Variation in heat shock protein expression at the latitudinal range limits of a widely‐distributed species,the Glanville fritillary butterfly (Melitaea cinxia)

Studies of heat shock response show a correlation with local climate, although this is more often across altitudinal than latitudinal gradients. In the present study, differences in constitutive but not inducible components of heat shock response are detected among populations of the Glanville fritillary butterfly Melitaea cinxia L. that exist at the species' latitudinal range limits (Finland and Spain). The study demonstrates that macroclimatic differences between these sites should cause greater exposure of the Spanish population to higher temperatures. Thermal stress treatments are used to estimate differences in the expression of four genes potentially relevant for tolerating these temperatures. For the analysis, three heat‐shock proteins and glyceraldehyde‐3‐phosphate dehydrogenase (G3PDH), a glycolysis enzyme that also modulates cell growth based on metabolic state, are chosen. Two constitutive differences are found between the sites. First, insects from Spain have higher levels of Hsp 21.4 than those from Finland regardless of thermal stress treatment; this protein is not inducible. Second, insects from Finland have higher levels of G3PDH. The two remaining Hsps, Hsp20.4 and Hsp90, show dramatic up‐regulation at higher temperatures, although there are no significant differences between insects from the different populations in either constitutive levels or inducibility. In nature, differences between the study populations likely occur in the expression of all four genes that were studied, although these differences would be directly climate‐induced in Hsp20.4 and Hsp90 and constitutive in Hsp21.4 and G3PDH. Inducibility may mitigate the need for constitutive variation in traits that adapt insects to local climate.     

Viral Detection: Past,Present, and Future

Viruses are essentially composed of a nucleic acid (segmented or not, DNA, or RNA) and a protein coat. Despite their simplicity, these small pathogens are responsible for significant economic and humanitarian losses that have had dramatic consequences in the course of human history. Since their discovery, scientists have developed different strategies to efficiently detect viruses, using all possible viral features. Viruses shape, proteins, and nucleic acid are used in viral detection. In this review, the development of these techniques, especially for plant and mammalian viruses, their strengths and weaknesses as well as the latest cutting‐edge technologies that may be playing important roles in the years to come are described.     

Comparative analysis of fish environmental DNA reveals higher sensitivity achieved through targeted sequence-based metabarcoding

Environmental DNA (eDNA)-based methods of species detection are enabling various applications in ecology and conservation including large-scale biomonitoring efforts. qPCR is widely used as the standard approach for species-specific detection, often targeting a fish species of interest from aquatic eDNA. However, DNA metabarcoding has the potential to displace qPCR in certain eDNA applications. In this study, we compare the sensitivity of the latest Illumina NovaSeq 6000 NGS platform to qPCR TaqMan assays by measuring limits of detection and by analysing eDNA from water samples collected from Churchill River and Lake Melville, NL, Canada. Species-specific, targeted next generation sequencing (NGS) assays had significantly higher sensitivity than qPCR, with limits of detection 14- to 29-fold lower. For example, when analysing eDNA, qPCR detected Gadus ogac (Greenland cod) in 21% of samples, but targeted NGS detected this species in 29% of samples. General NGS assays were as sensitive as qPCR, while simultaneously detecting 15 fish species from eDNA samples. With over 34,000 fish species on the planet, parallel and sensitive methods such as NGS will be required to support effective biomonitoring at both regional and global scales.     

Arabidopsis peroxidase AtPRX53 influences cell elongation and susceptibility to Heterodera schachtii

Cyst nematodes establish and maintain feeding sites (syncytia) in the roots of host plants by altering expression of host genes. Among these genes are members of the large gene family of class III peroxidases, which have reported functions in a variety of biological processes. In this study, we used Arabidopsis-Heterodera schachtii as a model system to functionally characterize peroxidase 53 (AtPRX53). Promoter assays showed that under non-infected conditions AtPRX53 is expressed mainly in the root, the hypocotyl and the base of the pistil. Under infected conditions, the AtPRX53 promoter showed upregulation at the nematode penetration sites and in their migration paths. Interestingly, strong GUS activity was observed in H. schachtii-induced syncytia during the early stage of infection and remained strong in the syncytia of third-stage juveniles. Also, AtPRX53 showed upregulation in response to wounding and jasmonic acid treatments. Manipulation of AtPRX53 expression through overexpression and knockout mutation affected both plant morphology and nematode susceptibility. While AtPRX53 overexpression lines exhibited short hypocotyls, aberrant flower development and reduced nematode susceptibility to H. schachtii, the atprx53 mutant showed long hypocotyls and a 3-carpel silique phenotype as well as a non significant increase of nematode susceptibility. Taken together these data, therefore, indicate diverse roles of AtPRX53 in the wound response, flower development and syncytium formation.