Frequency of a natural truncated allele of <Emphasis Type="Italic">MdMLO19</Emphasis> in the germplasm of <Emphasis Type="Italic">Malus domestica</Emphasis>

Podosphaera leucotricha is the causal agent of powdery mildew (PM) in apple. To reduce the amount of fungicides required to control this pathogen, the development of resistant apple cultivars should become a priority. Resistance to PM was achieved in various crops by knocking out specific members of the MLO gene family that are responsible for PM susceptibility (S-genes). In apple, the knockdown of MdMLO19 resulted in PM resistance. However, since gene silencing technologies such as RNAi are perceived unfavorably in Europe, a different approach that exploits this type of resistance is needed. This work evaluates the presence of non-functional naturally occurring alleles of MdMLO19 in apple germplasm. The screening of the re-sequencing data of 63 apple individuals led to the identification of 627 single nucleotide polymorphisms (SNPs) in five MLO genes (MdMLO5, MdMLO7, MdMLO11, MdMLO18, and MdMLO19), 127 of which were located in exons. The T-1201 insertion of a single nucleotide in MdMLO19 caused the formation of an early stop codon, resulting in a truncated protein lacking 185 amino acids, including the calmodulin-binding domain. The presence of the insertion was evaluated in 115 individuals. It was heterozygous in 64 and homozygous in 25. Twelve of the 25 individuals carrying the insertion in homozygosity were susceptible to PM. After barley, pea, cucumber, and tomato, apple would be the fifth species for which a natural non-functional mlo allele has been found.     

Phylogenetic analysis of the genus <Emphasis Type="Italic">Argia</Emphasis> Rambur, 1842 (Odonata: Coenagrionidae), based on morphological characters of larvae and mitochondrial DNA sequences

The study of the evolutionary interrelationships among the species encompassed in the Neotropical genus Argia (Zygoptera: Coenagrionidae) has been neglected. The goal of this study is to infer the phylogenetic relationships among 36 species of Argia Rambur, 1842, using complementary data sets (i.e., larval morphology and mitochondrial DNA). The morphological data set comprises 76% of the larvae currently described for this genus and includes 97 morphological characters. From those, 47 characters have not been previously used in taxonomic studies involving dragonflies’ larvae. This is the first cladistic study based on larvae morphology for species within the suborder Zygoptera. Data partitions were analyzed individually, as well as total evidence, using parsimony and Bayesian inference as criteria for optimal-tree selection. The results support the monophyly of the North American species of Argia. This genus can be identified by the combination of eight synapomorphies, four of which are exclusively found in Argia. According to the optimal trees, the individual data sets (i.e., morphology and DNA sequences) have a high level of homoplasy, resulting in soft polytomies and low support for several nodes. The specific relationships of the terminal units differ between the phylogenies; nonetheless, there is historical congruence among them. Within Argia, five clades were consistently recovered. Most of those clades have been identified, at least in part, in previous phylogenetic and taxonomic studies. Indubitably, the morphological characters from larvae have historical signal useful for cladistic and taxonomic inference. Therefore, it should be a priority to pay more attention to this source of characters.     

An Emerging Approach for Parallel Quantification of Intracellular Protozoan Parasites and Host Cell Characterization Using TissueFAXS Cytometry

Characterization of host-pathogen interactions is a fundamental approach in microbiological and immunological oriented disciplines. It is commonly accepted that host cells start to change their phenotype after engulfing pathogens. Techniques such as real time PCR or ELISA were used to characterize the genes encoding proteins that are associated either with pathogen elimination or immune escape mechanisms. Most of such studies were performed in vitro using primary host cells or cell lines. Consequently, the data generated with such approaches reflect the global RNA expression or protein amount recovered from all cells in culture. This is justified when all host cells harbor an equal amount of pathogens under experimental conditions. However, the uptake of pathogens by phagocytic cells is not synchronized. Consequently, there are host cells incorporating different amounts of pathogens that might result in distinct pathogen-induced protein biosynthesis. Therefore, we established a technique able to detect and quantify the number of pathogens in the corresponding host cells using immunofluorescence-based high throughput analysis. Paired with multicolor staining of molecules of interest it is now possible to analyze the infection profile of host cell populations and the corresponding phenotype of the host cells as a result of parasite load.     

The tadpole of Scinax skuki (Anura: Hylidae) from the type locality,with a description of its larval skeleton

Herein, we provide external and internal morphological data of Scinax skuki tadpoles from its type locality. The benthic tadpole of S. skuki has eyes and nostrils positioned dorsally, vent tube dextral and reaching the free margin of the ventral fin, oral disk ventral with posterior margin concave when partially closed, labial tooth row formula 2/3, and the presence of nonpigmented spurs behind the lower jaw. These characters, together with the absence of a tectum parietale, and the shapes of the pars articularis quadrati and suprarostral, are useful for species identification and may be informative for systematic purposes.     

Biodiversity impacts from water consumption on a global scale for use in life cycle assessment

Purpose

Agriculture is a major water user worldwide, potentially depriving many ecosystems of water. Comprehensive global impact assessment methodologies are therefore required to assess impacts from water consumption on biodiversity. Since scarcity of water, as well as species richness, varies greatly between different world regions, a spatially differentiated approach is needed. Therefore, our aim is to enhance a previously published methodology in terms of spatial and species coverage.

Methods

We developed characterization factors for lifecycle impact assessment (LCIA) targeting biodiversity loss of various animal taxa (i.e., birds, reptiles, mammals, and amphibians) in wetlands. Data was collected for more than 22,000 wetlands worldwide, distinguishing between surface water- and groundwater-fed wetlands. Additionally, we account for a loss of vascular plant species in terrestrial ecosystems, based on precipitation. The characterization factors are expressed as global fractions of potential species extinctions (PDF) per cubic meter of water consumed annually and are developed with a spatial resolution of 0.05 arc degrees. Based on the geographic range of species, as well as their current threat level, as indicated by the International Union for Conservation of Nature (IUCN), we developed a vulnerability indicator that is included in the characterization factor.

Results and discussion

Characterization factors have maximal values in the order of magnitude of 10^?11 PDF·year/m³ for animal taxa combined and 10^?12 PDF·year/m³ for vascular plants. The application of the developed factors for global cultivation of wheat, maize, cotton, and rice highlights that the amount of water consumption alone is not sufficient to indicate the places of largest impacts but that species richness and vulnerability of species are indeed important factors to consider. Largest impacts are calculated for vascular plants in Madagascar, for maize, and for animal taxa; in Australia and the USA for surface water consumption (cotton); and in Algeria and Tunisia for groundwater consumption (cotton).

Conclusions

We developed a spatially differentiated approach to account for impacts from water consumption on a global level. We demonstrated its functionality with an application to a global case study of four different crops.

     

A Dynamic Gene Regulatory Network Model That Recovers the Cyclic Behavior of Arabidopsis thaliana Cell Cycle

Cell cycle control is fundamental in eukaryotic development. Several modeling efforts have been used to integrate the complex network of interacting molecular components involved in cell cycle dynamics. In this paper, we aimed at recovering the regulatory logic upstream of previously known components of cell cycle control, with the aim of understanding the mechanisms underlying the emergence of the cyclic behavior of such components. We focus on Arabidopsis thaliana, but given that many components of cell cycle regulation are conserved among eukaryotes, when experimental data for this system was not available, we considered experimental results from yeast and animal systems. We are proposing a Boolean gene regulatory network (GRN) that converges into only one robust limit cycle attractor that closely resembles the cyclic behavior of the key cell-cycle molecular components and other regulators considered here. We validate the model by comparing our in silico configurations with data from loss- and gain-of-function mutants, where the endocyclic behavior also was recovered. Additionally, we approximate a continuous model and recovered the temporal periodic expression profiles of the cell-cycle molecular components involved, thus suggesting that the single limit cycle attractor recovered with the Boolean model is not an artifact of its discrete and synchronous nature, but rather an emergent consequence of the inherent characteristics of the regulatory logic proposed here. This dynamical model, hence provides a novel theoretical framework to address cell cycle regulation in plants, and it can also be used to propose novel predictions regarding cell cycle regulation in other eukaryotes.