The influences of host plant and genetic resistance to Bacillus thuringiensis on trade-offs between offspring number and growth rate in cabbage loopers, Trichoplusia ni

2006 ◽  
Vol 31 (2) ◽  
pp. 172-178 ◽  
Author(s):  
Alida F. Janmaat ◽  
Judith H. Myers
Keyword(s):  
Growth Rate ◽  
Bacillus Thuringiensis ◽  
Host Plant ◽  
Trichoplusia Ni ◽  
Genetic Resistance ◽  
Offspring Number ◽  
Trade Offs

Positive association between resistance to Bacillus thuringiensis and overwintering survival of cabbage loopers, Trichoplusia ni (Lepidoptera: Noctuidae)

2008 ◽  
Vol 98 (3) ◽  
pp. 317-322 ◽  
Author(s):  
V. Caron ◽  
J.H. Myers
Keyword(s):  
Bacillus Thuringiensis ◽  
Trichoplusia Ni ◽  
Positive Association ◽  
Pest Species ◽  
Development Of Resistance ◽  
Trade Offs ◽  
Major Pest ◽  
Selection For ◽  
Overwintering Survival ◽  
Lepidoptera Noctuidae

AbstractDevelopment of resistance to insecticides has generally been associated with fitness costs that may be magnified under challenging conditions. Lepidopterans which are resistant to the biopesticide Bacillus thuringiensis subsp. kurstaki (Btk) have been shown to have reduced fitness, such as lower survival when subjected to overwintering stress. Recently, resistance to Btk has been found in some populations of Trichoplusia ni Hübner in greenhouses in British Columbia. This situation provides an opportunity to investigate potential trade-offs between overwintering survival and insecticide resistance in a major pest species. Here, we assess the survival and eventual fecundity of Btk resistant and susceptible T. ni pupae exposed to cool temperatures. Contrary to our expectations, resistant T. ni had higher overwintering survival than susceptible individuals. This is the first account of a potential advantage associated with Btk resistance. Resistant and susceptible moths had reduced fecundity and smaller progeny after cold exposure compared to controls, and this may counteract the survival advantage. Nevertheless, it seems unlikely that this is sufficient to select out the resistant phenotype in the presence of strong selection for resistance and in the absence of immigration of susceptible moths. The appearance of resistance without evidence of a trade-off in overwintering survival presents a major challenge to management in production greenhouses.

scholarly journals Bacillus thuringiensis Bel Protein Enhances the Toxicity of Cry1Ac Protein to Helicoverpa armigera Larvae by Degrading Insect Intestinal Mucin

2009 ◽  
Vol 75 (16) ◽  
pp. 5237-5243 ◽  
Author(s):  
Shangling Fang ◽  
Li Wang ◽  
Wei Guo ◽  
Xia Zhang ◽  
Donghai Peng ◽  
...  
Keyword(s):  
Bacillus Thuringiensis ◽  
Helicoverpa Armigera ◽  
Trichoplusia Ni ◽  
Knockout Mutant ◽  
Gene Encoding ◽  
In Vitro Degradation ◽  
Intestinal Mucin ◽  
Helicoverpa Armígera ◽  
Cry1ac Protein

ABSTRACT Bacillus thuringiensis has been used as a bioinsecticide to control agricultural insects. Bacillus cereus group genomes were found to have a Bacillus enhancin-like (bel) gene, encoding a peptide with 20 to 30% identity to viral enhancin protein, which can enhance viral infection by degradation of the peritrophic matrix (PM) of the insect midgut. In this study, the bel gene was found to have an activity similar to that of the viral enhancin gene. A bel knockout mutant was constructed by using a plasmid-free B. thuringiensis derivative, BMB171. The 50% lethal concentrations of this mutant plus the cry1Ac insecticidal protein gene were about 5.8-fold higher than those of the BMB171 strain. When purified Bel was mixed with the Cry1Ac protein and fed to Helicoverpa armigera larvae, 3 μg/ml Cry1Ac alone induced 34.2% mortality. Meanwhile, the mortality rate rose to 74.4% when the same amount of Cry1Ac was mixed with 0.8 μg/ml of Bel. Microscopic observation showed a significant disruption detected on the midgut PM of H. armigera larvae after they were fed Bel. In vitro degradation assays showed that Bel digested the intestinal mucin (IIM) of Trichoplusia ni and H. armigera larvae to various degrading products, similar to findings for viral enhancin. These results imply Bel toxicity enhancement depends on the destruction of midgut PM and IIM, similar to the case with viral enhancin. This discovery showed that Bel has the potential to enhance insecticidal activity of B. thuringiensis-based biopesticides and transgenic crops.

Effects of host plant,Gossypium hirsutum L., on sexual attraction of cabbage looper moths,Trichoplusia ni (Hübner) (Lepidoptera: Noctuidae)

1994 ◽  
Vol 20 (11) ◽  
pp. 2959-2974 ◽  
Author(s):  
P. J. Landolt ◽  
R. R. Heath ◽  
J. G. Millar ◽  
K. M. Davis-Hernandez ◽  
B. D. Dueben ◽  
...  
Keyword(s):  
Gossypium Hirsutum ◽  
Host Plant ◽  
Trichoplusia Ni ◽  
Sexual Attraction ◽  
Cabbage Looper ◽  
Gossypium Hirsutum L ◽  
Lepidoptera Noctuidae

scholarly journals Evolutionary and ecological perspectives on the wheat phenotype

2021 ◽  
Vol 288 (1958) ◽  
pp. 20211259
Author(s):  
Victor O. Sadras
Keyword(s):  
Precision Agriculture ◽  
Current Model ◽  
Crop Improvement ◽  
Wheat Yield ◽  
High Yield ◽  
Striking Similarity ◽  
Stabilizing Selection ◽  
Grain Number ◽  
Offspring Number ◽  
Trade Offs

Technologies, from molecular genetics to precision agriculture, are outpacing theory, which is becoming a bottleneck for crop improvement. Here, we outline theoretical insights on the wheat phenotype from the perspective of three evolutionary and ecologically important relations—mother–offspring, plant–insect and plant–plant. The correlation between yield and grain number has been misinterpreted as cause-and-effect; an evolutionary perspective shows a striking similarity between crop and fishes. Both respond to environmental variation through offspring number; seed and egg size are conserved. The offspring of annual plants and semelparous fishes, lacking parental care, are subject to mother–offspring conflict and stabilizing selection. Labile reserve carbohydrates do not fit the current model of wheat yield; they can stabilize grain size, but involve trade-offs with root growth and grain number, and are at best neutral for yield. Shifting the focus from the carbon balance to an ecological role, we suggest that labile carbohydrates may disrupt aphid osmoregulation, and thus contribute to wheat agronomic adaptation. The tight association between high yield and low competitive ability justifies the view of crop yield as a population attribute whereby the behaviour of the plant becomes subordinated within that of the population, with implications for genotyping, phenotyping and plant breeding.

scholarly journals Escherichia colipopulations adapt to complex, unpredictable fluctuations without any trade-offs across environments

2016 ◽  
Author(s):  
Shraddha Karve ◽  
Devika Bhave ◽  
Dhanashri Nevgi ◽  
Sutirth Dey
Keyword(s):  
Escherichia Coli ◽  
Growth Rate ◽  
Growth Rates ◽  
Complex Environments ◽  
Multiple Stresses ◽  
Trade Off ◽  
Trade Offs ◽  
Fluctuating Environments ◽  
Laboratory Populations ◽  
Lower Variation

AbstractIn nature, organisms are simultaneously exposed to multiple stresses (i.e. complex environments) that often fluctuate unpredictably. While both these factors have been studied in isolation, the interaction of the two remains poorly explored. To address this issue, we selected laboratory populations ofEscherichia coliunder complex (i.e. stressful combinations of pH, H2O2and NaCl) unpredictably fluctuating environments for ~900 generations. We compared the growth rates and the corresponding trade-off patterns of these populations to those that were selected under constant values of the component stresses (i.e. pH, H2O2and NaCl) for the same duration. The fluctuation-selected populations had greater mean growth rate and lower variation for growth rate over all the selection environments experienced. However, while the populations selected under constant stresses experienced severe tradeoffs in many of the environments other than those in which they were selected, the fluctuation-selected populations could by-pass the across-environment trade-offs completely. Interestingly, trade-offs were found between growth rates and carrying capacities. The results suggest that complexity and fluctuations can strongly affect the underlying trade-off structure in evolving populations.

scholarly journals Massive Phenotypic Measurements Reveal Complex Physiological Consequences of Differential Translation Efficacies

2017 ◽  
Author(s):  
Adam Paul Arkin ◽  
Guillaume Cambray
Keyword(s):  
Growth Rate ◽  
Translation Initiation ◽  
Protein Production ◽  
Protein Biosynthesis ◽  
Cellular Growth ◽  
Sequence Variants ◽  
Release Rates ◽  
Trade Offs ◽  
Fluctuating Environments ◽  
Protein Overproduction

ABSTRACTControl of protein biosynthesis is at the heart of resource allocation and cell adaptation to fluctuating environments. One gene’s translation often occurs at the expense of another’s, resulting in global energetic and fitness trade-offs during differential expression of various functions. Patterns of ribosome utilization—as controlled by initiation, elongation and release rates—are central to this balance. To disentangle their respective determinants and physiological impacts, we complemented measurements of protein production with highly parallelized quantifications of transcripts’ abundance and decay, ribosome loading and cellular growth rate for 244,000 precisely designed sequence variants of an otherwise standard reporter. We find highly constrained, non-monotonic relationships between measured phenotypes. We show that fitness defects derive either from protein overproduction, with efficient translation initiation and heavy ribosome flows; or from unproductive ribosome sequestration by highly structured, slowly initiated and overly stabilized transcripts. These observations demonstrate physiological impacts of key sequence features in natural and designed transcripts.

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