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Testing insecticidal activity of novel chemically synthesized siRNA against Plutella xylostella under laboratory and field conditions.

Gong L, Chen Y, Hu Z, Hu M - PLoS ONE (2013)

Bottom Line: Quantitative Real-time PCR was used to confirm silencing and detected that the transcript levels of P. xylostella AChE2 (PxAChE2) were reduced by 5.7-fold compared to the control group.Finally, effects of the siRNAs on treated plants of Brassica oleracea and Brassica alboglabra were investigated with different siRNA doses.Our results showed that Si-ace2_001 had no negative effects on plant morphology, color and growth of vein under our experimental conditions.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Pesticide and Chemical Biology, College of Natural Resources and Environment, South China Agricultural University, Guangzhou, China.

ABSTRACT

Background: Over the last 60 years, synthetic chemical pesticides have served as a main tactic in the field of crop protection, but their availability is now declining as a result of the development of insect resistance. Therefore, alternative pest management agents are needed. However, the demonstration of RNAi gene silencing in insects and its successful usage in disrupting the expression of vital genes opened a door to the development of a variety of novel, environmentally sound approaches for insect pest management.

Methodology/principal findings: Six small interfering RNAs (siRNAs) were chemically synthesized and modified according to the cDNA sequence of P. xylostella acetylcholine esterase genes AChE1 and AChE2. All of them were formulated and used in insecticide activity screening against P. xylostella. Bioassay data suggested that Si-ace1_003 and Si-ace2_001 at a concentration of 3 µg cm(-2) displayed the best insecticidal activity with 73.7% and 89.0%, mortality, respectively. Additional bioassays were used to obtain the acute lethal concentrations of LC50 and LC90 for Si-ace2_001, which were 53.66 µg/ml and 759.71 µg/ml, respectively. Quantitative Real-time PCR was used to confirm silencing and detected that the transcript levels of P. xylostella AChE2 (PxAChE2) were reduced by 5.7-fold compared to the control group. Consequently, AChE activity was also reduced by 1.7-fold. Finally, effects of the siRNAs on treated plants of Brassica oleracea and Brassica alboglabra were investigated with different siRNA doses. Our results showed that Si-ace2_001 had no negative effects on plant morphology, color and growth of vein under our experimental conditions.

Conclusions: The most important finding of this study is the discovery that chemically synthesized and modified siRNA corresponding to P. xylostella AChE genes cause significant mortality of the insect both under laboratory and field conditions, which provides a novel strategy to control P. xylostella and to develop bio-pesticides based on the RNA interference technology.

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Real-time PCR data were normalized to the expression of PxAchE2 in the samples treated with Si-ace2_001 or DEPC water as shown by RT-PCR gel pictures at the bottom of each panel.Each point represents the mean±SEM from three independent experiments and asterisk means significant differences (P<0.05) between the two groups.
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pone-0062990-g004: Real-time PCR data were normalized to the expression of PxAchE2 in the samples treated with Si-ace2_001 or DEPC water as shown by RT-PCR gel pictures at the bottom of each panel.Each point represents the mean±SEM from three independent experiments and asterisk means significant differences (P<0.05) between the two groups.

Mentions: Effects of Si-ace2_001 on the mRNA levels of P. xylostella AChE2 are presented in Figure 4. Compared with the control group, a significant decrease (P<0.05) in mRNA levels of AChE gene was observed, with up to 5.7 fold down-regualtion. In the same treated samples, a significant decrease of AChE activity in the Si-ace2_001 treatment groups was observed with a 1.7 fold down-regulation (P<0.05) (Figure 5).


Testing insecticidal activity of novel chemically synthesized siRNA against Plutella xylostella under laboratory and field conditions.

Gong L, Chen Y, Hu Z, Hu M - PLoS ONE (2013)

Real-time PCR data were normalized to the expression of PxAchE2 in the samples treated with Si-ace2_001 or DEPC water as shown by RT-PCR gel pictures at the bottom of each panel.Each point represents the mean±SEM from three independent experiments and asterisk means significant differences (P<0.05) between the two groups.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3646892&req=5

pone-0062990-g004: Real-time PCR data were normalized to the expression of PxAchE2 in the samples treated with Si-ace2_001 or DEPC water as shown by RT-PCR gel pictures at the bottom of each panel.Each point represents the mean±SEM from three independent experiments and asterisk means significant differences (P<0.05) between the two groups.
Mentions: Effects of Si-ace2_001 on the mRNA levels of P. xylostella AChE2 are presented in Figure 4. Compared with the control group, a significant decrease (P<0.05) in mRNA levels of AChE gene was observed, with up to 5.7 fold down-regualtion. In the same treated samples, a significant decrease of AChE activity in the Si-ace2_001 treatment groups was observed with a 1.7 fold down-regulation (P<0.05) (Figure 5).

Bottom Line: Quantitative Real-time PCR was used to confirm silencing and detected that the transcript levels of P. xylostella AChE2 (PxAChE2) were reduced by 5.7-fold compared to the control group.Finally, effects of the siRNAs on treated plants of Brassica oleracea and Brassica alboglabra were investigated with different siRNA doses.Our results showed that Si-ace2_001 had no negative effects on plant morphology, color and growth of vein under our experimental conditions.

View Article: PubMed Central - PubMed

Affiliation: Key Laboratory of Pesticide and Chemical Biology, College of Natural Resources and Environment, South China Agricultural University, Guangzhou, China.

ABSTRACT

Background: Over the last 60 years, synthetic chemical pesticides have served as a main tactic in the field of crop protection, but their availability is now declining as a result of the development of insect resistance. Therefore, alternative pest management agents are needed. However, the demonstration of RNAi gene silencing in insects and its successful usage in disrupting the expression of vital genes opened a door to the development of a variety of novel, environmentally sound approaches for insect pest management.

Methodology/principal findings: Six small interfering RNAs (siRNAs) were chemically synthesized and modified according to the cDNA sequence of P. xylostella acetylcholine esterase genes AChE1 and AChE2. All of them were formulated and used in insecticide activity screening against P. xylostella. Bioassay data suggested that Si-ace1_003 and Si-ace2_001 at a concentration of 3 µg cm(-2) displayed the best insecticidal activity with 73.7% and 89.0%, mortality, respectively. Additional bioassays were used to obtain the acute lethal concentrations of LC50 and LC90 for Si-ace2_001, which were 53.66 µg/ml and 759.71 µg/ml, respectively. Quantitative Real-time PCR was used to confirm silencing and detected that the transcript levels of P. xylostella AChE2 (PxAChE2) were reduced by 5.7-fold compared to the control group. Consequently, AChE activity was also reduced by 1.7-fold. Finally, effects of the siRNAs on treated plants of Brassica oleracea and Brassica alboglabra were investigated with different siRNA doses. Our results showed that Si-ace2_001 had no negative effects on plant morphology, color and growth of vein under our experimental conditions.

Conclusions: The most important finding of this study is the discovery that chemically synthesized and modified siRNA corresponding to P. xylostella AChE genes cause significant mortality of the insect both under laboratory and field conditions, which provides a novel strategy to control P. xylostella and to develop bio-pesticides based on the RNA interference technology.

Show MeSH
Related in: MedlinePlus