PLNT PTH 830

SPECIAL TOPICS IN PLANT PATHOLOGY:

BIOLOGICAL CONTROL OF PLANT PATHOGENS

WINTER QUARTER offering

 

 

Classroom:       201C Kottman Hall,  203 Selby Hall / video-linked

Discussion:       Arranged with all students following enrollment; 1 hr per week

Credit:              1 or 2 credit hours*     

Prerequisites:    None, but any 600-level course plant biology, plant pathology, crop science, and/or microbiology would be helpful

Instructor:          B. McSpadden Gardener, 214 Selby Hall, 330 202-3565, bbmg+@osu.edu

Office hours:     Fridays 2 to 4 pm.

 

 

Rationale for the course:

Much has been written on the biological control of plant pathogens; however, relatively few biocontrol products are in use commercially ant these represent only a small market share of inputs used for plant disease control.  Recent developments in the fields of plant pathology, microbial ecology, seed technology, molecular biology, and genomics point the way to more effective biocontrol technologies.  Understanding these developments will be critical for students to properly research, develop, and/or recommend useful applications of biopesticide products.

To contribute effectively to the advancement of the field, students need to understand the current status of biological research and development. Given the large volume of literature on the subject, students will also need to learn how to efficiently and critically evaluate journal articles and other sources of information related to plant disease management.

 

 

Course Objectives:   Upon completion of the course, students should be able to:

Describe the history and current status of biological control research

Name several sources in which the results of biocontrol research can be found

Define the mechanisms by which biological control occurs and the experimental methods used to identify which mechanisms are active

Describe the diversity of microorganisms known to be involved in biological control

Describe the ecological hurdles to achieving effective biological control in the field

List several management options that will lead to more effective biological control

Name several biocontrol products that are widely used by growers and the reasons for their adoption

Define some questions whose answers will lead to progress in biocontrol research

Critically evaluate the literature on the biological control of plant pathogens

Use scientific literature to write, synthesize, and present to an audience a critical review of a research related to course content

Course Structure:

This is an advanced seminar course with a 1-hr section for discussion of assigned primary literature related to the course topic.  Two introductory lectures will be presented, followed by eight discussion sessions. A minimum of two papers will be presented in each class session. Two sessions will be led by outside experts.

 

Assignments will consist of required readings, participation in paper discussions, and a critical review of one or more journal articles selected by the student from the attached reading list.  Paper critiques will consist of a 20-minute, student-led presentation, and a 1-3 pg review of the paper highlighting the hypotheses, assumptions, assertions, evidence, and implications of the work. These reviews are due on the day of the student’s presentation. Each student will be required to provide TWO paper critiques.

 

*Students wishing to get 2 hrs of credit will also be required to either

a) take a 1-hr written final exam covering the assigned readings, or

b) submit a mini-review (2000-4000 words) on a topic of the student’s choice that is related to the biological control of plant pathogens, due by December 1st. Topic selection should be made in consultation with the instructor.

 

Minireview Topic Suggestions

Identifying new biocontrol agents.

Improving current inoculation strategies.

Review of biocontrol by a genus (e.g. Ampelomyces, Bacillus, Burkholderia, Paecilomyces, Pseudomonas, Streptomyces, Trichoderma/Gliocladium)

Genetic engineering: plants and microbes for biocontrol

Environmental engineering: maximizing natural biocontrol

Risk assessment in biocontrol

 

Required Textbook:  No specific textbook is required, but students are encouraged to purchase one or both books listed on the reading list for their personal libraries.  Readings will be taken from selected book chapters, journal articles, and online resources. Copies of these readings will be provided to the class as PDF files and distributed by e-mail.

 

Methods of Evaluation:  

Course grades will be determined as follows:

2nd student-led presentation                   40%

Participation in discussion                      20%

2nd written paper critique                       40%

 

Note: For students taking the course for 2 hr of credit, the above components will account for only 50% of the final grade, and the minireview or final exam will account for the other 50%.

 

Grading will be letter grades assigned by the instructor.

 


 

Academic Misconduct:  Academic misconduct erodes the integrity of the University and is unacceptable.  Suspected cases will be forwarded to the University’s Committee on Academic Misconduct for action as outlined in the OSU Student Resource Guide / Code of Student Conduct which is available online at http://studentaffairs.osu.edu/resource_csc.asp. 

 

Students with disabilities: If you have a disability, please tell one or both instructors about it.  We will work with any student who desires an accommodation based on the impact of a disability but you need to let us know before we can accommodate your specific needs.  Additional assistance is also available through the Office for Disability Services - Room 150 Pomerene Hall or by calling 614-292-3307.

 


 

PLNT PTH 830: Reading List

 Book References

Biological Control of Crop Diseases. 2002. S. Gnanamanickam ed. Marcel Dekker: New York, NY.

Cook, R.J. and K.F. Baker. 1983. The nature and practice of biological control of plant pathogens. APS Press: St. Paul, MN.

 

Assigned Reading List

Two of the articles in each section will be assigned.

Review articles will not be assigned for student presentations in class but should be read prior to reading articles.

 

1. Introduction

McSpadden Gardener, B. B., and Fravel, D. R. 2002. Biological control of plant pathogens: Research, commercialization, and application in the USA. Online. Plant Health Progress doi:10.1094/PHP-2002-0510-01-RV. ( Also online http://www.apsnet.org/online/feature/biocontrol/top.html)

Baker, K.F. 1987. Evolving concepts of biological control of plant pathogens. Ann. Rev. Phytopathology 25:67-85.

 

2. Mechanisms Direct and Indirect

Vallad and Goodman. 2005. Systemic acquired resistance and induced systemic resistance in conventional agriculture. Crop Sci 44:1920-1934.

Raaijmakers, J. et al. 2002. Antibiotic production by bacterial biocontrol agents. Antonie van Leeuwenhoek 81(1-4)2002.  p.537-547.

Silva et al. 2005. Rhizobacterial induction of systemic resistance in tomato plants: non-specific protection and increase in enzyme activities. Biol. Control. 29:288-295.

Ryu et al. 2003 Bacterial volatiles promote growth in Arabidopsis. Proc. Nat. Acad. Sci. USA 100:4927-4932.

Shishido et al. 2005. Biological control efficiency of fusarium wilt of tomato by nonpathogenic F. oxysporum Fo-B2 in different environments. Phytopathology 95:1072-1080.

Jones and Prusky. 2002. Expression of an antifungal peptide in Saccharomyces: A new approach for biological control of the post harvest disease caused by C. coccodes. Phytopathology 92:33-37.

 

3. Microbial Diversity

Borneman, J.  et al. 2006. Identifying microorganisms involved in specific in situ functions: experimental design considerations for rRNA gene-based population studies and sequence-selective PCR assays. in Manual of Environmental Microbiology 3rd ed. ASM Press:Washington D.C. in press

Yin, B. et al. 2003. Identification of fungal rDNA associated with soil suppressiveness against Heterodera schachtii using oligonucleotide fingerprinting. Phytopathology 93:1006-1013

Yin, B. et al. 2003b. YinBacterial rRNA genes associated with soil suppressiveness against the plant-parasitic nematode Heterodera schachtii. Appl. Environ. Microbiol. 69: 1573-1580

Berg et al. 2005. Endophytic and ecotphytic potato-associated bacterial communities differ in structure and antagonistic function against plant pathogenic fungi. FEMS Microb. Ecol. 51:215-229.

McSpadden Gardener, B., Weller, D. 2001. Changes in populations of rhizosphere bacteria associated with take-all disease of wheat. Appl. and Environ. Microbiol. 67:4414-4425.

 

 

4. Ecology of biocontrol

Kerry, B. 2000. Rhizosphere interactions and the exploitation of microbial agents for the biological control of plant parasitic nematodes. . Ann. Rev. Phytopathology 38:423-441.

Anderson, L. M., Stockwell, V. O., and Loper, J. E. 2004. An extracellular protease of Pseudomonas fluorescens inactivates antibiotics of Pantoea agglomerans. Phytopathology 94:1228-1234.

Schouten et al 2004. Defense responses of Fusarium oxysporum to 2,4-DAPG, a broad spectrum antibiotic produced by Pseudomonas fluorescens. Mol. Plant Microb Interact. 17:1201-1211.

Phillips et al. 2004. Microbial products trigger amino acid exudation from plant roots. Plant Physiol. 136:2887-2994.

Kovach et al. 2000. Use of honey and bumble bees to disseminate Trichoderma harzianum 1295-22 to strawberries for Botrytis control. Biol. Control 18:235-242.

  

5. Soilborne disease control

Weller. D. Raaijmakers, J., McSpadden Gardener, B. and Thomashow S et al 2002. Microbial populations responsible for specific soil suppressivenes. Ann. Rev. Phytopathology 40:309-348.

Cook, R. J., Weller, D. M., Youssef El-Banna, A., Vakoch, D., and Zhang, H. 2002. Yield responses of direct-seeded wheat to rhizobacteria and fungicide seed treatments. Plant Dis. 86:780-784.

Ramette, A. et al. 2003. Prevalence of fluorescent psuedomonads producing antifungal phloroglucinols and/or hydrogen cyanide in soils naturally suppressive or conducive to tobacco root rot. FEMS Microb. Ecol. 44:35-43.

McSpadden Gardener, B. et al 2005. Distribution of phlD+ bacteria in corn and soybean fields. Phytopathology 95:715-724.

Hoitink, H. and Boehm, M. 1999. Biocontrol within the context of soil microbial communities: A substrate dependent phenomenon. Ann. Rev. Phytopathol. 37:427-446.

Scheuerell, S. J et al. 2005. Suppression seedling damping-off caused by Pythium ultimum, P. irregulare, and Rhizoctonia solani in container media amended with a diverse range of Pacific Northwest compost sources. Phytopathology 95:306-315.

 

6. Foliar and above-ground disease control

Milgroom, M. and Cortesi, P. 2004. Biological control of chestnut blight with hypoviulence: A critical review.  Ann. Rev. Phytopathology 42:311-338.

Andrews, J. 1992. Biological control in the phyllosphere. Ann. Rev. Phytopathology30:603-633.

Stockwell, V. O., Johnson, K. B., Sugar, D., and Loper, J. E. 2002.Antibiosis contributes to biological control of fire blight by Pantoea agglomerans strain Eh252 in orchards. Phytopathology 92:1202-1209.

Johnson, K. B., Stockwell, V. O., Sawyer, T. L., and Sugar, D. 2000. Assessment of environmental factors influencing growth and spread of Pantoea agglomerans on and among blossoms of pear and apple. Phytopatholog 90:1285-1294.

Thomson and Gauk. 2003. Influence of age of apple flowers on growth of Erwinia amylovora and biological control agents. Plant Dis. 87:502-509.

Kessel et al 2005. Modeling spatial characteristics in the biological control of fungi at leaf scale: Competitive substrate colonization by Botrytis cinerea and the saprophytic antagonist Ulocladium atrum. Phytopathology 95:439-448.

 

7. Postharvest disease control

Janisiewicz, W. and Korsten, L. 2002. Biological control of postharvest diseases of fruits. 40: 411-441.

de Capdeville, G., Wilson, C. L., Beer, S. V., and Aist, J. R. 2002. Alternative disease control agents induce resistance to blue mold in harvested ‘Red Delicious’ apple fruit. Phytopathology 92:900-908.

Janisiewicz, W. J., and Peterson, D. L. 2004. Susceptibility of the stem pull area of mechanically harvested apples to blue mold decay and its control with a biocontrol agent. Plant Dis. 88:662-664.

El-Ghaouth, A., Smilanick, J. L., Brown, G. E., Ippolito, A., Wisniewski, M., and Wilson, C. L. 2000. Application of Candida saitoana and glycolchitosan for the control of postharvest diseases of apple and citrus fruit under semi-commercial conditions. Plant Dis. 84:243-248

 

8. Commercialization

Fravel D. 2005. Commercialization and implementation of biocontrol. Ann Rev Phytopathology 43:337-359.

Elliot et al 2001. Viability and stability of biological control agents on cotton and snap bean seeds. Pest Mgmt. Sci. 57:695-706.

Batson et al 2001 Biological seed treatment evalutations for control of the seedling disease complex of cotton, 2000. B&C Tests 16:F12

Batson et al 2001 Biological seed treatment evalutations for control of the seedling disease complex of snap bean, 2000. B&C Tests 16:V81

Bargabus et al. 2004. Screening for the identification of potential biological control agents that induce systemic acquired resistance in sugarbeet. Biol. Control 30:342-350

Mercier, J and Lindow. S.E. 2001. Field performance of antagonistic bacteria identified in a novel assay for biological control of fireblight. Biol. Control 22: 66-71.

 

9. Regulations and Risk Assessment

Cook, R. 1993. Making greater use of microbial inoculants in agriculture. Ann. Rev. Phytopathology 31:53-80.

EPA. 1996. Microbial pesticide test guidelines. OPPTS 885.0001. Overview for Microbial pest control agents. EPA 712-C-96-280.

EPA. 1996. Microbial pesticide test guidelines. OPPTS 885.5000. Background for microbial pesticide testing. EPA 712-C-96-056.

Timms-Wilson et al. 2004. Risk assessment for engineered bacteria used in biocontrol of fungal disease in agricultural crops. Plant and Soil 266:57-67.

Blouin-Bankhead et al 2004. Minimal changes in rhizosphere population structure following root colonization by wild type and transgenic biocontrol strains. FEMS Microb. Ecol 49:307-318.

 

10. Integration

Paulitz, T. and Belanger, R. 2001. Biological control in greenhouse systems. Ann. Rev. Phytopathology 39:103-133.

Sikora, R. 1992. Management of antagonistic potential in agricultural ecosystems for the biological control of plant parasitic nematodes. Ann. Rev. Phytopathology 30:245-270.

Jacobsen et al. 2004. The role of Bacillus-based biological control agents in integrated pest management systems: Plant diseases. Phytopathology 94:1272-1275.

Guetsky et al. 2001. Combining biocontrol agents to reduce the variability of biological control. Phytopathology 91:621-627.

Raupach and Kloepper. 1998. Mixtures of PGPR enhance biological control of multiple cucumber pathogens. Phytopathology 88:1158-1164.

Stevens et al. 2003. Integration of soil solarization with chemical, biological, and cultural control for the management of soilborne disease of vegetables. Plant Soil 253:493-506.