Helicoverpa armigera and Helicoverpa zea are major caterpillar pests of Old and New World agriculture, respectively. Both, particularly H. armigera, are extremely polyphagous, and H. armigera has ...developed resistance to many insecticides. Here we use comparative genomics, transcriptomics and resequencing to elucidate the genetic basis for their properties as pests.
We find that, prior to their divergence about 1.5 Mya, the H. armigera/H. zea lineage had accumulated up to more than 100 more members of specific detoxification and digestion gene families and more than 100 extra gustatory receptor genes, compared to other lepidopterans with narrower host ranges. The two genomes remain very similar in gene content and order, but H. armigera is more polymorphic overall, and H. zea has lost several detoxification genes, as well as about 50 gustatory receptor genes. It also lacks certain genes and alleles conferring insecticide resistance found in H. armigera. Non-synonymous sites in the expanded gene families above are rapidly diverging, both between paralogues and between orthologues in the two species. Whole genome transcriptomic analyses of H. armigera larvae show widely divergent responses to different host plants, including responses among many of the duplicated detoxification and digestion genes.
The extreme polyphagy of the two heliothines is associated with extensive amplification and neofunctionalisation of genes involved in host finding and use, coupled with versatile transcriptional responses on different hosts. H. armigera's invasion of the Americas in recent years means that hybridisation could generate populations that are both locally adapted and insecticide resistant.
The dynamic nature of gene regulatory networks allows cells to rapidly respond to environmental change. However, the underlying temporal connections are missed, even in kinetic studies, as ...transcription factor (TF) binding within at least one time point is required to identify primary targets. The TF-regulated but unbound genes are dismissed as secondary targets. Instead, we report that these genes comprise transient TF-target interactions most relevant to rapid signal transduction. We temporally perturbed a master TF (Basic Leucine Zipper 1, bZIP1) and the nitrogen (N) signal it transduces and integrated TF regulation and binding data from the same cell samples. Our enabling approach could identify primary TF targets based solely on gene regulation, in the absence of TF binding. We uncovered three classes of primary TF targets: (i) poised (TF-bound but not TF-regulated), (ii) stable (TF-bound and TF-regulated), and (iii) transient (TF-regulated but not TF-bound), the largest class. Unexpectedly, the transient bZIP1 targets are uniquely relevant to rapid N signaling in planta, enriched in dynamic N-responsive genes, and regulated by TF and N signal interactions. These transient targets include early N responders nitrate transporter 2.1 and NIN-like protein 3, bound by bZIP1 at 1—5 min, but not at later time points following TF perturbation. Moreover, promoters of these transient targets are uniquely enriched with cis-regulatory motifs coinherited with bZIP1 binding sites, suggesting a recruitment role for bZIP1. This transient mode of TF action supports a classic, but forgotten, "hit-and-run" transcription model, which enables a "catalyst TF" to activate a large set of targets within minutes of signal perturbation.
Coral reefs worldwide are suffering mass mortalities from marine heat waves. With the aim of enhancing coral bleaching tolerance, we evolved 10 clonal strains of a common coral microalgal ...endosymbiont at elevated temperatures (31°C) for 4 years in the laboratory. All 10 heat-evolved strains had expanded their thermal tolerance in vitro following laboratory evolution. After reintroduction into coral host larvae, 3 of the 10 heat-evolved endosymbionts also increased the holobionts' bleaching tolerance. Although lower levels of secreted reactive oxygen species (ROS) accompanied thermal tolerance of the heat-evolved algae, reduced ROS secretion alone did not predict thermal tolerance in symbiosis. The more tolerant symbiosis exhibited additional higher constitutive expression of algal carbon fixation genes and coral heat tolerance genes. These findings demonstrate that coral stock with enhanced climate resilience can be developed through ex hospite laboratory evolution of their microalgal endosymbionts.
Fish and other seafood may contain organic mercury but also beneficial nutrients such as n-3 polyunsaturated fatty acids. We endeavored to study whether maternal fish consumption during pregnancy ...harms or benefits fetal brain development. We examined associations of maternal fish intake during pregnancy and maternal hair mercury at delivery with infant cognition among 135 mother-infant pairs in Project Viva, a prospective U.S. pregnancy and child cohort study. We assessed infant cognition by the percent novelty preference on visual recognition memory (VRM) testing at 6 months of age. Mothers consumed an average of 1.2 fish servings per week during the second trimester. Mean maternal hair mercury was 0.55 ppm, with 10% of samples > 1.2 ppm. Mean VRM score was 59.8 (range, 10.9-92.5). After adjusting for participant characteristics using linear regression, higher fish intake was associated with higher infant cognition. This association strengthened after adjustment for hair mercury level: For each additional weekly fish serving, offspring VRM score was 4.0 points higher 95% confidence interval (CI), 1.3 to 6.7. However, an increase of 1 ppm in mercury was associated with a decrement in VRM score of 7.5 (95% CI, -13.7 to -1.2) points. VRM scores were highest among infants of women who consumed > 2 weekly fish servings but had mercury levels ≤ 1.2 ppm. Higher fish consumption in pregnancy was associated with better infant cognition, but higher mercury levels were associated with lower cognition. Women should continue to eat fish during pregnancy but choose varieties with lower mercury contamination.
In this study, we explore the population genetics of the Russian wheat aphid (RWA) (Diuraphis noxia), one of the world’s most invasive agricultural pests, in north‐western China. We have analysed the ...data of 10 microsatellite loci and mitochondrial sequences from 27 populations sampled over 2 years in China. The results confirm that the RWAs are holocyclic in China with high genetic diversity indicating widespread sexual reproduction. Distinct differences in microsatellite genetic diversity and distribution revealed clear geographic isolation between RWA populations in northern and southern Xinjiang, China, with gene flow interrupted across extensive desert regions. Despite frequent grain transportation from north to south in this region, little evidence for RWA translocation as a result of human agricultural activities was found. Consequently, frequent gene flow among northern populations most likely resulted from natural dispersal, potentially facilitated by wind currents. We also found evidence for the long‐term existence and expansion of RWAs in China, despite local opinion that it is an exotic species only present in China since 1975. Our estimated date of RWA expansion throughout China coincides with the debut of wheat domestication and cultivation practices in western Asia in the Holocene. We conclude that western China represents the limit of the far eastern native range of this species. This study is the most comprehensive molecular genetic investigation of the RWA in its native range undertaken to date and provides valuable insights into the history of the association of this aphid with domesticated cereals and wild grasses.
Methylation of cytosine is one of the main epigenetic mechanisms involved in controlling gene expression. Here we show that the pea aphid (Acyrthosiphon pisum) genome possesses homologues to all the ...DNA methyltransferases found in vertebrates, and that 0.69% (±0.25%) of all cytosines are methylated. Identified methylation sites are predominantly restricted to the coding sequence of genes at CpG sites. We identify twelve methylated genes, including genes that interact with juvenile hormone, a key endocrine signal in insects. Bioinformatic prediction using CpG ratios for all predicted genes suggest that a large proportion of genes are methylated within the pea aphid.
Tetrabromobisphenol A (TBBPA) is a brominated flame retardant that has been shown to be a potential thyroid disrupting chemical. Currently, TBBPA is not included in the UN’s list of endocrine ...disruptors and adverse effects of TBBPA in mammals has not been fully investigated. However, there is clear evidence that TBBPA exerts adverse health effects on reproduction of aquatic species. Therefore, it is important to provide more information on potential endocrine disruptive effects of TBBPA in vertebrate species. In this study we investigated the effect of TBBPA on transcript levels of estrogen receptors (ERs) and thyroid receptors (TRs) in the gonadal tissue of goldfish in vivo and in vitro. ERβ mRNA levels were significantly lower in testis and ovary following exposure to TBBPA. TRα mRNA levels were also downregulated in testis tissue. Importantly, these phenotypic effects occurred at lower, environmentally relevant, concentrations in vivo. Furthermore, exposure to TBBPA also reduced ERβ and TRα mRNA abundance in goldfish testes and ovaries in vivo, which is similar to previously observed T3 responses in these tissues. These findings suggest that TBBPA may be a thyroid hormone mimic, capable of disrupting reproduction by affecting steroid hormone receptors. Our findings suggest that it is important to study TBBPA as an endocrine disruptor in aquatic organisms as it may have implications for both conservation and aquaculture.
•TBBPA reduces TRα mRNA expression, in vivo and in vitro, in gonadal tissue of goldfish (Carassius auratus).•TBBPA reduces Erβ mRNA expression, in vivo and in vitro, in gonadal tissue of goldfish (Carassius auratus).•TBBPA may be a thyroid hormone mimic and can affect reproductively important steroid receptors.•TBBPA should continue to be studied as an endocrine disruptor in aquatic organisms.
Pigs from the F₂ generation of a Duroc x Pietrain resource population were evaluated to discover QTL affecting carcass composition and meat quality traits. Carcass composition phenotypes included ...primal cut weights, skeletal characteristics, backfat thickness, and LM area. Meat quality data included LM pH, temperature, objective and subjective color information, marbling and firmness scores, and drip loss. Additionally, chops were analyzed for moisture, protein, and fat composition as well as cook yield and Warner-Bratzler shear force measurements. Palatability of chops was determined by a trained sensory panel. A total of 510 F₂ animals were genotyped for 124 microsatellite markers evenly spaced across the genome. Data were analyzed with line cross, least squares regression interval, mapping methods using sex and litter as fixed effects and carcass weight or slaughter age as covariates. Significance thresholds of the F-statistic for single QTL with additive, dominance, or imprinted effects were determined on chromosome- and genome-wise levels by permutation tests. A total of 94 QTL for 35 of the 38 traits analyzed were found to be significant at the 5% chromosome-wise level. Of these 94 QTL, 44 were significant at the 1% chromosome-wise, 28 of these 44 were also significant at the 5% genome-wise, and 14 of these 28 were also significant at the 1% genome-wise significance thresholds. Putative QTL were discovered for 45-min pH and pH decline from 45 min to 24 h on SSC 3, marbling score and carcass backfat on SSC 6, carcass length and number of ribs on SSC 7, marbling score on SSC 12, and color measurements and tenderness score on SSC 15. These results will facilitate fine mapping efforts to identify genes controlling carcass composition and meat quality traits that can be incorporated into marker-assisted selection programs to accelerate genetic improvement in pig populations.
Assessments of urban green drainage infrastructure (UGDI) have always been a headache in contemporary times which is a roadblock to enticing investors. This study prioritized the underlying ...sustainability indicators of UGDI systems in Ghana. After an exhaustive literature review, some identified sustainability indicators were compounded into semi-structured questionnaires. Sixty-two built environment professionals were asked to rate the significance of each indicator. A parametric test was used to prioritize the indicators. The results indicated that the most significant underlying sustainability indicators were; 'Flood control', 'Compliance with sustainable development goals', 'multi-functionality', 'energy efficiency and GHG emissions' and 'Initial Construction Cost'. To understand how UGDI performs with regards to flood and pollution mitigation, specific geographical performance indicators are required. This is an under-explored area in the Ghanaian context. Hence, the indicators espoused in this study serve as a starting point for the development of appropriate frameworks to aid the implementation of UGDI.
Upon publication of the original article 1, it was noticed that Dr Papanicolaou’s surname was spelt incorrectly. The correct spelling is “Papanicolaou”, as shown in the author list of this erratum.
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