This course serves as one of the core courses in the Field of Plant Pathology and is meant to be a complement to material introduced and covered in the other core courses: PLPA 301, PLPA 470, and PLPA 601. The goal of PLPA 602 is to provide students with a fundamental understanding of the basic biology of fungal, oomycete, prokaryotic (bacterial), nematode, and viral plant pathogens. A further goal is to provide students with a working understanding of the major concepts, techniques, and current research in pathogen biology. Topics will cover aspects of pathogen biology appropriate to the particular pathogen group, from phylogenetics and systematics to cell and developmental biology to ecology and disease management.
The key biological attributes of the major groups of pathogens will be detailed in informal lectures, discussions, and selected demonstrations. Emphasis will be placed biological characteristics important to the parasitic and saprobic development, ecology, and management of these organisms. Practical aspects of pathogen biology, including isolation, identification, and assessing virulence will also be addressed. Students will be exposed to the pertinent literature and research in the biology of each of the pathogen groups.
After completing the course, students will:
1) have a thorough understanding of :
-the evolution and diversity of organisms and viruses
-the fundamental aspects of reproductive development
-the ecological relationships of pathogens with plants and their environment
2) be familiar with
-common and unique traits and behaviors among the different groups of
-major genera and species within each pathogen group
-methodologies used to investigate the biology of each pathogen group
-current research trends in the study of pathogen biology
-disease management practices common to each pathogen group
3) be able to:
-use knowledge of pathogen biology to identify current and new potential
developmental or behavioral targets for disease control
-critically evaluate evidence and arguments in support of disease management
4) be comfortable in developing and presenting an effective oral presentation that conveys reasoned arguments of a scientific nature
Lectures and discussions:
Lectures and discussions will follow the sequence below:
Fungi - weeks 1 through 3
Oomycetes - weeks 4 through 6
Bacteria - weeks 7, 8 and 10
Nematodes - week 9
Viruses - weeks 11 through 13
Approximately 6 lectures and 2-3 discussions will be devoted to each pathogen group, with the exception of nematodes, which will be discussed in one lecture period.
Discussion periods on Thursday afternoons will be used for more in-depth discussions of material introduced in lectures or may be used for hands-on activities and demonstrations. Active participation of ALL students is expected in discussions. Frequently, discussion session will be held jointly with PLPA 601. These sessions will be used to cover material of mutual interest to both courses.
Summary of topics covered for each pathogen group:
Fungi. This portion of the course is intended to provide students with a broad exposure to the biology of fungi. Emphasis will be placed on biological characteristics important to parasitic and saprobic development, on diversity and on the ecology of these organisms. Topics to be discussed included hyphal growth, hyphal fusion, asexual, sexual, and pathogenic development, and how fungi communicate with themselves and with other organisms. This section of the course will examine how genomics has contributed to our knowledge of the fungal cell and its interactions with other organisms. Students will be exposed to the pertinent literature and research in fungal biology.
Oomycetes. This course is intended to provide students with a broad exposure to the biology of oomycetes. The key attributes of this important group of animal, plant, and invertebrate pathogens will be detailed largely in informal lectures and hands-on demonstrations. Emphasis will be placed biological characteristics important to the parasitic and saprobic development and ecology of these organisms. This includes asexual and sexual development as well as the developmental ecology of major oomycete species. Practical aspects of oomycete biology, including their isolation and identification will also be addressed. Students will be exposed to the pertinent literature and research in oomycete biology. We will become familiar with the major genera of plant pathogenic oomycetes as well as other important non-phytopathogenic genera. Students will be expected to be conversant in all aspects of oomycete biology.
Prokaryotes. Prokaryotes are diverse microbes; those that cause disease or are otherwise associated with plants are not too different from prokaryotes that occupy other niches. We will consider how prokaryotes are characterized both phenotypically and genetically. We will discuss the several techniques used for characterization. We will consider the requirements for growth and how growth can be measured axenically and in association with plants. We will become familiar with 10 important genera of prokaryotic plant pathogens and the diseases caused by species of them. For several groups, we will learn about peculiarities. We will consider the similarities and the differences in the biology and the epidemiology of the several pathogens as they may lead to different strategies for control or management of disease. We will consider aspects to bear in mind when working with bacterial plant pathogens such that experiments are reasonably designed and data are interpreted properly. Finally, we will consider how fundamental studies of prokaryotic plant pathogens have impacted practical control of plant diseases
Viruses. Over the course of six class meetings, we will review the viral functions required for infection and the survival of the virus. After completing this section of PLPA 602, students will be expected to be familiar with at least six of the major groups of plant viruses, their genome organization and replication, viral gene functions, and modes of transmission. Your appreciation of the biology of these viruses should be sufficient to allow you to recommend and justify the rationale for disease management strategies
Readings will be selected from the pertinent primary and secondary literature in fungal, oomycete, bacterial, nematode, and viral biology. These readings will be used to supplement material presented in lectures or to serve as foci for discussion of specific topics. All readings will be posted as PDF files on the class website, at least one week prior their use in discussions or in lecture.
Exams will be administered following the series of lectures devoted to each pathogen group. These would be scheduled roughly at 3 (fungi), 6 (oomycetes), 10 (bacteria and nematodes), and 13 (viruses) weeks into the semester. Exams may consist of take-home exams or in-class exams at the discretion of the several instructors. Students will be responsible for material covered in lectures as well as discussions.
Students will be expected to complete a class project whose goal is to integrate concepts introduced during class meetings and to highlight comparisons within and among the pathogen groups. We will integrate what we are learning by addressing the disease problems of a single crop plant, tomato. Working individually, in small groups, and as a class, we will consider the biology of the pathogens as a guide to disease control and management strategies. Students and their groups will design a management strategy and make two oral presentations. Feedback on presentation styles and content will be provided by both fellow students and instructors. Details of the project will be discussed during the first discussion session on Jan 26.
Your grade in this class will be based on your performance on each of the four exams as well as on your participation in discussions and the class project as outlined below:
Exam 1 (Fungi) 20%
Exam 2 (Oomycetes) 20%
Exam 3 (Bacteria/Nematodes) 20%
Exam 4 (Viruses) 20%
Discussion and class project 20%
The highest standards of academic conduct are to be followed in this class. The work you submit for the class project must have been prepared exclusively for this course and must originate with you in form and content. You must fully and specifically acknowledge all contributing sources. Collaborative work, such as peer critique and review is exempt from such acknowledgement.
Plagiarism in any form will not be tolerated. For more information about Cornell’s Code of Academic Integrity and Plagiarism, see: http://cuinfo.cornell.edu/Academic/AIC.html Tentative Course Schedule
Tues Jan 24
Thurs Jan 26
Key pathogen representatives
Thurs Jan 26
combined discussion; diseases of tomato
Tues Jan 31
Diversity, ecological niches, communication, and behavior