Convergent Adaptation and Specialization of Eukaryotic Pathogens across Agricultural Systems

• Authors: Nicole Marie Gerardo, Emory University
• Book Title: The Convergent Evolution of Agriculture in Humans and Insects
• Publisher: MIT Press Direct
• Publication Place: Cambridge, Massachusetts; London, England
• Publication Date: 2022
• Type of Work: Chapter | Final Publisher PDF
• Publisher DOI: http://doi.org/10.7551/mitpress/13600.001.0001
• Subjects: Biology, Plant Physiology; Biology, Parasitology; Health Sciences, Pathology
• Keywords: domestication of crops; hosts; pathogens; human agriculture; fungal crops of ants; agricultural pathogens; host defense; adaptation; specialization; selection; divergence; co-divergence; host jumps

Abstract

Domestication of crops provides an opportunity for pathogens to exploit novel, abundant hosts. Pathogens specializing on human crops have repeatedly emerged over the history of human agriculture. Similarly, pathogens have tracked domestication of the fungal crops of ants (Caldera et al. 2009). Like pathogens in nondomesticated systems, agricultural pathogens often face selection pressures to overcome host defenses, and such adaptation may lead to increased specialization (Flor 1956; Burdon 1987; Thompson and Burdon 1992). Specialization may lock pathogens into narrow host ranges, such that as host crops diverge from one another, either through intentional or unintentional selection by their domesticators, pathogens also diverge, potentially leading to patterns of co-divergence between the pathogens and their hosts. Alternatively, despite specialization, pathogens may make occasional host jumps, switching to hosts distantly related to the original host, which can lead to the emergence of novel disease.