PLANT PATHOLOGY

The main goal of this course is to provide the body of knowledge on plant diseases caused by biotic and abiotic agents. Diseases reduce yield and commercial value of medicinal plants, they also cause loss of quality. Moreover, this course will provide the knowledge on the management of the main diseases of medicinal plants with an environmentally friendly approach.

The course will mainly consist of lectures, but laboratory exercises are planned; the activities will include i) the recognition of the main symptoms of plant diseases; ii) learning the main techniques of isolation of fungal pathogens from infected plant tissues.

Students are required to participate actively during both the lectures and laboratory activities. Furthermore, students will be asked to prepare a report on a monographic topic chosen with the teacher which will then have to be presented during the course as a power point. This will allow students to acquire a series of knowledge related to the following aspects: a) perform a bibliographic research by consulting articles and websites on the chosen topic, taking care to select the most reliable bibliographic sources; b) prepare a report on the basis of a well-drawn outline; c) set up a power point by choosing appropriate images and structuring the slides in an appropriate manner; d) present a talk in public and answer to the questions of the teacher.

General aspects. Introduction to Plant Pathology. Disease definition. Diseases classification. General features of viroids, virus, phytoplasma, bacteria and fungi.

Plant disease diagnosis Koch’s postulates. Methods of diagnosis: conventional and innovative (immunological and molecular methods).

Parasitism, pathogenicity and disease development. Infectious disease cycle: inoculation, penetration, infection process, colonization, dissemination. Pathogen’s specialization: formae speciales, races and patovar.

How pathogens attack plants: microbial toxins, enzymes and proteins, growth regulators. Disease classification on the basis of the pathogenicity mechanisms.

How plants defend themselves against pathogens: preexisting structural and chemical-biochemical defenses and induced structural and chemical-biochemical defenses. Genetics of plant diseaes: variability of plant pathogens, immunity, tolerance, disease escape and true resistance: horizontal or polygenic and vertical or monogenic.

Plant disease epidemiology. Environmental factors tha affect development of epidemics.

Control of plant diseases (general aspects and definitions): prevention (exclusion, eradication), chemical methods and genetic resistance. Biological and integrated control. Drawbacks of the use of chemical control of plant diseases

Specific plant diseases. Powdery mildew of grape (Oidium tuckeri – Uncinula necator), Gray mold of grape (Botrytis cinerea – Botryotinia fuckeliana = Sclerotinia fuckeliana), Chestnut blight (Cryphonectria parasitica), Late blight of potatoe and tomatoe (Phytophthora infestans), Downy mildew of grape (Plasmopara viticola), Mal secco of citrus (Phoma tracheiphila), Crown gall (Agrobacterium tumefaciens), Citrus Tristeza Virus (CTV).

Suggested Readings

1) Belli G. Elementi di Patologia vegetale. Piccin Editore, 2011 (Nuova Edizione)

2) G.L. Schumann. e D'Arcy C.J. - Essential Plant Pathology, 2nd Edition, APS Press.

Additional resources

3) Agrios N., Plant Pathology. Academic Press.

4) Buchanan B.B., Gruissem W. e Jones R.L. Biochimica e Biologia molecolare delle piante, Zanichelli Editore.