013). Given that the RNAi effect is transferred to GPA progeny, it was hypothesized that the negative impact on fecundity of RNAi may be higher over several GPA generations. To test this, 0- to 2-day-old nymphs were seeded at one nymph per plant on four of each of the dsRack1, dsGFP, dsMpC002, and dsMpPIntO2 transgenic A. thaliana plants. The total numbers of adults and progeny were counted at 2, 3, and 4 weeks post-GPA inoculation (constituting about three generations of aphids). Total aphid numbers slowly declined over 4 weeks and reached a 30–40% reduction on dsMpPInt02 and dsRack1 plants and up to 60% on dsMpC002 plants compared with dsGFP plants (Fig. 4). DsRack1, dsMpC002, and dsMpPInt02 treatments all resulted in a significant reduction in the aphid population at 4 weeks (Student’s t-test, n=4, P<0.0009). Only dsMpC002 resulted in a significant reduction in population size by week 3 (Student’s t-test, n=4, P=0.011). Thus, the RNAi-mediated down-regulation of GPA genes reduces GPA fecundity over several generations and can further reduce the exponential growth of aphid populations over a longer time frame (Fig. 4). Plant-mediated RNAi of MpC002 is more effective at reducing the GPA population than that of Rack1 and MpPIntO2.


Persistence and transgenerational effect of plant-mediated RNAi in aphids.

Coleman AD, Wouters RH, Mugford ST, Hogenhout SA - J. Exp. Bot. (2014)

Aphid population growth is reduced by 40–60% on dsRack1, dsMpPInt02, and dsMpC002 transgenic A. thaliana. Aphid populations were established on dsRack1-, dsMpPInt02-, dsMpC002-, or dsGFP-expressing A. thaliana over 4 weeks. The mean total aphid population ±SEM from three biological replicates with n=4 per replicate is plotted for each time point, together with an exponential curve fitted to the data (GenStat). Curves plotted were: dsGFP, A=0.37(t)4.05; dsMpPInt02, A=1+0.76(t)3.16; dsRack1, A=1+0.35(t)3.76; dsMpC002, A=1+0.77(t)2.83 where A=total population and t=time in weeks. An asterisk with a corresponding P-value (to three decimal places) indicates a significant difference in treatments at 2, 3, or 4 weeks compared with dsGFP (Student’s t-test, n=4, P<0.05).
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Figure 4: Aphid population growth is reduced by 40–60% on dsRack1, dsMpPInt02, and dsMpC002 transgenic A. thaliana. Aphid populations were established on dsRack1-, dsMpPInt02-, dsMpC002-, or dsGFP-expressing A. thaliana over 4 weeks. The mean total aphid population ±SEM from three biological replicates with n=4 per replicate is plotted for each time point, together with an exponential curve fitted to the data (GenStat). Curves plotted were: dsGFP, A=0.37(t)4.05; dsMpPInt02, A=1+0.76(t)3.16; dsRack1, A=1+0.35(t)3.76; dsMpC002, A=1+0.77(t)2.83 where A=total population and t=time in weeks. An asterisk with a corresponding P-value (to three decimal places) indicates a significant difference in treatments at 2, 3, or 4 weeks compared with dsGFP (Student’s t-test, n=4, P<0.05).
Mentions: It was previously shown that plant-mediated RNAi of Rack1, MpPIntO2, and MpC002 resulted in decreased aphid fecundity by ~10–20% at 16 d (Pitino et al., 2011; Pitino and Hogenhout, 2013). Given that the RNAi effect is transferred to GPA progeny, it was hypothesized that the negative impact on fecundity of RNAi may be higher over several GPA generations. To test this, 0- to 2-day-old nymphs were seeded at one nymph per plant on four of each of the dsRack1, dsGFP, dsMpC002, and dsMpPIntO2 transgenic A. thaliana plants. The total numbers of adults and progeny were counted at 2, 3, and 4 weeks post-GPA inoculation (constituting about three generations of aphids). Total aphid numbers slowly declined over 4 weeks and reached a 30–40% reduction on dsMpPInt02 and dsRack1 plants and up to 60% on dsMpC002 plants compared with dsGFP plants (Fig. 4). DsRack1, dsMpC002, and dsMpPInt02 treatments all resulted in a significant reduction in the aphid population at 4 weeks (Student’s t-test, n=4, P<0.0009). Only dsMpC002 resulted in a significant reduction in population size by week 3 (Student’s t-test, n=4, P=0.011). Thus, the RNAi-mediated down-regulation of GPA genes reduces GPA fecundity over several generations and can further reduce the exponential growth of aphid populations over a longer time frame (Fig. 4). Plant-mediated RNAi of MpC002 is more effective at reducing the GPA population than that of Rack1 and MpPIntO2.

Bottom Line: Moreover, gene expression levels returned to wild-type levels within ~6 d after removal of the aphids from the transgenic plants, indicating that a continuous supply of dsRNA is required to maintain the RNAi effect.Target genes were also down-regulated in nymphs born from mothers exposed to dsRNA-producing transgenic plants, and the RNAi effect lasted twice as long (12-14 d) in these nymphs.In a field setting, a reduction of the aphid reproduction by 40-60% would dramatically decrease aphid population growth, contributing to a substantial reduction in agricultural losses.

View Article: PubMed Central - PubMed

Affiliation: Department of Cell and Developmental Biology, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK.

Show MeSH
Related in: MedlinePlus