Fungal Endophytes

Abstract

Plants contain microorganisms that live inside their tissues without causing disease. These microorganisms, called endophytes, are generally overlooked because they are hidden from view. However, endophytes have diverse effects on plants, ecosystems, agriculture and human history. This chapter reviews the biology of endophytic fungi and their importance for plants, people, and biotechnology. Some common forage grasses contain endophytic fungi that produce toxic alkaloids. The alkaloids defend the grasses against herbivores, both insects and mammals, and affect plant growth. These endophytes have intimate associations with their hosts, and have coevolved with them over millions of years. In other cases, the endophytes may protect the plant host against pathogens, be latent pathogens themselves, or be accidental guests with no obvious effects on plant health. Fungal endophytes are very diverse, especially in the tropics, and include many new and unnamed species. On a practical level, endophytes are being exploited for pest control and drug discovery. Our knowledge of endophytes and their importance is still fragmentary, with many aspects waiting to be studied.