Department of Biology & Biochemistry, Unit Catalogue 2008/09 |
BB30138 Plant-microorganism interactions |
| Credits: 6 |
| Level: Honours |
| Semester: 2 |
| Assessment: ES 20%, EX 80% |
| Requisites: |
| Before taking this unit you must take BB20032 |
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Aims & Learning Objectives: Aims: To provide an understanding of the processes involved in infection and colonisation of plants by parasitic microorganisms that lead to disease. To detail the chemical signals exchanged as key components of recognition events. To reveal the potential range of defences of plats: constitutive, induced non-specifically by damage, or specifically by pathogens. After taking this course, the student should be able to: * describe and explain the biochemical and physical factors which determine the outcome of interactions between microorganisms and plants; * explain how pathogens can avoid, negate or suppress host defences; * explain different strategies by pathogens for obtaining nutrients from plant hosts; * explain alternative strategies for control of plant diseases. Content: Resistance genes, their structure and function. Constitutive resistance based on existing structural barriers such as cuticle, secondary cell walls and on antimicrobial chemicals such as saponins and phenolics; detoxifying enzymes; toxin binding sites. Induced resistance comprising formation of physical barriers such as new or altered cell walls, vascular occlusions, de novo synthesis of phytoalexins. 'Defence-related genes'. Triggering of defence by stress or wounding, microbial elicitors or a recognition event. Infection structures of pathogenic fungi. Pahtogenicity determinants including depolymerases, toxins, polysaccarides, siderophores, detoxifying enzymes; their structure, modes of action and role. Contrasting strategies of obligate biotrophs and facultative nectrotrophs. Pathogenicity and virulence genes; molecular strategies to identify them. |