Evolution of Resistance Genes in Plants

2008 ◽  
pp. 1-25 ◽  
Author(s):  
Shunyuan Xiao ◽  
Wenming Wang ◽  
Xiaohua Yang
Keyword(s):  
Resistance Genes ◽  
Evolution Of Resistance

scholarly journals An overview of the evolution of overproduced esterases in the mosquito Culex pipiens

1998 ◽  
Vol 353 (1376) ◽  
pp. 1707-1711 ◽  
Author(s):  
M. Raymond ◽  
C. Chevillon ◽  
T. Guillemaud ◽  
T. Lenormand ◽  
N. Pasteur
Keyword(s):  
Resistance Genes ◽  
Culex Pipiens ◽  
Population Level ◽  
Chemical Application ◽  
Gene Level ◽  
Genetic Mechanisms ◽  
Evolution Of Resistance ◽  
Passive Transportation ◽  
Term Monitoring

Insecticide resistance genes have developed in a wide variety of insects in response to heavy chemical application. Few of these examples of adaptation in response to rapid environmental change have been studied both at the population level and at the gene level. One of these is the evolution of the overproduced esterases that are involved in resistance to organophosphate insecticides in the mosquito Culex pipiens . At the gene level, two genetic mechanisms are involved in esterase overproduction, namely gene amplification and gene regulation. At the population level, the co–occurrence of the same amplified allele in distinct geographic areas is best explained by the importance of passive transportation at the worldwide scale. The long–term monitoring of a population of mosquitoes in southern France has enabled a detailed study to be made of the evolution of resistance genes on a local scale, and has shown that a resistance gene with a lower cost has replaced a former resistance allele with a higher cost.

scholarly journals Addicted? Reduced host resistance in populations with defensive symbionts

2016 ◽  
Vol 283 (1833) ◽  
pp. 20160778 ◽  
Author(s):  
Julien Martinez ◽  
Rodrigo Cogni ◽  
Chuan Cao ◽  
Sophie Smith ◽  
Christopher J. R. Illingworth ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Insect Resistance ◽  
Resistance Genes ◽  
Host Resistance ◽  
Major Effect ◽  
Insect Host ◽  
Insect Genome ◽  
Resistant Allele ◽  
Wide Range ◽  
Evolution Of Resistance

Heritable symbionts that protect their hosts from pathogens have been described in a wide range of insect species. By reducing the incidence or severity of infection, these symbionts have the potential to reduce the strength of selection on genes in the insect genome that increase resistance. Therefore, the presence of such symbionts may slow down the evolution of resistance. Here we investigated this idea by exposing Drosophila melanogaster populations to infection with the pathogenic Drosophila C virus (DCV) in the presence or absence of Wolbachia , a heritable symbiont of arthropods that confers protection against viruses. After nine generations of selection, we found that resistance to DCV had increased in all populations. However, in the presence of Wolbachia the resistant allele of pastrel —a gene that has a major effect on resistance to DCV—was at a lower frequency than in the symbiont-free populations. This finding suggests that defensive symbionts have the potential to hamper the evolution of insect resistance genes, potentially leading to a state of evolutionary addiction where the genetically susceptible insect host mostly relies on its symbiont to fight pathogens.

scholarly journals Genetic and Biochemical Characterization of Field-Evolved Resistance to Bacillus thuringiensis Toxin Cry1Ac in the Diamondback Moth, Plutella xylostella

2004 ◽  
Vol 70 (12) ◽  
pp. 7010-7017 ◽  
Author(s):  
Ali H. Sayyed ◽  
Ben Raymond ◽  
M. Sales Ibiza-Palacios ◽  
Baltasar Escriche ◽  
Denis J. Wright
Keyword(s):  
Bacillus Thuringiensis ◽  
Resistance Genes ◽  
Plutella Xylostella ◽  
Biochemical Characterization ◽  
Diamondback Moth ◽  
Field Population ◽  
Laboratory Population ◽  
Binding Studies ◽  
Slow Increase ◽  
Evolution Of Resistance

ABSTRACT The long-term usefulness of Bacillus thuringiensis Cry toxins, either in sprays or in transgenic crops, may be compromised by the evolution of resistance in target insects. Managing the evolution of resistance to B. thuringiensis toxins requires extensive knowledge about the mechanisms, genetics, and ecology of resistance genes. To date, laboratory-selected populations have provided information on the diverse genetics and mechanisms of resistance to B. thuringiensis, highly resistant field populations being rare. However, the selection pressures on field and laboratory populations are very different and may produce resistance genes with distinct characteristics. In order to better understand the genetics, biochemical mechanisms, and ecology of field-evolved resistance, a diamondback moth (Plutella xylostella) field population (Karak) which had been exposed to intensive spraying with B. thuringiensis subsp. kurstaki was collected from Malaysia. We detected a very high level of resistance to Cry1Ac; high levels of resistance to B. thuringiensis subsp. kurstaki Cry1Aa, Cry1Ab, and Cry1Fa; and a moderate level of resistance to Cry1Ca. The toxicity of Cry1Ja to the Karak population was not significantly different from that to a standard laboratory population (LAB-UK). Notable features of the Karak population were that field-selected resistance to B. thuringiensis subsp. kurstaki did not decline at all in unselected populations over 11 generations in laboratory microcosm experiments and that resistance to Cry1Ac declined only threefold over the same period. This finding may be due to a lack of fitness costs expressed by resistance strains, since such costs can be environmentally dependent and may not occur under ordinary laboratory culture conditions. Alternatively, resistance in the Karak population may have been near fixation, leading to a very slow increase in heterozygosity. Reciprocal genetic crosses between Karak and LAB-UK populations indicated that resistance was autosomal and recessive. At the highest dose of Cry1Ac tested, resistance was completely recessive, while at the lowest dose, it was incompletely dominant. A direct test of monogenic inheritance based on a backcross of F1 progeny with the Karak population suggested that resistance to Cry1Ac was controlled by a single locus. Binding studies with 125I-labeled Cry1Ab and Cry1Ac revealed greatly reduced binding to brush border membrane vesicles prepared from this field population.

The effective dominance of resistance genes in relation to the evolution of resistance

1981 ◽  
Vol 12 (5) ◽  
pp. 573-581 ◽  
Author(s):  
Roger J. Wood ◽  
Gopalakrishnan S. Mani
Keyword(s):  
Resistance Genes ◽  
Evolution Of Resistance

scholarly journals Bacterial recombination promotes the evolution of multi-drug-resistance in functionally diverse populations

2011 ◽  
Vol 279 (1733) ◽  
pp. 1477-1484 ◽  
Author(s):  
Gabriel G. Perron ◽  
Alexander E. G. Lee ◽  
Yun Wang ◽  
Wei E. Huang ◽  
Timothy G. Barraclough
Keyword(s):  
Drug Resistance ◽  
Resistance Genes ◽  
Pathogenic Bacteria ◽  
Inhibitory Effect ◽  
Multi Drug Resistance ◽  
Acinetobacter Baylyi ◽  
Functional Interference ◽  
Evolution Of Resistance ◽  
Multiple Strains ◽  
Functionally Diverse

Bacterial recombination is believed to be a major factor explaining the prevalence of multi-drug-resistance (MDR) among pathogenic bacteria. Despite extensive evidence for exchange of resistance genes from retrospective sequence analyses, experimental evidence for the evolutionary benefits of bacterial recombination is scarce. We compared the evolution of MDR between populations of Acinetobacter baylyi in which we manipulated both the recombination rate and the initial diversity of strains with resistance to single drugs. In populations lacking recombination, the initial presence of multiple strains resistant to different antibiotics inhibits the evolution of MDR. However, in populations with recombination, the inhibitory effect of standing diversity is alleviated and MDR evolves rapidly. Moreover, only the presence of DNA harbouring resistance genes promotes the evolution of resistance, ruling out other proposed benefits for recombination. Together, these results provide direct evidence for the fitness benefits of bacterial recombination and show that this occurs by mitigation of functional interference between genotypes resistant to single antibiotics. Although analogous to previously described mechanisms of clonal interference among alternative beneficial mutations, our results actually highlight a different mechanism by which interactions among co-occurring strains determine the benefits of recombination for bacterial evolution.

Sign in / Sign up

Export Citation Format

Share Document