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ARS Home » Pacific West Area » Davis, California » Crops Pathology and Genetics Research » Research » Publications at this Location » Publication #355624

Research Project: Integrated Disease Management Strategies for Woody Perennial Species

Location: Crops Pathology and Genetics Research

Title: Characterization of phenotypic variation and genome aberrations observed among Phytophthora ramorum isolates from diverse hosts

Author
item Elliot, Marianne - Washington State University Extension Service
item Yuzon, Jennifer - University Of California, Davis
item Malar, Mathu - Council Of Scientific And Industrial Research (CSIR)
item Tripathy, Sucheta - Council Of Scientific And Industrial Research (CSIR)
item Bui, Mai - US Department Of Agriculture (USDA)
item Chastagner, Gary - Washington State University Extension Service
item Coats, Katie - Washington State University Extension Service
item Rizzo, David - University Of California, Davis
item Garbelotto, Matteo - University Of California
item Kasuga, Takao

Submitted to: BMC Genomics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/22/2018
Publication Date: 5/2/2018
Citation: Elliot, M., Yuzon, J., Malar, M.C., Tripathy, S., Bui, M., Chastagner, G.A., Coats, K., Rizzo, D.M., Garbelotto, M., Kasuga, T. 2018. Characterization of phenotypic variation and genome aberrations observed among Phytophthora ramorum isolates from diverse hosts. BMC Genomics. 19:320. https://doi.org/10.1186/s12864-018-4709-7.
DOI: https://doi.org/10.1186/s12864-018-4709-7

Interpretive Summary:

Technical Abstract: Accumulating evidence suggests that genome plasticity allows filamentous plant pathogens to adapt to changing environments. Recently, the generalist plant pathogen Phytophthora ramorum has been documented to undergo irreversible phenotypic alterations accompanied by chromosomal aberrations when infecting trunks of mature oak trees (genus Quercus). In contrast, genomes and phenotypes of the pathogen derived from the foliage of California bay (Umbellularia californica) are usually stable. We define this phenomenon as host-induced phenotypic diversification (HIPD). P. ramorum also causes a severe foliar blight in some ornamental plants such as Rhododendron spp. and Viburnum spp., and isolates from these hosts occasionally show phenotypes resembling those from oak trunks that carry chromosomal aberrations. The aim of this study was to investigate variations in phenotypes and genomes of P. ramorum isolates from non-oak hosts and substrates to determine whether HIPD changes may be equivalent to those among isolates from oaks. We analyzed genomes of diverse non-oak isolates including those taken from foliage of Rhododendron and other ornamental plants, as well as from natural host species, soil, and water. Isolates recovered from artificially inoculated oak logs were also examined. We identified diverse chromosomal aberrations including copy neutral loss of heterozygosity (cnLOH) and aneuploidy in isolates from non-oak hosts. Most identified aberrations in non-oak hosts were also common among oak isolates; however, trisomy, a frequent type of chromosomal aberration in oak isolates was not observed in isolates from Rhododendron. This work cross-examined phenotypic variation and chromosomal aberrations in P. ramorum isolates from oak and non-oak hosts and substrates. The results suggest that HIPD comparable to that occurring in oak hosts occurs in non- oak environments such as in Rhododendron leaves. Rhododendron leaves are more easily available than mature oak stems and thus can potentially serve as a model host for the investigation of HIPD, the newly described plant-pathogen interaction.