Publications

characterisation of european and north american phytophthora ramorum isolates due to their morphology and mating behaviour in vitro with heterothallic phytophthora species.	vegetative growth rate, and size of sporangia, chlamydospores and oospores from 94 p. ramorum isolates were measured and the isolates were paired in vitro with four different heterothallic phytophthora species isolated from infected nursery plants in germany. p. ramorum isolates originated from different european countries and from canada and the usa. 66 of the 67 european isolates were determined as mating type a1; only one isolate was of mating type a2. of the 27 north american isolates tested ...	2005	16175788
characterization of a phytophthora mating hormone.	water molds of the genus phytophthora include many plant pathogens responsible for epidemics such as potato blight and sudden oak death, causing global economic damages. sexual reproduction is of biological importance in phytophthora and has been believed to be stimulated by unknown endogenous factors named a hormones. we describe here the chemical characterization of a phytophthora mating hormone, a1, which was obtained from approximately 2 tons of culture fluid of one mating type of a species ...	2005	16166510
mosaic origin of the heme biosynthesis pathway in photosynthetic eukaryotes.	heme biosynthesis represents one of the most essential metabolic pathways in living organisms, providing the precursors for cytochrome prosthetic groups, photosynthetic pigments, and vitamin b(12). using genomic data, we have compared the heme pathway in the diatom thalassiosira pseudonana and the red alga cyanidioschyzon merolae to those of green algae and higher plants, as well as to those of heterotrophic eukaryotes (fungi, apicomplexans, and animals). phylogenetic analyses showed the mosaic ...	2005	16093570
phytophthora ramorum: integrative research and management of an emerging pathogen in california and oregon forests.	phytophthora ramorum, causal agent of sudden oak death, is an emerging plant pathogen first observed in north america associated with mortality of tanoak (lithocarpus densiflorus) and coast live oak (quercus agrifolia) in coastal forests of california during the mid-1990s. the pathogen is now known to occur in north america and europe and have a host range of over 40 plant genera. sudden oak death has become an example of unintended linkages between the horticultural industry and potential impac ...	2005	16078887
examining the strength and possible causes of the relationship between fire history and sudden oak death.	fire can be a dominant process in the ecology of forest vegetation and can also affect forest disease dynamics. little is known about the relationship between fire and an emerging disease epidemic called sudden oak death, which is caused by a new pathogen, phytophthora ramorum. this disease has spread across a large, fire-prone portion of california, killing great numbers of oaks and tanoaks and infecting most associated woody plants. suitable hosts cover a much broader geographic range, raising ...	2005	15891855
a transmembrane phospholipase d in phytophthora; a novel pld subfamily.	phospholipase d (pld) is a ubiquitous enzyme in eukaryotes that participates in various cellular processes. its catalytic domain is characterized by two hkd motifs in the c-terminal part. until now, two subfamilies were recognized based on their n-terminal domain structure. the first has a px domain in combination with a ph domain and is designated as pxph-pld. members of the second subfamily, named c2-pld, have a c2 domain and have, so far, only been found in plants. here we describe a novel pl ...	2005	15826868
on-site dna extraction and real-time pcr for detection of phytophthora ramorum in the field.	phytophthora ramorum is a recently described pathogen causing oak mortality (sudden oak death) in forests in coastal areas of california and southern oregon and dieback and leaf blight in a range of tree, shrub, and herbaceous species in the united states and europe. due to the threat posed by this organism, stringent quarantine regulations are in place, which restrict the movement of a number of hosts. fast and accurate diagnostic tests are required in order to characterize the distribution of ...	2005	16269700
is variation in susceptibility to phytophthora ramorum correlated with population genetic structure in coast live oak (quercus agrifolia)?	california coastal woodlands are suffering severe disease and mortality as a result of infection from phytophthora ramorum. quercus agrifolia is one of the major woodland species at risk. this study investigated within- and among-population variation in host susceptibility to inoculation with p. ramorum and compared this with population genetic structure using molecular markers. susceptibility was assessed using a branch-cutting inoculation test. trees were selected from seven natural population ...	2005	15720634
transmission of phytophthora ramorum in mixed-evergreen forest in california.	abstract during 2001 to 2003, the transmission biology of phytophthora ramorum, the causal agent of sudden oak death, was studied in mixedevergreen forest, a common forest type in northern, coastal california. investigation of the sources of spore production focused on coast live oak (quercus agrifolia) and bay laurel (umbellularia californica), dominant hosts that comprised 39.7 and 46.2% of the individuals at the study site, respectively. all tests for inoculum production from the surface of i ...	2005	18943326
a rapid diagnostic test to distinguish between american and european populations of phytophthora ramorum.	abstract a new devastating disease in the united states, commonly known as sudden oak death, is caused by phytophthora ramorum. this pathogen, which previously was described attacking species of rhododendron and viburnum in germany and the netherlands, has established itself in forests on the central coast of california and is killing scores of native oak trees (lithocarpus densiflora, quercus agrifolia, q. kelloggii, and q. parvula var. shrevei). the phytosanitary authorities in the european un ...	2004	18943486
molecular detection of phytophthora ramorum, the causal agent of sudden oak death in california, and two additional species commonly recovered from diseased plant material.	abstract sudden oak death is a disease currently devastating forest ecosystems in several coastal areas of california. the pathogen causing this is phy-tophthora ramorum, although species such as p. nemorosa and p. pseudo-syringae often are recovered from symptomatic plants as well. a molecular marker system was developed based on mitochondrial sequences of the cox i and ii genes for detection of phytophthora spp. in general, and p. ramorum, p. nemorosa, and p. pseudosyringae in particular. the ...	2004	18943487
plant pathology. nurseries may have shipped sudden oak death pathogen nationwide.		2004	15044777
rapid identification of phytophthora ramorum using pcr-sscp analysis of ribosomal dna its-1.	the primary objectives of this study were to determine if a single-strand conformation polymorphism (sscp) analysis can be used for rapid identification of phytophthora ramorum, an important quarantine plant pathogen worldwide, and to further assess the potential of the sscp technique as a taxonomic tool for the genus phytophthora.	2004	15059217
production of gametangia by phytophthora ramorum in vitro.	until now gametangia have not been obtained between paired european a1 and american a2 isolates of phytopthora ramorum in vitro. their production in artificial culture relies on interspecific pairings. using p. drechsleri and p. cambivora testers, 51 of 110 p. ramorum isolates from across europe were all shown to be a1s; while 32 of 38 american isolates from across california and southwest oregon were shown to be a2s. however, these interspecific pairings are complex, unusually slow and unpredic ...	2004	15446716
ecological society of america meeting. fighting sudden oak death with fire?		2004	15326331
aflp and phylogenetic analyses of north american and european populations of phytophthora ramorum.	the genetic structure within and between usa and european populations of the emerging phytopathogen phytophthora ramorum was examined. four primer combinations were used for amplified fragment length polymorphism (aflp) fingerprinting of 67 usa isolates from california and oregon, and 18 european isolates from belgium, germany, the netherlands, spain and the uk. in addition, three dna regions (its, cox ii, and nad 5) of additional phytophthora species were amplified by polymerase chain reaction, ...	2004	15209278
biological control of phytophthora ramorumon rhododendron.	phytophthora ramorum was found in poland in 2000 as the causal agent of rhododendron blight. besides eradication of diseased plants and rhododendron growing around, chemical and biological control of the pathogen is necessary. in this study in vitro activity of grapefruit extract and chitosan in the inhibition of p. ramorum growth and sporulation and their efficacy in the control of leaf and stem rot development was evaluated. amendment of v8 juice agar and soil leachate with grapefruit extract ...	2004	15756859
detection and quantification of phytophthora ramorum from california forests using a real-time polymerase chain reaction assay.	abstract the timely and accurate detection of pathogens is a critical aid in the study of the epidemiology and biology of plant diseases. in the case of regulated organisms, the availability of a sensitive and reliable assay is essential when trying to achieve early detection of the pathogen. we developed and tested a real-time, nested polymerase chain reaction (pcr) assay for the detection of phytophthora ramorum, causal agent of sudden oak death. this technique then was implemented as part of ...	2004	18943796
phytopthora ramorum in belgium: 2002 survey results and research efforts.	phytophthora ramorum is a new and aggressive phytophthora species that causes leaf blight and dieback symptoms on viburnum and rhododendron plants in europe. a variant of this fungus is responsible for sudden oak death (sod) in california and oregon. in europe, problems so far are mostly restricted to nursery plants of rhododendron and viburnum while in the us, the fungus has been isolated from over 20 host species and is responsible for massive killing of oak trees (mostly quercus agrifolia and ...	2003	15151294
phylogenetic relationships of phytophthora ramorum, p. nemorosa, and p. pseudosyringae, three species recovered from areas in california with sudden oak death.	sudden oak death has been an emerging disease problem in coastal california and has caused significant losses in forest ecosystems in some regions of the state. the causal agent of this disease has been described as phytophthora ramorum with two other less aggressive species, p. nemorosa and p. pseudosyringae, recovered from some symptomatic plants. the phylogenetic relationship of these species with other members of the genus was examined by sequence alignment of 667 bp of the mitochondrially-e ...	2003	15000239
sudden oak death: phytophthora ramorum exhibits transatlantic differences.		2003	12825493
molecular differentiation and diversity among the california red oaks (fagaceae; quercus section lobatae).	a recent epidemic of phytopthora (sudden oak death) in coastal woodlands of california is causing severe mortality in some oak species belonging to the red oak (lobatae) group. to predict the risks of spread of this disease, an understanding of the relationships among california's red oak species and of their population genetic structure is needed. we focus here on relationships among the four species of red oak. whereas morphological distinction of quercus wislizeni and quercus parvula can pose ...	2003	12761621