Fungi have many kinds of unique associations with plants. These associations can benefit both the fungus and the plant, or can be detrimental to the plants and cause disease and even plant death. Land plants evolved over 425 million years ago, and fungi have been associated with their evolutionary development over the millennia. In reference to nutrient sequestration, fungal associations with plants are characterized as biotrophic, necrotrophic, or a mixture of these types. Biotrophs usually grow only on living plant tissue extracting nutrients from living plant cells. They can be pathogenic or symbiotic. In a symbiotic relationship, fungi gain carbon from the plant in exchange for nutrients and water unattainable by the plant. Necrotrophs promote host cell death to acquire nutrients for growth and reproduction. Each type of association is equipped with its own unique collection of biochemical and mechanical infection and colonization mechanisms. In turn, plants have evolved to have a complex network of genes to interact with a broad range of fungi. This chapter will provide an overview of three different types of fungal infection and colonization patterns with examples relevant to soybean as well as define defense mechanisms that the plant uses to interact with these microbes.
Part of the book: Fungal Pathogenicity