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Insecticide resistance mechanisms in the green peach aphid Myzus persicae (Hemiptera: Aphididae) II: Costs and benefits.

Silva AX, Bacigalupe LD, Luna-Rudloff M, Figueroa CC - PLoS ONE (2012)

Bottom Line: As M. persicae feeds upon a huge diversity of hosts, it has been exposed to a wide variety of plant allelochemicals, which probably have promoted a wide range of detoxification systems.Our results show a significant interaction between host and IRM on the intrinsic rate of increase (r(m)).Hence, our results suggest that the trade-off among resistance mechanisms might be quite complex, with a multiplicity of costs and benefits depending on the environment.

View Article: PubMed Central - PubMed

Affiliation: Instituto de Ciencias Ambientales y Evolutivas, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile.

ABSTRACT

Background: Among herbivorous insects that have exploited agro-ecosystems, the peach-potato aphid, Myzus persicae, is recognized as one of the most important agricultural pests worldwide. Uses over 400 plant species and has evolved different insecticides resistance mechanisms. As M. persicae feeds upon a huge diversity of hosts, it has been exposed to a wide variety of plant allelochemicals, which probably have promoted a wide range of detoxification systems.

Methodology/principal findings: In this work we (i) evaluated whether insecticide resistance mutations (IRM) in M. persicae can give an advantage in terms of reproductive fitness when aphids face two hosts, pepper (Capsicum annuum) a suitable host and radish (Raphanus sativus) the unfavorable host and (ii) examined the transcriptional expression of six genes that are known to be up-regulated in response to insecticides. Our results show a significant interaction between host and IRM on the intrinsic rate of increase (r(m)). Susceptible genotypes (not carrying insensitivity mutations) had a higher r(m) on pepper, and the transcriptional levels of five genes increased on radish. The r(m) relationship was reversed on the unfavorable host; genotypes with multiple IRM exhibited higher r(m), without altering the transcriptional levels of the studied genes. Genotypes with one IRM kept a similar r(m) on both hosts, but they increased the transcriptional levels of two genes.

Conclusions/significance: Although we have studied only nine genotypes, overall our results are in agreement with the general idea that allelochemical detoxification systems could constitute a pre-adaptation for the development of insecticide resistance. Genotypes carrying IRM exhibited a higher r(m) than susceptible genotypes on radish, the more unfavorable host. Susceptible genotypes should be able to tolerate the defended host by up-regulating some metabolic genes that are also responding to insecticides. Hence, our results suggest that the trade-off among resistance mechanisms might be quite complex, with a multiplicity of costs and benefits depending on the environment.

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Norms of reaction in reproductive fitness (rm) of Myzus persicae genotypes in different host.For nine genotypes with three different genetic configurations of insecticide resistance mutations (IRM) is shows the mean in rm (mean ± SE) in two host, pepper (suitable) and radish (unfavorable).The green circles correspond to mean in genotypes sensitive (S, N = 3), the yellow circles corresponds to mean in simple resistant (SR, N = 4), and the red circles corresponds to multiple resistant genotype (MR, N = 2). The interaction HOST X IRM was significant (F2,6 = 5.771, P = 0.040, from nested ANOVA).
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pone-0036810-g001: Norms of reaction in reproductive fitness (rm) of Myzus persicae genotypes in different host.For nine genotypes with three different genetic configurations of insecticide resistance mutations (IRM) is shows the mean in rm (mean ± SE) in two host, pepper (suitable) and radish (unfavorable).The green circles correspond to mean in genotypes sensitive (S, N = 3), the yellow circles corresponds to mean in simple resistant (SR, N = 4), and the red circles corresponds to multiple resistant genotype (MR, N = 2). The interaction HOST X IRM was significant (F2,6 = 5.771, P = 0.040, from nested ANOVA).

Mentions: Table 2 shows descriptive statistics for intrinsic rate of increase (rm) and body mass, for each tested genotype on both host plants (suitable and unfavorable). The results shown no variation for reproductive fitness (χ2[1] = 0.000001, P = 0.999) among lines within genotypes; thus, line was removed from the final model. On the other hand, reproductive fitness was, as expected, positively affected by body mass (b = 0.227, SE = 0.020; F1, 230 = 131.42, P<0.0001). In addition, not all genotypes responded in the same fashion to both hosts; that is, there was an interaction between genotype and host (χ2[1] = 8.477, P = 0.004). Within each genotype, aphid reproductive fitness was significantly lower on the unfavorable host (radish) for S genotypes (N36-1, Sur25A). Finally, our results also shown a significant interaction between host and IRM on reproductive fitness (F2,6 = 5.771, P = 0.040). In particular, on pepper, the S genotypes had a higher reproductive fitness than SR and MR genotypes. However, the relationship was reversed on radish: S genotypes showed a lower reproductive fitness than SR and MR ones (Figure 1).


Insecticide resistance mechanisms in the green peach aphid Myzus persicae (Hemiptera: Aphididae) II: Costs and benefits.

Silva AX, Bacigalupe LD, Luna-Rudloff M, Figueroa CC - PLoS ONE (2012)

Norms of reaction in reproductive fitness (rm) of Myzus persicae genotypes in different host.For nine genotypes with three different genetic configurations of insecticide resistance mutations (IRM) is shows the mean in rm (mean ± SE) in two host, pepper (suitable) and radish (unfavorable).The green circles correspond to mean in genotypes sensitive (S, N = 3), the yellow circles corresponds to mean in simple resistant (SR, N = 4), and the red circles corresponds to multiple resistant genotype (MR, N = 2). The interaction HOST X IRM was significant (F2,6 = 5.771, P = 0.040, from nested ANOVA).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3369902&req=5

pone-0036810-g001: Norms of reaction in reproductive fitness (rm) of Myzus persicae genotypes in different host.For nine genotypes with three different genetic configurations of insecticide resistance mutations (IRM) is shows the mean in rm (mean ± SE) in two host, pepper (suitable) and radish (unfavorable).The green circles correspond to mean in genotypes sensitive (S, N = 3), the yellow circles corresponds to mean in simple resistant (SR, N = 4), and the red circles corresponds to multiple resistant genotype (MR, N = 2). The interaction HOST X IRM was significant (F2,6 = 5.771, P = 0.040, from nested ANOVA).
Mentions: Table 2 shows descriptive statistics for intrinsic rate of increase (rm) and body mass, for each tested genotype on both host plants (suitable and unfavorable). The results shown no variation for reproductive fitness (χ2[1] = 0.000001, P = 0.999) among lines within genotypes; thus, line was removed from the final model. On the other hand, reproductive fitness was, as expected, positively affected by body mass (b = 0.227, SE = 0.020; F1, 230 = 131.42, P<0.0001). In addition, not all genotypes responded in the same fashion to both hosts; that is, there was an interaction between genotype and host (χ2[1] = 8.477, P = 0.004). Within each genotype, aphid reproductive fitness was significantly lower on the unfavorable host (radish) for S genotypes (N36-1, Sur25A). Finally, our results also shown a significant interaction between host and IRM on reproductive fitness (F2,6 = 5.771, P = 0.040). In particular, on pepper, the S genotypes had a higher reproductive fitness than SR and MR genotypes. However, the relationship was reversed on radish: S genotypes showed a lower reproductive fitness than SR and MR ones (Figure 1).

Bottom Line: As M. persicae feeds upon a huge diversity of hosts, it has been exposed to a wide variety of plant allelochemicals, which probably have promoted a wide range of detoxification systems.Our results show a significant interaction between host and IRM on the intrinsic rate of increase (r(m)).Hence, our results suggest that the trade-off among resistance mechanisms might be quite complex, with a multiplicity of costs and benefits depending on the environment.

View Article: PubMed Central - PubMed

Affiliation: Instituto de Ciencias Ambientales y Evolutivas, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile.

ABSTRACT

Background: Among herbivorous insects that have exploited agro-ecosystems, the peach-potato aphid, Myzus persicae, is recognized as one of the most important agricultural pests worldwide. Uses over 400 plant species and has evolved different insecticides resistance mechanisms. As M. persicae feeds upon a huge diversity of hosts, it has been exposed to a wide variety of plant allelochemicals, which probably have promoted a wide range of detoxification systems.

Methodology/principal findings: In this work we (i) evaluated whether insecticide resistance mutations (IRM) in M. persicae can give an advantage in terms of reproductive fitness when aphids face two hosts, pepper (Capsicum annuum) a suitable host and radish (Raphanus sativus) the unfavorable host and (ii) examined the transcriptional expression of six genes that are known to be up-regulated in response to insecticides. Our results show a significant interaction between host and IRM on the intrinsic rate of increase (r(m)). Susceptible genotypes (not carrying insensitivity mutations) had a higher r(m) on pepper, and the transcriptional levels of five genes increased on radish. The r(m) relationship was reversed on the unfavorable host; genotypes with multiple IRM exhibited higher r(m), without altering the transcriptional levels of the studied genes. Genotypes with one IRM kept a similar r(m) on both hosts, but they increased the transcriptional levels of two genes.

Conclusions/significance: Although we have studied only nine genotypes, overall our results are in agreement with the general idea that allelochemical detoxification systems could constitute a pre-adaptation for the development of insecticide resistance. Genotypes carrying IRM exhibited a higher r(m) than susceptible genotypes on radish, the more unfavorable host. Susceptible genotypes should be able to tolerate the defended host by up-regulating some metabolic genes that are also responding to insecticides. Hence, our results suggest that the trade-off among resistance mechanisms might be quite complex, with a multiplicity of costs and benefits depending on the environment.

Show MeSH
Related in: MedlinePlus