Porosity imaging in porous media using synchrotron tomographic techniques

This paper describes novel uses of synchrotron radiation in examining porosity distributions within porous media. Tomographic energy dispersive diffraction imaging and Tomographic X-ray fluorescence have been combined within one measurement method and used to highlight the porosity distribution in a typical sample of English Chalk

Identification and Characterisation CRN Effectors in <em>Phytophthora capsici </em>Shows Modularity and Functional Diversity

Phytophthora species secrete a large array of effectors during infection of their host plants. The Crinkler (CRN) gene family encodes a ubiquitous but understudied class of effectors with possible but as of yet unknown roles in infection. To appreciate CRN effector function in Phytophthora, we devised a simple Crn gene identification and annotation pipeline to improve effector prediction rates. We predicted 84 full-length CRN coding genes and assessed CRN effector domain diversity in sequenced Oomycete genomes. These analyses revealed evidence of CRN domain innovation in Phytophthora and expansion in the Peronosporales. We performed gene expression analyses to validate and define two classes of CRN effectors, each possibly contributing to infection at different stages. CRN localisation studies revealed that P. capsici CRN effector domains target the nucleus and accumulate in specific sub-nuclear compartments. Phenotypic analyses showed that few CRN domains induce necrosis when expressed in planta and that one cell death inducing effector, enhances P. capsici virulence on Nicotiana benthamiana. These results suggest that the CRN protein family form an important class of intracellular effectors that target the host nucleus during infection. These results combined with domain expansion in hemi-biotrophic and necrotrophic pathogens, suggests specific contributions to pathogen lifestyles. This work will bolster CRN identification efforts in other sequenced oomycete species and set the stage for future functional studies towards understanding CRN effector functions

Phenotypic and functional analyses of CRN effector domains <i>in planta</i>.

<p>A) Only three CRNs caused necrosis after over-expression in plants. Bars show average values for at least three independent infiltration events with four or more infiltration sites per construct per event. B) One CRN had a direct effect on virulence of <i>P. capsici</i>. Lesion size for all other CRNs was similar to that of the empty vector (EV) control. Error bars show standard deviations within the samples. Lesion size was measured during three independent infection events using four infection sites per construct. C) Onset of necrosis was not responsible for increased virulence. Panel 2 shows necrosis onset (dotted circles) for 79_188, but no increase in <i>P</i>. <i>capsici</i> lesion size (full circles) as seen for 83_152 (Panel 3). Panel A, X-axis: necrosis score as defined by picture panels on the right, Panel B X-Axis, Lesion size in mm.</p