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Inocybe cervenianensis (Agaricales, Inocybaceae), a new species in the I. flavoalbida clade from Italy
No full textDovana, Francesco, Bizio, Enrico, Garbelotto, Matteo, Ferisin, Giuliano (2021): Inocybe cervenianensis (Agaricales, Inocybaceae), a new species in the I. flavoalbida clade from Italy. Phytotaxa 484 (2): 227-236, DOI: 10.11646/phytotaxa.484.2.7, URL: http://dx.doi.org/10.11646/phytotaxa.484.2.
FIGURE 2. Inocybe cervenianensis. Fresh basidiomes. A Holotype- GDOR623. B Coll. MCVE21684 in Inocybe cervenianensis (Agaricales, Inocybaceae), a new species in the I. flavoalbida clade from Italy
No full textFIGURE 2. Inocybe cervenianensis. Fresh basidiomes. A Holotype- GDOR623. B Coll. MCVE21684. Photos: A by G. Ferisin; B by E. Bizio.Published as part of Dovana, Francesco, Bizio, Enrico, Garbelotto, Matteo & Ferisin, Giuliano, 2021, Inocybe cervenianensis (Agaricales, Inocybaceae), a new species in the I. flavoalbida clade from Italy, pp. 227-236 in Phytotaxa 484 (2) on page 230, DOI: 10.11646/phytotaxa.484.2.7, http://zenodo.org/record/542166
Soil- and waterborne Phytophthora species linked to recent outbreaks in Northern California restoration sites
Full text linkMany studies around the globe have identified plant production facilities as major sources of plant pathogens that may be released in the wild, with significant consequences for the health and integrity of natural ecosystems. Recently, a large number of soilborne and waterborne species belonging to the plant pathogenic genus Phytophthora have been identified for the first time in California native plant production facilities, including those focused on the production of plant stock used in ecological restoration efforts. Additionally, the same Phytophthora species present in production facilities have often been identified in failing restoration projects, further endangering plant species already threatened or endangered. To our knowledge, the identification of Phytophthora species in restoration areas and in plant production facilities that produce plant stock for restoration projects is a novel discovery that finds many land managers unprepared, due to a lack of previous experience with these pathogens. This review summarizes some of the key knowledge about the genus Phytophthora in general and lists some of the many soilborne and waterborne species recently recovered from some California restoration sites and plant production facilities
FIGURE 1. Maximum Likelihood phylogram obtained from the general nrITS and RPB2 in Inocybe cervenianensis (Agaricales, Inocybaceae), a new species in the I. flavoalbida clade from Italy
No full textFIGURE 1. Maximum Likelihood phylogram obtained from the general nrITS and RPB2 sequence alignment of Inocybe spp. Mallocybe arthrocystis and Mallocybe leucoblema were used as outgroup taxa. Only MLB values ≥70% and BPP values ≥0.95 are given above clade branches. Newly sequenced collections are in bold. For each collection, the specific epithet (as present in GenBank), voucher, GenBank accession numbers of the RPB2/ITS sequences are reported. The /- notation indicates the sequence as missing for that collection.Published as part of Dovana, Francesco, Bizio, Enrico, Garbelotto, Matteo & Ferisin, Giuliano, 2021, Inocybe cervenianensis (Agaricales, Inocybaceae), a new species in the I. flavoalbida clade from Italy, pp. 227-236 in Phytotaxa 484 (2) on page 229, DOI: 10.11646/phytotaxa.484.2.7, http://zenodo.org/record/542166
Inter- and Intra-Continental Genetic Variation in the Generalist Conifer Wood Saprobic Fungus Phlebiopsis gigantea
Full text linkPhlebiopsis gigantea (Fr.) Jülich is a well-known generalist conifer wood saprobe and a biocontrol fungus used in several world countries to prevent stump infection by tree pathogenic Heterobasidion fungal species. Previous studies have reported the presence of regional and continental genetic differentiation in host-specific fungi, but the presence of such differentiation for generalist wood saprobes such as P. gigantea has not been often studied or demonstrated. Additionally, little information exists on the distribution of this fungus in western North America. The main purposes of this study were: (I) to assess the presence of P. gigantea in California, (II) to explore the genetic variability of P. gigantea at the intra and inter-continental levels and (III) to analyze the phylogeographic relationships between American and European populations. Seven loci (nrITS, ML5–ML6, ATP6, RPB1, RPB2, GPD and TEF1-α) from 26 isolates of P. gigantea from coniferous forests in diverse geographic distribution and from different hosts were analyzed in this study together with 45 GenBank sequences. One hundred seventy-four new sequences were generated using either universal or specific primers designed in this study. The mitochondrial ML5–ML6 DNA and ATP6 regions were highly conserved and did not show differences between any of the isolates. Conversely, DNA sequences from the ITS, RPB1, RPB2, GPD and TEF1-α loci were variable among samples. Maximum likelihood analysis of GPD and TEF1-α strongly supported the presences of two different subgroups within the species but without congruence or geographic partition, suggesting the presence of retained ancestral polymorphisms. RPB1 and RPB2 sequences separated European isolates from American ones, while the GPD locus separated western North American samples from eastern North American ones. This study reports the presence of P. gigantea in California for the first time using DNA-based confirmation and identifies two older genetically distinct subspecific groups, as well as three genetically differentiated lineages within the species: one from Europe, one from eastern North America and one from California, with the latter presumably including individuals from the rest of western North America. The genetic differentiation identified here among P. gigantea individuals from coniferous forests from different world regions indicates that European isolates of this fungus should not be used in North America (or vice versa), and, likewise, commercially available eastern North American P. gigantea isolates should not be used in western North America forests. The reported lack of host specificity of P. gigantea was documented by the field survey and further reinforces the need to only use local isolates of this biocontrol fungus, given that genetically distinct exotic genotypes of a broad generalist microbe may easily spread and permanently alter the microbial biodiversity of native forest ecosystems
Human-mediated migration of plants, their pathogens and parasites
No full textThe adoption of agriculture in several parts of the world during the early Neolithic period led to a fundamental change in human migration. By introducing newly domesticated crops into new environments, pathogens and parasites were also inadvertently transferred from their regions of origin and underwent a considerable population growth. In the newly settled regions, some pests of indigenous plants adapted to new crops by host switching. This review is limited to three basic migration events and mainly to agricultural crops of the temperate zone: (1) the migration of the first farmers from SE Asia to Europe, (2) European expansion from the 16th century onward, (3) modern globalization since the 20th century. Molecular analyses offer the opportunity to study the evolutionary history of pest populations, their origin and dynamics and their spread around the world. Cereals’ rusts and powdery mildew, storage insects were the first to spread with wheat species, barley, and pulses from the Levant across Eurasia. The Columbian exchange of crops to and from the Americas brought entirely new pests to Europe while old world pathogens spread to the Americas and subsequently to all other regions colonized by Europeans. Modern globalization further facilitated the spread of pathogens and insects worldwide, as previously inconceivable amounts of agricultural products, business travelers, and maybe tourists have elevated global accessibility. This is illustrated by case studies based on fungi and insects. In the near future, pests will have colonized all crops in all countries where they can exist according to their agro-climatic requirements.Open Access funding enabled and organized by Projekt DEAL.Universität Hohenheim (3153
Inocybe cervenianensis Ferisin, Bizio, Aiardi, Bersan & Dovana 2021, sp. nov.
No full text<i>Inocybe cervenianensis</i> Ferisin, Bizio, Aiardi, Bersan & Dovana, <i>sp. nov.</i> Figs. 2–4 <p>MycoBank no.: MB 835592</p> <p> Etymology:—the specific epithet “ <i>cervenianensis ”</i> derives from the old latin name of Cervignano del Friuli, a city in Friuli Venezia Giulia Region where the holotype was collected.</p> <p> Diagnosis:— <i>Inocybe cervenianensis</i> is characterised by its medium-sized basidiomes, with brown to ochraceous pileus, covered with whitish velipellis, stipe entirely pruinose, with more or less marginate bulb, brownish with pinkish tinges on the middle but constantly whitish in the upper part. Microscopically, it is characterised by amygdaliform spores, pleurocystidia and cheilocystidia ranging from slenderly fusiform, sublageniform to ventricose-fusiform and caulocystidia mixed with cauloparacystidia descending to the base of the stipe.</p> <p> Type:— ITALY. Friuli Venezia Giulia: Cervignano del Friuli, Parco Europa Unita, on the ground under <i>Quercus ilex</i>, 23 December 2018, <i>G</i> <i>.</i> <i>Ferisin</i> (GDOR623!, GenBank: nrITS MT 448877, <i>RPB2</i> MT 458139).</p>Published as part of <i>Dovana, Francesco, Bizio, Enrico, Garbelotto, Matteo & Ferisin, Giuliano, 2021, Inocybe cervenianensis (Agaricales, Inocybaceae), a new species in the I. flavoalbida clade from Italy, pp. 227-236 in Phytotaxa 484 (2)</i> on page 233, DOI: 10.11646/phytotaxa.484.2.7, <a href="http://zenodo.org/record/5421667">http://zenodo.org/record/5421667</a>
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The disease ecology, epidemiology and population genetics, of the emergent forest pathogen Phytophthora ramorum in a coastal California watershed.
Full text linkSudden Oak Death (SOD), caused by the oomycete pathogen, Phytophthora ramorum, is an introduced forest disease causing large-scale tree mortality in the oak woodlands of California. Pathogen dynamics are bound to be affected by site ecology, forest structure and composition and by interactions among sympatric pathogens. In the four chapters included in this dissertation I address various aspects of the both ecology and epidemiology of the Sudden Oak Death disease, including the competition between three sympatric species of Phytophthora, the population structure of the P.ramorum on its three main hosts, California bay laurel (Umbellularia californica), tanoak (Notholithocarpus densiflorus) and coast live oak (Quercus agrifolia), and at sites with different levels of disease incidence and the population structure of isolates found in two different substrates, soil and bay laurel leaves, in various weather conditions. Using molecular tools coupled with an intensive multi-year field sampling approach, all within a coastal California watershed with a relatively long and uniform history of disease presence, I determined the following: When in competition with other Phytophthora species, specifically P. nemorosa, P. ramorum prevalence increases to levels higher than those of the competing species when abundant rainfall triggers its sporulation. Despite P. nemorsa having a broader geographic range, it exhibits a narrower ecological amplitude and, in any given region, occupies fewer sites than P. ramorum. Results additionally suggest that, perhaps due to priority effects, P. nemorosa can persist at levels comparable to those of P. ramorum in ecologically suitable plots when climate favors P. ramorum dormancy.Shifts in weather, primarily levels of rainfall are accurate predictors in the likelihood of both bay laurel and oak infection as well as transitions between dormant and active infection of the pathogen itself. Additionally site specific factors such as aspect, bay laurel density and bay laurel basal area drive differences in levels of both disease incidence and prevalence on both bay laurel and oak hosts. For oaks specifically, infection rates are greater among larger trees, yet levels of mortality are greater among smaller trees. Neighborhood effects such as proximity to infected bay laurel foliage, and surrounding bay laurel density and basal area are important factors in predicting oak infection. Ten microsatellites were used for genetic analyses on cultures from successful isolations to determine differences in population structure between different substrates, namely populations isolated from soil versus aerial populations isolated from bay laurel leaves in various weather conditions. Migration of genotypes among sites was low and spatially limited during dry periods, but intensity and range of migration of genotypes significantly increased for leaf populations during wet periods. Only leaf genotypes persisted significantly between years, and genotypes present in different substrates were distributed differently in soil and leaves. It was concluded that epidemics start rapidly at the onset of favorable climatic conditions through highly transmissible leaf genotypes, and that soil populations are transient and may be less epidemiologically relevant than previously thought.Population structure of the pathogen in each of the three main hosts was examined to provide evidence of contagion pathways among hosts, as well as differences in population structure in wet vs. dry years and at sites with various levels of disease incidence and prevalence. The relationships among P. ramorum populations in bay laurels, oaks and tanoaks were analyzed and structure was found to exist among hosts. It was determined that bay laurel is the source population for both tanoak and oak infection, and that tanoak contributes minimally to oak infection. In spite of their common source of inoculum, oaks and tanoaks were found to be sinks that select for different pathogen genotypes, due to the variance in selection pressure in each host type. Additionally, different sites supported a dominance of different genotypes, more genotypes overall and more persistent genotypes, when compared to other sites, and these ‘hotspots’ are likely to play a more significant epidemiological and evolutionary role for the pathogen.Together these results help to advance the state of knowledge surrounding the ecology, epidemiology and population genetics of the Sudden Oak Death pathogen in California, add to the growing body of research on invasive plant pathogens, support theories of invasion biology and most importantly can be applied to regulatory and land management practices in attempt to mitigate the spread of this disease. Chair Dat
Citizen Science Uncovers Phytophthora ramorum as a Threat to Several Rare or Endangered California Manzanita Species
No full textThe Sudden Oak Death (SOD) Blitzes consist of yearly surveys led by citizen scientists designed to map the distribution of Phytophthora ramorum, cause of the forest disease called SOD, across northern California. During the 2017 Santa Cruz County SOD Blitz, six rare or endangered Arctostaphylos (manzanita) species were found to be possibly symptomatic for the first time. Symptoms included branch cankers and associated canopy mortality, and affected multiple individuals per species. Isolates of P. ramorum were obtained from each of the six species and, through a 30-day-long inoculation experiment on live plants, Koch’s postulates were completed for each one of them, conclusively determining that they all are hosts of this pathogen. Two additional manzanita species were later found to be apparently symptomatic in Marin County. Inoculations on detached branches using an isolate of P. ramorum obtained from one of the six rare species from Santa Cruz County were successful, suggesting that these two species may also be hosts of P. ramorum. Detached leaves of all eight species were also successfully inoculated at the University of California-Berkeley in fall 2018 and then again in spring 2019. In these cases, the same isolate was used for all inoculations, in order to obtain information on the comparative susceptibility of the eight species in question. Both branch and leaf inoculations identified significant interspecific differences in susceptibility. The production of sporangia was low on all species but it was not zero, suggesting that sporulation may cause within-plant and limited across-plant contagion, especially in rainy years
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