Plant Pathology: Academic Programs: Courses / Syllabi

PATH 8400 - Host-Pathogen Interactions

Principles of physiology and genetics of parasitism and disease resistance. Emphasis is placed upon how the genetic basis for host-pathogen compatibility and incompatibility is related to structural, physiological, and biochemical responses in diseased plants and to mechanisms of resistance.

Instructor - Tim Denny
Credit Hours - 3
Course Offered - spring semester of even-numbered years

Prerequisite

PATH 3530-3530L and PGEN 3580-3580L and (BCMB 4020/6020 or PBIO(CRSS)(BIOL) 4500/6500)

GENERAL COURSE INFORMATION

Instructor: Dr. Tim Denny
Office: Room 3303 Plant Science Bldg.
tdenny@uga.edu, (706) 542-1282

Class Schedule

We meet Tuesdays and Thursdays 3rd period (11:00 a.m.-12:15 p.m.) in Room 2102 Plant Science Building. Class time is a mix of lecture and discussion. Anyone who wishes can attend and participate in the lectures (bring your friends!). A proposed lecture schedule is provided on a separate sheet.

Course Overview

This course focuses almost entirely on the interactions of plants and pathogens during pathogenesis. The emphasis is at the molecular level, drawing heavily on the disciplines of genetics, biochemistry, molecular biology, and cell biology. Several of the mutualistic and antagonistic interactions illustrate broader principles and contribute to our fundamental understanding of biological processes. The outcome of the these interactions have a strong impact on agricultural productivity, and so are also of applied importance.

Establishment of a relationship between a plant and a microorganism may involve colonization, infection, nodulation, or systemic spread of a microbe in or on a plant. In the microbe, our focus will be on the mechanisms of host detection, colonization/multiplication, virulence, and the maintenance of the infection. Microbial signals that alter host physiology and morphology will be examined. In the plant, our focus will be on the genes, gene products and biochemical events that control plant-microbe interactions. We are especially interested in plant perception of microbial signals, plant signal transduction pathways and associated local and systemic defense mechanisms. We will also consider the potential of genetically altered plants to improve agriculture, and the social and ethical issues of this approach.

Course Objectives

• Present a conceptual and factual framework of host-microbe interactions
• Examine selected examples of current research on host-pathogen interactions.
• Encourage critical analysis of terms, concepts and scientific literature.
• Foster conjecture regarding the cellular and molecular aspects of host-pathogen interactions.

Course Mechanics

Text: There is no assigned textbook for this course. A list of relevant books will be provided separately. Although now going out of date, the single best text is still Molecular Plant Pathology edited by M. Dickinson and J. Benyon (2000, CRC Press OR 2003, BIOS Scientific). It is available from Amazon.com for less than $60. This book reviews most aspects of the material covered in this course. Selected books may be placed on reserve at the UGA Science Library; you will be notified if this occurs.

Supplemental Reading: Copies of the articles that you are expected to read and be familiar with will be provided via WebCT or as hard copies in Room 2108. (Remember that the copying machine in the Plant Pathology office is NOT to be used for class material). For the hard copies of articles there will be two sets: One in a 3-ring binder that should not circulate outside of the lab or the plant pathology conference room; Another in manila folders that you can take with you to another site for several hours or overnight after ~9:00 p.m. Please be considerate of other students when taking these materials and return them as quickly as possible.

Grant Proposal: Each student will write scientific research grant proposal on a question relevant to host-microbe interactions. Details regarding preparation of the proposals will be provided separately early in the semester. Students will select topics of interest to them (in consultation with the instructor), and a written ‘outline’ must be approved by the instructor before the indicated date. As part of the preparation process, each student will write a constructive review of one draft proposal and later a critical review of one proposal as if they were a member of a grant review panel. These reviews will constitute part of your grade, not the grade of the students whose proposals you are reviewing; the instructor will assign the final grade to the proposals. Written components of this project that are not handed in on time will be docked one letter grade per day for the first two days; after this a student will receive no points for that component.

Exams: There will be a mid-term and final exam. About a week before each exam, students will be given a short list of essay questions, some of which will appear on the test (instructor’s choice). You can prepare for the exam using any resource, including other students, but the tests will be written from memory during the exam period. If a student has a legitimate reason for missing the exam period, then a make-up time will be arranged.

Student Responsibilities

You are expected to attend class regularly, keep up with assigned readings, and contribute to class discussions. I encourage you to ask questions during or after class. Most importantly, I want you to THINK about the course material! Your attendance and general participation in the class constitutes a small amount of your final grade.

All academic work must meet the standards contained in "A Culture of Honesty." Students are responsible for informing themselves about those standards before performing any academic work (for more detailed information go to: http://www.uga.edu/ovpi/honesty/acadhon.htm).

Grading

General participation 5%
Midterm exam 25%
Research proposal 25% (5% on draft, 20% on final version)
Proposal reviews 10% (5% for each)
Final exam 35%
Total 100%

PATH 8400, Proposed Course Schedule - Spring 2006

Date / Topic
1/10 Course introduction, key concepts and terms, leaf and plant cell wall structure
1/12 continued
1/17 Introduction to bacterial plant pathogens
1/19 Ralstonia solanacearum: a model bacterial pathogen
1/24 Agrobacterium tumefaciens: molecular pathogenesis and plant transformation
1/26 Two-way communication in Rhizobium-plant interactions
1/31 Plant cell wall degrading enzymes in disease
2/2 Phytoanticipins – preexisting defense mechanisms
2/7 Introduction to plant pathogenic viruses (Deom)
2/9 Current research in plant pathogenic viruses (Deom)
2/14 Introduction to fungal plant pathogens (Gold)
2/16Current research with Ustilago maydis, the corn smut pathogen (Gold)
2/21 Introduction to plant path nematodes and current molecular research (Hussey)
2/23 Hrp gene clusters and type III protein secretion by bacteria
2/28 MIDTERM EXAM (covers through 2/23)
3/2 Elicitors and PR proteins
3/7 The gene-for-gene hypothesis and secreted effector molecules
3/9 continued (Grant Proposal Topic Approved BY TODAY)
Spring Break, 3/13-17
3/21 Activities of pathogenic fungi outside the host (prepenetration and penetration)
3/23 continued
3/28 Phytotoxins – structure, mode of action, and roles in pathogenesis
3/30 Plant resistance genes and signal transduction pathways
4/4 continued (Proposal draft due to reviewer and instructor)
4/6 Defense signal transduction, programed cell death, HR, and active oxygen
4/11 continued (Proposal review due to author and instructor)
4/13 Induced resistance - local and systemic
4/18 continued
4/20 Induced defenses – phytoalexins, cell wall appositions, etc.
4/24 Final revised proposals due
4/25 Converting knowledge of pathogenesis into methods of disease control
4/27 Class discussion: Social and ethical issues of using transgenic plants for disease control
5/1 Final review of proposals due to instructor
5/2 Question and answer/review session (optional)
5/9 Noon to 3:00 p.m. FINAL EXAM (may try to reschedule for before May 6)

This course syllabus is a general plan for the course; deviations announced to the class by the instructor may be necessary.