Progress 01/12/15 to 09/30/18
Outputs
Target Audience:Target audiences include: scientists who conduct research in biological control and microbial ecology; industry entities who are involved in the development and production of biological control agents and agricultural chemicals; growers/producers who use biological agents and biorational products s to manage plant diseases. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?Two graduate students working in Gary Yuen's lab gained training in this project. How have the results been disseminated to communities of interest?Research results from this project were reported in eleven national and international scientific and industry conferences and published in 12 scientific journal articles. In addtion, a review paper on the use of microbial inoculants was published as a book chapter. Information on use of biological control for field crop diseases was presented in six extension publications. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
Disease caused by soilborne plant pathogens (fungi, nematodes, and bacteria) and soil fertility are critical factors that affect crop yields. Root microbial communities can benefit crop growth by inhibiting root pathogens or facilitating nutrient uptake. The use of beneficial microbes, however, is not widespread because the diversity of commercialized microbes is very low, and knowledge of environmental influences on their activity is slim. The ultimate goal of this project, part of the multistate project W3147: "Managing Plant Microbe Interactions in Soil to Promote Sustainable Agriculture", was to provide microbe-based tools to enhance crop productivity while reducing dependency on inputs of synthetic pesticides and inorganic fertilizers. Outcomes include new biological control and plant growth promoting agents; new bio-rational chemicals; systems integrating cultural practices with microbial biocontrol agents to provide effective control of soilborne diseases; and better understanding of how crop environments regulate microbial growth and activity. The information generated in this project ultimately will be useful in development of beneficial microbes into practical, sustainable, and effective tools to raise crop productivity. Goal 1 - To identify and characterize new biological agents, microbial community structure and function, naturally suppressive soils, cultural practices, and organic amendments that provide management of diseases caused by soilborne plant pathogens. Goal 1. Objective 1 - To identify cultural practices that provide the management of diseases caused by soilborne plant pathogens of Nebraska crops through the enhancement of indigenous or introduced populations of Lysobacter and/or Bacillus. Major activities: Field experiments were conducted in Nebraska locations to evaluate K20, a novel derivative of the pharmaceutical drug kanamycin A, for control of Fusarium head blight, a destructive disease of wheat. In other field experiments, commercial soybean seed treatments with biological agents (Bacillus firmus and Pasteuria nishizawae) were evaluated for control of the soybean cyst nematode (SCN) Heterodera glycines. Results: Under Nebraska field conditions, the kanamycin derivative K20 reduced Fusarium head blight severity as effectively as commercial fungicides. Commercial soybean seed treatments with Bacillus and Pasteuria had no effects on SCN reproduction or soybean seed yield. Key outcomes: Our findings with K20 could stimulate research to modify safe, inexpensive natural products to have enhanced activity against plant pathogens and spur commercial development of new biorational pesticides for soilborne pathogens. Use of such biorational products could reduce synthetic pesticide inputs to the environment. The results with biological soybean seed treatments point to the need for greater search for and development of new and more effective biological control agents for soilborne diseases. Goal 1. Objective 2. Isolate and identify new biocontrol-effective strains of Bacillus Major activities: Nebraska isolates of bacteria were screened for antagonism against fungal pathogens and tested in the greenhouse for control of Fusarium root rot on corn, wheat and soybean. Select bacilli strains were tested for the ability to enhance the growth of these crops, and characterized for physiological traits (e.g. phosphate solubilization; production of biosurfactants, siderophores, proteases, and auxins) associated with plant growth promotion. Results: Strains of bacteria reduced Fusarium root rot severity by 15-65% in greenhouse tests. Effective bacterial species included Burkholderia ambifara and Bacillus simplex which had not be reported previously as biocontrol agents. Four bacilli strains, including B. simplex, promoted growth of corn, soybean and wheat, increasing shoot mass by 93-126% and root mass by 127-197% compared to the controls. Growth promotion was related to a variety of physiological traits including IAA production. Key outcomes: Identification of new bacterial strains with the ability to suppress root rot or the ability to promote plant growth enhance provides new organisms for further study and development toward the creation of commercially effective biocontrol products. Goal 1. Objective 3. Characterize Nebraska disease suppressive soils as to the microbial community involved in suppression of soilborne pathogens Major activities: Work began to characterize soil microbial communities in Nebraska fields continuously cropped with corn for over 40 years, compared to fields with conventional crop rotation. Soil in continuously cropped fields are presumed to have unique microbial communities suppressive to root pathogens because corn root diseases were not evident in the those fields. Results Soil samples were collected and microbial DNA was extracted for sequence analysis. Data analysis for microbial community profile is in progress. Key outcomes: Although this research is not completed, microbiome analysis would generate information as to continuous cropping alters microbial communities to influence root diseases. This information, in turn, could lead to the development of cropping strategies that can create disease suppressive soils or the identification of beneficial microbes from the disease suppressive soils. Goal 2 - To understand how microbial populations and microbial gene expression are regulated by the biological (plants and microbes) and physical environment and how they influence disease. Objective - To determine how cultural practices that enhance Lysobacter and/or Bacillus populations affect their ability to express mechanisms important to biological control. Major activities: Interactions of the bacterium Lysobacter enzymogenes (biocontrol agent against fungi and nematodes) with different plant species were studied in greenhouse and field experiments. One set of experiments evaluated the degree to which the bacterium can colonize roots of various economic crops and cover crops commonly planted in the Midwest. Another set of experiments used qPCR to monitor expression of biocontrol genes by the bacterium when applied to root systems of different plant species and when cultured under various nutrient conditions. The genes included biosynthesis genes for HSAF (an antimicrobial secondary metabolite) and lytic enzymes (chitinases and glucanases). In separate in vitro studies, biochemical factors were investigated for their roles in regulating biosynthesis of HSAF by Lysobacter These factors included pilG, a two-component signal transduction protein; LeDSF3, a fatty acid-derived signaling molecule; and Lsp, Ax21-family proteins known to regulate virulence in plant and animal pathogenic bacteria. Results: When Lysobacter was applied to seed of various plant species, highest populations of the bacterium were detected in cereal rye roots and lower populations in roots of other plants, e.g. wheat and beet. Analysis of Lysobacter gene expression in bacteria-treated root systems revealed different temporal patterns for expression of HSAF and lytic enzyme synthesis genes depending on the gene and the plant species to which the bacterium was applied. Gene expression also varied in time and magnitude dependent upon the carbohydrate and concentration supplied to the bacterium. Through mutation analysis, PilG was found to be a negative regulation factor for HSAF production, whereas LeDSF3 and Lsp proteins were involved in positive regulation of HSAF biosynthesis. Key outcomes: These accomplishments contribute to knowledge about mechanisms involved in pathogen biocontrol, regulation of these mechanisms at the cellular level, and the influence of plant and environmental factors on the expression of these mechanisms. This information could potentially result in the development of strategies to improve the efficacy of biocontrol agents.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2018
Citation:
Rufus J. Akinrinlola, Gary Y. Yuen, Rhae A. Drijber, and Anthony O. Adesemoye. Evaluation of Bacillus Strains for Plant Growth Promotion and Predictability of Efficacy by In Vitro Physiological Traits, International Journal of Microbiology, vol. 2018, Article ID 5686874, 11 pages, 2018. https://doi.org/10.1155/2018/5686874.
- Type:
Theses/Dissertations
Status:
Published
Year Published:
2018
Citation:
Rufus J. Akinrinlola. Evaluation of bacillus strains for plant growth promotion potentials on corn (Zea mays), wheat (Triticum aestivum), and soybean (Glycine max). MS Thesis. University of Nebraska-Lincoln. May, 2018.
- Type:
Journal Articles
Status:
Published
Year Published:
2018
Citation:
Parikh L. and Adesemoye, A. O. 2018. Impact of delivery method on the efficacy of biological control agents and the virulence of Fusarium root rot pathogen in the greenhouse. Biocontrol Science and Technology 28:12, 1191-1202. DOI:10.1080/09583157.2018.1520198: 1-12.
- Type:
Journal Articles
Status:
Published
Year Published:
2018
Citation:
Parikh, L., Eskelson, M. J., Adesemoye, A. O. 2018. Relationship of in vitro and in planta screening: improving the selection process for biological control agents against Fusarium root rot in row crops. Archives of Phytopathology and Plant Protection 51: 156-169.
- Type:
Other
Status:
Published
Year Published:
2018
Citation:
Adesemoye, A. O., Eskelson, M. J., and Kodati, S. 2018. Evaluation of biological products for the management of fungal leaf spots of wheat in Nebraska, 2017. Plant Disease Management Reports. Report 12:CF089.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2018
Citation:
Parikh, L. and Adesemoye, A. O. 2018. Metabolomics approach to elucidate the mechanisms underlying biological control of Fusarium root rot by PGPR. International Congress of Plant Pathology (ICPP)-American Phytopathological Society (APS) Joint Conference, Boston, MA. August 1 to 5, 2018.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2018
Citation:
Akinrinlola, R., Adesemoye, A. O., and Yuen G. Y. 2018. Evaluation of PGPR strains in multiple crop hosts and predictability of growth promotion efficacy by PGPR traits. International Congress of Plant Pathology (ICPP)-American Phytopathological Society (APS) Joint Conference, Boston, MA. August 1 to 5, 2018.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2018
Citation:
Parikh, L. and Adesemoye, A. O. 2018. Co-inoculation of Burkholderia ambifara C628 and Bacillus simplex R180 reduced Fusarium root rot disease in corn. The 9th International Integrated Pest Management (IPM) Symposium, Baltimore, Maryland. March 19-22, 2018.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2018
Citation:
Parikh, L., Albala, S. A., and Adesemoye, A. O. Characterization and bioactivity of lipopeptides produced by Bacillus simplex and Burkholderia ambifaria. The 11th International Plant Growth-Promoting Rhizobacteria Workshop, June 17-211, 2018 at Victoria, British Columbia, Canada.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2018
Citation:
Kodati, S. and Adesemoye, A. O. 2018. Biology-based strategies for integrated management of Rhizoctonia solani in soybean fields. The 9th International Integrated Pest Management (IPM) Symposium, Baltimore, Maryland. March 19-22, 2018.
- Type:
Conference Papers and Presentations
Status:
Awaiting Publication
Year Published:
2018
Citation:
Dongxue Shi and Gary Y. Yuen. 2018. Temporal and Spatial Patterns of Antibiotic and Lytic Enzyme Gene Expression in the Rhizosphere by the Biocontrol Bacterium Lysobacter enzymogenes C3. 2018 APS North Central Division Meeting, June 12-14, 2018. Fargo, ND.
|
Progress 10/01/16 to 09/30/17
Outputs
Target Audience:Target audiences include: scientists who conduct research in biological control and microbial ecology; industry entities who are involved in the development and production of biological control agents and agricultural chemicals; growers/producers who use biological agents and biorational products s to manage plant diseases. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?Two graduate students working in Gary Yuen's lab and postdoctoral researcher in Tony Adesemoye's lab gained training in this project. How have the results been disseminated to communities of interest?Results on the identification of novel biological control and plant growth promoting agents were reported in two presentations at scientific conferences and a publication in a scientific journal (publication in press). Results on suppression of Fusarium head blight using K20 and on the role of Ax21 proteins in Lysobacter enzymogenes were published separately in scientific journals. What do you plan to do during the next reporting period to accomplish the goals?Goal 1 - Objective 1 Conduct greenhouse and field experiments examining the integration of nematode-inhibitory cover crops and application of bacterial biocontrol agents for the control of soybean cyst nematode. Goal 1 - Objective 2 Continue with the screening of isolated organisms. Further studies on the isolates that have been characterized. Goal 1 - Objective 3 Conduct an analysis of the DNA sequence reads that are generated from the two Nebraska continous corm soils Goal 2 Conduct experiments on the effects of environment factors on in vivo expression of biocontrol genes by Lysobacter enzymogenes conduct experiments on the activation of induced resistance pathways by Lysobacter enzymogenes applied to different plant species.
Impacts
What was accomplished under these goals?
Plant disease caused by soilborne plant pathogens (fungi, nematodes, and bacteria) and soil fertility are critical factors that influence crop productivity. The two factors are interrelated in that control of root disease improves nutrient uptake from soil by roots, while soil nutrient availability can affect a crop's ability to withstand or tolerate attack by pathogens. Microbial communities that inhabit soil and/or roots can benefit crop growth by inhibiting root pathogens and/or by facilitating nutrient uptake. The use of beneficial microbes, however, is not widespread because the diversity microbes for commercialization is very low, and knowledge of how environmental conditions influence their activity is slim. The ultimate goal of this is project, part of the multistate project W3147: "Managing Plant Microbe Interactions in Soil to Promote Sustainable Agriculture", is to provide microbe-based tools that contribute to greater crop productivity while reducing dependency on inputs of synthetic pesticides and inorganic fertilizers. This goal will be reached by discovering new microbes and microbe-derived chemicals that inhibit plant pathogens and enhance plant growth; identifying cropping practices that foster beneficial microbe activity; and providing information on environmental factors that affect beneficial microbes. Expected outcomes from this project include new biological control and plant growth promoting agents; new bio-rational chemicals; systems integrating cultural practices with microbial biocontrol agents to provide effective control of soilborne diseases; and better understanding of how crop environments regulate microbial growth and activity. The information generated in this project ultimately will be useful in development of beneficial microbes into practical, sustainable, and effective tools to raise crop productivity. Goal 1 - To identify and characterize new biological agents, microbial community structure and function, naturally suppressive soils, cultural practices, and organic amendments that provide management of diseases caused by soilborne plant pathogens. Goal 1. Objective 1 - To identify cultural practices that provide the management of diseases caused by soilborne plant pathogens of Nebraska crops through the enhancement of indigenous or introduced populations ofLysobacterand/orBacillus. Major activities: K20, a novel derivative of the antibiotic kanamycin, was tested in the field for control of Fusarium head blight, one of the most economically important diseases of wheat. Data collected/discussion of results: K20 applied alone or in combination with half-strength commercial fungicides reduced head blight severity as effectively as commercial fungicides applied full strength. K20 might be useful alone as a fungicide and as an adjunct with reduced levels of synthetic fungicides. Key outcomes: Our findings could stimulate research to modify safe, inexpensive natural products to have enhanced activity against plant pathogens and spur commercial development of new biorational pesticides for soilborne pathogens. Use of such biorational products could reduce synthetic pesticide inputs to the environment. Goal 1. Objective 2. Isolate and identify new biocontrol-effective strains of Bacillus Major activities: Over 150 isolates of bacteria and Trichoderma (fungi) were screened for plant growth promotion and antagonism against fungal pathogens. Select isolates were tested in the greenhouse and the field for control of Rhizoctonia root rot on soybean. Select bacilli strains were tested for the ability to enhance the growth of corn, soybean, and wheat, and characterized for physiological traits (e.g. phosphate solubilization; production of biosurfactants, siderophores, proteases, and auxins). Data collected/discussion of results: Effective strains of biological control and plant growth promoting agents were identified. Strains of Burkholderia ambifara, Bacillus simplex, and Trichoderma reduced Fusarium growth by 35-95% in lab tests, and reduced root rot severity by 15-65% in the greenhouse. Four bacilli strains, including B. simplex, promoted growth of corn, soybean and wheat, increasing shoot mass by 93-126% and root mass by 127-197% compared to the controls. Growth promotion by these strains was related to a variety of physiological traits. Key outcomes: Burkholderia ambifara and Bacillus simplex, were unknown previously to suppress root disease rot or promote plant growth. Identification of new bacterial species with these attributes provides new organisms for further study and development toward commercially effective biocontrol products. Goal 1. Objective 3. Characterize Nebraska disease suppressive soils as to the microbial community involved in suppression of soilborne pathogens Major activities: Work began in characterizing soil microbial communities in Nebraska fields continuously cropped with corn for over 40 years, compared to fields with conventional crop rotation. Because corn root diseases were not evident in the continuously cropped fields, soil in those fields are presumed to have unique microbial communities suppressive to root pathogens. Samples of soils were collected in 2016 at several time periods, and microbial DNA was extracted in 2017 for sequence analysis. DNA libraries were developed and sent to a commercial sequencing facility Data collected/discussion of results DNA sequence analysis for microbial community profile is in progress. Key outcomes: Microbiome analysis of soils with continuous corn cropping and crop rotation would generate information as to how cropping practices alter microbial communities to influence root diseases. This information, in turn, would lead to the development of cropping strategies that can create natural disease suppressive soils or the identification of beneficial microbes from the disease suppressive soils. Goal 2 - To understand how microbial populations and microbial gene expression are regulated by the biological (plants and microbes) and physical environment and how they influence disease. Objective - To determine how cultural practices that enhance Lysobacter and/or Bacillus populations affect their ability to express mechanisms important to biological control. Major activities completed/experiments conducted: a. Ax21 proteins (Lsp) regulate virulence in plant- and animal-pathogenic bacteria, but their function in the biocontrol agents is unknown. Lsp genes in Lysobacter enzymogenes OH11 were deleted and the mutants were compared with the wildtype for production of the antibiotic HSAF. b. Lysobacter enzymogenes produces the antibiotic HSAF and lytic enzymogenes (chitinases and glucanases) as key biocontrol mechanisms, but methodology to monitor production of these factors in soil and roots was lacking. A qPCR method was developed to measure in vivo expression of HSAF, glucanase, and chitinase biosysnthesis genes and was applied in an experiment to quantify bacterial gene expression in soybean roots treated with strains of L. enzymogenes. Data collected & discussion of results a. Deletion of Lsp genes in L. enzymogenes resulted in reduced production of HSAF, demonstrating that Lsp proteins are involved in positive regulation of HSAF biosynthesis. b. Preliminary qPCR analysis of Lysobacter-treated roots revealed different temporal patterns for expression of bacterial genes depending on the root region and the bacterial strain.Results show the method is sensitive and precise enough for extensive study bacterial interactions with plant and environmental factors. Key outcomes: These accomplishments contribute to knowledge about mechanisms involved in pathogen biocontrol, regulation of these mechanisms at the cellular level, and the influence of plant and environmental factors on the expression of these mechanisms. This information could potentially result in the development of strategies to improve the efficacy of biocontrol agents.
Publications
- Type:
Book Chapters
Status:
Published
Year Published:
2017
Citation:
Adesemoye, A. O., Yuen, G., Watts, D. B. 2017. Microbial inoculants for optimized plant nutrients use in integrated pest and input management systems. In Probiotics and Plant Health. Arora N.K, Mehnaz. S., and Balestrini, R. (Ed.), Microbial inoculants for optimized plant nutrients use in integrated pest and input management systems. Springer pp. 21-40. DOI 10.1007/978-981-10-3473-2.
- Type:
Journal Articles
Status:
Published
Year Published:
2017
Citation:
Liang Z., D. Lee, I. Dweikat, D. Wedin, G. Yuen, R. Drijber. 2017. Molecular diversity of arbuscular mycorrhizae in roots of Juniperus virginiana invasive to grasslands. SSSAJ 81:526-536. doi:10.2136/sssaj2016.05.0133.
- Type:
Journal Articles
Status:
Awaiting Publication
Year Published:
2017
Citation:
Parikh, L., Eskelson, M. J., and Adesemoye, A. O. Relationship of in vitro and in planta screening: improving the selection process for biological control agents against Fusarium root rot in row crops. Archives of Phytopathology and Plant Protection (In Press).
- Type:
Journal Articles
Status:
Published
Year Published:
2017
Citation:
Takemoto, J., G.Y. Yuen, C.C. Jochum, C.T. Chang, Y. Kawasaki, and G.W. Miller, 2017. Suppression of wheat Fusarium head blight by novel amphiphilic aminoglycoside fungicide K20. Fungal Biology https://doi.org/10.1016/j.funbio.2017.12.001.
- Type:
Journal Articles
Status:
Published
Year Published:
2017
Citation:
Wang, R., Xu, H., Zhang, J., Yuen, G.Y., Liu, H., Qian, G., and Liu, F. 2017. Lsp family proteins regulate antibiotic biosynthesis in Lysobacter enzymogenes. AMB Express 7(1):123. doi: 10.1186/s13568-017-0421-2. Epub 2017 Jun 13.
- Type:
Journal Articles
Status:
Published
Year Published:
2017
Citation:
Yuen, G.Y., K.C. Broderick, C.C. Jochum, C.J. Chen, and E.P. Caswell-Chen. 2017. Control of cyst nematodes by Lysobacter enzymogenes strain C3 and the role of the antibiotic HSAF in the biological control activity. Biological Control https://doi.org/10.1016/j.biocontrol.2017.11.007.
- Type:
Other
Status:
Awaiting Publication
Year Published:
2017
Citation:
Akinrinlola, R., Adesemoye, A. O., and Yuen G. Y. 2017 Bacillus strains as plant growth-promoting agents for the Great Plains agricultural region. Abstract of paper presented at the 2017 meeting of the Northcentral Division of the American Phytopathological Society, Champaign, IL. June 14-16, 2017.
- Type:
Other
Status:
Published
Year Published:
2017
Citation:
Adesemoye, A. O., Shapiro, C. A., Rethwisch, M., and Maharjan, B. Potential benefits of biological products in nutrient management. Nebguide G2294. Nebraska Extension
- Type:
Other
Status:
Published
Year Published:
2017
Citation:
Adesemoye, A. O. 2017. Biologicals in plant disease management. NebGuide G2290, Nebraska Extension
- Type:
Other
Status:
Published
Year Published:
2017
Citation:
Adesemoye, A. O. 2017. Introduction to biological products for crop production and protection Extension Circular EC3019, Nebraska Extension
- Type:
Other
Status:
Published
Year Published:
2017
Citation:
Parikh, L., Eskelson, M., and Adesemoye, A. O 2017. Biological control of Fusarium root rot on row crops in the Great Plains using PGPR and Trichoderma species. Abstract of paper presented at the 2017 Annual Meeting of the American Phytopathological Society, APS, San Antonio, Texas. August 5-9, 2017. https://apsnet.confex.com/apsnet/2017/meetingapp.cgi/Paper/4820
|
Progress 10/01/15 to 09/30/16
Outputs
Target Audience:Target audiences reached this year include scientists who conduct research in biological control and microbial ecology; industry entities who are involved in the development and production of biological control agents and agricultural chemicals; growers/producers who use biologicals to manage plant diseases. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?This year, the project has provided for the training of a post-doctoral researcher, two masters students, and a doctoral student. In addition, two undergraduate students working part-time on this project gained valuable skills and experience in agricultural research. How have the results been disseminated to communities of interest?Results from this project were reported in scientific journals and presentation at scientifica on conferences. In addition, results were reported at the annual meeting of the multistate research project W-3147. Elements of the research in this project were shared with grower audiences in extension presentations delivered by T. Adesemoye Crop, and presented to undergraduate and graduate-level students in general plant pathology and biological control courses taught by G. Yuen. What do you plan to do during the next reporting period to accomplish the goals?Goal 1 - To identify and characterize new biological agents, microbial community structure and function, naturally suppressive soils, cultural practices, and organic amendments that provide management of diseases caused by soilborne plant pathogens. Objective 1 - To identify cultural practices that provide the management of diseases caused by soilborne plant pathogens of Nebraska crops through the enhancement of indigenous or introduced populations ofLysobacterand/orBacillus Evaluate combinations of bacterial biocontrol agent Lysobacter enzymogenes and cover cropping with cereal rye for effects on soybean cyst nematode and other root pathogens. Goal 1. Objective 2. Isolate and identify new biocontrol-effective strains of Bacillus Continue the isolation, screening, and characterization of potential biological control and plant growth promoting bacteria. Goal 1. Objective 3. Characterize Nebraska disease suppressive soils as to the microbial community involved in suppression of soilborne pathogens Continue ongoing efforts in profiling the microbial community of soils from two Nebraska fields continuously cropped with corn. Goal 2 - To understand how microbial populations and microbial gene expression are regulated by the biological (plants and microbes) and physical environment and how they influence disease. Objective - To determine how cultural practices that enhance Lysobacter and/or Bacillus populations affect their ability to express mechanisms important to biological control. Continue field experiments comparing various cover crop species for root colonization by Lysobacter enzymogenes Begin investigations on the effects of root exudates from different plant species on Lysobacter enzymogenes as to growth and expression of physiological traits. Begin metabolomic analysis of Burkeholderia ambifara to identify metabolites involved in biological control.
Impacts
What was accomplished under these goals?
Disease caused by soilborne plant pathogens and soil fertility are two critical factors that influence crop productivity. The factors are interrelated as root disease affects nutrient uptake by roots while nutrient availability can affect a plant's ability to withstand pathogen attack. Some soil and root inhabiting microbes can benefit crop growth by inhibiting root pathogens and/or by facilitating nutrient uptake. The use of beneficial microbes, however, is not widespread because a) the diversity of commercially available microbial agents is very low, and knowledge of how environmental conditions influence the activity of beneficial of microbial agents is limited. The ultimate goal of this is project, which is a part of the multistate research project W3147: "Managing Plant Microbe Interactions in Soil to Promote Sustainable Agriculture", is to provide microbe-based tools that contribute to greater crop productivity while reducing dependency on input of synthetic pesticides and inorganic fertilizers. This goal will be accomplished by discovering new microbes with the potential to inhibit plant pathogens and to enhance plant growth; identifying cropping practices that enhance beneficial microbe populations and activity levels; providing new information as to how soil and root environmental factors affect the functioning of beneficial microbes. Expected outcomes from this project include new biological control and plant growth promoting agents; disease management systems integrating cultural practices with microbial biocontrol agents; and better understanding of how crop environments regulate microbial growth and activity. The information generated in this project ultimately will be useful in fostering the general development of beneficial microbes into practical, sustainable, and effective tools to raise crop productivity. The results from the second year of this project represent significant progress towards achieving the anticipated outcomes. Accomplishments in specific goals and objectives. Goal 1 - To identify and characterize new biological agents, microbial community structure and function, naturally suppressive soils, cultural practices, and organic amendments that provide management of diseases caused by soilborne plant pathogens. Objective 1 - To identify cultural practices that provide the management of diseases caused by soilborne plant pathogens of Nebraska crops through the enhancement of indigenous or introduced populations ofLysobacterand/orBacillus. Major activities completed / experiments conducted Field experiments were conducted in 3 Nebraska locations to evaluate the effectiveness of commercial soybean seed treatments with biological agents, for control of Heterodera glycines, the soybean cyst nematode (SCN). The seed treatments include strains of the bacterial species Bacillus firmus and Pasteuria nishizawae (the latest commercially-available biocontrol agents for nematode control) combined with commercial fungicides and insecticides, as well as standard seed treatment chemicals with no biological agents. Data collected SCN soil populations in three field experiments were measured before planting of treated soybean seed and after harvest to determine SCN reproduction during the soybean growing season. Yield of soybean seed was measured at the end of the season. Summary statistics and discussion of results Neither of the biocontrol agents decreased SCN reproduction or increased yield compared to standard seed treatments with no biological agents. Key outcomes or other accomplishments realized Under Nebraska conditions, the biocontrol agents appear to provide no additional SCN control or yield effects beyond SCN-resistant varieties and chemical seed treatments. The results point to a need for greater search for effective biocontrol agents. Goal 1. Objective 2. Isolate and identify new biocontrol-effective strains ofBacillus Major activities completed / experiments conducted Nebraska isolates of bacteria classified in Bacillusand related genera ("bacilli") and in other genera were evaluated for antagonism to fungal pathogens. Some were evaluated in the greenhouse for control of Fusarium root rot on corn, wheat and soybean. Bacilli strains were evaluated for growth enhancement in corn and characterized for in vitro physiological traits. Data collected Antagonism of new bacterial isolates against plant pathogenic fungi and bacteria was assessed in plate inhibition tests. Biocontrol of Fusarium root rot by new bacterial isolates was based on ratings of disease levels occurring on corn, wheat and soybean roots. Growth promotion of corn was based on measurements of root and shoot weights and lengths 1 month after planting of bacteria treated seed. Characterization of bacilli strains thus far include phosphate solubilization and production of biosurfactants, siderophores, proteases, and auxins. Summary statistics and discussion of results Strains in the bacterial species Burkholderia ambifara were highly inhibitory to fungal pathogens in plate inhibition tests and were effective in suppressing Fusarium root rot in corn, wheat and soybean. Some bacilli strains exhibited high levels of growth enhancement in corn. No correlation exists between their ability to promote plant growth and specific in vitro traits. Key outcomes or other accomplishments realized Identification of new bacterial strains with the ability to suppress root rot or the ability to promote plant growth enhance provides new organisms for further study and development. Included among these strains are Burkholderia ambifara, Bacillus safensis, Paenibacillus graminis, and Paenibacillus cineris which have not been reported previously to possess beneficial attributes. This discovery widens the diversity of microbes from which biocontrol products might be developed. Goal 1. Objective 3. Characterize Nebraska disease suppressive soils as to the microbial community involved in suppression of soilborne pathogens Major activities completed / experiments conducted Experiments were initiated to characterize the soil microbial communities in disease suppressive soils. Samples of soils from Nebraska fields that have been continuously cropped with corn for 40 and 103 years with no histories of root disease were collected at several periods in 2016. Microbial DNA was extracted from each soil sample and made available for DNA sequence analysis. Data collected Sequence analysis of extracted DNA is still in progress. Goal 2 - To understand how microbial populations and microbial gene expression are regulated by the biological (plants and microbes) and physical environment and how they influence disease. Objective - To determine how cultural practices that enhanceLysobacterand/orBacilluspopulations affect their ability to express mechanisms important to biological control. Major activities completed/experiments conducted Repeated greenhouse experiments were completed evaluating the ability of a biological control bacterium Lysobacter enzymogenes C3 to multiply in the rhizospheres of various economic crops and cover crops commonly planted in the Midwest. A mini-plot field experiment was conducted in to verify root colonization potential by C3 on select plant species. Data collected Roots from plants that were treated with C3 were analyzed for C3 populations by dilution plating onto a selective medium. Summary statistics and discussion of results C3 survived and multiplied in the root systems of certain plant species, with highest C3 populations on cereal rye and lower populations on other plants, e.g. wheat. Key outcomes or other accomplishments realized The effectiveness of a biocontrol agents is dependent on its ability to sustain populations in the environment. The finding that root colonization by L. enzymogenes is plant species dependent indicates the biocontrol agent-plant interaction needs to be considered in order to develop an effective biological control product.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2016
Citation:
Zhou, L., Yuen, G., Wang, Y., Wei, L., and Ji, G. 2016. Evaluation of bacterial biological control agents for control of root-knot nematode disease on tomato. Crop Protection 84: 8-13.
- Type:
Theses/Dissertations
Status:
Published
Year Published:
2016
Citation:
Kelsie M. Musil. 2016. Evaluations of Biological Control Agents for the Management of Soybean Cyst Nematode (Heterodera glycines) In Soybean (Glycine max L. Merr.). Masters' Thesis. University of Nebraska-Lincoln.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2016
Citation:
K. MUSIL and G. Yuen, 2016. Population dynamics of the biocontrol agent Lysobacter enzymogenes in the rhizospheres of soybean and cereal rye. Poster presented at 2016 North Central Division Meeting. Abstract published in Phytopathology 106:S4.191.
- Type:
Book Chapters
Status:
Awaiting Publication
Year Published:
2016
Citation:
Adesemoye, A. O., Yuen, G., and Watts, D. B. 2016. Microbial inoculants for optimized plant nutrients use in integrated pest and input management systems. In: Probiotics and Plant Health. Arora N.K, Mehnaz S., and Balestrini R. (Ed.), Springer.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2016
Citation:
Adesemoye, A. O., and Wei, H-H. 2016 Effects of Clonostachys species on charcoal rot disease caused by Macrophomina phaseolina in soybean. American Phytopathological Society Annual Meeting, Florida. August 2016.
- Type:
Journal Articles
Status:
Published
Year Published:
2016
Citation:
Adesemoye, A. O., H-H. Wei, and Harveson, R. M. 2016. Identification of Erwinia rhapontici, as the causal agent of crown and shoot rot and pink seed of pea in Nebraska. Plant Health Progress 17:155-157.
- Type:
Conference Papers and Presentations
Status:
Published
Year Published:
2016
Citation:
Oliveira-Hofman, C., Su�rez Victor, V., Mollet, K.A., Adesemoye, A.O., Meinke, L.J., and Peterson, J.A. 2016. Potential predators and entomopathogens of western corn rootworm in continuous cornfields in Nebraska. Entomological Society of America North Central Region
- Type:
Other
Status:
Published
Year Published:
2016
Citation:
Adesemoye, A. O. 2016. Biological products for disease management in field crops. Crop Production Clinic Proceedings. pp 169. Published by Nebraska Extension.
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Progress 01/12/15 to 09/30/15
Outputs
Target Audience:Target audiences include: scientists who conduct research in biological control and microbial ecology; industry entities who are involved in the development and production of biological control agents and agricultural chemicals; growers/producers who use biologicals to manage plant diseases. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?Three graduate students are training in this project. A new masters student has started research on the biocontrolactivity of new bacilli strains. A new doctoral student commenced research on the effects of rhizosphere nutrients on the production of HSAF, an antibiotic involved in biocontrol. A third student is continuing research for her masters degree on thecolonization of crop root bybacterial biocontrol agents and the use of the agents in controlling the soybeancyst nematode. How have the results been disseminated to communities of interest?The results obtained this year were reported to the scientificcommunity in the form of publications in scientific journals and papers presented at scientific conferences. What do you plan to do during the next reporting period to accomplish the goals?Goal 1 - New isolated bacilli and strains of Lysobacter will be evaluated in vitro and pot experiments for effects on fungal and bacterial pathogens and for effects on plant growth. Putative disease suppressive soils will be tested for suppression against corn pathogens. Microbialcommunity profiles of these soilswill be establish through culture-based andgenomic methods. Experiments will be conducted in the field with cereal rye and soybean to determine the degree to whichLysobacter enzymogenes can multiply in the root systems.Corn, wheat, anda number of cover crop specieswill be compared as hosts for rootcolonization by Lysobacter enzymogenes. Goal 2- Nutrient (C-source)content and composition will be investigated as factors affectingthe movement andgrowthof Lysobacter enzymogenesand the production of antifungalcompoundsby the bacterium.
Impacts
What was accomplished under these goals?
Biological control methods are need for better management of crop diseases caused by soilborne pathogens. The primary goal of thisproject, as part of the multistate research project W3147, is to develop sustainable, biologically-based methods to control soilborne pathogens. These methods ultimately will impact agriculture by enhancing crop productivity and reducing use of synthetic fungicides or nematicides. This project has as its goals, two of the objectives described for W3147. The goals and objectives in this project are: Goal 1 - To identify and characterize new biological agents, microbial community structure and function, naturally suppressive soils, cultural practices, and organic amendments that provide management of diseases caused by soilborne plant pathogens; Objective 1 - To identify cultural practices that provide the management of diseases caused by soilborne plant pathogens of Nebraska crops through the enhancement of indigenous or introduced populations ofLysobacterand/orBacillus. Objective 2. Isolate and identify new biocontrol-effective strains ofBacillus Objective 3. Characterize Nebraska disease suppressive soils as to the microbial community involved in suppression of soilborne pathogens Goal 2 - To understand how microbial populations and microbial gene expression are regulated by the biological (plants and microbes) and physical environment and how they influence disease. Objective - To determine how cultural practices that enhanceLysobacterand/orBacilluspopulations affect their ability to express mechanisms important to biological control. The results from this first year of this project represent significant progress towards achieving the anticipated outcomes. Expected outcomes include new biocontrol agents; a system integrating cultural practices with microbial biocontrol agents to provide effective control of soilborne diseases; and better understanding of how soil environmental factors regulate microbial growth and activity. Goal 1 - To identify and characterize new biological agents, microbial community structure and function, naturally suppressive soils, cultural practices, and organic amendments that provide management of diseases caused by soilborne plant pathogens. Objective 1 - To identify cultural practices that provide the management of diseases caused by soilborne plant pathogens of Nebraska crops through the enhancement of indigenous or introduced populations ofLysobacterand/orBacillus. Major activities completed / experiments conducted: Greenhouse experiments were conducted to evaluate the degree to whichLysobacter, a biological control bacterium used against soilborne fungal pathogens and nematodes, can multiply in the rhizospheres of cereal rye, an annual grass commonly used in Nebraska as a cover crop, and soybean Data collected: When applied to seed of cereal rye of soybean, Lysobacter survived and multiplied in association with roots systems of both plant species. Summary statistics and discussion of results: The results indicate that the bacterium can be delivered to a root system via seed treatment and that the plant root system subsequently serves as a substrate or environment for growth of the bacterium. Key outcomes or other accomplishments realized: The findings point to the potential of applying biocontrol bacteria to seed of a cover crop as a practical method for delivering a biocontrol agent to soil in agricultural fields. Goal 1. Objective 2. Isolate and identify new biocontrol-effective strains ofBacillus Major activities completed / experiments conducted: Strains ofBacillusand related genera were isolated from Nebraska soils and identified by DNA sequence analysis. Experiments were initiated to compare the new isolates for antagonism against multiple species of fungal plant pathogen. G. Yuen collaborated in a study conducted in China on the use of bacterial antagonists of nematodes to control tomato root-knot disease caused byMeloidogyne. Data collected: Some of the bacilli bacteria isolated from Nebraska soils were identified to species recognized to have biocontrol and plant growth-promotion potential, while others have not been reported to have these attributes. In field experiments on control of tomato root-knot disease,Bacillus methylotrophicusstrain R2-2 andLysobacter antibioticusstrain 13-6 were found to provide disease control and yield enhancement at levels comparable to those provided by chemical nematicides abamectin, carbofuran and fosthiazate. Summary statistics and discussion of results This is the first demonstration that strains ofB. methylotrophicusandL. antibioticuscan suppress disease caused by root-knot nematodes in the field. Key outcomes or other accomplishments realized The demonstration that bacterial strains can provide nematode control comparable to chemical nematicides should heighten interest in the development of biological control agents as alternatives to chemical nematicides. This outcome is particularly significant in respects to the replacement of carbofuran which has high human and animal toxicity but still used in many parts of the world. Goal 1. Objective 3. Characterize Nebraska disease suppressive soils as to the microbial community involved in suppression of soilborne pathogens Major activities completed / experiments conducted: Experiments were designed to characterize the soil microbial communities in fields with continuous cropping of corn as compared to conventional crop rotation. Soils from Nebraska fields that have been continuously cropped with corn for 40 and 103 years with no histories of root disease will be used in the experiments. Data collected: None was collected in this reporting period. Goal 2 - To understand how microbial populations and microbial gene expression are regulated by the biological (plants and microbes) and physical environment and how they influence disease. Objective - To determine how cultural practices that enhanceLysobacterand/orBacilluspopulations affect their ability to express mechanisms important to biological control. Major activities completed/experiments conducted: A panel of organic compound, representing common constituents of root exudates and organic soil amendments, were evaluated as carbon sources for the growth of Lysobacter. A study was completed on the role of pilG, a regulatory gene inLysobacter,in regulating production of HSAF, an antibiotic complex involved in biocontrol. Data collected; Lysobacter utilized most of the organic compounds tested as substrates for growth, with multiplication rate being higher in some compounds than others. PilG was found to down regulate HSAF production. Summary statistics and discussion of results 1.Identification of carbon sources that support growth of Lysobacterprovides candidate compounds to be used investigating nutrient effects on HSAF production 2.The finding that the pilG regulation pathway suppresses antibiotic production suggests that inconsistent biocontrol efficacy by Lysobacter could be related to the suppression of antibiotic production in response to yet unknown environmental cues, Key outcomes or other accomplishments realized. Identification of the environmental cues that activate pilG regulation might provide inroads to improving the effectiveness of biocontrol byLysobacter.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2015
Citation:
Zhou, X., Qian, G., Chen, Y., Du, L., Liu, F., and Yuen, G. 2015. PilG is involved in the regulation of surface motility and antifungal antibiotic biosynthesis in the biological control agent Lysobacter enzymogenes. Phytopathology 105:1318-1324.
- Type:
Journal Articles
Status:
Accepted
Year Published:
2015
Citation:
Zhou, L., Yuen, G., Wang, Y., Wei, L., and Ji, G. 2015. Evaluation of bacterial biological control agents for control of root-knot nematode disease on tomato. Crop Protection: accepted for publication 12-17-2015.
- Type:
Journal Articles
Status:
Published
Year Published:
2015
Citation:
Han, Y., Y. Wang, S. Tombosa, S. Wright, J. Huffman, G. Yuen, G. Qian, F. Liu, Y. Shen, and L. Du. 2015. Identification of a small molecule signaling factor that regulates the biosynthesis of the antifungal polycyclic tetramate macrolactam HSAF in Lysobacter enzymogenes. Appl. Microbiol. Biotechnol. 99:801811.
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