{'fraction_non_alphanumeric': 0.025552486187845305, 'fraction_numerical': 0.0, 'mean_word_length': 5.1923076923076925, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
An evolutionary framework for host shifts - jumping ships for survival.

Host jumping is a process by which pathogens settle in new host groups and is a cornerstone in the evolution of pathogens, as it leads to pathogen diversification. For facultative pathogens host jumping is not surprising, as they can reproduce even if they kill their host. It was thought that host jumps are rare in obligate biotrophic pathogens, but molecular phylogenetics revealed the contrary. Here, I review some concepts and recent findings and present several hypotheses on the matter. In short, pathogens evolve and diversify by host jumps, followed by radiation, specialisation, and speciation. Host jumps are facilitated by e.g. effector innovations, stress, compatible pathogens, and physiological similarities. Host jumping, subsequent establishment, and speciation takes place rapidly: within centuries and millennia rather than millions of years. If pathogens are unable to evolve into neutral to mutualistic relationships, they will eventually be removed from the host population despite balancing trade-offs. Thus, generally, plant pathogens only survive in the course of evolution, if they jump hosts. This is also reflected by the diversity patterns in many genera of plant pathogens, leading to a mosaic pattern of hosts over time, in which the original host group becomes increasingly obscure. This article is protected by copyright. All rights reserved.