AUTHOR=Meng Yuling , Huang Yihua , Wang Qinhu , Wen Qujiang , Jia Jinbu , Zhang Qiang , Huang Guiyan , Quan Junli , Shan Weixing 

TITLE=Phenotypic and genetic characterization of resistance in Arabidopsis thaliana to the oomycete pathogen Phytophthora parasitica

JOURNAL=Frontiers in Plant Science

VOLUME=6

YEAR=2015

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2015.00378

DOI=10.3389/fpls.2015.00378

ISSN=1664-462X

ABSTRACT=<p>The interaction between <italic>Arabidopsis thaliana</italic> and the oomycete pathogen <italic>Phytophthora parasitica</italic> emerges as a model for exploring the molecular basis and evolution of recognition and host defense. Phenotypic variation and genetic analysis is essential to dissect the underlying mechanisms in plant–oomycete interaction. In this study, the reaction phenotypes of 28 <italic>A. thaliana</italic> accessions to <italic>P. parasitica</italic> strain Pp016 were examined using detached leaf infection assay. The results showed the presence of four distinct groups based on host response and disease development. Of all the accessions examined, Zurich (Zu-1) is highly resistant to <italic>P. parasitica</italic>. Microscopic characterization showed that rapid and severe hypersensitive response at the primary infection epidermal cells is associated with disease resistance. Furthermore, Zu-1 is resistant to a set of 20 diverse <italic>P. parasitica</italic> strains, which were collected from different host plants and exhibited differential specificities on a set of tobacco cultivars. However, Zu-1 is susceptible to <italic>P. parasitica</italic> when the root is inoculated, suggesting differential expression of associated resistance genes in the root and foliar tissues. Genetic analysis by crossing Zu-1 and the susceptible accession Landsberg (Ler) showed that the resistance in Zu-1 to <italic>P. parasitica</italic> is semi-dominant, as shown by infection assays of F<sub>1</sub> progenies, and is likely conferred by a single locus, defined as <italic>RPPA1<sup><italic>Zu-1</italic></sup></italic> (for Resistance to <italic>P. parasitica</italic> 1), as shown by analysis of F<sub>2</sub> segregating populations. By employing specific-locus amplified fragment sequencing (SLAF-seq) strategy to identify molecular markers potentially linked to the locus, the strongest associated region was determined to be located between 7.1 and 11.2 Mb in chromosome IV. The future cloning of <italic>RPPA1<sup><italic>Zu-1</italic></sup></italic> locus will facilitate improved understanding of plant broad-spectrum disease resistance to oomycete pathogens.</p>