scholarly journals Anther-Feeding-Induced RNAi in Brassicogethes aeneus Larvae

2021 ◽  
Vol 3 ◽  
Author(s):  
Jonathan Willow ◽  
Liina Soonvald ◽  
Silva Sulg ◽  
Riina Kaasik ◽  
Ana Isabel Silva ◽  
...  
Keyword(s):  
Gene Silencing ◽  
Messenger Rna ◽  
Life Stage ◽  
Control Treatment ◽  
Pest Species ◽  
Sequence Specificity ◽  
Brassicogethes Aeneus ◽  
Crop Pest ◽  
Significant Gene ◽  
Larval Bioassay

The biosafety aspect of applying double-stranded RNA (dsRNA) in crop pest management is rooted in dsRNA's mode of action, which displays nucleotide sequence-specificity to a particular region of a messenger RNA (mRNA), against which the insecticidal dsRNA is designed. This prominent and promising class of insecticides therefore has the potential to target a single pest species while conferring negligible effect on non-target organisms. Recent studies examining the effect of target-specific dsRNA in adults of the pollen beetle Brassicogethes aeneus, a major pest of oilseed rape (Brassica napus) crops in Europe, suggest the potential for developing a gene-silencing approach within integrated B. aeneus management. The present study examines the efficacy of target-specific dsRNA on target-mRNA silencing, and subsequent gene-silencing-induced mortality, in B. aeneus larvae, as this life stage represents a critical target for achieving optimal integrated B. aeneus control. Treatment applications occurred via feeding on dsRNA-treated anthers for 3 d. We observed variable gene-silencing efficacy, all target treatments having a significant or marginally significant effect after 3 d of dsRNA feeding, with greater variability at 6 d. These results further validated significant gene-silencing-induced mortality observed for one of the target treatments. Moreover, gene-silencing-induced mortality occurred at a quicker rate in B. aeneus larvae compared to what has been previously observed in B. aeneus adults. Finally, we consider refinements that must be made to B. aeneus larval bioassay setups to promote and strengthen future larval studies regarding this important crop pest species.

scholarly journals First Evidence of Bud Feeding-Induced RNAi in a Crop Pest via Exogenous Application of dsRNA

Insects ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 769
Author(s):  
Jonathan Willow ◽  
Liina Soonvald ◽  
Silva Sulg ◽  
Riina Kaasik ◽  
Ana Isabel Silva ◽  
...  
Keyword(s):  
Nucleotide Sequence ◽  
Gene Silencing ◽  
Oilseed Rape ◽  
Dietary Exposure ◽  
Exposure Period ◽  
Sequence Specificity ◽  
Pollen Beetle ◽  
Brassicogethes Aeneus ◽  
Model Control ◽  
Potential Strategy

Spray-induced gene silencing (SIGS) is a potential strategy for agricultural pest management, whereby nucleotide sequence-specific double-stranded RNA (dsRNA) can be sprayed onto a crop; the desired effect being a consumption of dsRNA by the target pest, and subsequent gene silencing-induced mortality. Nucleotide sequence-specificity is the basis for dsRNA’s perceived biosafety. A biosafe approach to pollen beetle (Brassicogethes aeneus) management in oilseed rape (Brassica napus) agroecosystems is needed. We examined the potential for SIGS in B. aeneus, via bud feeding, a field-relevant dsRNA exposure route. Oilseed rape buds were uniformly treated with dsRNA designed to target αCOP in B. aeneus. Our model control dsRNA (dsGFP) remained detectable on buds throughout the entire 3 d exposure period. When applied at 5 µg/µL, dsαCOP induced significant αCOP silencing 3 d after dietary exposure to buds treated with this dsαCOP concentration. We also observed a trend of increased αCOP silencing with increasing concentrations of dsαCOP at both 3 and 6 d. Furthermore, we observed a marginally significant and significant reduction in B. aeneus survival at 10 and 15 d, respectively. Our results suggest potential for developing a SIGS approach to B. aeneus management—though further experiments are needed to more fully understand this potential.

Biological traits of the predatory mirid Macrolophus praeclarus, a candidate biocontrol agent for the Neotropical region

2021 ◽  
pp. 1-9
Author(s):  
Meritxell Pérez-Hedo ◽  
Carolina Gallego ◽  
Amy Roda ◽  
Barry Kostyk ◽  
Mónica Triana ◽  
...  
Keyword(s):  
Developmental Rate ◽  
Predation Rate ◽  
Developmental Time ◽  
Control Treatment ◽  
Thermal Constant ◽  
Biological Traits ◽  
Pest Species ◽  
Tomato Plants ◽  
Defensive Responses ◽  
Predatory Mirid

Abstract The predatory mirid Macrolophus praeclarus is widely distributed throughout the Americas, and is reported to prey upon several horticultural pest species. However, little is known about its biology, thermal requirements, crop odour preferences, phytophagy, and capability to induce defensive responses in plants. When five temperatures studied (20, 25, 30, 33 and 35°C) were tested and Ephestia kuehniella was used as prey, the developmental time from egg to adult on tomato, was longest at 20°C (56.3 d) and shortest at 33°C (22.7 d). The ability of nymphs to develop to adults decreased as the temperature increased, with the highest number of nymphs reaching the adult stage at 20°C (78.0%) and lowest at 35°C (0%). The lower and upper developmental thresholds were estimated at 11.2° and 35.3°C, respectively. The maximum developmental rate occurred at 31.7°C and the thermal constant was 454.0 ± 8.1 degree days. The highest predation rate of E. kuehniella eggs was obtained at 30°C. In Y-tube olfactory choice tests, M. praeclarus selected tomato, sweet pepper and eggplant odours more frequently than no plant control treatment. Macrolophus praeclarus feeding did not damage tomato plants compared to another zoophytophagous mirid, Nesidiocoris tenuis, which caused necrotic rings. The phytophagy of M. praeclarus induced defensive responses in tomato plants through the upregulation of the jasmonic acid metabolic pathway. The implications of the findings for using M. praeclarus in tomato biological control programmes in the Americas are discussed.

scholarly journals Evolution of DNA Replication Origin Specification and Gene Silencing Mechanisms

2020 ◽  
Author(s):  
Y. Hu ◽  
A. Tareen ◽  
Y-J. Sheu ◽  
W. T. Ireland ◽  
C. Speck ◽  
...  
Keyword(s):  
Dna Replication ◽  
Gene Silencing ◽  
Origin Recognition Complex ◽  
Replication Initiation ◽  
Separate Analysis ◽  
Genome Replication ◽  
Sequence Specificity ◽  
Sequence Motifs ◽  
Origin Firing ◽  
Α Helix

AbstractDNA replication in eukaryotic cells initiates from chromosomal locations, called replication origins, that bind the Origin Recognition Complex (ORC) prior to S phase. Origin establishment is guided by well-defined DNA sequence motifs in Saccharomyces cerevisiae and some other budding yeasts, but most eukaryotes lack sequence-specific origins. At present, the mechanistic and evolutionary reasons for this difference are unclear. A 3.9 Å structure of S. cerevisiae ORC-Cdc6-Cdt1-Mcm2-7 (OCCM) bound to origin DNA revealed, among other things, that a loop within Orc2 inserts into a DNA minor groove and an α-helix within Orc4 inserts into a DNA major groove1. We show that this Orc4 α-helix mediates the sequence-specificity of origins in S. cerevisiae. Specifically, mutations were identified within this α-helix that alter the sequence-dependent activity of individual origins as well as change global genomic origin firing patterns. This was accomplished using a massively parallel origin selection assay analyzed using a custom mutual-information-based modeling approach and a separate analysis of whole-genome replication profiling and statistics. Interestingly, the sequence specificity of DNA replication initiation, as mediated by the Orc4 α-helix, has evolved in close conjunction with the gain of ORC-Sir4-mediated gene silencing and the loss of RNA interference.

Host-induced gene silencing and spray-induced gene silencing for crop protection against viruses.

2021 ◽  
pp. 72-85
Author(s):  
Angela Ricci ◽  
Silvia Sabbadini ◽  
Laura Miozzi ◽  
Bruno Mezzetti ◽  
Emanuela Noris
Keyword(s):  
Gene Silencing ◽  
Plant Pathogens ◽  
Crop Protection ◽  
Plant Defence ◽  
Transcriptional Gene Silencing ◽  
Target Sequence ◽  
Sequence Specificity ◽  
Rna Molecules ◽  
Political Concern ◽  
Post Transcriptional Gene Silencing

Abstract Since the beginning of agriculture, plant virus diseases have been a strong challenge for farming. Following its discovery at the very beginning of the 1990s, the RNA interference (RNAi) mechanism has been widely studied and exploited as an integrative tool to obtain resistance to viruses in several plant species, with high target-sequence specificity. In this chapter, we describe and review the major aspects of host-induced gene silencing (HIGS), as one of the possible plant defence methods, using genetic engineering techniques. In particular, we focus our attention on the use of RNAi-based gene constructs to introduce stable resistance in host plants against viral diseases, by triggering post-transcriptional gene silencing (PTGS). Recently, spray-induced gene silencing (SIGS), consisting of the topical application of small RNA molecules to plants, has been explored as an alternative tool to the stable integration of RNAi-based gene constructs in plants. SIGS has great and innovative potential for crop defence against different plant pathogens and pests and is expected to raise less public and political concern, as it does not alter the genetic structure of the plant.

scholarly journals Evolution of DNA replication origin specification and gene silencing mechanisms

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Y. Hu ◽  
A. Tareen ◽  
Y-J. Sheu ◽  
W. T. Ireland ◽  
C. Speck ◽  
...  
Keyword(s):  
Dna Replication ◽  
Gene Silencing ◽  
Dna Sequence ◽  
Origin Recognition Complex ◽  
Separate Analysis ◽  
Sequence Specificity ◽  
Replication Origins ◽  
Origin Firing ◽  
Dna Sequence Specificity ◽  
Α Helix

Abstract DNA replication in eukaryotic cells initiates from replication origins that bind the Origin Recognition Complex (ORC). Origin establishment requires well-defined DNA sequence motifs in Saccharomyces cerevisiae and some other budding yeasts, but most eukaryotes lack sequence-specific origins. A 3.9 Å structure of S. cerevisiae ORC-Cdc6-Cdt1-Mcm2-7 (OCCM) bound to origin DNA revealed that a loop within Orc2 inserts into a DNA minor groove and an α-helix within Orc4 inserts into a DNA major groove. Using a massively parallel origin selection assay coupled with a custom mutual-information-based modeling approach, and a separate analysis of whole-genome replication profiling, here we show that the Orc4 α-helix contributes to the DNA sequence-specificity of origins in S. cerevisiae and Orc4 α-helix mutations change genome-wide origin firing patterns. The DNA sequence specificity of replication origins, mediated by the Orc4 α-helix, has co-evolved with the gain of ORC-Sir4-mediated gene silencing and the loss of RNA interference.

scholarly journals RNA interference as a gene silencing tool to controlTuta absolutain tomato (Solanum lycopersicum)

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e2673 ◽  
Author(s):  
Roberto A. Camargo ◽  
Guilherme O. Barbosa ◽  
Isabella Presotto Possignolo ◽  
Lazaro E. P. Peres ◽  
Eric Lam ◽  
...  
Keyword(s):  
Rna Interference ◽  
Gene Silencing ◽  
Target Gene ◽  
Target Genes ◽  
Larval Mortality ◽  
Tuta Absoluta ◽  
Specific Gene ◽  
Gene Transcript ◽  
Pest Species ◽  
In Planta

RNA interference (RNAi), a gene-silencing mechanism that involves providing double-stranded RNA molecules that match a specific target gene sequence, is now widely used in functional genetic studies. The potential application of RNAi-mediated control of agricultural insect pests has rapidly become evident. The production of transgenic plants expressing dsRNA molecules that target essential insect genes could provide a means of specific gene silencing in larvae that feed on these plants, resulting in larval phenotypes that range from loss of appetite to death. In this report, we show that the tomato leafminer (Tuta absoluta), a major threat to commercial tomato production, can be targeted by RNAi. We selected two target genes (Vacuolar ATPase-AandArginine kinase) based on the RNAi response reported for these genes in other pest species. In view of the lack of an artificial diet forT. absoluta, we used two approaches to deliver dsRNA into tomato leaflets. The first approach was based on the uptake of dsRNA by leaflets and the second was based on “in planta-induced transient gene silencing” (PITGS), a well-established method for silencing plant genes, used here for the first time to deliverin planta-transcribed dsRNA to target insect genes.Tuta absolutalarvae that fed on leaves containing dsRNA of the target genes showed an ∼60% reduction in target gene transcript accumulation, an increase in larval mortality and less leaf damage. We then generated transgenic ‘Micro-Tom’ tomato plants that expressed hairpin sequences for both genes and observed a reduction in foliar damage byT. absolutain these plants. Our results demonstrate the feasibility of RNAi as an alternative method for controlling this critical tomato pest.

FIELD OBSERVATIONS OF PREDATION BY PHIDIPPUS AUDAX (ARANEAE: SALTICIDAE) ON ARTHROPODS ASSOCIATED WITH COTTON

1989 ◽  
Vol 24 (2) ◽  
pp. 266-273 ◽  
Author(s):  
Orrey P. Young
Keyword(s):  
Pest Species ◽  
Potential Prey ◽  
Field Site ◽  
Old Field ◽  
Tarnished Plant Bug ◽  
Crop Pest ◽  
Total Potential ◽  
Cucumber Beetle ◽  
Phidippus Audax ◽  
Spotted Cucumber Beetle

Evidence of 58 predation events by Phidippus audax (Hentz) was obtained during 17–31 October 1986 from a 0.1 ha old field site that included cotton in the Delta of Mississippi. Three crop pest species accounted for 60% of the prey records: tarnished plant bug (TPB) (22%), spotted cucumber beetle (SCB) (22%), and three-cornered alfalfa hopper (TAH) (16%). Censuses (35) of cotton at this site indicated that the most abundant potential prey, SCB, had one of the lowest capture rates by P. audax, 1.9%. Other spiders as a group were captured at a rate of 11.4%, TAH at a rate of 10.2%, and TPB at a rate of 4.3%. Considering the total potential arthropod prey population, P. audax consumed approximately 3.3% during a 2-week period. Predation by P. audax usually occurred between 1030 and 1500 hours, with 7.6% of the P. audax population expected to be consuming prey at any one time. It is estimated that in late-season habitats P. audax may remove ca. 10% of the TPB population every 1–2 weeks.

Potential distributional changes of invasive crop pest species associated with global climate change

2017 ◽  
Vol 82 ◽  
pp. 83-92 ◽  
Author(s):  
Yingwei Yan ◽  
Yi-Chen Wang ◽  
Chen-Chieh Feng ◽  
Peng-Hui Maffee Wan ◽  
Klarissa Ting-Ting Chang
Keyword(s):  
Climate Change ◽  
Global Climate Change ◽  
Global Climate ◽  
Pest Species ◽  
Crop Pest

MicroRNA-mediated gene silencing: are we close to a unifying model?

2012 ◽  
Vol 3 (1) ◽  
pp. 29-40 ◽  
Author(s):  
Victoria James ◽  
Sybil C.K. Wong ◽  
Tyson V. Sharp
Keyword(s):  
Gene Expression ◽  
Gene Silencing ◽  
Messenger Rna ◽  
Transcriptional Regulators ◽  
Effector Proteins ◽  
Specific Reference ◽  
Functional Studies ◽  
Non Coding Rna ◽  
Almost All ◽  
Terminal Effector

AbstractMicroRNAs (miRNAs) comprise a group of small non-coding RNA –21 nucleotides in length. They act as post-transcriptional regulators of gene expression by forming base pairing interactions with target messenger RNA (mRNA). At least 1000 miRNAs are predicted to be expressed in humans and are encoded for in the genome of almost all organisms. Functional studies indicate that every cellular process studied thus far is regulated at some level by miRNAs. Given this expansive role, it is not surprising that disruption of this crucial pathway underlies the initiation of, or in the least, contributes to the development and progression of numerous human diseases and physiological disorders. This review will focus on the latest developments in uncovering the mechanism(s) of miRNA-mediated silencing with specific reference to the function of terminal effector proteins, how translation of target mRNA is inhibited and whether we are moving towards understanding this fundamental gene silencing paradigm.

scholarly journals RNA interference as a gene silencing tool to control Tuta absoluta in tomato (Solanum lycopersicum)

2016 ◽  
Author(s):  
Roberto A Camargo ◽  
Guilherme O Barbosa ◽  
Isabella Presotto Possignolo ◽  
Lazaro E. P. Peres ◽  
Eric Lam ◽  
...  
Keyword(s):  
Rna Interference ◽  
Gene Silencing ◽  
Target Gene ◽  
Target Genes ◽  
Larval Mortality ◽  
Tuta Absoluta ◽  
Specific Gene ◽  
Gene Transcript ◽  
Pest Species ◽  
In Planta

RNA interference (RNAi), a gene-silencing mechanism that involves providing double-stranded RNA molecules that match a specific target gene sequence, is now widely used in functional genetic studies. The potential application of RNAi-mediated control of agricultural insect pests has rapidly become evident. The production of transgenic plants expressing dsRNA molecules that target essential insect genes could provide a means of specific gene silencing in larvae that feed on these plants, resulting in larval phenotypes that range from loss of appetite to death. In this report, we show that the tomato leafminer (Tuta absoluta), a major threat to commercial tomato production, can be targeted by RNAi. We selected two target genes [Vacuolar ATPase-A and Arginine kinase] based on the RNAi response reported for these genes in other pest species. In view of the lack of an artificial diet for T. absoluta, we used two approaches to deliver dsRNA into tomato leaflets. The first approach was based on the uptake of dsRNA by leaflets and the second was based on “in planta-induced transient gene silencing” (PITGS), a well-established method for silencing plant genes, used here for the first time to deliver in planta-transcribed dsRNA to target insect genes. Tuta absoluta larvae that fed on leaves containing dsRNA of the target genes showed an ~60% reduction in target gene transcript accumulation, an increase in larval mortality and less leaf damage. We then generated transgenic ‘Micro-Tom’ tomato plants that expressed hairpin sequences for both genes and observed a reduction in foliar damage by T. absoluta in these plants. Our results demonstrate the feasibility of RNAi as an alternative method for controlling this critical tomato pest.

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