Skip to Main Content
U.S. Forest Service
Caring for the land and serving people

United States Department of Agriculture

Home > Search > Publication Information

  1. Share via EmailShare on FacebookShare on LinkedInShare on Twitter
    Dislike this pubLike this pub
    Author(s): Annelies Vercauteren; Xavier Boutet; Anne Chandelier; Kurt Heungens; Martine Maes
    Date: 2010
    Source: In: Frankel, Susan J.; Kliejunas, John T.; Palmieri, Katharine M. 2010. Proceedings of the Sudden Oak Death Fourth Science Symposium. Gen. Tech. Rep. PSW-GTR-229. Albany, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station. pp. 101-104
    Publication Series: General Technical Report (GTR)
    PDF: Download Publication  (21.44 KB)

    Description

    Phytophthora ramorum has three populations belonging to the same species: the two North American populations (NA1 and NA2) and the European population (EU1). All three populations are genetically distinct lineages, as revealed by different molecular marker systems. P. ramorum is also heterothallic, with two opposite mating types, A1 and A2. All NA1 and NA2 isolates are of the A2 mating type. All EU1 isolates have been identified as A1, except for three A2 isolates collected in Belgium in 2002 and 2003. Since 2004, no isolates of the A2 mating type have been reported in Europe, which limits the risk of sexual recombination in Europe. In contrast, several EU1 isolates have been reported in nurseries in North America, some even at sites where NA1 isolates were also found. Although sexual reproduction in nature has not been observed yet, the presence of isolates of both mating types at a single site might lead to genetic recombination, which could lead to an increase in pathogen fitness and host range. The formation of sexual resting oospores might also increase the long-term survival of P. ramorum. The ability of plant pathogen populations to respond to novel challenges from their environment, such as host resistance and pesticide exposure, depends on their mechanisms for generating genetic variation.

    Germinating oospores have been obtained in vitro from crosses between EU1-A1 and NA1- A2 isolates as well as between EU1-A1 and EU1-A2 isolates (Boutet and others, unpublished), but at a low frequency. To determine the nature of sexual recombination in P. ramorum, germinating oospores of a cross between an NA1-A2 isolate and an EU1-A1 isolate were genotyped with microsatellite markers that were heterozygous in the parental isolates. All crosses contained alleles of both parents, confirming exchange of genetic material, but meiotic irregularities occurred frequently. Non-Mendelian inheritance events were also observed. This included inheritance of more than two alleles at a single locus or loss of alleles from one of the parents at a separate locus. The aneuploid progeny was also mitotically unstable: zoospore and hyphal tip derivatives of the progenies showed genotypic rearrangements as well as phenotypic variation. These data indicate that progenies from crossings between P. ramorum isolates are often aneuploid and genetically unstable.

    Publication Notes

    • You may send email to psw_communications@fs.fed.us to request a hard copy of this publication.
    • (Please specify exactly which publication you are requesting and your mailing address.)
    • We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
    • This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.

    Citation

    Vercauteren, Annelies; Boutet, Xavier; Chandelier, Anne; Heungens, Kurt; Maes, Martine. 2010. Unstable Aneuploid Progenies of Phytophthora ramorum. In: Frankel, Susan J.; Kliejunas, John T.; Palmieri, Katharine M. 2010. Proceedings of the Sudden Oak Death Fourth Science Symposium. Gen. Tech. Rep. PSW-GTR-229. Albany, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station. pp. 101-104

    Related Search


    XML: View XML
Show More
Show Fewer
Jump to Top of Page
https://www.fs.usda.gov/treesearch/pubs/35070