RESEARCH, ACQUISITION, MANAGEMENT, AND DOCUMENTATION OF PLANT GENETIC RESOURCES
Location: Plant Germplasm Introduction and Testing
Title: Fungal pathogens of plants in the Homogocene
Submitted to: Current Advances in Molecular Mycology
Publication Type: Book / Chapter
Publication Acceptance Date: December 30, 2009
Publication Date: January 1, 2010
Citation: Newcombe, G., Dugan, F.M. 2010. Fungal pathogens of plants in the Homogocene. Current Advances in Molecular Mycology. book chaper.
Interpretive Summary: The Homogocene is that time period wherein commerce and exploration have resulted in widespread geographic dispersal of the world's biota. The beginning of the Homogocene is conventionally taken as 1500 AD, although there are many examples of plants or animals being moved about on regional scales well prior to that date. This chapter examines what is known (and not known) about the movement of fungi, especially plant pathogenic fungi, during the Homogocene. In particular, it examines the genetic mechanisms that may explain whether or not plants are susceptible to introduced fungal pathogens, or if plants are introduced to new locales, whether or not they are susceptible to native pathogens.
Resistance and susceptibility of plants to phytopathogenic fungi are examined in the context of invasion biology of the past 500 years. This time period is sometimes called the Homogocene, dating from about 1500 AD. In particular, genetic mechanisms are evoked to explain 'exapted resistance', the 'rule of ten' and 'host switching'. Buffon's Law, plus the 'pathogen release' hypothesis (incorporating the 'pathogen reunions' concept) are critiqued for multiple situations in which alien pathogens encounter native plants, or visa versa, or in which alien pathogens attack naturalized but alien plants in novel environments. Specific examples, largely from Uredinales, but also from ascomycetes and pseudo-fungi (e.g., Phytophthora) are examined with reference to given genes documented in the fungus and host. Also examined are effects of host or pathogen hybridization and fungi as facilitators of plant invasions.