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Driving Pest Insect Populations: Agricultural Chemicals Lead to an Adaptive Syndrome in Nilaparvata Lugens St å l (Hemiptera: Delphacidae)

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ABSTRACT

The brown planthopper (BPH) is a devastating pest of rice throughout Asia. In this paper we document the BPH biogeographic range expansion in China over the 20-year period, 1992 to 2012. We posed the hypothesis that the range expansion is due to a syndrome of adaptations to the continuous presence of agricultural chemicals (insecticides and a fungicide) over the last 40 years. With respect to biogeography, BPH ranges have expanded by 13% from 1992 to 1997 and by another 3% from 1997 to 2012. In our view, such expansions may follow primarily from the enhancing effects of JGM, among other agricultural chemicals, and from global warming. JGM treatments led to increased thermotolerance, recorded as decreased mortality under heat stress at 40 ± 1 °C (down from 80% to 55%) and increased fecundity (by 49%) at 34 °C. At the molecular level, JGM treatments led to increased abundances of mRNA encoding Acetyl Co-A carboxylase (Acc) (up 25%) and Hsp70 (up 32%) in experimental BPH. RNAi silencing of Hsp70 and Acc eliminated the JGM effects on fecundity and silencing Hsp70 reduced JGM-induced thermotolerance. Integrated with global climate change scenarios, such syndromes in pest insect species have potential for regional- and global-scale agricultural disasters.

No MeSH data available.


JGM treatments led to Hsp70-mediated increased thermotolerance, reported as proportional mortality.Comparing thecontrol and JGM-treated groups shows the JGM treatment increased survivorship. JGM + dsGfp, JGM + dsHsp70, and JGM + dsAcc represent a control dsRNA and Hsp70 and Acc gene silencing treatments. n = 3 independent biological replicates, 60 adult females per biological replicate.
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f3: JGM treatments led to Hsp70-mediated increased thermotolerance, reported as proportional mortality.Comparing thecontrol and JGM-treated groups shows the JGM treatment increased survivorship. JGM + dsGfp, JGM + dsHsp70, and JGM + dsAcc represent a control dsRNA and Hsp70 and Acc gene silencing treatments. n = 3 independent biological replicates, 60 adult females per biological replicate.

Mentions: Mortality rates of JGM-treated adults following 48 h of temperature stress at 40 °C declined from about 80% in controls to approximately 55% in BPHs treated with JGM, JGM + dsGFP or JGM + dsAcc (Fig. 3). Suppressing Hsp70 expression led to increased mortality, up about 42% to circa 80% after 48 h of temperature stress (Fig. 3), eliminating JGM-enhanced thermotolerance. Using LT50 values as a direct measure of thermotolerance at 40 °C, LT50 for untreated controls and for JGM + dsHsp70-treated experiments were similar at about 30 h while JGM, JGM + dsGFP and JGM + dsAcc treatments led to similar results, with LT50 values of about 45 h–50 h (Fig. 4; Table 1).


Driving Pest Insect Populations: Agricultural Chemicals Lead to an Adaptive Syndrome in Nilaparvata Lugens St å l (Hemiptera: Delphacidae)
JGM treatments led to Hsp70-mediated increased thermotolerance, reported as proportional mortality.Comparing thecontrol and JGM-treated groups shows the JGM treatment increased survivorship. JGM + dsGfp, JGM + dsHsp70, and JGM + dsAcc represent a control dsRNA and Hsp70 and Acc gene silencing treatments. n = 3 independent biological replicates, 60 adult females per biological replicate.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5120279&req=5

f3: JGM treatments led to Hsp70-mediated increased thermotolerance, reported as proportional mortality.Comparing thecontrol and JGM-treated groups shows the JGM treatment increased survivorship. JGM + dsGfp, JGM + dsHsp70, and JGM + dsAcc represent a control dsRNA and Hsp70 and Acc gene silencing treatments. n = 3 independent biological replicates, 60 adult females per biological replicate.
Mentions: Mortality rates of JGM-treated adults following 48 h of temperature stress at 40 °C declined from about 80% in controls to approximately 55% in BPHs treated with JGM, JGM + dsGFP or JGM + dsAcc (Fig. 3). Suppressing Hsp70 expression led to increased mortality, up about 42% to circa 80% after 48 h of temperature stress (Fig. 3), eliminating JGM-enhanced thermotolerance. Using LT50 values as a direct measure of thermotolerance at 40 °C, LT50 for untreated controls and for JGM + dsHsp70-treated experiments were similar at about 30 h while JGM, JGM + dsGFP and JGM + dsAcc treatments led to similar results, with LT50 values of about 45 h–50 h (Fig. 4; Table 1).

View Article: PubMed Central - PubMed

ABSTRACT

The brown planthopper (BPH) is a devastating pest of rice throughout Asia. In this paper we document the BPH biogeographic range expansion in China over the 20-year period, 1992 to 2012. We posed the hypothesis that the range expansion is due to a syndrome of adaptations to the continuous presence of agricultural chemicals (insecticides and a fungicide) over the last 40 years. With respect to biogeography, BPH ranges have expanded by 13% from 1992 to 1997 and by another 3% from 1997 to 2012. In our view, such expansions may follow primarily from the enhancing effects of JGM, among other agricultural chemicals, and from global warming. JGM treatments led to increased thermotolerance, recorded as decreased mortality under heat stress at 40 ± 1 °C (down from 80% to 55%) and increased fecundity (by 49%) at 34 °C. At the molecular level, JGM treatments led to increased abundances of mRNA encoding Acetyl Co-A carboxylase (Acc) (up 25%) and Hsp70 (up 32%) in experimental BPH. RNAi silencing of Hsp70 and Acc eliminated the JGM effects on fecundity and silencing Hsp70 reduced JGM-induced thermotolerance. Integrated with global climate change scenarios, such syndromes in pest insect species have potential for regional- and global-scale agricultural disasters.

No MeSH data available.