scholarly journals Efficiency of RNA interference is improved by knockdown of dsRNA nucleases in tephritid fruit flies

Open Biology ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 190198 ◽  
Author(s):  
Alison Tayler ◽  
Daniel Heschuk ◽  
David Giesbrecht ◽  
Jae Yeon Park ◽  
Steve Whyard
Keyword(s):  
Rna Interference ◽  
Fruit Fly ◽  
Target Cells ◽  
Pest Species ◽  
Melanin Synthesis ◽  
Bactrocera Tryoni ◽  
Double Stranded Rna ◽  
Rnai Efficiency ◽  
Gene Transcripts ◽  
Tephritid Fruit Flies

RNA interference (RNAi) in insects is routinely used to ascertain gene function, but also has potential as a technology to control pest species. For some insects, such as beetles, ingestion of small quantities of double-stranded RNA (dsRNA) is able to knock down a targeted gene's expression. However, in other species, ingestion of dsRNA can be ineffective owing to the presence of nucleases within the gut, which degrade dsRNA before it reaches target cells. In this study, we observed that nucleases within the gut of the Queensland fruit fly ( Bactrocera tryoni ) rapidly degrade dsRNA and reduce RNAi efficacy. By complexing dsRNA with liposomes within the adult insect's diet, RNAi-mediated knockdown of a melanin synthesis gene, yellow , was improved significantly, resulting in strong RNAi phenotypes. RNAi efficiency was also enhanced by feeding both larvae and adults for several days on dsRNAs that targeted two different dsRNase gene transcripts. Co-delivery of both dsRNase-specific dsRNAs and yellow dsRNA resulted in almost complete knockdown of the yellow transcripts. These findings show that the use of liposomes or co-feeding of nuclease-specific dsRNAs significantly improves RNAi inhibition of gene expression in B. tryoni and could be a useful strategy to improve RNAi-based control in other insect species.

scholarly journals Commensal microbiota modulates larval foraging behaviour, development rate and pupal production in Bactrocera tryoni

2019 ◽  
Vol 19 (S1) ◽  
Author(s):  
Juliano Morimoto ◽  
Binh Nguyen ◽  
Shabnam T. Tabrizi ◽  
Ida Lundbäck ◽  
Phillip W. Taylor ◽  
...  
Keyword(s):  
Development Time ◽  
Foraging Behaviour ◽  
Fruit Fly ◽  
Mass Rearing ◽  
Insect Larvae ◽  
Bactrocera Tryoni ◽  
Commensal Microbiota ◽  
Survival And Growth ◽  
Horizontal Acquisition ◽  
Tephritid Fruit Flies

Abstract Backround Commensal microbes can promote survival and growth of developing insects, and have important fitness implications in adulthood. Insect larvae can acquire commensal microbes through two main routes: by vertical acquisition from maternal deposition of microbes on the eggshells and by horizontal acquisition from the environment where the larvae develop. To date, however, little is known about how microbes acquired through these different routes interact to shape insect development. In the present study, we investigated how vertically and horizontally acquired microbiota influence larval foraging behaviour, development time to pupation and pupal production in the Queensland fruit fly (‘Qfly’), Bactrocera tryoni. Results Both vertically and horizontally acquired microbiota were required to maximise pupal production in Qfly. Moreover, larvae exposed to both vertically and horizontally acquired microbiota pupated sooner than those exposed to no microbiota, or only to horizontally acquired microbiota. Larval foraging behaviour was also influenced by both vertically and horizontally acquired microbiota. Larvae from treatments exposed to neither vertically nor horizontally acquired microbiota spent more time overall on foraging patches than did larvae of other treatments, and most notably had greater preference for diets with extreme protein or sugar compositions. Conclusion The integrity of the microbiota early in life is important for larval foraging behaviour, development time to pupation, and pupal production in Qflies. These findings highlight the complexity of microbial relations in this species, and provide insights to the importance of exposure to microbial communities during laboratory- or mass-rearing of tephritid fruit flies.

scholarly journals Population differences and domestication effects on mating and remating frequencies in Queensland fruit fly

2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Khandaker Asif Ahmed ◽  
Heng Lin Yeap ◽  
Gunjan Pandey ◽  
Siu Fai Lee ◽  
Phillip W. Taylor ◽  
...  
Keyword(s):  
Genetic Variation ◽  
Reproductive Strategies ◽  
Natural Variation ◽  
Captive Breeding ◽  
Strain Differences ◽  
Fruit Fly ◽  
Inhibitory Effect ◽  
Pest Species ◽  
Bactrocera Tryoni ◽  
Male Genotype

AbstractFemales of many insect species are unreceptive to remating for a period following their first mating. This inhibitory effect may be mediated by either the female or her first mate, or both, and often reflects the complex interplay of reproductive strategies between the sexes. Natural variation in remating inhibition and how this phenotype responds to captive breeding are largely unexplored in insects, including many pest species. We investigated genetic variation in remating propensity in the Queensland fruit fly, Bactrocera tryoni, using strains differing in source locality and degree of domestication. We found up to threefold inherited variation between strains from different localities in the level of intra-strain remating inhibition. The level of inhibition also declined significantly during domestication, which implied the existence of genetic variation for this trait within the starting populations as well. Inter-strain mating and remating trials showed that the strain differences were mainly due to the genotypes of the female and, to a lesser extent, the second male, with little effect of the initial male genotype. Implications for our understanding of fruit fly reproductive biology and population genetics and the design of Sterile Insect Technique pest management programs are discussed.

RNA interference and double-stranded-RNA-activated pathways

2004 ◽  
Vol 32 (6) ◽  
pp. 952-956 ◽  
Author(s):  
C.A. Sledz ◽  
B.R.G. Williams
Keyword(s):  
Rna Interference ◽  
Primary Response ◽  
Janus Kinase ◽  
Interferon Response ◽  
Target Cells ◽  
Double Stranded Rna ◽  
Interferon Stimulated Genes ◽  
Specific Effects ◽  
Dependent Protein ◽  
Short Hairpin Rnas

RNAi (RNA interference) has become a powerful tool to determine gene function. Different methods of expressing the short ds (double-stranded) RNA intermediates required for interference in mammalian systems have been developed, including the introduction of si (short interfering) RNAs by direct transfection or driven from transfected plasmids or lentiviral vectors encoding sh (short hairpin) RNAs. Although RNAi relies upon a high degree of specificity, recent findings suggest that off-target non-specific effects can be encountered. We found that transfection of siRNAs can results in an interferon-mediated activation of the JAK/STAT (Janus kinase/signal transducer and activator of transcription) pathway and global up-regulation of interferon-stimulated genes. This effect is mediated in part by the dsRNA-dependent protein kinase PKR, as this kinase is activated by the 21 bp siRNA, and is required in response to the siRNAs. However, the transcription factor IRF3 (interferon-regulatory factor 3) is also activated by siRNA as a primary response, resulting in the stimulation of genes independent of an interferon response. In cells deficient in IRF3, this response is blunted, but can be restored by re-introduction of IRF3. Thus siRNAs induce complex signalling responses in target cells, leading to effects beyond the selective silencing of specific genes.

scholarly journals Climate Change and Invasion Expansion Jointly Reshape Geographic Ranges of Invasive Tephritid Fruit Flies

2021 ◽  
Author(s):  
Zihua Zhao ◽  
Yu Zhang ◽  
Gonzalo A Avila ◽  
Peng Han ◽  
Xubin Pan ◽  
...  
Keyword(s):  
Geographic Distribution ◽  
Fruit Fly ◽  
Economic Loss ◽  
Bactrocera Dorsalis ◽  
Pest Species ◽  
Geographic Ranges ◽  
The Past ◽  
Data Coverage ◽  
Geographic Distributions ◽  
Tephritid Fruit Flies

Abstract Human-mediated species introductions have greatly contributed significantly to the current global alteration of the biosphere, with many invasive species rapidly expanding their geographic ranges, leading to changes in biodiversity and disruptions of ecosystem functioning. With a modified SDM that considers both extensive data coverage and the distance to previously already occupied areas, we show continued shifts and expansions of geographic ranges of two globally invasive tephritid pest species Bactrocera dorsalis and Ceratitis capitata). Both tephritid pests are still expanding globally, with their geographic ranges estimated to have expanded by 65% and 22% in the past three decades. The potential future geographic distributions of B. dorsalis and C. capitata under four scenarios of Representative Concentration Pathways (RCPs) for 2050 highlighted some key changes when compared to their current occurrences. Under all four RCPs by 2050, the potential geographic distribution of C. capitata was predicted to shrink by 5-14%, while the distribution of B. dorsalis was predicted to increase by 12-15%. Under different climate scenarios for 2050, B. dorsalis could experience a notable poleward expansion with increasing connectivity in its future geographic distribution. The two tephritids will continue to co-occur in Africa, with B. dorsalis experiencing higher suitability in most regions where they overlap. Climate changes were estimated to contribute more, than non-equilibrial invasion expansion, to changes in the geographic ranges of the two tephritid pests. The forecasted potential geographic distributions could enhance regional biosecurity preparedness in future climates and mitigate proactively the economic loss from these fruit fly pests.

scholarly journals Double-Stranded RNA-Degrading Enzymes Reduce the Efficiency of RNA Interference in Plutella xylostella

Insects ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 712
Author(s):  
Jin-Zhi Chen ◽  
Ying-Xia Jiang ◽  
Miao-Wen Li ◽  
Jian-Wen Li ◽  
Ben-Hu Zha ◽  
...  
Keyword(s):  
Rna Interference ◽  
Plutella Xylostella ◽  
Intestinal Tract ◽  
Fluorescent Protein ◽  
Green Fluorescent Protein Gene ◽  
Double Stranded Rna ◽  
Degrading Enzymes ◽  
Rnai Efficiency ◽  
Green Fluorescent

DsRNA-degrading enzymes (dsRNases) have been recognized as important factors in reducing RNA interference (RNAi) efficiency in different insect species. However, dsRNases in Plutella xylostella are still unknown. We identified the full-length cDNAs of PxdsRNase1, PxdsRNase2, PxdsRNase3, and PxdsRNase4. Gene expression profile showed that PxdsRNase1 was mainly expressed in the hemolymph; and that PxdsRNase2 and PxdsRNase3 were mainly expressed in the intestinal tract. The expression of PxCht (Chitinase of P. xylostella) in P. xylostella larvae injected with the mixture of dsPxCht (dsRNA of PxCht) and dsPxdsRNase1 (dsRNA of PxdsRNase1), dsPxdsRNase2 (dsRNA of PxdsRNase2), or dsPxdsRNase3 (dsRNA of PxdsRNase3) was significantly higher than that in the larvae injected with the mixture of dsGFP (dsRNA of green fluorescent protein gene, GFP) and dsPxCht; the transcription level of PxCht in the larvae feeding on the mixture of dsPxCht and dsPxdsRNase1, dsPxdsRNase2, or dsPxdsRNase3 was significantly higher than that in the larvae feeding on the mixture of dsPxCht and dsGFP. The recombinant protein of PxdsRNase1 degraded dsRNA rapidly, PxdsRNase3 cleaved dsRNA without complete degradation, and PxdsRNase2 could not degrade dsRNA in vitro. These results suggested that PxdsRNases1, PxdsRNases2, and PxdsRNases3 were involved in the dsRNA degradation to reduce RNAi efficiency with different mechanisms.

scholarly journals Ecological Drivers and Sex-Based Variation in Body Size and Shape in the Queensland Fruit Fly, Bactrocera tryoni (Diptera: Tephritidae)

Insects ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 390
Author(s):  
Yufei Zhou ◽  
Juanita Rodriguez ◽  
Nicole Fisher ◽  
Renee A. Catullo
Keyword(s):  
Body Size ◽  
Fluctuating Asymmetry ◽  
Morphological Traits ◽  
Geographic Distance ◽  
Fruit Fly ◽  
Wing Shape ◽  
The Body ◽  
Economic Losses ◽  
Pest Species ◽  
Bactrocera Tryoni

The Queensland fruit fly (Bactrocera tryoni; Q-fly) is an Australian endemic horticultural pest species, which has caused enormous economic losses. It has the potential to expand its range to currently Q-fly-free areas and poses a serious threat to the Australian horticultural industry. A large number of studies have investigated the correlation between environmental factors and Q-fly development, reproduction, and expansion. However, it is still not clear how Q-fly morphological traits vary with the environment. Our study focused on three morphological traits (body size, wing shape, and fluctuating asymmetry) in Q-fly samples collected from 1955 to 1965. We assessed how these traits vary by sex, and in response to latitude, environmental variables, and geographic distance. First, we found sexual dimorphism in body size and wing shape, but not in fluctuating asymmetry. Females had a larger body size but shorter and wider wings than males, which may be due to reproductive and/or locomotion differences between females and males. Secondly, the body size of Q-flies varied with latitude, which conforms to Bergmann’s rule. Finally, we found Q-fly wing shape was more closely related to temperature rather than aridity, and low temperature and high aridity may lead to high asymmetry in Q-fly populations.

scholarly journals RNA Interference-Mediated Knockdown of Male Fertility Genes in the Queensland Fruit Fly Bactrocera tryoni (Diptera: Tephritidae)

Insects ◽  
2018 ◽  
Vol 9 (3) ◽  
pp. 96 ◽  
Author(s):  
Carlos Cruz ◽  
Alison Tayler ◽  
Steve Whyard
Keyword(s):  
Rna Interference ◽  
Fruit Fly ◽  
Bactrocera Tryoni ◽  
Transcript Levels ◽  
Rnai Technology ◽  
Significant Gene ◽  
Horticultural Pest ◽  
Fertility Genes ◽  
Negative Controls ◽  
Competition Assays

The Queensland fruit fly, Bactrocera tryoni, is Australia’s most important horticultural pest. The Sterile Insect Technique (SIT) has been used to control this species for decades, using radiation to sterilize males before field-release. This method of sterilization can potentially reduce the insects’ abilities to compete for mates. In this study, RNA interference (RNAi) techniques were examined for their potential to sterilize male B. tryoni without adversely affecting mating competitiveness. B. tryoni adults were injected or fed double-stranded RNAs (dsRNAs) targeting spermatogenesis genes (tssk1, topi and trxt); quantitative reverse-transcriptase PCR analyses confirmed that transcript levels were reduced 60–80% for all three genes following injections. Feeding produced a significant gene knockdown for tssk1 and trxt after three days, but interestingly, two genes (trxt and topi) produced an excess of transcripts after 10 days of feeding. Despite these fluctuations in transcript levels, all three dsRNAs impacted the fecundity of treated males, with tssk1- and topi-dsRNA-treated males producing 75% fewer viable offspring than the negative controls. Mating competition assays demonstrated that dsRNA-treated males can actively compete with untreated males. These findings suggest that RNAi technology could serve as an alternative to radiation as a means of sterilizing these insects in an SIT program.

scholarly journals Highly Variable Dietary RNAi Sensitivity Among Coleoptera

2021 ◽  
Vol 12 ◽  
Author(s):  
Jonathan Willow ◽  
Eve Veromann
Keyword(s):  
Rna Interference ◽  
Scientific Literature ◽  
Crop Yields ◽  
Plant Biotechnology ◽  
Pest Species ◽  
Forest Trees ◽  
Future Directions ◽  
Double Stranded Rna ◽  
Plant Pests ◽  
Insect Order

Many herbivorous beetles (Order Coleoptera) contribute to serious losses in crop yields and forest trees, and plant biotechnology solutions are being developed with the hope of limiting these losses. Due to the unprecedented target-specificity of double-stranded RNA (dsRNA), and its utility in inducing RNA interference (RNAi) when consumed by target pest species, dsRNA-based plant biotechnology approaches represent the cutting edge of current pesticide research and development. We review dietary RNAi studies in coleopterans and discuss prospects and future directions regarding RNAi-based management of coleopteran plant pests. Herein, we also provide a balanced overview of existing studies in order to provide an accurate re-assessment of dietary RNAi sensitivity in coleopterans, despite the limitations to the existing body of scientific literature. We further discuss impediments to our understanding of RNAi sensitivity in this important insect order and identify critical future directions for research in this area, with an emphasis on using plant biotechnology approaches.

scholarly journals Comparative Trap Catches of Male Bactrocera, Dacus, and Zeugodacus Fruit Flies (Diptera: Tephritidae) With Four Floral Phenylbutanoid Lures (Anisyl Acetone, Cue-Lure, Raspberry Ketone, and Zingerone) in Queensland, Australia

2020 ◽  
Vol 49 (4) ◽  
pp. 815-822 ◽  
Author(s):  
Jane E Royer ◽  
Keng Hong Tan ◽  
David G Mayer
Keyword(s):  
Pest Management ◽  
Fruit Fly ◽  
Quantitative Comparison ◽  
Pest Species ◽  
Bactrocera Tryoni ◽  
Raspberry Ketone ◽  
Relative Attractiveness ◽  
Similar Range ◽  
Multiple Species ◽  
Trap Catches

Abstract The male fruit fly attractants, cue-lure (CL) and raspberry ketone (RK), are important in pest management. These volatile phenylbutanoids occur in daciniphilous Bulbophyllum Thouar (Orchidaceae: Asparagales) orchids, along with zingerone (ZN) and anisyl acetone (AA). While these four compounds attract a similar range of species, their relative attractiveness to multiple species is unknown. We field tested these compounds in two fruit fly speciose locations in north Queensland, Australia (Lockhart and Cairns) for 8 wk. Of 16 species trapped in significant numbers, 14 were trapped with CL and RK, all in significantly greater numbers with CL traps than RK traps (at least in higher population locations). This included the pest species Bactrocera tryoni (Froggatt) (Diptera: Tephritidae) (CL catches ca. 5× > RK), Bactrocera neohumeralis (Hardy) (Diptera: Tephritidae) and Bactrocera bryoniae (Tryon) (Diptera: Tephritidae) (CL catches ca. 3× > RK), and Bactrocera frauenfeldi (Schiner) (Diptera: Tephritidae) (in Cairns—CL catches ca. 1.6× > RK). Seven species were trapped with AA, and all were also caught in CL and RK traps in significantly greater numbers, with the exception of B. frauenfeldi. For this species, catches were not statistically different with CL, RK, and AA in Lockhart, and RK and AA in Cairns. Seven species were trapped with ZN, two at this lure only, and the remainder also with CL or RK but in significantly greater numbers. This is the first quantitative comparison of the relative attractiveness of CL, RK, AA, and ZN against multiple species, and supports the long-held but untested assumption that CL is broadly more attractive lure than RK.

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