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Write an account of how plants defend themselves against attack by pathogens and parasites.
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Clare Johnson Queens College 17th January 2004 Write an account of how plants defend themselves against attack by pathogens and parasites Parasitic organisms such as bacteria, viruses, fungi, nematodes and insects have evolved ways to exploit the food, shelter and in the case of viruses, the replication machinery of plants as well as animals. Animals have a circulating adaptive immune system to protect them from pathogens but plants, which have no such system have evolved other forms of anti-microbial defence. In general, plants defend themselves against pathogens by a combination of two forms: structural characteristics that act as physical barriers and prevent the pathogen from entering the plant, and biochemical reactions which face the pathogen if it manages to breach the initial basal defenses and succeeds in penetrating the plant. The structural characteristics are passive and non-specific where as the biochemical reactions are more host specific with the cells and tissues of the plant...
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