Changes in the genetic composition of Myzus persicae nicotianae populations in Chile and frequency of insecticide resistance mutations

Author(s):  
Marco A. Cabrera-Brandt ◽  
Amalia Kati ◽  
María E. Rubio-Meléndez ◽  
Christian C. Figueroa ◽  
Eduardo Fuentes-Contreras

Abstract Myzus persicae is a cosmopolitan aphid that is highly polyphagous and an important agricultural pest. The subspecies M. persicae nicotianae has been described for highly specialized phenotypes adapted to tobacco (Nicotiana tabacum). In Chile, the population of M. persicae nicotianae was originally composed of a single red genotype that did not possess insecticide resistance mutations. However, in the last decade, variation in the colour of tobacco aphids has been observed in the field. To determine whether this variation stems from the presence of new genotypes, sampling was carried out across the entire distribution of tobacco cultivation regions in Chile. The aphids collected were genotyped, and the frequency of kdr (L1014F), super-kdr (M918T), modification of acetylcholinesterase (MACE) and nicotinic acetylcholine receptor β subunit (nAChRβ) mutations associated with insecticide resistance was determined. A total of 16 new genotypes of M. persicae nicotianae were detected in Chile: four of them possessed the MACE mutation, and none of them possessed the kdr, super-kdr or nAChRβ mutation. The previously described red genotype was not detected in any of the sampled fields over two seasons. These results raise questions about the mechanisms underlying changes in the genetic structure of M. persicae nicotianae populations in Chile. Future research aimed at addressing these questions could provide new insight into aphid evolution and agricultural practices.

2003 ◽  
Vol 93 (4) ◽  
pp. 289-297 ◽  
Author(s):  
T. Guillemaud ◽  
A. Brun ◽  
N. Anthony ◽  
M.H. Sauge ◽  
R. Boll ◽  
...  

AbstractIntensive chemical treatments have led to the development of a number of insecticide resistance mechanisms in the peach–potato aphid Myzus persicae (Sulzer). Some of these mechanisms are known to be associated with negative pleiotropic effects (resistance costs). Molecular and biochemical methods were used to determine the genotypes or phenotypes associated with four insecticide resistance mechanisms in single aphids from sexually-reproducing populations in southern France. The mechanisms considered were E4 and FE4 carboxylesterase overproduction, modified acetycholinesterase, and kdr and rdl resistance-associated mutations. A new method for determining individual kdr genotypes is presented. Almost all resistant individuals overproduced FE4 carboxylesterase, whereas modified acetylcholinesterase was rare. Both the kdr and rdl resistance mutations were present at high frequencies in French sexually-reproducing populations. The frequencies of insecticide resistance genes were compared before and after sexual reproduction in one peach orchard at Avignon to evaluate the potential impact of selection on the persistence of resistance alleles in the over-wintering phase. The frequencies of the kdr and rdl mutations varied significantly between autumn and spring sampling periods. The frequency of the kdr mutation increased, probably due to pyrethroid treatments at the end of the winter. Conversely, the frequency of the rdl mutation decreased significantly during winter, probably because of a fitness cost associated with this mutation.


2008 ◽  
Vol 27 (2) ◽  
pp. 236-247 ◽  
Author(s):  
Ron F. van Toor ◽  
Stephen P. Foster ◽  
James A. Anstead ◽  
Samantha Mitchinson ◽  
Brian Fenton ◽  
...  

2021 ◽  
Vol 118 (23) ◽  
pp. e2100559118
Author(s):  
Michela Panini ◽  
Olga Chiesa ◽  
Bartlomiej J. Troczka ◽  
Mark Mallott ◽  
Gian Carlo Manicardi ◽  
...  

The evolution of resistance to insecticides threatens the sustainable control of many of the world’s most damaging insect crop pests and disease vectors. To effectively combat resistance, it is important to understand its underlying genetic architecture, including the type and number of genetic variants affecting resistance and their interactions with each other and the environment. While significant progress has been made in characterizing the individual genes or mutations leading to resistance, our understanding of how genetic variants interact to influence its phenotypic expression remains poor. Here, we uncover a mechanism of insecticide resistance resulting from transposon-mediated insertional mutagenesis of a genetically dominant but insecticide-susceptible allele that enables the adaptive potential of a previously unavailable recessive resistance allele to be unlocked. Specifically, we identify clones of the aphid pest Myzus persicae that carry a resistant allele of the essential voltage-gated sodium channel (VGSC) gene with the recessive M918T and L1014F resistance mutations, in combination with an allele lacking these mutations but carrying a Mutator-like element transposon insertion that disrupts the coding sequence of the VGSC. This results in the down-regulation of the dominant susceptible allele and monoallelic expression of the recessive resistant allele, rendering the clones resistant to the insecticide bifenthrin. These findings are a powerful example of how transposable elements can provide a source of evolutionary potential that can be revealed by environmental and genetic perturbation, with applied implications for the control of highly damaging insect pests.


2021 ◽  
Vol 13 (6) ◽  
pp. 3423
Author(s):  
Phillip Warsaw ◽  
Steven Archambault ◽  
Arden He ◽  
Stacy Miller

Farmers markets are regular, recurring gatherings at a common facility or area where farmers and ranchers directly sell a variety of fresh fruits, vegetables, and other locally grown farm products to consumers. Markets rebuild and maintain local and regional food systems, leading to an outsized impact on the food system relative to their share of produce sales. Previous research has demonstrated the multifaceted impacts that farmers markets have on the communities, particularly economically. Recent scholarship in the United States has expanded inquiry into social impacts that markets have on communities, including improving access to fresh food products and increasing awareness of the sustainable agricultural practices adopted by producers, as well developing tools for producers and market stakeholders to measure their impact on both producers and communities. This paper reviews the recent scholarship on farmers markets to identify recent trends and synthesizes the current evidence describing the ways in which farmers markets contribute to the wellbeing of their communities, as well as identifying areas for additional future research.


2021 ◽  
Vol 54 (7) ◽  
pp. 1-39
Author(s):  
Ankur Lohachab ◽  
Saurabh Garg ◽  
Byeong Kang ◽  
Muhammad Bilal Amin ◽  
Junmin Lee ◽  
...  

Unprecedented attention towards blockchain technology is serving as a game-changer in fostering the development of blockchain-enabled distinctive frameworks. However, fragmentation unleashed by its underlying concepts hinders different stakeholders from effectively utilizing blockchain-supported services, resulting in the obstruction of its wide-scale adoption. To explore synergies among the isolated frameworks requires comprehensively studying inter-blockchain communication approaches. These approaches broadly come under the umbrella of Blockchain Interoperability (BI) notion, as it can facilitate a novel paradigm of an integrated blockchain ecosystem that connects state-of-the-art disparate blockchains. Currently, there is a lack of studies that comprehensively review BI, which works as a stumbling block in its development. Therefore, this article aims to articulate potential of BI by reviewing it from diverse perspectives. Beginning with a glance of blockchain architecture fundamentals, this article discusses its associated platforms, taxonomy, and consensus mechanisms. Subsequently, it argues about BI’s requirement by exemplifying its potential opportunities and application areas. Concerning BI, an architecture seems to be a missing link. Hence, this article introduces a layered architecture for the effective development of protocols and methods for interoperable blockchains. Furthermore, this article proposes an in-depth BI research taxonomy and provides an insight into the state-of-the-art projects. Finally, it determines possible open challenges and future research in the domain.


2021 ◽  
Vol 54 (3) ◽  
pp. 1-28
Author(s):  
Jun Huang ◽  
Debiao He ◽  
Mohammad S. Obaidat ◽  
Pandi Vijayakumar ◽  
Min Luo ◽  
...  

Voting is a formal expression of opinion or choice, either positive or negative, made by an individual or a group of individuals. However, conventional voting systems tend to be centralized, which are known to suffer from security and efficiency limitations. Hence, there has been a trend of moving to decentralized voting systems, such as those based on blockchain. The latter is a decentralized digital ledger in a peer-to-peer network, where a copy of the append-only ledger of digitally signed and encrypted transactions is maintained by each participant. Therefore, in this article, we perform a comprehensive review of blockchain-based voting systems and classify them based on a number of features (e.g., the types of blockchain used, the consensus approaches used, and the scale of participants). By systematically analyzing and comparing the different blockchain-based voting systems, we also identify a number of limitations and research opportunities. Hopefully, this survey will provide an in-depth insight into the potential utility of blockchain in voting systems and device future research agenda.


2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Kumar Saurabh Singh ◽  
Erick M. G. Cordeiro ◽  
Bartlomiej J. Troczka ◽  
Adam Pym ◽  
Joanna Mackisack ◽  
...  

AbstractThe aphid Myzus persicae is a destructive agricultural pest that displays an exceptional ability to develop resistance to both natural and synthetic insecticides. To investigate the evolution of resistance in this species we generated a chromosome-scale genome assembly and living panel of >110 fully sequenced globally sampled clonal lines. Our analyses reveal a remarkable diversity of resistance mutations segregating in global populations of M. persicae. We show that the emergence and spread of these mechanisms is influenced by host–plant associations, uncovering the widespread co‐option of a host-plant adaptation that also offers resistance against synthetic insecticides. We identify both the repeated evolution of independent resistance mutations at the same locus, and multiple instances of the evolution of novel resistance mechanisms against key insecticides. Our findings provide fundamental insights into the genomic responses of global insect populations to strong selective forces, and hold practical relevance for the control of pests and parasites.


2007 ◽  
Vol 2 (2) ◽  
pp. 61-73 ◽  
Author(s):  
Sally Rao ◽  
Indrit Troshani

Mobile services are heralded to create a tremendous spectrum of business opportunities. User acceptance of these services is of paramount importance. Consequently, a deeper insight into theory-based research is required to better understand the underlying motivations that lead users to adopting mobile services. As mobile services bring additional functional dimensions, including hedonic and experiential aspects, using extant models for predicting mobile services acceptance by individuals may be inadequate. The aim of this paper is to explore, analyse and critically assess the use of existing acceptance theories in the light of the evolving and ubiquitous mobile services and their underlying technologies. Constructs affecting consumer adoption behaviour are discussed and relevant propositions are made. Managerial implications are explored and future research directions are also identified.


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