Journal articles on the topic 'Soilborn pathogen'
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1
You, Ming Pei, Jay Ram Lamichhane, Jean-Noël Aubertot, and Martin J. Barbetti. "Understanding Why Effective Fungicides Against Individual Soilborne Pathogens Are Ineffective with Soilborne Pathogen Complexes." Plant Disease 104, no. 3 (March 2020): 904–20. http://dx.doi.org/10.1094/pdis-06-19-1252-re.
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Annual forage legumes across southern Australia continue to be devastated by soilborne diseases. Nine fungicide seed treatments (thiram, metalaxyl, iprodione, phosphonic acid, propamocarb, fluquinconazole, difenoconazole + metalaxyl, ipconazole + metalaxyl, sedaxane + difenoconazole + metalaxyl) and four foliar fungicide treatments (phosphonic acid, metalaxyl, propamocarb, iprodione) were tested on four subterranean clover cultivars against individual oomycete soilborne pathogens Pythium irregulare, Aphanomyces trifolii, and Phytophthora clandestina and the fungal pathogen Rhizoctonia solani. Best treatments were then further tested across southern Australia in 2 years of field experiments. Under controlled conditions, seed treatment with thiram was best against damping-off caused by P. irregulare across the four cultivars (Woogenellup, Riverina, Seaton Park, Meteora), while metalaxyl was the most effective for maximizing root and shoot weights. Against A. trifolii, metalaxyl, iprodione, difenoconazole + metalaxyl, ipconazole + metalaxyl, and sedaxane + difenoconazole + metalaxyl, all reduced damping-off; sedaxane + difenoconazole + metalaxyl, fluquinconazole, and ipconazole + metalaxyl all reduced lateral root disease across two or more cultivars; while iprodione, thiram, and sedaxane + difenoconazole + metalaxyl increased shoot dry weight. Against P. clandestina, metalaxyl was the most effective in reducing tap and lateral root rot followed by ipconazole + metalaxyl or phosphonic acid for tap and lateral rot, respectively. Against R. solani, there were no effects of fungicides. For P. irregulare and P. clandestina, there were strong seed fungicide × cultivar interactions (P < 0.001). Under controlled conditions for foliar fungicide spray treatments, phosphonic acid was best at preventing productivity losses from A. trifolii, but was ineffective against P. clandestina, P. irregulare, or R. solani. Overall, controlled environment studies highlighted strong potential for utilizing seed treatments against individual pathogens to ensure seedling emergence and early survival, with seed and foliar sprays enhancing productivity by reducing seedling damping-off and root disease from individual pathogens. However, in field experiments over 2 years across southern Australia against naturally occurring soilborne pathogen complexes involving these same pathogens, only rarely did fungicide seed treatments or foliar sprays tested show any benefit. It is evident that currently available fungicide seed and/or foliar spray treatment options do not offer effective field mitigation of damping-off and root disease on annual forage legumes that underpin livestock production across southern Australia. The main reason for this failure relates to the unpredictable and ever-changing soilborne pathogen complexes involved, highlighting a need to now refocus away from fungicide options, particularly toward developing and deploying new host tolerances, but also in deploying appropriate cultural control options.
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Dawadi, Sujan, Fulya Baysal-Gurel, Karla M. Addesso, Prabha Liyanapathiranage, and Terri Simmons. "Fire Ant Venom Alkaloids: Possible Control Measure for Soilborne and Foliar Plant Pathogens." Pathogens 10, no. 6 (May 27, 2021): 659. http://dx.doi.org/10.3390/pathogens10060659.
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The purpose of this study was to evaluate fire ant venom alkaloids and an alarm pheromone analog against several plant pathogens, including Botrytis cinerea, Fusarium oxysporum, Phytophthora nicotianae, P. cryptogea, Pseudomonas syringae, Phytopythium citrinum, Rhizoctonia solani, Sclerotonia rolfsii, Xanthomonas axonopodis, and X. campestris. All pathogens were tested against red imported fire ant venom alkaloid extract and alarm pheromone compound for growth inhibition in in vitro assay. The venom alkaloid extract inhibited fungal and oomycete pathogens. Neither of the treatments were effective against bacterial pathogens. Three soilborne pathogens, P. nicotianae, R. solani, F. oxysporum, and one foliar pathogen, B. cinerea were selected for further in-vivo assays on impatiens (Impatiens walleriana ‘Super Elfin XP violet’). Total plant and root weight were higher in venom alkaloid treated plants compared to an inoculated control. The venom alkaloid treatment reduced damping-off, root rot severity, and pathogen recovery in soilborne pathogen inoculated plants. Similarly, venom alkaloid reduced Botrytis blight. However, higher venom rates caused foliar phytotoxicity on plants. Therefore, additional work is needed to evaluate rates of venom alkaloids or formulations to eliminate negative impacts on plants. Overall, these results suggest that red imported fire ant venom alkaloids may provide a basis for new products to control soilborne and foliar plant pathogens.
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Dawadi, Sujan, Fulya Baysal-Gurel, Karla M. Addesso, Jason B. Oliver, and Terri Simmons. "Impact of Cover Crop Usage on Soilborne Diseases in Field Nursery Production." Agronomy 9, no. 11 (November 14, 2019): 753. http://dx.doi.org/10.3390/agronomy9110753.
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Soilborne pathogens are a significant economic problem for nursery production in the Southeastern United States. The goal of this study was to determine the impact of cover crops on soilborne disease suppressiveness in such systems. Soils from red maple (Acer rubrum L.) plantation fields grown with and without cover crops were sampled, either while the cover crops were growing (pre-disked) or post-season, following cover crop incorporation into the soil (post-disked). Greenhouse bioassays were conducted using red maple seeds on inoculated (with Rhizoctonia solani (J.G. Kühn) or Phytophthora nicotianae (Breda de Haan)) and non-inoculated field soils. The damping-off, root rot disease severity, percent recovery of Rhizoctonia and Phytophthora, and pseudomonad population were examined during the two years of the experiment. Results showed that cover crop incorporation was beneficial for inducing disease supressiveness characteristics of soil. Cover crop incorporation into the soil significantly or numerically reduced disease severity and pathogen recovery in infested soil compared to the bare soil treatment. Cover crop incorporation was found to be partially associated with the reduction of seedling damping-off. The pseudomonad microbial population was greater when cover crop was present, and is thought to be antagonist to soilborne pathogens. Therefore, cover crops can be integrated in field nursery production systems to suppress soilborne pathogens.
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Hilbig, Bridget E., and Edith B. Allen. "Fungal pathogens and arbuscular mycorrhizal fungi of abandoned agricultural fields: potential limits to restoration." Invasive Plant Science and Management 12, no. 03 (August 9, 2019): 186–93. http://dx.doi.org/10.1017/inp.2019.19.
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AbstractLittle is known about impacts of soilborne pathogen legacies on reestablishment of native plant species in abandoned agricultural fields. We tested whether pathogens found in abandoned citrus orchards affect growth of native and invasive plant species in a controlled greenhouse experiment. In previous research, we identified several species of ascomycete (Fusarium spp.) and oomycete (Pythium spp.) pathogens from field roots and soils. The invasive annual grass, ripgut brome [Bromus diandrus (Roth.)], and native forbs, common fiddleneck [Amsinckia intermedia Fisch. & C.A. Mey.], coastal tidytips [Layia platyglossa (Fisch. & C.A. Mey.) A. Gray], and California goldfields [Lasthenia californica (DC. ex Lindl.)], were grown together in four different field soil treatments. Using pesticides on soils collected from abandoned citrus fields, we created four soil treatments that excluded different groups of potential pathogens: (1) untreated control (2) metalaxyl (oomyceticide) (3) fludioxonil (fungicide), and (4) steam-sterilized. Fludioxonil increased aboveground biomass of L. platyglossa (P = 0.005) and L. californica (P= 0.02) compared with sterile and metalaxyl-treated soils. Lasthenia californica had decreased arbuscular mycorrhizal colonization with metalaxyl, suggesting metalaxyl has non-target effects on mycorrhizae. Fludioxonil decreased potential pathogens in L. californica roots while having no effect on mycorrhizal colonization. Bromus diandrus had higher biomass in sterile and fludioxonil-treated soils than untreated soils (P = 0.0001), suggesting a release from soilborne pathogens. The release from soilborne pathogens with the use of fludioxonil in both native forbs and B. diandrus, combined with overall higher biomass across treatments in B. diandrus, suggests that pathogen impacts in a field setting are insufficient to reduce success of this invasive grass, and use of a fungicide would not benefit native species in mixed stands with B. diandrus.
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Li, Mei, Thomas Pommier, Yue Yin, Jianing Wang, Shaohua Gu, Alexandre Jousset, Joost Keuskamp, et al. "Indirect reduction of Ralstonia solanacearum via pathogen helper inhibition." ISME Journal 16, no. 3 (October 20, 2021): 868–75. http://dx.doi.org/10.1038/s41396-021-01126-2.
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AbstractThe rhizosphere microbiome forms a first line of defense against soilborne pathogens. To date, most microbiome enhancement strategies have relied on bioaugmentation with antagonistic microorganisms that directly inhibit pathogens. Previous studies have shown that some root-associated bacteria are able to facilitate pathogen growth. We therefore hypothesized that inhibiting such pathogen helpers may help reduce pathogen densities. We examined tripartite interactions between a model pathogen, Ralstonia solanacearum, two model helper strains and a collection of 46 bacterial isolates recovered from the tomato rhizosphere. This system allowed us to examine the importance of direct (effects of rhizobacteria on pathogen growth) and indirect (effects of rhizobacteria on helper growth) pathways affecting pathogen growth. We found that the interaction between rhizosphere isolates and the helper strains was the major determinant of pathogen suppression both in vitro and in vivo. We therefore propose that controlling microbiome composition to prevent the growth of pathogen helpers may become part of sustainable strategies for pathogen control.
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Okubara, Patricia A., Amy B. Peetz, and Richard M. Sharpe. "Cereal Root Interactions with Soilborne Pathogens—From Trait to Gene and Back." Agronomy 9, no. 4 (April 13, 2019): 188. http://dx.doi.org/10.3390/agronomy9040188.
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Realizing the yield potential of crop plants in the presence of shifting pathogen populations, soil quality, rainfall, and other agro-environmental variables remains a challenge for growers and breeders worldwide. In this review, we discuss current approaches for combatting the soilborne phytopathogenic nematodes, Pratylenchus and Heterodera of wheat and barley, and Meloidogyne graminicola Golden and Birchfield, 1965 of rice. The necrotrophic fungal pathogens, Rhizoctonia solani Kühn 1858 AG-8 and Fusarium spp. of wheat and barley, also are discussed. These pathogens constitute major causes of yield loss in small-grain cereals of the Pacific Northwest, USA and throughout the world. Current topics include new sources of genetic resistance, molecular leads from whole genome sequencing and genome-wide patterns of hosts, nematode or fungal gene expression during root-pathogen interactions, host-induced gene silencing, and building a molecular toolbox of genes and regulatory sequences for deployment of resistance genes. In conclusion, improvement of wheat, barley, and rice will require multiple approaches.
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King, Stephen R., Angela R. Davis, Wenge Liu, and Amnon Levi. "Grafting for Disease Resistance." HortScience 43, no. 6 (October 2008): 1673–76. http://dx.doi.org/10.21273/hortsci.43.6.1673.
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The primary purpose of grafting vegetables worldwide has been to provide resistance to soilborne diseases. The potential loss of methyl bromide as a soil fumigant combined with pathogen resistance to commonly used pesticides will make resistance to soilborne pathogens even more important in the future. The major disease problems addressed by grafting include fusarium wilt, bacterial wilt, verticillium wilt, monosporascus root rot, and nematodes. Grafting has also been shown in some instances to increase tolerance to foliar fungal diseases, viruses, and insects. If the area devoted to grafting increases in the future, there will likely be a shift in the soil microbial environment that could lead to the development of new diseases or changes in the pathogen population of current diseases. This shift in pathogen populations could lead to the development of new diseases or the re-emergence of previously controlled diseases. Although grafting has been demonstrated to control many common diseases, the ultimate success will likely depend on how well we monitor for changes in pathogen populations and other unexpected consequences.
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Biernacki, M., and B. D. Bruton. "Quantitative Response of Cucumis melo Inoculated with Root Rot Pathogens." Plant Disease 85, no. 1 (January 2001): 65–70. http://dx.doi.org/10.1094/pdis.2001.85.1.65.
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This experiment quantified the effects of three root rot pathogens on muskmelon (Cucumis melo L., var. cantalupensis) growth traits using computerized image analysis. Plants were grown from seed in sand infested with the soilborne pathogen Monosporascus cannonballus, Acremonium cucurbitacearum, or Rhizopycnis vagum. After 28 days in the growth chamber, images of plants were analyzed to quantify their response. Compared to noninoculated muskmelons, inoculated plants had significantly increased mean root diameter (45%), decreased root length (26%, primarily in roots of <0.5 mm diameter), decreased number of root tips (27%), decreased rhizosphere volume (40%), and decreased cumulative and mean surface area of leaves (24%). Effects of M. cannonballus on muskmelon growth were significantly different compared to A. cucurbitacearum and R. vagum. Isolate effects manifested a greater magnitude of difference on muskmelon traits than those observed at the species level. Multivariate analyses of plant responses were more powerful than univariate analyses to differentiate among effects of pathogen species and pathogen isolates. Discriminant analysis were useful to identify groups of plant traits modified by each fungal species or isolate at low disease levels. Digital image analyses proved to be a useful technique in quantitative assessment of plant damage caused by soilborne root rot pathogens.
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Molinero-Ruiz, Leire. "Recent advances on the characterization and control of sunflower soilborne pathogens under climate change conditions." OCL 26 (August 31, 2018): 2. http://dx.doi.org/10.1051/ocl/2018046.
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The control of soilborne crop pathogens is conditioned by the limited management options due to difficult access to active infection courts and to restrictions in the use of synthetic pesticides in Europe. For most soilborne sunflower pathogens, an effective management relies on genetic resistance which is, however, hindered by new pathogen populations (new races). Special emphasis is thus put on updated monitoring and characterization of pathogens and on the enlargement of the set of tools for disease management. Concerning characterization, advances on the population structure of Verticillium dahliae affecting sunflower by means of genetic, molecular and pathogenic approaches are presented. Also in relation to increases of sunflower wilt diseases recently observed, the fungus Cadophora malorum has been identified in Russia and reported as a new pathogen of this crop. Third, new races of Plasmopara halstedii (sunflower downy mildew), have been identified in Spain and Portugal. Most of them have a high virulence, since they overcome several genes for resistance. With regard to alternatives for disease control, entomopathogenic fungi (EF) constitute a novel tool. Used for years in Integrated Pest Management strategies due to their efficacy in controlling insect pests affecting crops, new ecological roles of these fungi have recently been reported. The EF species Beauveria bassiana and Metarhizium brunneum have been assessed by their in vitro effect against V. dahliae and C. malorum by our research group. Our results suggest that antibiosis and/or competition for ecological niche are operating in some EF-pathogen interactions. In summary, pathogen characterization is essential for genetic resistance for worldwide environments of sunflower production. Moreover, the security of sunflower yield and profitability is dependent not only on effective genetic resistance, but also on additional new control options that can be included in successful strategies of sunflower disease management.
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Handelsman, Jo, and Eric V. Stabb. "Biocontrol of Soilborne Plant Pathogens." Plant Cell 8, no. 10 (October 1996): 1855. http://dx.doi.org/10.2307/3870235.
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Rosskopf, Erin, Francesco Di Gioia, Jason C. Hong, Cristina Pisani, and Nancy Kokalis-Burelle. "Organic Amendments for Pathogen and Nematode Control." Annual Review of Phytopathology 58, no. 1 (August 25, 2020): 277–311. http://dx.doi.org/10.1146/annurev-phyto-080516-035608.
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The loss of methyl bromide as a soil fumigant and minimal advances in the development and registration of new chemical fumigants has resulted in a resurgence of interest in the application of organic amendments (OAs) for soilborne plant pathogen and plant-parasitic nematode management. Significant progress has been made in the characterization of OAs, application of strategies for their use, and elucidation of mechanisms by which they suppress soilborne pests. Nonetheless, their utility is limited by the variability of disease control, expense, and the logistics of introducing them into crop production systems. Recent advances in molecular techniques have led to significant progress in the elucidation of the role of bacteria and fungi and their metabolic products on disease suppression with the addition of OAs. Biosolarization and anaerobic soil disinfestation, developed to manipulate systems and favor beneficial microorganisms to maximize their impact on plant pathogens, are built on a strong historical research foundation in OAs and the physical, chemical, and biological characteristics of disease-suppressive soils. This review focuses on recent applications of OAs and their potential for the management of soilborne plant pathogens and plant-parasitic nematodes, with emphasis primarily on annual fruit and vegetable production systems.
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Srđanov, Jovana. "The possibility of using biochar in plant protection from pathogens." Biljni lekar 50, no. 5 (2022): 322–33. http://dx.doi.org/10.5937/biljlek2205322s.
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Literature review showed, that the utilization of organic amendments has been proposed to decrease the incidence of plant diseases caused by soilborne pathogens. Biochar can be effective against both soilborne pathogens (e.g. Fusarium spp., Phytophthora spp., Rhizoctonia solani) and airborne (e.g. Botrytis cinerea, different species of powdery mildew). Five different mechanisms have been pro posed to explain biochar disease suppression: (1)-induction of systemic resistance in host plants; (2)enhanced abundance and activities of beneficial microbes, including mycorrhizal fungi; (3)-modification of soil quality in terms of nutrient availability and abiotic conditions such as liming eff ECT; (4)-direct fungitoxic effect of biochar; (5)-sorption of allelopathic, phytotoxic compounds that can directly harm plant roots and thus promote pathogen attacks. Potential side-effects of biochar have been reported, like the possibility of absorbing agrochemicals like herbicides, insecticides and fungicides, thus reducing their efficacy. A lot of investigations on the mechanisms underlying biochar disease suppression, as well as long-term field experiments, are very needed to make biochar a safe, affordable and effective tool for the control of these plant pathogens.
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Warren, Herman L. "Advances in Soilborne Diseases Soilborne Plant Pathogens G. W. Bruehl." BioScience 38, no. 10 (November 1988): 707. http://dx.doi.org/10.2307/1310882.
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Rekah, Yael, D. Shtienberg, and J. Katan. "Spatial Distribution and Temporal Development of Fusarium Crown and Root Rot of Tomato and Pathogen Dissemination in Field Soil." Phytopathology® 89, no. 9 (September 1999): 831–39. http://dx.doi.org/10.1094/phyto.1999.89.9.831.
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The spatial distribution and temporal development of tomato crown and root rot, caused by Fusarium oxysporum f. sp. radicis-lycopersici, were studied in naturally infested fields in 1996 and 1997. Disease progression fit a logistic model better than a monomolecular one. Geostatistical analyses and semivariogram calculations revealed that the disease spreads from infected plants to a distance of 1.1 to 4.4 m during the growing season. By using a chlorate-resistant nitrate nonutilizing (nit) mutant of F. oxysporum f. sp. radicis-lycopersici as a “tagged” inoculum, the pathogen was found to spread from one plant to the next via infection of the roots. The pathogen spread to up to four plants (2.0 m) on either side of the inoculated focus plant. Root colonization by the nit mutant showed a decreasing gradient from the site of inoculation to both sides of the inoculated plant. Simulation experiments in the greenhouse further established that this soilborne pathogen can spread from root to root during the growing season. These findings suggest a polycyclic nature of F. oxysporum f. sp. radicis-lycopersici, a deviation from the monocyclic nature of many nonzoosporic soilborne pathogens.
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Geraats, Bart P. J., Peter A. H. M. Bakker, and L. C. van Loon. "Ethylene Insensitivity Impairs Resistance to Soilborne Pathogens in Tobacco and Arabidopsis thaliana." Molecular Plant-Microbe Interactions® 15, no. 10 (October 2002): 1078–85. http://dx.doi.org/10.1094/mpmi.2002.15.10.1078.
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Transgenic ethylene-insensitive tobacco (Tetr) plants spontaneously develop symptoms of wilting and stem necrosis when grown in nonautoclaved soil. Fusarium oxysporum, F. solani, Thielaviopsis basicola, Rhizopus stolonifer, and two Pythium spp. were isolated from these diseased Tetr plants and demonstrated to be causal agents of the disease symptoms. Pathogenicity of the two Pythium isolates and four additional Pythium spp. was tested on ethylene-insensitive tobacco and Arabidopsis seedlings. In both plant species, ethylene insensitivity enhanced susceptibility to the Pythium spp., as evidenced by both a higher disease index and a higher percentage of diseased plants. Based on the use of a DNA probe specific for Pythium spp., Tetr plants exhibited more pathogen growth in stem and leaf tissue than similarly diseased control plants. These results demonstrate that ethylene signaling is required for resistance to different root pathogens and contributes to limiting growth and systemic spread of the pathogen.
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Liu, Bo, Debbie Roos, Shawn Buttler, Brantlee Richter, and Frank J. Louws. "Vegetable Seedling Diseases Associated with Earthworm Castings Contaminated with Phytophthora capsici and Pythium Attrantheridium." Plant Health Progress 13, no. 1 (January 2012): 15. http://dx.doi.org/10.1094/php-2012-0421-01-rs.
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Earthworms and worm castings have been recommended for their beneficial effects in increasing yields and suppressing soilborne diseases. However, in a few cases, earthworm castings have been shown to harbor soilborne pathogens. The research documents that earthworm castings used as an amendment in soilless potting mixes at several organic farms in North Carolina were contaminated with Phytophthora capsici and several Pythium species. Phytophthora capsici and P. attrantheridium were subsequently isolated from rotted roots of vegetable seedlings grown in the potting mix. Commercial producers of earthworm castings should only use clean plant material to maintain earthworms and earthworm castings should be ascertained as pathogen-free before incorporation into plant growth media. Accepted for publication 30 January 2012. Published 21 April 2012.
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Weller, David M. "Pseudomonas Biocontrol Agents of Soilborne Pathogens: Looking Back Over 30 Years." Phytopathology® 97, no. 2 (February 2007): 250–56. http://dx.doi.org/10.1094/phyto-97-2-0250.
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Pseudomonas spp. are ubiquitous bacteria in agricultural soils and have many traits that make them well suited as biocontrol agents of soilborne pathogens. Tremendous progress has been made in characterizing the process of root colonization by pseudomonads, the biotic and abiotic factors affecting colonization, bacterial traits and genes contributing to rhizosphere competence, and the mechanisms of pathogen suppression. This review looks back over the last 30 years of Pseudomonas biocontrol research and highlights key studies, strains, and findings that have had significant impact on shaping our current understanding of biological control by bacteria and the direction of future research.
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Henry, Peter M., Ana M. Pastrana, Johan H. J. Leveau, and Thomas R. Gordon. "Persistence of Fusarium oxysporum f. sp. fragariae in Soil Through Asymptomatic Colonization of Rotation Crops." Phytopathology® 109, no. 5 (May 2019): 770–79. http://dx.doi.org/10.1094/phyto-11-18-0418-r.
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Asymptomatic plant colonization is hypothesized to enhance persistence of pathogenic forms of Fusarium oxysporum. However, a correlation between pathogen populations on living, asymptomatic plant tissues and soilborne populations after tillage has not been demonstrated. Living and dead tissues of broccoli, lettuce, spinach, wheat, cilantro, raspberry, and strawberry plants grown in soil infested with F. oxysporum f. sp. fragariae (the cause of Fusarium wilt of strawberry) were assayed to quantify the incidence of infection and extent of colonization by this pathogen. All crops could be infected by F. oxysporum f. sp. fragariae but the extent of colonization varied between plant species. Pathogen population densities on nonliving crown tissues incorporated into the soil matrix were typically greater than those observed on living tissues. Crop-dependent differences in the inoculum density of F. oxysporum f. sp. fragariae in soil were only observed after decomposition of crop residue. Forty-four weeks after plants were incorporated into the soil, F. oxysporum f. sp. fragariae soil population densities were positively correlated with population densities on plant tissue fragments recovered at the same time point. Results indicate that asymptomatic colonization can have a significant, long-term impact on soilborne populations of Fusarium wilt pathogens. Cultural practices such as crop rotation should be leveraged to favor pathogen population decline by planting hosts that do not support extensive population growth on living or decomposing tissues.
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Kuan, T. L. "Inoculum Thresholds of Soilborne Pathogens: Overview." Phytopathology 78, no. 6 (1988): 867. http://dx.doi.org/10.1094/phyto-78-867.
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GabrielsonB, R. :L. "Inoculum Thresholds of Soilborne Pathogens: Fungi." Phytopathology 78, no. 6 (1988): 868. http://dx.doi.org/10.1094/phyto-78-868.
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Schaad, N. W. "Inoculum Thresholds of Soilborne Pathogens: Bacteria." Phytopathology 78, no. 6 (1988): 872. http://dx.doi.org/10.1094/phyto-78-872.
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Smith, R. Stace. "Inoculum Thresholds of Soilborne Pathogens: Viruses." Phytopathology 78, no. 6 (1988): 875. http://dx.doi.org/10.1094/phyto-78-875.
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Torrey, John G. "Soilborne Plant Pathogens. George W. Bruehl." Quarterly Review of Biology 62, no. 4 (December 1987): 447. http://dx.doi.org/10.1086/415660.
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Lumsden, Robert D., and George C. Papavizas. "Biological control of soilborne plant pathogens." American Journal of Alternative Agriculture 3, no. 2-3 (1988): 98–101. http://dx.doi.org/10.1017/s0889189300002253.
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AbstractSoilborne plant pathogens cause major economic losses in agricultural crops, and the present methods for control of diseases brought about by these pathogens are inadequate. Alternatives are also needed to substitute for the use of chemical fungicides. Many of these are known to induce tumors in experimental animals and are thus regarded by some investigators as potential human carcinogens when present as residues in food and water. In addition, such alternative control measures are needed because of the potential threat of development of resistance to fungicides, especially systemic fungicides, by fungal plant pathogens, and because of nontarget side effects on other plant pathogens and on beneficial microorganisms. Alternative disease control is sometimes possible through development of crop plants resistant to disease. Unfortunately, however, resistance is lacking or not available for many diseases caused by soilborne plant pathogens. Another biological means of controlling disease which is presently gaining much attention is biological control. Several systems of biological control are presently being explored and may be developed in a few years into reliable alternatives to conventional chemical control methods. The use of the mycoparasite Sporidesmium sclerotivorum, for example, against several diseases caused by Sclerotinia species is promising. Talaromyces flavus may in the future be exploited for use against several wilt diseases caused by Verticillium dahliae. Finally, practical control of several diseases caused by Pythium spp., Rhizoctonia solani, and Sclerotium rolfsii may eventually become possible through the use of Trichoderma spp. and Gliocladium virens. Development of these biological control systems will require much additional research directed toward a better understanding of the basic biology and mechanisms of action of beneficial fungi against plant pathogens. In addition, extensive cooperation will be required among research scientists, governmental agencies responsible for regulating the use of pestcontrol systems, and most importantly, private industry to develop biological control agents for the market and to coordinate acceptance and use by producers and acceptance by consumers.
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Shlevin, Eli, Yitzhak Mahrer, and Jaacov Katan. "Effect of Moisture on Thermal Inactivation of Soilborne Pathogens Under Structural Solarization." Phytopathology® 94, no. 2 (February 2004): 132–37. http://dx.doi.org/10.1094/phyto.2004.94.2.132.
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Structural solarization of greenhouses for sanitation by closing them involves dry heating to 60°C and higher with a consequent low relative humidity (RH) (≈15%), thus requiring an extended period for thermal inactivation of pathogens. In an attempt to enhance pathogen control by increasing moisture during the hot hours of the day, various regimes of inoculum moistening were studied. However, wetting inoculum of Fusarium oxysporum f. sp. melonis and F. oxysporum f. sp. radicis-lycopersici resulted in less effective pathogen control compared with that of dry heating. Fifty percent effective dose (ED50) values of thermal inactivation of wetted and dry inoculum for the former pathogen were 18 and 7 days, respectively, and for the latter, a respective 9 and 4 days. This was because wetting resulted in inoculum cooling due to evaporation, which eventually led to its drying. A model describing the drying of wet inoculum in a wetted greenhouse, based on the fact that there was an ≈10°C difference between greenhouse and ambient temperatures, was proposed. A double-tent system reduced this difference to 1 to 2°C, reduced moisture loss, and led to improved inoculum inactivation of F. oxysporum f. sp. radicis-lycopersici. Thus, the ED50 value of thermal inactivation was reduced from 15 days to 1 day, because this system provided both high temperature (≈60°C) and high RH (≈100%), resulting in effective wet heating.
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Malcolm, Glenna M., Gretchen A. Kuldau, Beth K. Gugino, and María del Mar Jiménez-Gasco. "Hidden Host Plant Associations of Soilborne Fungal Pathogens: An Ecological Perspective." Phytopathology® 103, no. 6 (June 2013): 538–44. http://dx.doi.org/10.1094/phyto-08-12-0192-le.
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Much of the current knowledge on population biology and ecology of soilborne fungal pathogens has been derived from research based on populations recovered from plants displaying disease symptoms or soil associated with symptomatic plants. Many soilborne fungal pathogens are known to cause disease on a large number of crop plants, including a variety of important agronomical, horticultural, ornamental, and forest plants species. For instance, the fungus Verticillium dahliae causes disease on >400 host plants. From a phytopathological perspective, plants on which disease symptoms have not been yet observed are considered to be nonhosts for V. dahliae. This term may be misleading because it does not provide information regarding the nature of the plant–fungus association; that is, a nonhost plant may harbor the fungus as an endophyte. Yet, there are numerous instances in the literature where V. dahliae has been isolated from asymptomatic plants; thus, these plants should be considered hosts. In this article, we synthesize scattered research that indicates that V. dahliae, aside from being a successful and significant vascular plant pathogen, may have a cryptic biology on numerous asymptomatic plants as an endophyte. Thus, we suggest here that these endophytic associations among V. dahliae and asymptomatic plants are not unusual relationships in nature. We propose to embrace the broader ecology of many fungi by differentiating between “symptomatic hosts” as those plants in which the infection and colonization by a fungus results in disease, and “asymptomatic hosts” as those plants that harbor the fungus endophytically and are different than true nonhosts that should be used for plant species that do not interact with the given fungus. In fact, if we broaden our definition of “host plant” to include asymptomatic plants that harbor the fungus as an endophyte, it is likely that the host ranges for some soilborne fungal pathogens are much larger than previously envisioned. By ignoring the potential for soilborne fungal pathogens to display endophytic relationships, we leave gaps in our knowledge about the population biology and ecology, persistence, and spread of these fungi in agroecosystems.
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Weiland, Jerry E., Chris Benedict, Inga A. Zasada, Carolyn R. Scagel, Bryan R. Beck, Anne Davis, Kim Graham, et al. "Late-summer Disease Symptoms in Western Washington Red Raspberry Fields Associated with Co-Occurrence of Phytophthora rubi, Verticillium dahliae, and Pratylenchus penetrans, but not Raspberry bushy dwarf virus." Plant Disease 102, no. 5 (May 2018): 938–47. http://dx.doi.org/10.1094/pdis-08-17-1293-re.
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Sixty percent of the $109 million processed red raspberry industry of the United States occurs in northern Washington State. In 2012, late-summer symptoms of vascular wilt and root disease were observed in many raspberry plantings. These symptoms were initially attributed to Verticillium dahliae. However, diagnostic tests for the pathogen were often contradictory and other soilborne pathogens (Phytophthora rubi and Pratylenchus penetrans) or Raspberry bushy dwarf virus (RBDV) might also have been involved. Therefore, a survey was conducted in 2013 and 2014 to (i) establish the incidence and soil population levels of V. dahliae in red raspberry production fields, (ii) compare among diagnostic methods and laboratories for detecting and quantifying V. dahliae from raspberry field soil, and (iii) assess which pathogens are associated with late-summer disease symptoms of raspberry. Plant and soil samples were collected from 51 disease sites and 20 healthy sites located in 24 production fields. Samples were analyzed for the presence and quantity of each pathogen using traditional plating and extraction methods (V. dahliae, P. rubi, and P. penetrans), quantitative polymerase chain reaction (qPCR) (V. dahliae and P. rubi), and enzyme-linked immunosorbent assay (RBDV). Results showed that V. dahliae was present in 88% of the production fields and that detection of the pathogen differed by method and by laboratory: qPCR detected V. dahliae in the soil from approximately three times as many sites (51 of 71 total sites) as by plating on NP10 semi-selective medium (15 of 71 total sites). Soil populations of V. dahliae were slightly greater at disease sites, but the pathogen was detected with similar frequency from healthy sites and it was rarely isolated from diseased plants (4%). P. rubi, P. penetrans, and RBDV were also common in production fields (79, 91, and 53% of fields, respectively). Both P. rubi (soil and root samples) and P. penetrans (root populations only), but not RBDV, were more frequently found at disease sites than healthy sites, and the amount of P. rubi detected by qPCR was greater from disease sites than healthy sites. In addition, P. rubi was isolated from 27% of the symptomatic plants located at disease sites. Regardless of detection method, V. dahliae, P. rubi, and P. penetrans, either with or without RBDV, were more likely to co-occur at disease sites (73%) than healthy sites (35%), suggesting that a soilborne disease complex is present in raspberry production fields. Results indicate that P. rubi is the primary pathogen most strongly associated with late-summer symptoms of disease, but root populations of P. penetrans and higher soil populations of V. dahliae may also be of concern. Therefore, disease control methods should focus on all three soilborne pathogens.
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Xia, Shitou, Yan Xu, Ryan Hoy, Julia Zhang, Lei Qin, and Xin Li. "The Notorious Soilborne Pathogenic Fungus Sclerotinia sclerotiorum: An Update on Genes Studied with Mutant Analysis." Pathogens 9, no. 1 (December 27, 2019): 27. http://dx.doi.org/10.3390/pathogens9010027.
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Ascomycete Sclerotinia sclerotiorum (Lib.) de Bary is one of the most damaging soilborne fungal pathogens affecting hundreds of plant hosts, including many economically important crops. Its genomic sequence has been available for less than a decade, and it was recently updated with higher completion and better gene annotation. Here, we review key molecular findings on the unique biology and pathogenesis process of S. sclerotiorum, focusing on genes that have been studied in depth using mutant analysis. Analyses of these genes have revealed critical players in the basic biological processes of this unique pathogen, including mycelial growth, appressorium establishment, sclerotial formation, apothecial and ascospore development, and virulence. Additionally, the synthesis has uncovered gaps in the current knowledge regarding this fungus. We hope that this review will serve to build a better current understanding of the biology of this under-studied notorious soilborne pathogenic fungus.
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Blok, Wim J., Jan G. Lamers, Aad J. Termorshuizen, and Gerrit J. Bollen. "Control of Soilborne Plant Pathogens by Incorporating Fresh Organic Amendments Followed by Tarping." Phytopathology® 90, no. 3 (March 2000): 253–59. http://dx.doi.org/10.1094/phyto.2000.90.3.253.
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A new method for the control of soilborne plant pathogens was tested for its efficacy in two field experiments during two years. Plots were amended with fresh broccoli or grass (3.4 to 4.0 kg fresh weight m-2) or left nonamended, and covered with an airtight plastic cover (0.135 mm thick) or left noncovered. In plots amended with broccoli or grass and covered with plastic sheeting, anaerobic and strongly reducing soil conditions developed quickly, as indicated by rapid depletion of oxygen and a decrease in redox potential values to as low as -200 mV. After 15 weeks, survival of Fusarium oxysporum f. sp. asparagi, Rhizoctonia solani, and Verticillium dahliae in inoculum samples buried 15 cm deep was strongly reduced in amended, covered plots in both experiments. The pathogens were not or hardly inactivated in amended, noncovered soil or nonamended, covered soil. The latter indicates that thermal inactivation due to increased soil temperatures under the plastic cover was not involved in pathogen inactivation. The results show the potential for this approach to control various soilborne pathogens and that it may serve as an alternative to chemical soil disinfestation for high-value crops under conditions where other alternatives, such as solarization or soil flooding, are not effective or not feasible.
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Eshel, Dani, Abraham Gamliel, Avshalom Grinstein, Pietro Di Primo, and Jaacov Katan. "Combined Soil Treatments and Sequence of Application in Improving the Control of Soilborne Pathogens." Phytopathology® 90, no. 7 (July 2000): 751–57. http://dx.doi.org/10.1094/phyto.2000.90.7.751.
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The effects of reduced doses of methyl bromide (MB) or metham sodium, heating, short solarization, and soil microbial activity, alone or in combination, on survival of soilborne fungal pathogens were tested in a controlled-environment system and field plots. Sublethal doses of heating or MB delayed germination of Sclerotium rolfsii sclerotia. Combining MB and heating treatments was more effective than either treatment alone in controlling S. rolfsii and Fusarium oxysporum f. sp. basilici. The application heating followed by fumigation with MB, was significantly more effective in delaying and reducing germination of S. rolfsii sclerotia and in controlling F. oxysporum f. sp. basilici than the opposite sequence. Further, incubation in soil and exposure to microbial activity of previously heated or MB-treated sclerotia increased the mortality rate, indicating a weakening effect. Similarly, incubation of chlamydospores of F. oxysporum f. sp. melonis and F. oxysporum f. sp. radicis-lycopersici in soil in the field after fumigation further reduced their survival, confirming the laboratory results. In field tests, combining MB or metham sodium at reduced doses with short solarization was more effective in controlling fungal pathogens than either treatment alone. Treatment sequence significantly affected pathogen control in the field, similar to its effect under controlled conditions. This study demonstrates a frequent synergistic effect of combining soil treatments and its potential for improving pathogen control and reducing pesticide dose, especially when an appropriate sequence was followed.
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Sanogo, S. "Interactive Effects of Two Soilborne Pathogens, Phytophthora capsici and Verticillium dahliae, on Chile Pepper." Phytopathology® 97, no. 1 (January 2007): 37–43. http://dx.doi.org/10.1094/phyto-97-0037.
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Phytophthora capsici and Verticillium dahliae are two mycelial microorganisms associated with wilt symptoms on chile pepper (Capsicum annuum). Both pathogens occur in the same field and can infect a single plant. This study examined the nature of the co-occurrence of P. capsici and V. dahliae. Chile pepper plants were inoculated with each pathogen separately or with both pathogens concomitantly or sequentially. In concomitant inoculations, plants were inoculated with a mixture of zoospores of P. capsici and conidia of V. dahliae. In sequential inoculations, plants were inoculated with zoospores of P. capsici 4 days prior to inoculation with conidia of V. dahliae, or plants were inoculated with conidia of V. dahliae 4 days prior to inoculation with zoospores of P. capsici. Stem necrosis and leaf wilting were visible 3 to 4 days earlier in plants inoculated with both P. capsici and V. dahliae than in plants inoculated with P. capsici alone. Stem necrosis and generalized plant wilting were observed in plants inoculated with P. capsici alone, and stem necrosis, generalized plant wilting, and vascular discoloration were observed in plants inoculated with both P. capsici and V. dahliae by 21 days after inoculation. These symptoms were not observed in control plants or plants inoculated with V. dahliae alone. The frequency of recovery of V. dahliae from stems was ≈85 to 140% higher across inoculum levels when plants were inoculated with both P. capsici and V. dahliae than when plants were inoculated by V. dahliae alone. Similarly, the frequency of recovery of V. dahliae from roots was ≈13 to 40% higher across inoculum levels when plants were inoculated with both P. capsici and V. dahliae than when plants were inoculated by V. dahliae alone. There was no apparent antagonism between the two pathogens when they were paired on growth media. In general, when P. capsici and V. dahliae were paired on growth media, mycelial growth of each pathogen grown alone was not significantly different from mycelial growth when the pathogens were paired. Results suggest that wilt development is hastened by the presence of both P. capsici and V. dahliae in the same plants. The presence of P. capsici and V. dahliae in the same inoculum court enhanced infection and colonization of chile pepper by V. dahliae.
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Galiana, Eric, Antoine Marais, Catherine Mura, Benoît Industri, Gilles Arbiol, and Michel Ponchet. "Ecosystem Screening Approach for Pathogen-Associated Microorganisms Affecting Host Disease." Applied and Environmental Microbiology 77, no. 17 (July 8, 2011): 6069–75. http://dx.doi.org/10.1128/aem.05371-11.
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ABSTRACTThe microbial community in which a pathogen evolves is fundamental to disease outcome. Species interacting with a pathogen on the host surface shape the distribution, density, and genetic diversity of the inoculum, but the role of these species is rarely determined. The screening method developed here can be used to characterize pathogen-associated species affecting disease. This strategy involves three steps: (i) constitution of the microbial community, using the pathogen as a trap; (ii) community selection, using extracts from the pathogen as the sole nutrient source; and (iii) molecular identification and the screening of isolates focusing on their effects on the growth of the pathogenin vitroand host disease. This approach was applied to a soilborne plant pathogen,Phytophthora parasitica, structured in a biofilm, for screening the microbial community from the rhizosphere ofNicotiana tabacum(the host). Two of the characterized eukaryotes interfered with the oomycete cycle and may affect the host disease. AVorticellaspecies acted through a mutualistic interaction withP. parasitica, disseminating pathogenic material by leaving the biofilm. APhomaspecies established an amensal interaction withP. parasitica, strongly suppressing disease by inhibitingP. parasiticagermination. This screening method is appropriate for all nonobligate pathogens. It allows the definition of microbial species as promoters or suppressors of a disease for a given biotope. It should also help to identify important microbial relationships for ecology and evolution of pathogens.
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Suchoff, David H., Frank J. Louws, and Christopher C. Gunter. "Yield and Disease Resistance for Three Bacterial Wilt-resistant Tomato Rootstocks." HortTechnology 29, no. 3 (June 2019): 330–37. http://dx.doi.org/10.21273/horttech04318-19.
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Interest and use of grafted tomato (Solanum lycopersicum) in the United States continues to grow. Pioneered in Asia, herbaceous grafting is a commonly used cultural practice to manage many soilborne pathogens. Bacterial wilt (BW), caused by the pathogen Ralstonia solanacearum, is an aggressive soilborne pathogen that affects tomato grown in the southeastern United States. Traditional fumigation methods have limited effectiveness in the management of this pathogen. The present study was conducted to compare the bacterial wilt resistance of three commercially available tomato rootstocks, which are purported to be resistant to bacterial wilt: ‘Cheong Gang’, ‘RST-04-106-T’, and ‘Shield’. The determinate hybrid tomato ‘Red Mountain’, which is susceptible to bacterial wilt, was used as the scion and nongrafted control. Three locations were used over 2 years in North Carolina: an on-farm site with a history of bacterial wilt and two North Carolina Department of Agriculture Research Stations with no recent history of bacterial wilt. No disease symptoms were observed in any of the three grafted treatments, whereas the nongrafted controls showed between 30% and 80% disease incidence at the on-farm location. The resultant rootstock-imparted resistance improved marketable yields by between 88% and 125% compared with the nongrafted plants. When grown in locations lacking BW there were no yield benefits to grafting with any of the three rootstocks.
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Husaini, Amjad M., Aafreen Sakina, and Souliha R. Cambay. "Host–Pathogen Interaction in Fusarium oxysporum Infections: Where Do We Stand?" Molecular Plant-Microbe Interactions® 31, no. 9 (September 2018): 889–98. http://dx.doi.org/10.1094/mpmi-12-17-0302-cr.
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Fusarium oxysporum, a ubiquitous soilborne pathogen, causes devastating vascular wilt in more than 100 plant species and ranks 5th among the top 10 fungal plant pathogens. It has emerged as a human pathogen, too, causing infections in immune-compromised patients. Therefore, it is important to gain insight into the molecular processes involved in the pathogenesis of this transkingdom pathogen. A complex network comprising interconnected and overlapping signal pathways—mitogen-activated protein kinase signaling pathways, Ras proteins, G-protein signaling components and their downstream pathways, components of the velvet (LaeA/VeA/VelB) complex, and cAMP pathways—is involved in perceiving the host. This network regulates the expression of various pathogenicity genes. However, plants have evolved an elaborate protection system to combat this attack. They, too, possess intricate mechanisms at the molecular level which, once triggered by pathogen attack, transduce signals to activate defense response. This review focuses on understanding and presenting a wholistic picture of the molecular mechanisms of F. oxysporum–host interactions in plant immunity.
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Panth, Milan, Fulya Baysal-Gurel, Terri Simmons, Karla M. Addesso, and Anthony Witcher. "Impact of Winter Cover Crop Usage in Soilborne Disease Suppressiveness in Woody Ornamental Production System." Agronomy 10, no. 7 (July 10, 2020): 995. http://dx.doi.org/10.3390/agronomy10070995.
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Diseases caused by soilborne pathogens are a major limitation to field grown nursery production. The application of cover crops for soilborne disease management has not been widely investigated in a woody ornamental nursery production system. The objective of this study was to explore the impact of winter cover crops usage on soilborne disease management in that system. Soils from established field plots of red maple (Acer rubrum L.) with and without winter cover crops (crimson clover (Trifolium incarnatum L.) or triticale (× Triticosecale W.)) were sampled following the senescence of the cover crops. Separate bioassays were performed using red maple cuttings on inoculated (with Phytopythium vexans, Phytophthora nicotianae or Rhizoctonia solani) and non-inoculated field soils. The results indicated that winter cover crop usage was helpful for inducing soil disease suppressiveness. There was lower disease severity and pathogen recovery when the cover crops were used compare to the non-cover cropped soil. However, there were no differences in maple plant fresh weight and root weight between the treatments. The rhizosphere pseudomonad microbial population was also greater when the cover crops were used. Similarly, the C:N ratio of the soil was improved with the cover crop usage. Thus, in addition to improving soil structure and reducing erosion, cover crops can provide improved management of soilborne diseases. Therefore, stakeholders can consider cover crop usage as an alternative sustainable management tool against soilborne diseases in field nursery production system.
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Pastrana, Ana María, María José Basallote-Ureba, Ana Aguado, and Nieves Capote. "Potential Inoculum Sources and Incidence of Strawberry Soilborne Pathogens in Spain." Plant Disease 101, no. 5 (May 2017): 751–60. http://dx.doi.org/10.1094/pdis-08-16-1177-re.
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The decline and death of strawberry plants in Spanish fruit production fields have mainly been attributed to the soilborne pathogens Macrophomina phaseolina, Phytophthora cactorum, and Fusarium spp. Inoculum sources of M. phaseolina and P. cactorum, and the incidence all three genera, were investigated in nurseries and fruit production fields over three consecutive seasons. M. phaseolina inoculum sources consisted of fumigated preplant fruit production soils (50%) and fumigated nursery soils (47%), although the pathogen could not be detected in nursery mother and runner plants. P. cactorum inoculum sources included nursery (20%) and preplant fruit production (17%) fumigated soils, and nursery runner plants (up to 15%). In fruit production plants, the average incidence of M. phaseolina and P. cactorum were 4.2 and 3.7%, respectively. Fusarium spp. inoculum sources could not be accessed extensively due to the lack of effective quantitative real-time PCR assays. Limited testing of nursery plants showed that Fusarium oxysporum f. sp. fragariae (Fof) was absent. In field production plants and soil, F. solani was the main pathogenic Fusarium spp., with Fof only identified once in a fruit production plant. Ineffectively fumigated soils in nurseries and production fields, along with infected runner plants, can be inoculum sources of soilborne strawberry pathogens in Spain.
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Okubara, Patricia A., Kurtis L. Schroeder, John T. Abatzoglou, and Timothy C. Paulitz. "Agroecological Factors Correlated to Soil DNA Concentrations of Rhizoctonia in Dryland Wheat Production Zones of Washington State, USA." Phytopathology® 104, no. 7 (July 2014): 683–91. http://dx.doi.org/10.1094/phyto-09-13-0269-r.
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The necrotrophic soilborne fungal pathogens Rhizoctonia solani AG8 and R. oryzae are principal causal agents of Rhizoctonia root rot and bare patch of wheat in dryland cropping systems of the Pacific Northwest. A 3-year survey of 33 parcels at 11 growers' sites and 60 trial plots at 12 Washington State University cereal variety test locations was undertaken to understand the distribution of these pathogens. Pathogen DNA concentrations in soils, quantified using real-time polymerase chain reaction, were correlated with precipitation, temperature maxima and minima, and soil texture factors in a pathogen-specific manner. Specifically, R. solani AG8 DNA concentration was negatively correlated with precipitation and not correlated with temperature minima, whereas R. oryzae concentration was correlated with temperature minima but not with precipitation. However, both pathogens were more abundant in soils with higher sand and lower clay content. Principal component analysis also indicated that unique groups of meteorological and soil factors were associated with each pathogen. Furthermore, tillage did not affect R. oryzae but affected R. solani AG8 at P = 0.06. Lower soil concentrations of R. solani AG8 but not R. oryzae occurred when the previously planted crop was a broadleaf (P < 0.05). Our findings showed that R. solani AG8 concentrations were consistent with the general distribution of bare patch symptoms, based on field observations and surveys of other pathogens, but was present at many sites in which bare patch symptoms were not evident. Management of Rhizoctonia root rot and bare patch should account for the likelihood that each pathogen is affected by a unique group of agroecological variables.
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Kondo, Norio. "Studies on the ecology and pathogenic specialization of soilborne pathogens affecting adzuki bean (Vigna angularis)." Journal of General Plant Pathology 84, no. 6 (August 23, 2018): 431–34. http://dx.doi.org/10.1007/s10327-018-0810-7.
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Parker, C. A., A. D. Rovira, K. J. Moore, P. T. W. Wong, and J. F. Kollmorgen. "Ecology and Management of Soilborne Plant Pathogens." Bulletin of the Torrey Botanical Club 112, no. 2 (April 1985): 201. http://dx.doi.org/10.2307/2996423.
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Mihajlovic, Milica, Emil Rekanovic, Jovana Hrustic, Mila Grahovac, and Brankica Tanovic. "Methods for management of soilborne plant pathogens." Pesticidi i fitomedicina 32, no. 1 (2017): 9–24. http://dx.doi.org/10.2298/pif1701009m.
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Soilborne pathogens cause significant economic losses in agricultural production all over the world. These species can survive for many years in the absence of a host plant by forming persistent structures such as microsclerotia, sclerotia, chlamydospores or oospores. Consequently, soilborne diseases are particularly difficult to predict, detect, diagnose and successfully control. Over the past 30 years, a fumigant, methyl bromide, has been widely used for their control in many crops. In 1992, methyl bromide was listed as an ozone-depleting substance under the Montreal Protocol ? an international treaty to protect the ozone layer. During the phaseout of methyl bromide, problems generated in agricultural production made it clear that dependence on a single method or a single chemical should be avoided. The objective of this review paper was to summarize the current knowledge about different methods of soilborne disease control including: crop rotation, steam soil disinfection, soil amendments, hydroponics and soilless growing systems, soil solarization, grafting, biological control and use of natural compounds, and chemical control. Positive and negative aspects of all available methods were reviewed. Benefits, achieved by simultaneous application of several methods based on different mechanisms of actions, are discussed.
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Anderson, J. B., and L. M. Kohn. "Clonality in Soilborne, Plant-Pathogenic Fungi." Annual Review of Phytopathology 33, no. 1 (September 1995): 369–91. http://dx.doi.org/10.1146/annurev.py.33.090195.002101.
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Durán, Paola, Gonzalo Tortella, Michael J. Sadowsky, Sharon Viscardi, Patricio Javier Barra, and Maria de la Luz Mora. "Engineering Multigenerational Host-Modulated Microbiota against Soilborne Pathogens in Response to Global Climate Change." Biology 10, no. 9 (September 3, 2021): 865. http://dx.doi.org/10.3390/biology10090865.
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Crop migration caused by climatic events has favored the emergence of new soilborne diseases, resulting in the colonization of new niches (emerging infectious diseases, EIDs). Soilborne pathogens are extremely persistent in the environment. This is in large part due to their ability to reside in the soil for a long time, even without a host plant, using survival several strategies. In this regard, disease-suppressive soils, characterized by a low disease incidence due to the presence of antagonist microorganisms, can be an excellent opportunity for the study mechanisms of soil-induced immunity, which can be applied in the development of a new generation of bioinoculants. Therefore, here we review the main effects of climate change on crops and pathogens, as well as the potential use of soil-suppressive microbiota as a natural source of biocontrol agents. Based on results of previous studies, we also propose a strategy for the optimization of microbiota assemblages, selected using a host-mediated approach. This process involves an increase in and prevalence of specific taxa during the transition from a conducive to a suppressive soil. This strategy could be used as a model to engineer microbiota assemblages for pathogen suppression, as well as for the reduction of abiotic stresses created due to global climate change.
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Weiland, Jerry E., Carolyn F. Scagel, Niklaus J. Grünwald, E. Anne Davis, Bryan R. Beck, Zachary S. L. Foster, and Valerie J. Fieland. "Soilborne Phytophthora and Pythium Diversity From Rhododendron in Propagation, Container, and Field Production Systems of the Pacific Northwest." Plant Disease 104, no. 6 (June 2020): 1841–50. http://dx.doi.org/10.1094/pdis-08-19-1672-re.
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Rhododendron root rot is a severe disease that causes significant mortality in rhododendrons. Information is needed about the incidence and identity of soilborne Phytophthora and Pythium species causing root rot in Pacific Northwest nurseries in order to better understand the disease etiology and to optimize disease control strategies. The last survey focusing solely on soilborne oomycete pathogens in rhododendron production was conducted in 1974. Since then, advances in pathogen identification have occurred, new species may have been introduced, pathogen communities may have shifted, and little is known about Pythium species affecting this crop. Therefore, a survey of root-infecting Phytophthora and Pythium species was conducted at seven nurseries from 2013 to 2017 to (i) document the incidence of root rot damage at each nursery and stage of production, (ii) identify soilborne oomycetes infecting rhododendron, and (iii) determine whether there are differences in pathogen diversity among nurseries and production systems. Rhododendrons from propagation, container, and field systems were sampled and Phytophthora and Pythium species were isolated from the roots and collar region. Root rot was rarely evident in propagation systems, which were dominated by Pythium species. However, severe root rot was much more common in container and field systems where the genus Phytophthora was also more prevalent, suggesting that Phytophthora species are the primary cause of severe root rot and that most contamination by these pathogens comes in after the propagation stage. In total, 20 Pythium species and 11 Phytophthora species were identified. Pythium cryptoirregulare, Pythium aff. macrosporum, Phytophthora plurivora, and Phytophthora cinnamomi were the most frequently isolated species and the results showed that Phytophthora plurivora has become much more common than in the past. Phytophthora diversity was also greater in field systems than in propagation or container systems. Risks for Phytophthora contamination were commonly observed during the survey and included placement of potting media in direct contact with field soil, the presence of dead plants that could serve as continuous sources of inoculum, and the presence of excess water as a result of poor drainage, overirrigation, or malfunctioning irrigation equipment. In the past, research on disease development and root rot disease control in rhododendron focused almost exclusively on Phytophthora cinnamomi. More research is needed on both of these topics for the other root-infecting species identified in this survey.
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Jacobs, Janette L., James D. Kelly, Evan M. Wright, Gregory Varner, and Martin I. Chilvers. "Determining the Soilborne Pathogens Associated with Root Rot Disease Complex of Dry Bean in Michigan." Plant Health Progress 20, no. 2 (January 1, 2019): 122–27. http://dx.doi.org/10.1094/php-11-18-0076-s.
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In Michigan, yield reduction as a result of diminished plant vigor owing to root rot is a major constraint associated with dry bean production and is exacerbated when fields have a history of short crop rotations. Replanting can be necessary when flooding, poor seed germination, or cool soil temperatures result in poor plant establishment, which may be compounded by increased disease pressure. To identify which soilborne pathogens are associated with root rot disease complex on dry bean and to determine their prevalence, a survey was conducted from 2014 to 2018. Dry beans with root rot symptoms were obtained from 39 field locations in 10 counties in Michigan. Rotted roots were washed, potential pathogens were cultured, and isolates were putatively identified into the major pathogen groups based on morphology. Additional identification was conducted with sequencing of the internal transcribed spacer of rDNA for oomycetes and Rhizoctonia and the translation elongation factor 1-α gene for Fusarium isolates. Among the 1,034 isolates obtained, Fusarium (54%) was recovered at the highest prevalence, and oomycetes and Rhizoctonia exhibited a consistent presence, ranging across years from 11 to 30.2% and from 9.3 to 41.8%, respectively. This survey provided baseline information on the prevalence of critical soilborne pathogens of dry bean in Michigan. In the future, additional genetic markers will be utilized to further identify organisms, a species characterization will be conducted to assess pathogenicity and virulence, and dry bean germplasm will be screened for resistance.
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Hyder, Naveen, James J. Sims, and Stephen N. Wegulo. "In Vitro Suppression of Soilborne Plant Pathogens by Coir." HortTechnology 19, no. 1 (January 2009): 96–100. http://dx.doi.org/10.21273/hortsci.19.1.96.
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Experiments conducted in vitro showed that coir [coconut (Cocos nucifera) mesocarp pith] suppressed growth of soilborne plant pathogens. Mycelial growth of Phytophthora capsici on potato dextrose agar (PDA) amended with an unsterilized coir suspension was strongly inhibited regardless of suspension concentration. Growth of P. capsici on PDA amended with a filter-sterilized coir suspension was uninhibited. Growth of Fusarium solani on water agar (WA) amended with unautoclaved coir was completely inhibited. Growth of F. solani on WA amended with autoclaved coir was uninhibited. Aspergillus terreus recovered from coir inhibited mycelial growth of various soilborne pathogens by up to 75%. The results from this study suggest that coir has the ability to suppress soilborne plant pathogens in vitro and this ability is largely due to microorganisms associated with the substrate.
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Ma, Minxiao, Paul W. J. Taylor, Deli Chen, Niloofar Vaghefi, and Ji-Zheng He. "Major Soilborne Pathogens of Field Processing Tomatoes and Management Strategies." Microorganisms 11, no. 2 (January 19, 2023): 263. http://dx.doi.org/10.3390/microorganisms11020263.
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Globally, tomato is the second most cultivated vegetable crop next to potato, preferentially grown in temperate climates. Processing tomatoes are generally produced in field conditions, in which soilborne pathogens have serious impacts on tomato yield and quality by causing diseases of the tomato root system. Major processing tomato-producing countries have documented soilborne diseases caused by a variety of pathogens including bacteria, fungi, nematodes, and oomycetes, which are of economic importance and may threaten food security. Recent field surveys in the Australian processing tomato industry showed that plant growth and yield were significantly affected by soilborne pathogens, especially Fusarium oxysporum and Pythium species. Globally, different management methods have been used to control diseases such as the use of resistant tomato cultivars, the application of fungicides, and biological control. Among these methods, biocontrol has received increasing attention due to its high efficiency, target-specificity, sustainability and public acceptance. The application of biocontrol is a mix of different strategies, such as applying antagonistic microorganisms to the field, and using the beneficial metabolites synthesized by these microorganisms. This review provides a broad review of the major soilborne fungal/oomycete pathogens of the field processing tomato industry affecting major global producers, the traditional and biological management practices for the control of the pathogens, and the various strategies of the biological control for tomato soilborne diseases. The advantages and disadvantages of the management strategies are discussed, and highlighted is the importance of biological control in managing the diseases in field processing tomatoes under the pressure of global climate change.
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Poole, Grant J., Martin Harries, D. Hüberli, S. Miyan, W. J. MacLeod, Roger Lawes, and A. McKay. "Predicting Cereal Root Disease in Western Australia Using Soil DNA and Environmental Parameters." Phytopathology® 105, no. 8 (August 2015): 1069–79. http://dx.doi.org/10.1094/phyto-07-14-0203-r.
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Root diseases have long been prevalent in Australian grain-growing regions, and most management decisions to reduce the risk of yield loss need to be implemented before the crop is sown. The levels of pathogens that cause the major root diseases can be measured using DNA-based services such as PreDicta B. Although these pathogens are often studied individually, in the field they often occur as mixed populations and their combined effect on crop production is likely to vary across diverse cropping environments. A 3-year survey was conducted covering most cropping regions in Western Australia, utilizing PreDicta B to determine soilborne pathogen levels and visual assessments to score root health and incidence of individual crop root diseases caused by the major root pathogens, including Rhizoctonia solani (anastomosis group [AG]-8), Gaeumannomyces graminis var. tritici (take-all), Fusarium pseudograminearum, and Pratylenchus spp. (root-lesion nematodes) on wheat roots for 115, 50, and 94 fields during 2010, 2011, and 2012, respectively. A predictive model was developed for root health utilizing autumn and summer rainfall and soil temperature parameters. The model showed that pathogen DNA explained 16, 5, and 2% of the variation in root health whereas environmental parameters explained 22, 11, and 1% of the variation in 2010, 2011, and 2012, respectively. Results showed that R. solani AG-8 soil pathogen DNA, environmental soil temperature, and rainfall parameters explained most of the variation in the root health. This research shows that interactions between environment and pathogen levels before seeding can be utilized in predictive models to improve assessment of risk from root diseases to assist growers to plan more profitable cropping programs.
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Brandl, M. T., B. M. Rosenthal, A. F. Haxo, and S. G. Berk. "Enhanced Survival of Salmonella enterica in Vesicles Released by a Soilborne Tetrahymena Species." Applied and Environmental Microbiology 71, no. 3 (March 2005): 1562–69. http://dx.doi.org/10.1128/aem.71.3.1562-1569.2005.
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ABSTRACT Nondestructive ingestion by soilborne protozoa may enhance the environmental resiliency of important bacterial pathogens and may model how such bacteria evade destruction in human macrophages. Here, the interaction of Salmonella enterica serovar Thompson with a soilborne Tetrahymena sp. isolate was examined using serovar Thompson cells labeled with the green fluorescent protein. The bacteria were mixed in solution with cells of Tetrahymena at several ratios. During incubation with serovar Thompson, Tetrahymena cells released a large number of vesicles containing green fluorescent serovar Thompson cells. In comparison, grazing on Listeria monocytogenes cells resulted in their digestion and thus the infrequent release of this pathogen in vesicles. The number of serovar Thompson cells per vesicle increased significantly as the initial ratio of serovar Thompson to Tetrahymena cells increased from 500:1 to 5,000:1. The density of serovar Thompson was as high as 50 cells per vesicle. Staining with propidium iodide revealed that a significantly higher proportion of serovar Thompson cells remained viable when enclosed in vesicles than when free in solution. Enhanced survival rates were observed in vesicles that were secreted by both starved (F = 28.3, P < 0.001) and unstarved (F = 14.09, P < 0.005) Tetrahymena cells. Sequestration in vesicles also provided greater protection from low concentrations of calcium hypochlorite. Thus, the release of this human pathogen from Tetrahymena cells in high-density clusters enclosed in a membrane may have important implications for public health.
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Kenerley, Chuck, and R. Hall. "Principles and Practice of Managing Soilborne Plant Pathogens." Mycologia 91, no. 3 (May 1999): 561. http://dx.doi.org/10.2307/3761363.
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Gullino, M. L., G. Gilardi, D. Bertetti, and A. Garibaldi. "Emerging soilborne pathogens and trends in their management." Acta Horticulturae, no. 1270 (February 2020): 9–22. http://dx.doi.org/10.17660/actahortic.2020.1270.2.
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