scholarly journals Current and projected global distribution of Phytophthora cinnamomi , one of the world's worst plant pathogens

2016 ◽  
Vol 23 (4) ◽  
pp. 1661-1674 ◽  
Author(s):  
Treena I. Burgess ◽  
John K. Scott ◽  
Keith L. Mcdougall ◽  
Michael J. C. Stukely ◽  
Colin Crane ◽  
...  
Keyword(s):  
Plant Pathogens ◽  
Phytophthora Cinnamomi ◽  
Global Distribution

scholarly journals Biological activity of 7beta-acetoxywithanolide D isolated from Acnistus arborescens

2018 ◽  
Vol 39 (6) ◽  
pp. 2835
Author(s):  
Joze Aparecida Marciano Corrêa ◽  
Diana Fortkamp ◽  
Camila Furtunato da Silva ◽  
Flávio Rocha ◽  
Luiz Humberto Gomes ◽  
...  
Keyword(s):  
Biological Activity ◽  
Secondary Metabolites ◽  
Plant Pathogens ◽  
Phytophthora Cinnamomi ◽  
Plant Secondary Metabolites ◽  
Alternative Methods ◽  
Development Of Resistance ◽  
Pathogen Control ◽  
Solanaceae Family ◽  
Promising Source

Many oomycete species are plant pathogens and are responsible for causing significant losses in agriculture. Currently, plant pathogen control is carried out by chemical, biological and physical methods. However, due to the development of resistance to these methods by some pathogens, it is imperative that alternative methods are developed. Brazilian biodiversity is well-known for its species richness and is considered a promising source of natural products. Among the vascular plants, the family Solanaceae A. Juss. (Solanaceae) is considered one of the largest, with distributions across all tropical and temperate regions of the world. The Solanaceae family presents a high diversity of species of economic importance as sources of food, medicinal and ornamental properties. Plants of this family are sources of secondary metabolites of various chemical classes that possess potential diverse applications. Therefore, chemical and biological investigations of these compounds are extremely important as they present alternatives for their potential use in the control of plant pathogens. Here, we report for the first time, the biological activity of 7beta-acetoxywithanolide D, a compound isolated from Acnistus arborescens, against the oomycete Phytophthora cinnamomi. With these results, we emphasize the importance of such studies on plant secondary metabolites, which may present coadjuvant options in the control of plant pathogens.

scholarly journals Global diversity and biogeography of the Zostera marina mycobiome

2020 ◽  
Author(s):  
Cassandra L. Ettinger ◽  
Laura E. Vann ◽  
Jonathan A. Eisen
Keyword(s):  
Fungal Community ◽  
Community Assembly ◽  
Zostera Marina ◽  
Plant Pathogens ◽  
High Throughput Sequencing ◽  
Marine Fungi ◽  
Its Region ◽  
Global Distribution ◽  
Rrna Gene ◽  
Fungal Community Composition

AbstractSeagrasses are marine flowering plants that provide critical ecosystem services in coastal environments worldwide. Marine fungi are often overlooked in microbiome and seagrass studies, despite terrestrial fungi having critical functional roles as decomposers, pathogens or endophytes in global ecosystems. Here we characterize the distribution of fungi associated with the seagrass, Zostera marina, using leaves, roots, and rhizosphere sediment from 16 locations across its full biogeographic range. Using high throughput sequencing of the ribosomal internal transcribed spacer (ITS) region and 18S ribosomal RNA gene, we first measured fungal community composition and diversity, then we tested hypotheses of neutral community assembly theory and the degree to which deviations suggested amplicon sequence variants (ASVs) were plant-selected or dispersal-limited, and finally we identified a core mycobiome and investigated the global distribution of differentially abundant ASVs. Our results show that the fungal community is significantly different between sites and follows a weak, but significant pattern of distance decay. Generally, there was evidence for both deterministic and stochastic factors contributing to community assembly of the mycobiome. The Z. marina core leaf and root mycobiomes are dominated by unclassified Sordariomycetes spp., unclassified Chytridiomycota lineages (including Lobulomycetaceae spp.), unclassified Capnodiales spp. and Saccharomyces sp. A few ASVs (e.g. Lobulomyces sp.) appear restricted to one or a handful of locations (e.g. possibly due to local adaptation, deterministic dispersal limitation or seasonal bloom events), while others (e.g. Saccharomyces sp.) are more ubiquitous across all locations suggesting a true global distribution and possible plant-selection. Fungal guilds associated with Z. marina were only weakly identified (10.12% of ITS region and 3.4% 18S rRNA gene ASV guild assignments were considered highly probable) including wood saprotrophs, ectomycorrhizal fungi, endophytic fungi and plant pathogens. Our results are similar to those found for other seagrass species. It is clear from the many unclassified fungal ASVs and fungal functional guilds, that our knowledge of marine fungi is still rudimentary. Further studies characterizing seagrass-associated fungi are needed to understand the roles of these microorganisms generally and when associated with seagrasses.

scholarly journals The plant pathogen Phytophthora cinnamomi influences habitat use by the obligate nectarivore honey possum (Tarsipes rostratus)

2016 ◽  
Vol 64 (2) ◽  
pp. 122 ◽  
Author(s):  
Shannon J. Dundas ◽  
Giles E. St J. Hardy ◽  
Patricia A. Fleming
Keyword(s):  
Habitat Use ◽  
Plant Species ◽  
Plant Pathogens ◽  
Phytophthora Cinnamomi ◽  
Habitat Preferences ◽  
Flowering Plant ◽  
Food Sources ◽  
Vegetation Communities ◽  
Vegetation Surveys ◽  
Honey Possum

Introduced plant pathogens can devastate susceptible plant communities, and consequently impact on animal communities reliant on plants for food and habitat. Specifically, plant pathogens change the floristic diversity of vegetation communities, thereby reducing availability of food sources for fauna (e.g. pollen and nectar) and result in major changes to habitat structure when canopy and understorey plant species succumb to disease. Phytophthora cinnamomi poses a threat to flowering plant species (e.g. Banksia species) which are important food sources for nectarivorous fauna. The honey possum (Tarsipes rostratus) is the only obligate nectarivorous non-flying mammal living on a restrictive diet of nectar and pollen; consequently, these tiny mammals are likely to be particularly vulnerable to the landscape-wide devastation caused by P. cinnamomi. We investigated habitat selection by honey possums in a vegetation community infested with P. cinnamomi to determine how these mammals respond to habitat affected by this pathogen. Over four seasons, 18 honey possums were fitted with radio-transmitters and tracked to identify habitat preferences. Vegetation surveys were compared for locations selected by honey possums (as determined from tracking) and randomly selected sites. Radio-tracking revealed that sites selected by honey possums were significantly taller, denser, and more floristically diverse than their paired random locations. The presence of P. cinnamomi influences habitat use by honey possums, but animals show resilience in terms of using the best of what is available in both P. cinnamomi–affected and unaffected locations. Habitat patches comprising less susceptible species, or plants that have yet to succumb to infection, provide refuge and food resources for honey possums. Management to reduce the spread of existing P. cinnamomi infestations and prevent contamination of new locations will benefit vegetation communities and associated faunal communities, while identifying honey possum food plant species that are resilient to the pathogen may support revegetation attempts.

scholarly journals Effect of Soil Solarization and Cover Crops on Populations of Selected Soilborne Plant Pathogens in Western Oregon

Plant Disease ◽  
2000 ◽  
Vol 84 (9) ◽  
pp. 952-960 ◽  
Author(s):  
J. N. Pinkerton ◽  
K. L. Ivors ◽  
M. L. Miller ◽  
L. W. Moore
Keyword(s):  
Cover Crops ◽  
Plant Pathogens ◽  
Field Experiments ◽  
Phytophthora Cinnamomi ◽  
Field Studies ◽  
Soil Solarization ◽  
Silty Clay ◽  
Population Densities ◽  
Deep Soil ◽  
Soil Pathogens

Field experiments were conducted in silty-clay loam in Corvallis, OR during the summers of 1995 and 1996 to study the effects of green manure cover crops (Sudan grass, rape, and barley), soil solarization, soil fumigation, and combinations of those treatments on population densities of soil pathogens Verticillium dahliae, Phytophthora cinnamomi, Pratylenchus penetrans, and Agrobacterium rhizogenes. Nylon mesh bags containing soil infested with V. dahliae and Phytophthora cinnamomiwere buried 5, 10, 20, and 30 cm deep. Soil solarization was performed over a 54- to 59-day period using a 0.6-mil clear polyethylene film. Maximum soil temperatures recorded at depths of 5, 10, 20, and 30 cm were 53, 48, 39, and 34°C in solarized soil, respectively; these temperatures were 8 to 16°C higher than in corresponding nonsolarized plots. Soil samples were collected before, during, and after solarization to quantify pathogen populations at those four depths. Pot or field studies were conducted subsequent to treatments to determine the effects of treatments on susceptible plants. Soil solarization, cover crops plus solarization, or fumigation with metam sodium resulted in a significant decrease (P< 0.05) in density of P. cinnamomi populations at all four depths and reduced (P< 0.05) V. dahliae at 5 and 10 cm. In greenhouse assays of solarized soils, disease severity was reduced (P< 0.05) for Verticillium spp. on eggplant and Phytophthora spp. on snapdragons. Cover crops alone were not effective in reducing P. cinnamomi and V. dahliae populations. Agrobacterium spp. population densities declined within solarized plots and incidence of crown gall on ‘Mazzard’ cherry rootstock planted in solarized plots was reduced significantly. Population densities of Pratylenchus penetranswere reduced in the upper 30-cm soil profile by solarization.Solarization for an 8-week period during the warmest months of summer could provide an additional management alternative for several important soilborne pathogens in western Oregon.

scholarly journals Volatile antimicrobials from Muscodor crispans, a novel endophytic fungus

Microbiology ◽  
2010 ◽  
Vol 156 (1) ◽  
pp. 270-277 ◽  
Author(s):  
Angela M. Mitchell ◽  
Gary A. Strobel ◽  
Emily Moore ◽  
Richard Robison ◽  
Joe Sears
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Endophytic Fungus ◽  
Amazon Basin ◽  
Plant Pathogens ◽  
Phytophthora Cinnamomi ◽  
Pythium Ultimum ◽  
Propanoic Acid ◽  
Human Pathogens ◽  
Black Sigatoka ◽  
Wide Range

Muscodor crispans is a recently described novel endophytic fungus of Ananas ananassoides (wild pineapple) growing in the Bolivian Amazon Basin. The fungus produces a mixture of volatile organic compounds (VOCs); some of the major components of this mixture, as determined by GC/MS, are propanoic acid, 2-methyl-, methyl ester; propanoic acid, 2-methyl-; 1-butanol, 3-methyl-;1-butanol, 3-methyl-, acetate; propanoic acid, 2-methyl-, 2-methylbutyl ester; and ethanol. The fungus does not, however, produce naphthalene or azulene derivatives as has been observed with many other members of the genus Muscodor. The mixture of VOCs produced by M. crispans cultures possesses antibiotic properties, as does an artificial mixture of a majority of the components. The VOCs of the fungus are effective against a wide range of plant pathogens, including the fungi Pythium ultimum, Phytophthora cinnamomi, Sclerotinia sclerotiorum and Mycosphaerella fijiensis (the black sigatoka pathogen of bananas), and the serious bacterial pathogen of citrus, Xanthomonas axonopodis pv. citri. In addition, the VOCs of M. crispans killed several human pathogens, including Yersinia pestis, Mycobacterium tuberculosis and Staphylococcus aureus. Artificial mixtures of the fungal VOCs were both inhibitory and lethal to a number of human and plant pathogens, including three drug-resistant strains of Mycobacterium tuberculosis. The gaseous products of Muscodor crispans potentially could prove to be beneficial in the fields of medicine, agriculture, and industry.

scholarly journals Soil Biodiversity and Root Pathogens in Agroecosystems

2021 ◽  
Author(s):  
María del Pilar Rodríguez Guzmán
Keyword(s):  
Food Webs ◽  
Plant Pathogens ◽  
Environmental Changes ◽  
Phytophthora Cinnamomi ◽  
Plant Diseases ◽  
Plant Roots ◽  
Soil Biodiversity ◽  
Irish Famine ◽  
Root Diseases ◽  
Root Pathogens

Soil ecosystem is a living and dynamic environment, habitat of thousands of microbial species, animal organisms and plant roots, integrated all of them in the food webs, and performing vital functions like organic matter decomposition and nutrient cycling; soil is also where plant roots productivity represent the main and first trophic level (producers), the beginning of the soil food web and of thousands of biological interactions. Agroecosystems are modified ecosystems by man in which plant, animal and microorganisms biodiversity has been altered, and sometimes decreased to a minimum number of species. Plant diseases, including root diseases caused by soil-borne plant pathogens are important threats to crop yield and they causes relevant economic losses. Soil-borne plant pathogens and the diseases they produce can cause huge losses and even social and environmental changes, for instance the Irish famine caused by Phytophthora infestans (1845–1853), or the harmful ecological alterations in the jarrah forests of Western Australia affected by Phytophthora cinnamomi in the last 100 years. How can a root pathogen species increase its populations densities at epidemic levels? In wild ecosystems usually we expect the soil biodiversity (microbiome, nematodes, mycorrhiza, protozoa, worms, etc.) through the trophic webs and different interactions between soil species, are going to regulate each other and the pathogens populations, avoiding disease outbreaks. In agroecosystems where plant diseases and epidemics are frequent and destructive, soil-borne plant pathogens has been managed applying different strategies: chemical, cultural, biological agents and others; however so far, there is not enough knowledge about how important is soil biodiversity, mainly microbiome diversity and soil food webs structure and function in the management of root pathogens, in root and plant health, in healthy food production, and maybe more relevant in the conservation of soil as a natural resource and derived from it, the ecosystem services important for life in our planet.

scholarly journals Survival of Plant Pathogens in Static Piles of Ground Green Waste

2008 ◽  
Vol 98 (5) ◽  
pp. 547-554 ◽  
Author(s):  
A. J. Downer ◽  
D. Crohn ◽  
B. Faber ◽  
O. Daugovish ◽  
J. O. Becker ◽  
...  
Keyword(s):  
Sclerotinia Sclerotiorum ◽  
Plant Pathogens ◽  
Phytophthora Cinnamomi ◽  
Chemical Degradation ◽  
Tree Crops ◽  
Green Waste ◽  
Armillaria Mellea ◽  
Tylenchulus Semipenetrans ◽  
Survival Modeling ◽  
Microbial Attack

Ground green waste is used as mulch in ornamental landscapes and for tree crops such as avocados. Survival of Armillaria mellea, Phytophthora cinnamomi, Sclerotinia sclerotiorum, and Tylenchulus semipenetrans was assessed for 8 weeks within unturned piles of either recently ground or partially composted green waste. S. sclerotiorum survived at the pile surface and at 10, 30, and 100 cm within the pile for the entire 8 weeks in both fresh green waste (FGW) and aged green waste (AGW). A. mellea and T. semipenetrans did not survive more than 2 days in FGW, while P. cinnamomi persisted for over 21 days in FGW. AGW was less effective in reducing pathogen viability than FGW, most likely because temperatures in AGW peaked at 45°C compared with 70°C in FGW. Survival modeling curves based on pile temperatures indicate the time to inactivate 10 propagules of pathogens was 11, 30, 363, and 50 days for A. mellea, P. cinnamomi, S. sclerotiorum, and T. semipenetrans, respectively. Sclerotia-forming pathogens pose the greatest risk for escape; to ensure eradication of persistent fungi, green waste stockpiles should be turned intermittently to mix pile contents and move pathogen propagules to a location within the pile where they are more likely to be killed by heat, microbial attack, or chemical degradation.

scholarly journals In Vitro Fungicidal Activity of Calcium and Potassium Salts on Several Commercially Significant Plant Pathogens

HortScience ◽  
2011 ◽  
Vol 46 (6) ◽  
pp. 913-916 ◽  
Author(s):  
Clive Kaiser ◽  
Philip B. Hamm ◽  
Stacy Gieck ◽  
Nicholas David ◽  
Lynn Long ◽  
...  
Keyword(s):  
Plant Pathogens ◽  
Phytophthora Cinnamomi ◽  
Pythium Ultimum ◽  
Calcium Acetate ◽  
Potassium Silicate ◽  
Phytophthora Cactorum ◽  
Potassium Salts ◽  
Phytophthora Megasperma ◽  
Calcium Propionate

In vitro dose responses of several calcium and potassium salts were determined on some commercially significant plant pathogens, including: Helminthosporium solani, Fusarium oxysporum f. sp. pisi race 2, Colletotricum coccodes, Phytophthora cactorum, Phytophthora cinnamomi, Phytophthora erythroseptica, Phytophthora infestans, Phytophthora megasperma, Pythium ultimum, and Venturia inaequalis. Mycelial growth inhibition was both salt-specific and dose-related. Pythium ultimum was completely inhibited by 75 mg·L−1 or greater calcium propionate, but needed 300 mg·L−1 or greater of calcium acetate and 40 mL·L−1 or greater of potassium silicate for complete inhibition. Phytophthora infestans was completely inhibited by 150 mg·L−1 or greater calcium acetate, 150 mg·L−1 or greater calcium propionate, or 5 mL·L−1 or greater potassium silicate. Phytophthora cactorum was completely inhibited by 300 mg·L−1 or greater calcium propionate, but required 600 mg·L−1 or greater calcium acetate and 10 mL·L−1 or greater potassium silicate for complete inhibition. Phytophthora cinnamomi was completely inhibited by calcium propionate at 600 mg·L−1 or greater or by 10 mL·L−1 or greater potassium silicate. Only potassium silicate inhibited Phytophthora megasperma, Phytophthora erthroseptica, V. inequalis, and H. solani at concentrations of 5 mL·L−1 or greater, 20 mL·L−1 or greater, 40 mL·L−1 or greater, or 80 mL·L−1 or greater, respectively. Potassium acetate did not completely inhibit any of the pathogens in this study when tested at concentrations 1200 mg·L−1 or less.

scholarly journals Topographic effects on dispersal patterns of Phytophthora cinnamomi at a stand scale in a Spanish heathland

2018 ◽  
Author(s):  
Enrique Cardillo ◽  
Angel Acedo ◽  
Enrique Abad
Keyword(s):  
Plant Pathogens ◽  
Phytophthora Cinnamomi ◽  
Topographic Effects ◽  
Dispersal Patterns ◽  
Long Distance ◽  
Long Distance Transport ◽  
Disease Patterns ◽  
Highly Correlated ◽  
Preferential Pathways ◽  
Disease Foci

AbstractPhytophthora cinnamomi is one of the most important plant pathogens in the world, causing root rot in more than a thousand plant species. This observational study was carried out on a P. cinnamomi infected heathland of Erica umbellata used as goat pasture. The patterns and shapes of disease foci and their distribution were described in a spatial and temporal context using an aerial photograph record. A set of topographic traits was selected on the basis of a disease dynamic hypothesis and their effects on observed spatial disease patterns were analyzed. Incipient infections situated in flat terrain expanded as compact circular front patterns with a low growth rate. On slopes, disease patches developed more rapidly down slope, forming parabolic shapes. The axis direction of the parabolas was highly correlated with terrain aspect, while the parabolic amplitude was associated with land curvature and slope. New secondary foci appeared over the years producing an accelerated increase of the affected surface. These new foci were observed in sites where disease density was higher or near sites more frequently visited by animals such as the stable or the forage crop. In contrast, a smaller number of disease foci occur in areas which animals are reluctant to visit, such as where they have a short range of vision. Our results suggest that 1) the growth of existing P. cinnamomi foci is controlled by a combination of root-to-root contact and water flows, 2) the increase in the diseased area arises mainly from the multiplication of patches, 3) the formation of new foci is mediated by long-distance transport due to the movement of animals and humans along certain preferential pathways, and 4) geomorphology and topography traits are associated with the epidemiology of this soil-borne pathogen.

scholarly journals Genome of the destructive oomycete Phytophthora cinnamomi provides insights into its pathogenicity and adaptive potential

BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Juanita Engelbrecht ◽  
Tuan A. Duong ◽  
S. Ashok Prabhu ◽  
Mohamed Seedat ◽  
Noëlani van den Berg
Keyword(s):  
Invasive Species ◽  
Genome Sequence ◽  
Plant Pathogens ◽  
Reference Genome ◽  
Phytophthora Cinnamomi ◽  
Genomic Research ◽  
High Quality ◽  
Irreversible Damage ◽  
Fungal Plant Pathogens ◽  
The Impact

Abstract Background Phytophthora cinnamomi is an oomycete pathogen of global relevance. It is considered as one of the most invasive species, which has caused irreversible damage to natural ecosystems and horticultural crops. There is currently a lack of a high-quality reference genome for this species despite several attempts that have been made towards sequencing its genome. The lack of a good quality genome sequence has been a setback for various genetic and genomic research to be done on this species. As a consequence, little is known regarding its genome characteristics and how these contribute to its pathogenicity and invasiveness. Results In this work we generated a high-quality genome sequence and annotation for P. cinnamomi using a combination of Oxford Nanopore and Illumina sequencing technologies. The annotation was done using RNA-Seq data as supporting gene evidence. The final assembly consisted of 133 scaffolds, with an estimated genome size of 109.7 Mb, N50 of 1.18 Mb, and BUSCO completeness score of 97.5%. Genome partitioning analysis revealed that P. cinnamomi has a two-speed genome characteristic, similar to that of other oomycetes and fungal plant pathogens. In planta gene expression analysis revealed up-regulation of pathogenicity-related genes, suggesting their important roles during infection and host degradation. Conclusion This study has provided a high-quality reference genome and annotation for P. cinnamomi. This is among the best assembled genomes for any Phytophthora species assembled to date and thus resulted in improved identification and characterization of pathogenicity-related genes, some of which were undetected in previous versions of genome assemblies. Phytophthora cinnamomi harbours a large number of effector genes which are located in the gene-poor regions of the genome. This unique genomic partitioning provides P. cinnamomi with a high level of adaptability and could contribute to its success as a highly invasive species. Finally, the genome sequence, its annotation and the pathogenicity effectors identified in this study will serve as an important resource that will enable future studies to better understand and mitigate the impact of this important pathogen.

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