Investigating the Host-Range of the Rust Fungus Puccinia psidii sensu lato across Tribes of the Family Myrtaceae Present in Australia

The exotic rust fungus Puccinia psidii sensu lato was first detected in Australia in April 2010. This study aimed to determine the host-range potential of this accession of the rust by testing its pathogenicity on plants of 122 taxa, representative of the 15 tribes of the subfamily Myrtoideae in the family Myrtaceae. Each taxon was tested in two separate trials (unless indicated otherwise) that comprised up to five replicates per taxon and six replicates of a positive control (Syzygium jambos). No visible symptoms were observed on the following four taxa in either trial: Eucalyptus grandis×camaldulensis, E. moluccana, Lophostemon confertus and Sannantha angusta. Only small chlorotic or necrotic flecks without any uredinia (rust fruiting bodies) were observed on inoculated leaves of seven other taxa (Acca sellowiana, Corymbia calophylla ‘Rosea’, Lophostemon suaveolens, Psidium cattleyanum, P. guajava ‘Hawaiian’ and ‘Indian’, Syzygium unipunctatum). Fully-developed uredinia were observed on all replicates across both trials of 28 taxa from 8 tribes belonging to the following 17 genera: Agonis, Austromyrtus, Beaufortia, Callistemon, Calothamnus, Chamelaucium, Darwinia, Eucalyptus, Gossia, Kunzea, Leptospermum, Melaleuca, Metrosideros, Syzygium, Thryptomene, Tristania, Verticordia. In contrast, the remaining 83 taxa inoculated, including the majority of Corymbia and Eucalyptus species, developed a broad range of symptoms, often across the full spectrum, from fully-developed uredinia to no visible symptoms. These results were encouraging as they indicate that some levels of genetic resistance to the rust possibly exist in these taxa. Overall, our results indicated no apparent association between the presence or absence of disease symptoms and the phylogenetic relatedness of taxa. It is most likely that the majority of the thousands of Myrtaceae species found in Australia have the potential to become infected to some degree by the rust, although this wide host range may not be fully realized in the field

Comparison of results of pathogenicity testing performed under controlled conditions with <i>Puccinia psidii</i> s.l. from Australia (DAR81284) (based on this study) and other accessions of the rust from Florida [19] and Brazil [21].

a<p>Only taxa that did not develop any uredinia with the Australian accession of the rust or with one of the other two accessions used in other studies are included.</p>b<p>+ = uredinia present; − = uredinia absent; × = taxon not tested.</p>c<p>Only taxa categorized as 100% resistant are included.</p>d<p>Synonym of <i>Feijoa sellowiana</i>.</p>e<p>Listed as <i>Asteromyrtus dulcia</i> in Zauza et al. <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0035434#pone.0035434-Zauza1" target="_blank">[21]</a>.</p>f<p>Only plants of accessions 15877 & 20010 from the CSIRO Australian Tree Seed Centre tested were found to be resistant.</p>g<p>Only plants of accession 18324 from the CSIRO Australian Tree Seed Centre tested were found to be resistant.</p>h<p>Identified to subspecies level in current study.</p>i<p>Only plants of accession 13953 from the CSIRO Australian Tree Seed Centre tested were found to be resistant.</p>j<p>This species was also found to be susceptible to the rust accession recently found in Japan in pathogenicity testing conducted by Kawanishi et al. <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0035434#pone.0035434-Kawanishi1" target="_blank">[11]</a>.</p>k<p>Only plants of accession 17763 from the CSIRO Australian Tree Seed Centre tested were found to be resistant.</p>l<p>With rust accession recovered from <i>Pimenta dioica</i>.</p>m<p>With rust accession recovered from <i>Melaleuca quinquenervia</i>.</p>n<p>Relates to accession RF12 from the CSIRO Australian Tree Seed Centre.</p

Plant taxa grouped according to disease symptoms at three weeks after inoculation with <i>Puccinia psidii</i> s.l. (ex Australia, DAR81284).

a<p>Scores based on scoring system in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0035434#pone-0035434-g001" target="_blank">Figure 1</a>.</p>b<p>Authorship of names presented in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0035434#pone.0035434.s001" target="_blank">Table S1</a>.Number in parentheses correspond to tribe number based on Wilson et al. <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0035434#pone.0035434-Wilson1" target="_blank">[29]</a>.</p>c<p>Teliospores present on one or more replicates.</p

Scoring system for disease symptoms.

<p>Scoring system used to categorize visible symptoms observed on leaves three weeks after inoculation of plants with <i>Puccinia psidii</i> s.l. (ex Australia, DAR81284). The three leaves with the most severe symptoms on a plant were scored and the highest individual leaf score per plant was assigned to that replicate.</p

Lipid Oxidation in Oil-in-Water Emulsions: Involvement of the Interfacial Layer

International audienceMore polyunsaturated fats in processed foods and fewer additives are a huge demand of public health agencies and consumers. Consequently, although foods have an enhanced tendency to oxidize, the usage of antioxidants, especially synthetic antioxidants, is restrained. An alternate solution is to better control the localization of reactants inside the food matrix to limit oxidation. This review establishes the state-of-the-art on lipid oxidation in oil-in-water (O/W) emulsions, with an emphasis on the role of the interfacial region, a critical area in the system in that respect. We first provide a summary on the essential basic knowledge regarding (i) the structure of O/W emulsions and interfaces and (ii) the general mechanisms of lipid oxidation. Then, we discuss the factors involved in the development of lipid oxidation in O/W emulsions with a special focus on the role played by the interfacial region. The multiple effects that can be attributed to emulsifiers according to their chemical structure and their location, and the interrelationships between the parameters that define the physicochemistry and structure of emulsions are highlighted. This work sheds new light on the interpretation of reported results that are sometimes ambiguous or contradictory