Population genetics of fungal diseases of plants

Abstract

Summary :Although parasitism is one of the most common lifestyles among eukaryotes, population genetics on parasites lag far behind those on free-living organisms. Yet, the advent of molecular markers offers great tools for studying important processes, such as dispersal, mating systems, adaptation to host and speciation. Here we highlight some studies that used molecular markers to address questions about the population genetics of fungal (including oomycetes) plant pathogens. We conclude that population genetics approaches have provided tremendous insights into the biology of a few fungal parasites and warrant more wide use in phytopathology. However, theoretical advances are badly needed to best apply the existing methods. Fungi are of prime interest not only because they are major parasites of plants and animals, but they also constitute tractable and highly useful models for understanding evolutionary processes. We hope that the emerging field of fungal evolution will attract more evolutionary biologists in the near future. (0)1 69 15 73 53. E-mail: Tatiana.Giraud@u-psud.fr genetics studies have also valuable practical applications, for instance for studying the evolution of drug resistance or new virulence. Another reason to study parasites is that they display a huge diversity of life cycles and lifestyles, thus providing great opportunity for comparative studies to test pathogen-specific questions or general issues about evolution. Nevertheless, the field of parasitology has yet to attract more evolutionary biologists. This is even truer for the field of phytopathology, despite the importance of crop diseases for human activities. Furthermore, there are few connections so far between scientists in the fields of parasitology and phytopathology despite their obvious common interests. Here we highlight some studies that used molecular markers to address questions about the population genetics of fungal plant pathogens, fungi being taken sensus lato, i.e. including oomycetes. We do not aim providing an exhaustive review, but instead we use selected examples, mainly from our own works, to illustrate peculiarities of the phytopathogenic lifestyle. We focus on the study of mating systems (i.e. selfing, outcrossing, clonality), between and within population dispersal and population structure due to host adaptation.

Genetic Analyses Suggest Separate Introductions of the Pine Pathogen Lecanosticta acicola Into Europe

“…The presence of sexual reproduction in a population can reflect the ability of the pathogen to become invasive in a new environment because it has an influence on pathogen overwintering, dissemination, infection biology, and its ability to adapt to environmental conditions (Barrett et al 2008;Bazin et al 2014;Giraud et al 2008). It is, however, commonly difficult to detect sexual recombination in a fungal population where this mode of reproduction is cryptic or facultative (Milgroom 1996;Saleh et al 2012).…”

“…Population genetics can provide a reliable means to identify and understand the invasion history of plant pathogens (Giraud et al 2008;Grünwald and Goss 2011). In this regard, a statistical method receiving increasing attention is approximate Bayesian computation (ABC) (Beaumont et al 2002.…”

Characterization of Single-Nucleotide-Polymorphism Markers for Plasmopara viticola, the Causal Agent of Grapevine Downy Mildew

“…To establish long-term management of fungicide resistance in natural populations of P. viticola, the underlying evolutionary mechanisms that drive the appearance, propagation, and maintenance of resistance need to be elucidated (2). The use of population genetics allows evaluation of the major determinants of fungicide resistance, i.e., selection, mutation, recombination, genetic drift, and gene flow (7).…”

Avaliação da diversidade genética e associação com patogenicidade de isolados de Moniliophthora perniciosa oriundos da Amazônia Brasileira

“…Marcadores moleculares oferecem excelentes ferramentas para o estudo da biologia de fitopatógenos em processos importantes, como dispersão, sistema de reprodução, adaptação a hospedeiros e especiação (GIRAUD et al, 2008). Os microssatélites ou SSR (Simple Sequence Repeats) são marcadores codominantes e de natureza multialélica, que consistem de sequências de 1-5 pares de bases repetidas em série, em número variável nos genomas (JARNE;LAGODA, 1996).…”