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LeBlanc N. Green Manures Alter Taxonomic and Functional Characteristics of Soil Bacterial Communities. MICROBIAL ECOLOGY 2023; 85:684-697. [PMID: 35112152 DOI: 10.1007/s00248-022-01975-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Accepted: 01/25/2022] [Indexed: 06/14/2023]
Abstract
Incorporation of plant biomass into soil as green manures can reduce soilborne diseases and improve crop and soil health in agricultural ecosystems. Soil microbial communities can mediate beneficial effects of these amendments, but their response to different types of green manures is poorly understood. This study tested the effect of green manures from broccoli, marigold, and sudangrass on taxonomic and functional characteristics of soil bacterial communities. Green manures were amended to field soil and maintained in microcosms artificially infested with the soilborne plant pathogen Verticillium dahliae. Lettuce seedlings were transplanted into green manure amended and fallow soil and maintained under growth chamber conditions for 12 weeks. Bacterial communities in bulk and rhizosphere soils were characterized using nanopore sequencing of 16S rRNA and shotgun metagenome libraries. Under microcosm conditions, all green manures reduced the abundance of the soilborne plant pathogen V. dahliae and altered the taxonomic composition of bacterial communities. Twelve weeks following amendment, green manures had differential effects on lettuce yield as well as the taxonomic diversity and composition of soil bacterial communities. In addition, multiple green manures increased the abundance of bacterial functional traits in rhizosphere soil related to iron and polysaccharide acquisition and decreased the abundance of functional traits related to bacterial protein secretion systems. This study demonstrates green manures alter the taxonomic composition and functional traits in soil bacterial communities suggesting these changes may impact beneficial effects of green manures on plant and soil health.
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Affiliation(s)
- Nicholas LeBlanc
- United States Department of Agriculture, Agricultural Research Service, Crop Improvement and Protection Research Unit, 1636 E. Alisal St., Salinas, CA, 93905, USA.
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2
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Chen D, Zebarth BJ, Goyer C, Comeau LP, Nahar K, Dixon T. Effect of Biofumigation on Population Densities of Pratylenchus spp. and Verticillium spp. and Potato Yield in Eastern Canada. AMERICAN JOURNAL OF POTATO RESEARCH : AN OFFICIAL PUBLICATION OF THE POTATO ASSOCIATION OF AMERICA 2022; 99:229-242. [PMID: 35437344 PMCID: PMC9007048 DOI: 10.1007/s12230-022-09875-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Accepted: 03/13/2022] [Indexed: 06/14/2023]
Abstract
Biofumigation has been proposed as an alternative to soil fumigation to manage soil-borne diseases including potato early dying disease complex (PED). This study examined the potential of using brown mustard (Mustard juncea) biofumigation to manage PED under rain-fed potato production in New Brunswick, Canada in two trials between 2017 and 2020 in comparison with chloropicrin fumigation and a conventional barley rotation. Biofumigation increased yield in one trial, but not in a second trial where the potato crop experienced severe drought, whereas chloropicrin fumigation increased yield in both trials. Biofumigation was effective in suppressing root-lesion nematode (RLN, Pratylenchus spp.) counts in both trials, but was ineffective in suppressing V. dahliae population density. Chloropicrin fumigation was effective in suppressing RLN counts and V. dahliae population density only in the hill where injected, but the effect was short-lived as the population density of V. dahliae in the hill increased to the level of the control in one potato growing season. Biofumigation may be an alternative to chloropicrin fumigation in managing PED, particularly in fields with high RLN population but relatively low Verticillium population density. However, neither biofumigation nor fumigation used alone may be sustainable in the short-term potato rotations commonly used in New Brunswick, and additional beneficial practices are required to sustain productivity in the long-term.
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Affiliation(s)
- Dahu Chen
- Fredericton Research and Development Centre, Agriculture and Agri-Food Canada, 95 Innovation Road, Fredericton, New Brunswick E3B 4Z7 Canada
| | - Bernie J. Zebarth
- Fredericton Research and Development Centre, Agriculture and Agri-Food Canada, 95 Innovation Road, Fredericton, New Brunswick E3B 4Z7 Canada
| | - Claudia Goyer
- Fredericton Research and Development Centre, Agriculture and Agri-Food Canada, 95 Innovation Road, Fredericton, New Brunswick E3B 4Z7 Canada
| | - Louis-Pierre Comeau
- Fredericton Research and Development Centre, Agriculture and Agri-Food Canada, 95 Innovation Road, Fredericton, New Brunswick E3B 4Z7 Canada
| | - Kamrun Nahar
- Fredericton Research and Development Centre, Agriculture and Agri-Food Canada, 95 Innovation Road, Fredericton, New Brunswick E3B 4Z7 Canada
| | - Tom Dixon
- McCain Foods (Canada) Ltd., 8800 Main Street, Florenceville-Bristol, New Brunswick E7L 1B2 Canada
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3
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Gutierrez J, Bakke A, Vatta M, Merrill AR. Plant Natural Products as Antimicrobials for Control of Streptomyces scabies: A Causative Agent of the Common Scab Disease. Front Microbiol 2022; 12:833233. [PMID: 35154047 PMCID: PMC8828645 DOI: 10.3389/fmicb.2021.833233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Accepted: 12/24/2021] [Indexed: 11/13/2022] Open
Abstract
The common scab disease caused by Streptomyces scabies, a soil-dwelling Gram-positive bacterium, is an economically important disease of potatoes and other tuber crops. The lack of effective treatments against this disease accounts for large economic losses globally. Plant extracts were screened to find several that effectively inhibited Streptomyces scabies growth in culture. Seven tinctures showed the greatest inhibition of S. scabies growth by reducing pathogen growth in culture by 75% or more. These extracts were myrrh, garlic, cayenne, barberry, frankincense, wild indigo root, and lavender. Myrrh extract from Commiphora myrrha, a resin made from tree sap, showed strong antibacterial activity by reducing the growth of S. scabies to 13% of the control. Additionally, a flavonoid library was screened to identify several compounds that were effective to control the pathogen growth. The flavonoids that showed the greatest inhibition of Streptomyces scabies growth were sophoraflavanone G, jaceosidin, baicalein, and quercetin. Minimum inhibitory concentrations for the effective flavonoids were calculated to be 6.8 ± 0.4 μM, 100.0 ± 2.1 μM, 202.9 ± 5.3 μM, and 285.2 ± 6.8 μM, respectively. The mean lethal doses for these flavonoids against Streptomyces scabies were 2.0 ± 0.1 μM, 22.6 ± 0.5 μM, 52.9 ± 1.3 μM, and 37.8 ± 1.0 μM, respectively. A live/dead assay showed complete cell death in the presence of sophoraflavanone G indicative of a bactericidal mechanism for flavonoid action on Streptomyces scabies. Scanning electron and transmission electron microscopy imaging showed damaged cell membrane morphologies when Streptomyces scabies was exposed to these flavonoids. Mycelia appeared as flat and deflated structures with contents seen as spewing from branching hyphae with numerous holes and tears in the membrane structure indicative of cell death. Sophoraflavanone G showed the greatest potency and potential as a natural antibiotic from the library of tested flavonoids. These results suggest that these plant compounds act on the pathogen through a bactericidal mechanism involving cell membrane destabilization and disruption leading to cell death.
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Arabidopsis P4 ATPase-mediated cell detoxification confers resistance to Fusarium graminearum and Verticillium dahliae. Nat Commun 2021; 12:6426. [PMID: 34741039 PMCID: PMC8571369 DOI: 10.1038/s41467-021-26727-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Accepted: 10/18/2021] [Indexed: 02/07/2023] Open
Abstract
Many toxic secondary metabolites produced by phytopathogens can subvert host immunity, and some of them are recognized as pathogenicity factors. Fusarium head blight and Verticillium wilt are destructive plant diseases worldwide. Using toxins produced by the causal fungi Fusarium graminearum and Verticillium dahliae as screening agents, here we show that the Arabidopsis P4 ATPases AtALA1 and AtALA7 are responsible for cellular detoxification of mycotoxins. Through AtALA1-/AtALA7-mediated vesicle transport, toxins are sequestered in vacuoles for degradation. Overexpression of AtALA1 and AtALA7 significantly increases the resistance of transgenic plants to F. graminearum and V. dahliae, respectively. Notably, the concentration of deoxynivalenol, a mycotoxin harmful to the health of humans and animals, was decreased in transgenic Arabidopsis siliques and maize seeds. This vesicle-mediated cell detoxification process provides a strategy to increase plant resistance against different toxin-associated diseases and to reduce the mycotoxin contamination in food and feed.
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Irreplaceable Role of Amendment-Based Strategies to Enhance Soil Health and Disease Suppression in Potato Production. Microorganisms 2021; 9:microorganisms9081660. [PMID: 34442738 PMCID: PMC8400219 DOI: 10.3390/microorganisms9081660] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 07/26/2021] [Accepted: 07/28/2021] [Indexed: 11/22/2022] Open
Abstract
Soilborne diseases are a major constraining factor to soil health and plant health in potato production. In the toolbox of crop management, soil amendments have shown benefits to control these diseases and improve soil quality. Most amendments provide nutrients to plants and suppress multiple soilborne pathogens. Soil amendments are naturally derived materials and products and can be classified into fresh or living plants, organic or inorganic matters, and microbial supplements. Fresh plants have unique functions and continuously exude chemicals to interact with soil microbes. Organic and inorganic matter contain high levels of nutrients, including nitrogen and carbon that plants and soil microorganisms need. Soil microorganisms, whether being artificially added or indigenously existing, are a key factor in plant health. Microbial communities can be considered as a biological reactor in an ecosystem, which suppress soilborne pathogens in various mechanisms and turn soil organic matter into absorbable forms for plants, regardless of amendment types. Therefore, soil amendments serve as an energy input, nutrient source, and a driving force of microbial activities. Advanced technologies, such as microbiome analyses, make it possible to analyze soil microbial communities and soil health. As research advances on mechanisms and functions, amendment-based strategies will play an important role in enhancing soil health and disease suppression for better potato production.
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Bautista-Jalón LS, Frenkel O, Tsror Lahkim L, Malcolm GM, Gugino BK, Lebiush S, Hazanovsky M, Milgroom MG, Del Mar Jiménez-Gasco M. Genetic Differentiation of Verticillium dahliae Populations Recovered from Symptomatic and Asymptomatic Hosts. PHYTOPATHOLOGY 2021; 111:149-159. [PMID: 33079020 DOI: 10.1094/phyto-06-20-0230-fi] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Verticillium dahliae is a soilborne fungal pathogen affecting many economically important crops that can also infect weeds and rotational crops with no apparent disease symptoms. The main research goal was to test the hypothesis that V. dahliae populations recovered from asymptomatic rotational crops and weed species are evolutionarily and genetically distinct from symptomatic hosts. We collected V. dahliae isolates from symptomatic and asymptomatic hosts growing in fields with histories of Verticillium wilt of potato in Israel and Pennsylvania (United States), and used genotyping-by-sequencing to analyze the evolutionary history and genetic differentiation between populations of different hosts. A phylogeny inferred from 26,934 single-nucleotide polymorphisms (SNPs) in 126 V. dahliae isolates displayed a highly clonal structure correlated with vegetative compatibility groups, and isolates grouped in lineages 2A, 2B824, 4A, and 4B, with 77% of the isolates in lineage 4B. The lineages identified in this study were differentiated by host of origin; we found 2A, 2B824, and 4A only in symptomatic hosts but isolates from asymptomatic hosts (weeds, oat, and sorghum) grouped exclusively within lineage 4B, and were genetically indistinguishable from 4B isolates sampled from symptomatic hosts (potato, eggplant, and avocado). Using coalescent analysis of 158 SNPs of lineage 4B, we inferred a genealogy with clades that correlated with geographic origin. In contrast, isolates from asymptomatic and symptomatic hosts shared some of the same haplotypes and were not differentiated. We conclude that asymptomatic weeds and rotational hosts may be potential reservoirs for V. dahliae populations of lineage 4B, which are pathogenic to many cultivated hosts.
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Affiliation(s)
- Laura S Bautista-Jalón
- Department of Plant Pathology and Environmental Microbiology, The Pennsylvania State University, University Park, PA 16802, U.S.A
| | - Omer Frenkel
- Department of Plant Pathology and Weed Research, Volcani Center, Rishon Lezion 7528809, Israel
| | - Leah Tsror Lahkim
- Department of Plant Pathology and Weed Research, Gilat Center, M.P. Negev, 8531100, Israel
| | - Glenna M Malcolm
- Department of Biology, The Pennsylvania State University, University Park, PA 16802, U.S.A
| | - Beth K Gugino
- Department of Plant Pathology and Environmental Microbiology, The Pennsylvania State University, University Park, PA 16802, U.S.A
| | - Sara Lebiush
- Department of Biology, The Pennsylvania State University, University Park, PA 16802, U.S.A
| | - Marina Hazanovsky
- Department of Biology, The Pennsylvania State University, University Park, PA 16802, U.S.A
| | - Michael G Milgroom
- School of Integrative Plant Science, Plant Pathology and Plant-Microbe Biology Section, Cornell University, Ithaca, NY 14853, U.S.A
| | - María Del Mar Jiménez-Gasco
- Department of Plant Pathology and Environmental Microbiology, The Pennsylvania State University, University Park, PA 16802, U.S.A
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Dung JKS. Verticillium Wilt of Mint in the United States of America. PLANTS 2020; 9:plants9111602. [PMID: 33218083 PMCID: PMC7698963 DOI: 10.3390/plants9111602] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 11/09/2020] [Accepted: 11/10/2020] [Indexed: 11/18/2022]
Abstract
Verticillium wilt, caused by the fungus Verticillium dahliae, is the most important and destructive disease of mint (Mentha spp.) in the United States (U.S.). The disease was first observed in commercial mint fields in the Midwestern U.S. in the 1920s and, by the 1950s, was present in mint producing regions of the U.S. Pacific Northwest. Verticillium wilt continues to be a major limiting factor in commercial peppermint (Mentha x piperita) and Scotch spearmint (Mentha x gracilis) production, two of the most important sources of mint oil in the U.S. The perennial aspect of U.S. mint production, coupled with the soilborne, polyetic nature of V. dahliae, makes controlling Verticillium wilt in mint a challenge. Studies investigating the biology and genetics of the fungus, the molecular mechanisms of virulence and resistance, and the role of soil microbiota in modulating host-pathogen interactions are needed to improve our understanding of Verticillium wilt epidemiology and inform novel disease management strategies. This review will discuss the history and importance of Verticillium wilt in commercial U.S. mint production, as well as provide a format to highlight past and recent research advances in an effort to better understand and manage the disease.
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Affiliation(s)
- Jeremiah K S Dung
- Central Oregon Agricultural Research and Extension Center, Department of Botany and Plant Pathology, Oregon State University, Madras, OR 97741, USA
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8
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Maina S, Misinzo G, Bakari G, Kim HY. Human, Animal and Plant Health Benefits of Glucosinolates and Strategies for Enhanced Bioactivity: A Systematic Review. Molecules 2020; 25:E3682. [PMID: 32806771 PMCID: PMC7464879 DOI: 10.3390/molecules25163682] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 08/08/2020] [Accepted: 08/10/2020] [Indexed: 12/14/2022] Open
Abstract
Glucosinolates (GSs) are common anionic plant secondary metabolites in the order Brassicales. Together with glucosinolate hydrolysis products (GSHPs), they have recently gained much attention due to their biological activities and mechanisms of action. We review herein the health benefits of GSs/GSHPs, approaches to improve the plant contents, their bioavailability and bioactivity. In this review, only literature published between 2010 and March 2020 was retrieved from various scientific databases. Findings indicate that these compounds (natural, pure, synthetic, and derivatives) play an important role in human/animal health (disease therapy and prevention), plant health (defense chemicals, biofumigants/biocides), and food industries (preservatives). Overall, much interest is focused on in vitro studies as anti-cancer and antimicrobial agents. GS/GSHP levels improvement in plants utilizes mostly biotic/abiotic stresses and short periods of phytohormone application. Their availability and bioactivity are directly proportional to their contents at the source, which is affected by methods of food preparation, processing, and extraction. This review concludes that, to a greater extent, there is a need to explore and improve GS-rich sources, which should be emphasized to obtain natural bioactive compounds/active ingredients that can be included among synthetic and commercial products for use in maintaining and promoting health. Furthermore, the development of advanced research on compounds pharmacokinetics, their molecular mode of action, genetics based on biosynthesis, their uses in promoting the health of living organisms is highlighted.
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Affiliation(s)
- Sylvia Maina
- Smart Farm Research Center, Korea Institute of Science and Technology (KIST), Gangneung, Gangwon 25451, Korea;
- College of Veterinary Medicine and Biomedical Sciences, Sokoine University of Agriculture, Morogoro 25523, Tanzania; (G.M.); (G.B.)
- SACIDS Africa Centre of Excellence for Infectious Diseases, Sokoine University of Agriculture, Morogoro 25523, Tanzania
| | - Gerald Misinzo
- College of Veterinary Medicine and Biomedical Sciences, Sokoine University of Agriculture, Morogoro 25523, Tanzania; (G.M.); (G.B.)
- SACIDS Africa Centre of Excellence for Infectious Diseases, Sokoine University of Agriculture, Morogoro 25523, Tanzania
| | - Gaymary Bakari
- College of Veterinary Medicine and Biomedical Sciences, Sokoine University of Agriculture, Morogoro 25523, Tanzania; (G.M.); (G.B.)
| | - Ho-Youn Kim
- Smart Farm Research Center, Korea Institute of Science and Technology (KIST), Gangneung, Gangwon 25451, Korea;
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Wheeler DL, Scott J, Dung JKS, Johnson DA. Evidence of a trans-kingdom plant disease complex between a fungus and plant-parasitic nematodes. PLoS One 2019; 14:e0211508. [PMID: 30759127 PMCID: PMC6373923 DOI: 10.1371/journal.pone.0211508] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Accepted: 01/15/2019] [Indexed: 11/23/2022] Open
Abstract
Disease prediction tools improve management efforts for many plant diseases. Prediction and downstream prevention demand information about disease etiology, which can be complicated for some diseases, like those caused by soilborne microorganisms. Fortunately, the availability of machine learning methods has enabled researchers to elucidate complex relationships between hosts and pathogens without invoking difficult-to-satisfy assumptions. The etiology of a destructive plant disease, Verticillium wilt of mint, caused by the fungus Verticillium dahliae was reevaluated with several supervised machine learning methods. Specifically, the objective of this research was to identify drivers of wilt in commercial mint fields, describe the relationships between these drivers, and predict wilt. Soil samples were collected from commercial mint fields. Wilt foci, V. dahliae, and plant-parasitic nematodes that can exacerbate wilt were quantified. Multiple linear regression, a generalized additive model, random forest, and an artificial neural network were fit to the data, validated with 10-fold cross-validation, and measures of explanatory and predictive performance were compared. All models selected nematodes within the genus Pratylenchus as the most important predictor of wilt. The fungus after which this disease is named, V. dahliae, was the fourth most important predictor of wilt, after crop age and cultivar. All models explained around 50% of the total variation (R2 ≤ 0.46), and exhibited comparable predictive error (RMSE ≤ 1.21). Collectively, these models revealed that the quantitative relationships between two pathogens, mint cultivars and age are required to explain wilt. The ascendance of Pratylenchus spp. in predicting symptoms of a disease assumed to primarily be caused by V. dahliae exposes the underestimated contribution of these nematodes to wilt. This research provides a foundation on which predictive forecasting tools can be developed for mint growers and reminds us of the lessons that can be learned by revisiting assumptions about disease etiology.
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Affiliation(s)
- David Linnard Wheeler
- Department of Plant Pathology, Washington State University, Pullman, WA, United States of America
| | - Jeness Scott
- Department of Botany and Plant Pathology, Oregon State University, Madras, OR, United States of America
| | - Jeremiah Kam Sung Dung
- Department of Botany and Plant Pathology, Oregon State University, Madras, OR, United States of America
| | - Dennis Allen Johnson
- Department of Plant Pathology, Washington State University, Pullman, WA, United States of America
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Avilés M, Borrero C. Identifying Characteristics of Verticillium Wilt Suppressiveness in Olive Mill Composts. PLANT DISEASE 2017; 101:1568-1577. [PMID: 30677335 DOI: 10.1094/pdis-08-16-1172-re] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The aims of this study were to assess the potential suppressive effects of different olive mill composts on Verticillium wilt and to elucidate the suppressive mechanisms. To this end, four olive mill composts from different crop areas with two maturation levels were selected. After conducting the Verticillium wilt bioassays in cotton, the suppressive effect was observed in only one compost. Compost maturation level did not affect disease development. The standardized area under the disease progress curve and microsclerotia concentration were associated with low API-ZYM enzymatic diversity, β-glucosidase activity, pH, and high electrical conductivity (EC). To assess the nature of suppressiveness in the suppressive compost, additional bioassays were performed with three treated compost-amended growing media (N-supplemented, autoclaved, and heat treated at 60°C for 6 days). Suppressiveness was partially reduced with heat treatments, where N-acetyl-β-glucosaminidase activity disappeared. In this compost, high oligotrophic actinomycete populations were associated with disease reduction. Therefore, plant growth media amended with different olive mill composts do not always show suppressiveness against Verticillium wilt. Enzymatic diversity, β-glucosidase activity, pH, and EC may be sufficient to predict where olive mill compost plant growth media will be effective in reducing Verticillium wilt and microsclerotia concentration. General and specific suppressiveness are involved in the mechanism of compost suppression.
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Affiliation(s)
- Manuel Avilés
- Dept. Ciencias Agroforestales, Escuela Técnica Superior de Ingeniería Agronómica, Universidad de Sevilla, Ctra. Utrera km 1, 41013 Sevilla, Spain
| | - Celia Borrero
- Dept. Ciencias Agroforestales, Escuela Técnica Superior de Ingeniería Agronómica, Universidad de Sevilla, Ctra. Utrera km 1, 41013 Sevilla, Spain
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11
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Wheeler DL, Johnson DA. Verticillium dahliae Infects, Alters Plant Biomass, and Produces Inoculum on Rotation Crops. PHYTOPATHOLOGY 2016; 106:602-13. [PMID: 26828231 DOI: 10.1094/phyto-07-15-0174-r] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Verticillium wilt, caused by Verticillium dahliae, reduces yields of potato and mint. Crop rotation is a potential management tactic for Verticillium wilt; however, the wide host range of V. dahliae may limit the effectiveness of this tactic. The hypothesis that rotation crops are infected by V. dahliae inoculum originating from potato and mint was tested by inoculation of mustards, grasses, and Austrian winter pea with eight isolates of V. dahliae. Inoculum density was estimated from plants and soil. Typical wilt symptoms were not observed in any rotation crop but plant biomass of some crops was reduced, not affected, or increased by infection of specific isolates. Each isolate was host-specific and infected a subset of the rotation crops tested but microsclerotia from at least one isolate were observed on each rotation crop. Some isolates were host-adapted and differentially altered plant biomass or produced differential amounts of inoculum on rotation crops like arugula and Austrian winter pea, which supported more inoculum of specific isolates than potato. Evidence of asymptomatic and symptomatic infection and differential inoculum formation of V. dahliae on rotation crops presented here will be useful in designing rotations for management of Verticillium wilt.
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Affiliation(s)
- D L Wheeler
- Department of Plant Pathology, Washington State University, Pullman 99164-6430
| | - D A Johnson
- Department of Plant Pathology, Washington State University, Pullman 99164-6430
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12
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Abstract
Soil health has been defined as the capacity of soil to function as a vital living system to sustain biological productivity, maintain environmental quality, and promote plant, animal, and human health. Building and maintaining soil health are essential to agricultural sustainability and ecosystem function. Management practices that promote soil health, including the use of crop rotations, cover crops and green manures, organic amendments, and conservation tillage, also have generally positive effects on the management of soilborne diseases through a number of potential mechanisms, including increasing soil microbial biomass, activity, and diversity, resulting in greater biological suppression of pathogens and diseases. However, there also may be particular disease issues associated with some soil health management practices. In this review, research and progress made over the past twenty years regarding soil health, sustainability, and soil health management practices, with an emphasis on their implications for and effects on plant disease and disease management strategies, are summarized.
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Affiliation(s)
- Robert P Larkin
- New England Plant, Soil, and Water Research Laboratory, USDA-ARS, Orono, Maine 04469-5753;
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14
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Cretoiu MS, Korthals GW, Visser JHM, van Elsas JD. Chitin amendment increases soil suppressiveness toward plant pathogens and modulates the actinobacterial and oxalobacteraceal communities in an experimental agricultural field. Appl Environ Microbiol 2013; 79:5291-301. [PMID: 23811512 PMCID: PMC3753968 DOI: 10.1128/aem.01361-13] [Citation(s) in RCA: 105] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2013] [Accepted: 06/22/2013] [Indexed: 11/20/2022] Open
Abstract
A long-term experiment on the effect of chitin addition to soil on the suppression of soilborne pathogens was set up and monitored for 8 years in an experimental field, Vredepeel, The Netherlands. Chitinous matter obtained from shrimps was added to soil top layers on two different occasions, and the suppressiveness of soil toward Verticillium dahliae, as well as plant-pathogenic nematodes, was assessed, in addition to analyses of the abundances and community structures of members of the soil microbiota. The data revealed that chitin amendment had raised the suppressiveness of soil, in particular toward Verticillium dahliae, 9 months after the (second) treatment, extending to 2 years following treatment. Moreover, major effects of the added chitin on the soil microbial communities were detected. First, shifts in both the abundances and structures of the chitin-treated soil microbial communities, both of total soil bacteria and fungi, were found. In addition, the abundances and structures of soil actinobacteria and the Oxalobacteraceae were affected by chitin. At the functional gene level, the abundance of specific (family-18 glycoside hydrolase) chitinase genes carried by the soil bacteria also revealed upshifts as a result of the added chitin. The effects of chitin noted for the Oxalobacteraceae were specifically related to significant upshifts in the abundances of the species Duganella violaceinigra and Massilia plicata. These effects of chitin persisted over the time of the experiment.
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Affiliation(s)
- Mariana Silvia Cretoiu
- Department of Microbial Ecology, Centre for Ecological and Evolutionary Studies, University of Groningen, Groningen, The Netherlands
| | - Gerard W. Korthals
- Applied Plant Research Institute, Wageningen University, Lelystad, The Netherlands
| | - Johnny H. M. Visser
- Applied Plant Research Institute, Wageningen University, Lelystad, The Netherlands
| | - Jan Dirk van Elsas
- Department of Microbial Ecology, Centre for Ecological and Evolutionary Studies, University of Groningen, Groningen, The Netherlands
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15
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Malcolm GM, Kuldau GA, Gugino BK, Jiménez-Gasco MDM. Hidden host plant associations of soilborne fungal pathogens: an ecological perspective. PHYTOPATHOLOGY 2013; 103:538-44. [PMID: 23301815 DOI: 10.1094/phyto-08-12-0192-le] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
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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Kinkel LL, Schlatter DC, Bakker MG, Arenz BE. Streptomyces competition and co-evolution in relation to plant disease suppression. Res Microbiol 2012; 163:490-9. [PMID: 22922402 DOI: 10.1016/j.resmic.2012.07.005] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2012] [Accepted: 07/04/2012] [Indexed: 01/01/2023]
Abstract
High densities of antagonistic Streptomyces are associated with plant disease suppression in many soils. Here we review use of inoculation and organic matter amendments for enriching antagonistic Streptomyces populations to reduce plant disease and note that effective and consistent disease suppression in response to management has been elusive. We argue that shifting the focus of research from short-term disease suppression to the population ecology and evolutionary biology of antagonistic Streptomyces in soil will enhance prospects for effective management. A framework is presented for considering the impacts of short- and long-term management on competitive and coevolutionary dynamics among Streptomyces populations in relation to disease suppression.
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Affiliation(s)
- Linda L Kinkel
- Department of Plant Pathology, University of Minnesota, Saint Paul, MN 55108, USA.
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Dung JKS, Johnson DA. Roles of Infected Seed Tubers and Soilborne Inoculum on Verticillium Wilt of 'Russet Burbank' Potato. PLANT DISEASE 2012; 96:379-383. [PMID: 30727111 DOI: 10.1094/pdis-07-11-0583] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Verticillium dahliae, causal agent of Verticillium wilt of potato, persists in soil as microsclerotia and can be found in infected tubers used for seed. The effects of naturally infected tubers and soilborne inoculum on Verticillium wilt symptoms were compared in the greenhouse. Infected and noninfected tubers were grown in infested and noninfested potting soil. Chlorosis and necrosis were measured and converted to area under senescence progress curves (AUSPC). Aboveground stems and progeny tubers were assayed for V. dahliae. Plants from infested soils exhibited significantly greater AUSPC than plants from noninfested soil. Plants grown from infected and noninfected tubers had similar AUSPC and interactions between infected tubers and infested soil were not observed. The pathogen was isolated from the vascular system of 94% of plants grown in infested soils and 8% of plants grown from infected tubers in noninfested soil. Plants grown in infested soil contained microsclerotia on 46% of stems while plants grown from infected tubers in noninfested soils exhibited microsclerotia on <1% of stems. Infected progeny tubers were only recovered from plants grown in infested soil. Seed tuber infection did not contribute to premature senescence or potential inoculum production, indicating that management efforts should focus on reducing soilborne inoculum.
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Affiliation(s)
- Jeremiah K S Dung
- Department of Plant Pathology, Washington State University, Pullman 99164
| | - Dennis A Johnson
- Department of Plant Pathology, Washington State University, Pullman 99164
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