Why preserve the biodiversity of plant pathogens?International Congress of Plant Pathology President David Ingram gives several reasons in his paper introduced below, including: 1) they serve a role in revealing genetic diversity in potential breeding material and provide vital screens for the development of new cultivars, 2) they are the raw material for much of the basic scientific research on life cycles and genetics that generate an understanding of pathogen variation, evolution and population dynamics, and 3) they constitute a potentially significant biotechnological resource of particular importance to the genetic engineer.
Most plant pathologists are employed to control or eradicate plant diseases from crops in agriculture, horticulture or forestry. However, every plant species, wild or cultivated, has one or more plant diseases naturally associated with it. Plant diseases are a normal part of every natural and semi-natural community, but their impact and role in these communities is usually unnoticed and unappreciated. In cropping ecosystems (monocultures), plant diseases often cause visible death and destruction leading to yield loss. In natural ecosystems (biologically diverse), they are an "unseen" influence on both the plant community and the evolution of individual species.
In natural communities plant diseases are in balance with their hosts; some host plants die, but enough survive to maintain the species. Plant pathogens, through the diseases they cause, influence the distribution of individuals of a species, the genetic variation of that species with respect to disease resistance, the balance between sexual and asexual reproduction in the host plant, and interactions with other organisms.
Unless pathogens are conserved along with the hosts, the selection pressure that influences the host will be lost and gradually the genes that confer resistance on the host will fall to extremely low frequencies and exist in danger of being lost also. For that reason, the 7th International Congress of Plant Pathology invites you to join in these online discussions on plant pathogen biodiversity and conservation.
David Ingram, President of the British Society for Plant Pathology, Regius Keeper of the Royal Botanic Garden in Edinburgh, and ICPP98 Congress President, leads off this online event with a thought provoking paper, Biodiversity and Plant Pathogens and Conservation.
Additional food for thought comes from a BBC article titled "Vole Power: Herbivores Prefer Diseased Plants". The article recounts discoveries demonstrating that plant diseases are an essential part of the ecosystem sometimes even nourishing their own controls. The paper reporting the findings "The effect of herbivory on the interaction between the clonal plant Trientalis europaea and its smut fungus Urocystis trientalis" by L. Ericson and A. Wennström was originally published in Oikos, volume 80, number 1, October 1997.
As part of the ecosystem, plant pathogens can also influence the distribution of plant species. Take the case study on oaks in a natural setting in the UK. The study of two oak species and powdery mildew demonstrates how plant species and their pathogens co-evolve over time.
What are your thoughts regarding preservation of plant pathogens? You are invited to express your views in this online discussion. In the discussion you may also comment directly on the need for a policy on conservation of plant pathogens similar to the draft proposal on conservation of fungi put forth by the British Mycological Society. As background, review six good reasons why we should all value the biodiversity of the earth. The Ecological Discussion on Plant Pathogens will run through 31 July, 1998.
Finally, some of you may wonder what a plant pathologist is and why they are an important component of the scientific community. Click here to find out more about plant pathologists and a few of the important diseases they work on, such as potato late blight (cause of the Irish potato famine), coffee rust (the reason many Europeans drink tea), and a new concern to many, destructive diseases of cocoa resulting in skyrocketing prices for chocolate.
This ICPP98 event is sponsored by:The International Society of Plant PathologyThe British Society for Plant PathologyThe American Phytopathological Society
Special thanks to the online event organizing committee:Avice Hall, University of Hertfordshire, UKAdrian Newton, Scottish Crop Research Institute, UKDavid Ingram, Congress President, UKJames MacDonald, University of California, USAAPSnet Staff, The American Phytopathological Society, USA