Advanced Methods for Spatial Analysis of Bioaerosol Long-Range Transport Processes

Research on bioaerosol is still in its infancy. The dynamics and, therefore, the effects on atmospheric processes and the biosphere are often underestimated, or have not yet been sufficiently investigated. Atmospheric models such as FLEXPART and HYSPLIT enable researchers to simulate the transport of particles in the atmosphere and provide information on where air-parcels originate from. In the following, we present two methods for combining results of these models with spatial information, e.g., about vegetation. The first method shows how spatial CORINE land cover distribution can be analyzed within the boundaries of HYSPLIT trajectories. In a second method, FLEXPART simulations are used in combination with COSMO rain data and tree maps to generate maps that indicate the potential origin of bioaerosol for selected periods of time

Species Richness, rRNA Gene Abundance, and Seasonal Dynamics of Airborne Plant-Pathogenic Oomycetes

Oomycetes, also named Peronosporomycetes, are one of the most important and widespread groups of plant pathogens, leading to significant losses in the global agricultural productivity. They have been studied extensively in ground water, soil, and host plants, but their atmospheric transport vector is not well characterized. In this study, the occurrence of airborne Oomycetes was investigated by Sanger sequencing and quantitative PCR of coarse and fine aerosol particle samples (57 filter pairs) collected over a 1-year period (2006–2007) and full seasonal cycle in Mainz, Germany. In coarse particulate matter, we found 55 different hypothetical species (OTUs), of which 54 were plant pathogens and 29 belonged to the genus Peronospora (downy mildews). In fine particulate matter (<3 μm), only one species of Hyaloperonospora was found in one sample. Principal coordinate analysis of the species composition revealed three community clusters with a dependence on ambient temperature. The abundance of Oomycetes rRNA genes was low in winter and enhanced during spring, summer, and fall, with a dominance of Phytophthora, reaching a maximum concentration of ∼1.6 × 106 rRNA genes per cubic meter of sampled air in summer. The presence and high concentration of rRNA genes in air suggests that atmospheric transport, which can lead to secondary infection, may be more important than currently estimated. This illustrates the need for more current and detailed datasets, as potential seasonal shifts due to changing meteorological conditions may influence the composition of airborne Oomycetes. An insight into the dynamics of airborne plant pathogens and their major drivers should be useful for improved forecasting and management of related plant diseases

Species Richness, rRNA Gene Abundance, and Seasonal Dynamics of Airborne Plant-Pathogenic Oomycetes

Oomycetes, also named Peronosporomycetes, are one of the most important and widespread groups of plant pathogens, leading to significant losses in the global agricultural productivity. They have been studied extensively in ground water, soil, and host plants, but their atmospheric transport vector is not well characterized. In this study, the occurrence of airborne Oomycetes was investigated by Sanger sequencing and quantitative PCR of coarse and fine aerosol particle samples (57 filter pairs) collected over a 1-year period (2006–2007) and full seasonal cycle in Mainz, Germany. In coarse particulate matter, we found 55 different hypothetical species (OTUs), of which 54 were plant pathogens and 29 belonged to the genus Peronospora (downy mildews). In fine particulate matter (<3 μm), only one species of Hyaloperonospora was found in one sample. Principal coordinate analysis of the species composition revealed three community clusters with a dependence on ambient temperature. The abundance of Oomycetes rRNA genes was low in winter and enhanced during spring, summer, and fall, with a dominance of Phytophthora, reaching a maximum concentration of ∼1.6 × 106 rRNA genes per cubic meter of sampled air in summer. The presence and high concentration of rRNA genes in air suggests that atmospheric transport, which can lead to secondary infection, may be more important than currently estimated. This illustrates the need for more current and detailed datasets, as potential seasonal shifts due to changing meteorological conditions may influence the composition of airborne Oomycetes. An insight into the dynamics of airborne plant pathogens and their major drivers should be useful for improved forecasting and management of related plant diseases

Comparison between qPCR measurements and COSMO-ART simulation.

<p>(a) DNA concentrations in copies m^-3 (cp m^-3) of coarse particle filter samples are given for multi-copy ITS region (cp m^-3 air: primary vertical axis) and simulations of pollen concentrations from COSMO-ART (sum of pollen grains per m³ air: on secondary vertical axis) during the birch-specific main-pollination period in 2010 (2010-03-30 / 2010-04-27, x-axis) for Mainz (b) Quantification results for single-copy <i>BP8</i> gene (cp m^-3 air: primary y axis) and pollen concentrations from COSMO-ART for Mainz and Löwenstein, as well as pollen concentrations averaged hourly in pollen m^-3 sampled via Burkard traps (secondary y axis) are summed corresponding to the sampling interval of the appropriate filter sample(y-axis) during the birch-specific main-pollination period in 2010 (2010-03-30 / 2010-04-27, x-axis). Pollen counts were provided from nearest available pollen measurement station in Löwenstein, Baden-Wurttemberg about 130 kilometers south-east of Mainz.</p

Equation parameter.

<p>Parameters used in Eqs <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0140949#pone.0140949.e001" target="_blank">1</a>–<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0140949#pone.0140949.e003" target="_blank">3</a> are given with their abbreviation, their definition and units.</p><p>Equation parameter.</p

Statistical Analysis.

<p>The Shapiro-Wilk-Test states, that data with a p-value higher than 0.05 is normally distributed.</p><p>Statistical Analysis.</p

Comparison of qPCR results with simulation and pollen trap data.

<p>DNA concentrations (cp m^-3) are listed for ITS multi-copy region and <i>BP8</i> single-copy gene for coarse and fine particle filter samples, respectively. The original measured DNA copies in the coarse particle fractions were divided by three to correct for the tricellular nature of <i>Betula pendula</i> pollen grains. Calculated pollen concentrations with COSMO-ART for Mainz and Löwenstein and measured pollen concentrations in pollen grains m^-3 via Burkard sampler in Löwenstein were averaged corresponding to the sampling interval of the appropriate filter sample; n.a.: not available.</p><p>Comparison of qPCR results with simulation and pollen trap data.</p