scholarly journals Length-dependent accumulation of double-stranded RNAs in plastids affects RNA interference efficiency in the Colorado potato beetle

2019 ◽  
Author(s):  
Wanwan He ◽  
Wenbo Xu ◽  
Letian Xu ◽  
Kaiyun Fu ◽  
Wenchao Guo ◽  
...  
Keyword(s):  
Rna Interference ◽  
Colorado Potato Beetle ◽  
Plant Protection ◽  
Larval Growth ◽  
High Accumulation ◽  
Potato Plants ◽  
Potato Beetle ◽  
Rnai Response ◽  
Rnai Effect

AbstractTransplastomic potato plants expressing double-stranded RNA (dsRNA) targeted against essential genes of the Colorado potato beetle (CPB) can be lethal to larvae by triggering an RNA interference (RNAi) response. High accumulation levels of dsRNAs in plastids are crucial to confer an efficient RNAi response in the insects. However, whether length and sequence of the dsRNA determine the efficacy of RNAi and/or influence the level of dsRNA accumulation in plastids is not known. Here we compared the RNAi efficacy of different lengths of dsRNA targeted against the CPB β–Actin gene (ACT) by feeding in vitro-synthesized dsRNAs to larvae. We show that, while the 60 bp dsRNA induced only a relatively low RNAi response in CPB, dsRNAs of 200 bp and longer caused high mortality and similar larval growth retardation. When the dsRNAs were expressed from the plastid (chloroplast) genome of potato plants, we found that their accumulation levels were correlated with length. dsRNA accumulation levels were positively associated with the observed mortality, suppression of larval growth and suppression of target gene expression. Importantly, transplastomic potato plants expressing the 200 bp dsRNA were better protected from CPB than plants expressing the 297 bp dsRNA, the best-performing line in our previous study. Our results suggest that the length of dsRNAs is an important factor that influences their accumulation levels in plastids and thus determines the strength of the insecticidal RNAi effect. Our findings will aid the design of optimized dsRNA expression constructs for plant protection by plastid-mediated RNAi.

scholarly journals Length-dependent accumulation of double-stranded RNAs in plastids affects RNA interference efficiency in the Colorado potato beetle

2020 ◽  
Vol 71 (9) ◽  
pp. 2670-2677 ◽  
Author(s):  
Wanwan He ◽  
Wenbo Xu ◽  
Letian Xu ◽  
Kaiyun Fu ◽  
Wenchao Guo ◽  
...  
Keyword(s):  
Rna Interference ◽  
Colorado Potato Beetle ◽  
Plant Protection ◽  
Larval Growth ◽  
High Accumulation ◽  
Potato Plants ◽  
Potato Beetle ◽  
Rnai Response ◽  
Rnai Effect

Abstract Transplastomic potato plants expressing double-stranded RNA (dsRNA) targeted against essential genes of the Colorado potato beetle (CPB) can be lethal to larvae by triggering an RNA interference (RNAi) response. High accumulation levels of dsRNAs in plastids are crucial to confer an efficient RNAi response in the insects. However, whether length and sequence of the dsRNA determine the efficacy of RNAi and/or influence the level of dsRNA accumulation in plastids is not known. We compared the RNAi efficacy of different lengths of dsRNA targeted against the CPB β-Actin gene (ACT) by feeding in vitro-synthesized dsRNAs to larvae. We showed that, while the 60 bp dsRNA induced only a relatively low RNAi response in CPB, dsRNAs of 200 bp and longer caused high mortality and similar larval growth retardation. When the dsRNAs were expressed from the plastid (chloroplast) genome of potato plants, we found that their accumulation were negatively correlated with length. The level of dsRNA accumulation was positively associated with the observed mortality, suppression of larval growth, and suppression of target gene expression. Importantly, transplastomic potato plants expressing the 200 bp dsRNA were better protected from CPB than plants expressing the 297 bp dsRNA, the best-performing line in our previous study. Our results suggest that the length of dsRNAs is an important factor that influences their accumulation in plastids and thus determines the strength of the insecticidal RNAi effect. Our findings will aid the design of optimized dsRNA expression constructs for plant protection by plastid-mediated RNAi.

scholarly journals Validating the potential of double-stranded RNA targeting Colorado potato beetle mesh gene in laboratory and field trials

2020 ◽  
Author(s):  
Marko Petek ◽  
Anna Coll ◽  
Rok Ferenc ◽  
Jaka Razinger ◽  
Kristina Gruden
Keyword(s):  
Colorado Potato Beetle ◽  
Field Trial ◽  
Larval Growth ◽  
Field Trials ◽  
Larval Survival ◽  
Innovative Technology ◽  
Feeding Experiments ◽  
Potato Beetle

ABSTRACTColorado potato beetle (CPB) is an agricultural pest of solanaceous crops, notorious for its rapid resistance development to chemical pesticides. Foliar spraying of dsRNA formulations is a promising innovative technology providing highly specific and environmentally acceptable option for CPB management.We designed dsRNA to silence CPB mesh gene (dsMESH) and performed laboratory feeding trials to assess impacts on beetle survival and development. We compared the effectiveness of in-vivo and in-vitro produced dsRNA in a series of laboratory experiments. We additionally performed a field trial in which the efficacy of dsRNA sprayed onto potato foliage was compared to a spinosad-based insecticide.We showed that dsMESH ingestion consistently and significantly impaired larval growth and decreased larval survival in laboratory feeding experiments. In-vivo produced dsRNA performed similarly as in-vitro synthesised dsRNA in laboratory settings. In the field trial, dsMESH was as effective in controlling CPB larvae as a commercial spinosad insecticide, its activity was however slower. We discuss limitations and benefits of a potential dsMESH-based CPB management strategy and list some important RNAi based CPB research topics, which will have to be addressed in future.

scholarly journals Potential of Proteinase Inhibitors for Insect Pest Control: The Case of the Colorado Potato Beetle

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 767D-767
Author(s):  
S. Overney ◽  
V.Q. Le ◽  
S. Visal ◽  
S. Yelle
Keyword(s):  
Colorado Potato Beetle ◽  
Proteinase Inhibitors ◽  
Insect Pest ◽  
Cysteine Proteases ◽  
Crop Damage ◽  
Cysteine Protease Inhibitor ◽  
In Vitro Assays ◽  
Potato Plants ◽  
Potato Beetle

Bioengineering economically important plants with proteinase inhibitors (PIs) is a promising method for the control of insect pests. In the case of the Colorado potato beetle (CPB; Leptinotarsa decemlineata Say), the major insect pest of potato fields, 80% of the digestive proteases are of cysteine type. We showed that 60% of these cysteine proteases are inhibited by oryzacystatins (OCs). The use of these cysteine protease inhibitor genes therefore appears of great interest for the production of Coleoptera-resistant transgenic plants of potato. Complementary studies of biochemical in vitro assays showed an apparent absence of direct interference between OCs and potato proteases. The high regeneration efficiency of the genetically transformed plants with OC gene and the “normal” phenotypical growth of the resulting transgenic potato plants suggested that these foreign genes do not interact with important physiological processes in the potato plants. In vivo assays of PIs against CPB at various developmental stages suggest the significant potential of OCs as an effective way to control CPB populations and crop damage.

scholarly journals Low Mismatch Rate between Double-Stranded RNA and Target mRNA Does Not Affect RNA Interference Efficiency in Colorado Potato Beetle

Insects ◽  
2020 ◽  
Vol 11 (7) ◽  
pp. 449
Author(s):  
Wanwan He ◽  
Wenbo Xu ◽  
Kaiyun Fu ◽  
Wenchao Guo ◽  
Jiang Zhang
Keyword(s):  
Rna Interference ◽  
Colorado Potato Beetle ◽  
Target Gene ◽  
Insect Pest ◽  
Larval Growth ◽  
Underlying Mechanism ◽  
Site Directed Mutagenesis ◽  
Potato Beetle ◽  
Effective Sirnas ◽  
Mismatch Rate

RNA interference (RNAi)-based technology has been proven as a novel approach for insect pest control. However, whether insects could evolve resistance to RNAi and the underlying mechanism is largely unknown. The target gene mutations were thought to be one of the potential ways to develop the resistance. Here we predicted the effective siRNA candidates that could be derived from dsRNA against the Colorado potato beetle (CPB) β-Actin gene (dsACT). By site-directed mutagenesis, we synthesized the dsRNAs with the defect in generation of effective siRNAs (and thus were supposed to have comparable low RNAi efficacy). We showed that, with mismatches to the target gene, all the dsRNA variants caused similar levels of silencing of target gene, mortality and larval growth retardation of CPB. Our results suggest that when the mismatch rate of dsACT and target β-Actin mRNA is less than 3%, the RNAi efficiency is not impaired in CPB, which might imply the low possibility of RNAi resistance evolving through the sequence mismatches between dsRNA and the target gene.

Transgenic potato plants expressing the nptII-gus marker genes affect survival and development of the Colorado potato beetle

Plant Science ◽  
2002 ◽  
Vol 162 (3) ◽  
pp. 373-380 ◽  
Author(s):  
Sébastien De Turck ◽  
Philippe Giordanengo ◽  
Anas Cherqui ◽  
Corinne Ducrocq-Assaf ◽  
Brigitte S Sangwan-Norreel
Keyword(s):  
Colorado Potato Beetle ◽  
Transgenic Potato ◽  
Marker Genes ◽  
Potato Plants ◽  
Potato Beetle ◽  
Survival And Development ◽  
Transgenic Potato Plants

scholarly journals Conjugated linoleic acid as a novel insecticide targeting the agricultural pest Leptinotarsa decemlineata

2019 ◽  
Author(s):  
Justin Clements ◽  
Russell L. Groves ◽  
JoAnn Cava ◽  
Caroline Barry ◽  
Scott Chapman ◽  
...  
Keyword(s):  
Linoleic Acid ◽  
Conjugated Linoleic Acid ◽  
Colorado Potato Beetle ◽  
Leptinotarsa Decemlineata ◽  
Larval Mortality ◽  
Larval Growth ◽  
The United States ◽  
Feeding Preference ◽  
Agricultural Pest ◽  
Potato Beetle

AbstractThe Colorado Potato Beetle, Leptinotarsa decemlineata, is a major agricultural pest of solanaceous crops in the United States. Historically, a multitude of insecticides have been used to control problematic populations. Due to increasing resistance to insecticides, novel compounds and methodologies are warranted for the control of beetle populations. Mixed-isomer conjugated linoleic acid has been studied in-depth for its beneficial properties to mammalian systems. At the same time, studies have demonstrated that conjugated linoleic acid can manipulate fatty acid composition in non-mammalian systems, resulting in embryo mortality. Consequently, experiments were conducted to assess the effects of foliar-applied conjugated linoleic acid on larval growth, embryogenesis, and feeding preference in Colorado potato beetle. Both maternal and deterrent effects of dietary conjugated linoleic acid were assessed. Conjugated linoleic acid demonstrated desirable insecticidal properties, including increased larval mortality, slowed larval development, antifeedant effects, and decreased egg viability after maternal ingestion.

Cooperation of enzymes involved in carbohydrate digestion of Colorado potato beetle (Leptinotarsa decemlineata, Say)

2019 ◽  
Vol 109 (05) ◽  
pp. 695-700
Author(s):  
E. Szilágyi ◽  
C. Hámori ◽  
P. Bíró-Molnár ◽  
L. Kandra ◽  
J. Remenyik ◽  
...  
Keyword(s):  
Colorado Potato Beetle ◽  
Leptinotarsa Decemlineata ◽  
Plant Protection ◽  
Hydrolysis Products ◽  
Potato Beetle ◽  
Activity Measurements ◽  
Optimum Ph ◽  
Leptinotarsa Decemlineata Say ◽  
Protection Activity ◽  
Carbohydrate Digestion

AbstractColorado potato beetle (Leptinotarsa decemlineata, Say) is the main pest of Solanaceae and its survival is mainly dependent on the carbohydrate digestion. Characterizing the gut enzymes may help us with finding effective inhibitors for plant protection. Activity measurements revealed that gut extracts contain α- and β-glucosidase in addition to α-amylase. For larvae, amylase activity was detected only in gut saturated with nutrients.Leptinotarsa decemlineataα-amylase (LDAmy) had optimum pH of 6.0 and was active under 30–40°C temperature measured on a selective α-amylase substrate, 2-chloro-4-nitrophenyl-4-O-α-D-galactopyranosyl-maltoside. HPLC analysis demonstrated dimer, trimer, and tetramer reducing end amylolytic products from 2-chloro-4-nitrophenyl-maltoheptaoside substrate in similar ratio than that of during porcine pancreatic α-amylase (PPA) catalyzed hydrolysis. The 4,6-O-benzylidene-modified substrate (BzG7PNP) is very stable toward hydrolysis byexo-glycosidases, therefore is very useful to monitor the digestion catalyzed by α-amylases exclusively. Similarly to PPA active site, three glycon and two aglycon binding sites are suggested for LDAmy based on the pattern of early hydrolysis products of BzG7PNP. The observed similarity between LDAmy and PPA raises the possibility of using known inhibitors of mammalian α-amylases to protect the potato plant from attack of Colorado potato beetle.

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