The global genetic structure of the wheat pathogen Mycosphaerella graminicola is characterized by high nuclear diversity, low mitochondrial diversity, regular recombination, and gene flow

Zhan, Jiasui; Pettway, R. E.; McDonald, Bruce A.

doi:10.1016/s1087-1845(02)00538-8

Cited by 274 publications

(309 citation statements)

References 47 publications

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“…For C. parasitica for instance, the chestnut blight disease introduced in USA during the 19 th century, genetic differentiation was different in populations for the native and introduced ranges sampled at a similar spatial scale (F ST = 0.11 vs 0.19 respectively; Milgroom et al, 1996). A similar trend for a higher genetic differentiation in the most recent introduced area was found for M. graminicola, an important wheat leaf pathogen (Zhan et al, 2003). Second, cryptic species or host races are commonly described in fungi (e.g.…”

Section: Dispersal and Gene Flowmentioning

confidence: 56%

Population genetics of fungal diseases of plants

et al. 2008

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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.

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Section: Dispersal and Gene Flowmentioning

confidence: 56%

Population genetics of fungal diseases of plants

et al. 2008

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“…Genetic variation, and therefore evolutionary potential, of populations can be underestimated when samples are over‐represented by identical genotypes (clones) generated by asexual reproduction of parents. This sample error is usually corrected using only one representative of the same genotype in the estimation of genetic variation (Zhan, Pettway, & McDonald, 2003). Unlike previous studies, isolates in the current study were prescreened molecularly and morphologically and only isolates with distinct genotypes were selected for sequence analysis (Wu et al., 2016).…”

Section: Discussionmentioning

confidence: 99%

Evidence for intragenic recombination and selective sweep in an effector gene of Phytophthora infestans

Yang

Ouyang

Fang

et al. 2018

Evolutionary Applications

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Effectors, a group of small proteins secreted by pathogens, play a critical role in the antagonistic interaction between plant hosts and pathogens through their dual functions in regulating host immune systems and pathogen infection capability. In this study, evolution in effector genes was investigated through population genetic analysis of Avr3a sequences generated from 96 Phytophthora infestans isolates collected from six locations representing a range of thermal variation and cropping systems in China. We found high genetic variation in the Avr3a gene resulting from diverse mechanisms extending beyond point mutations, frameshift, and defeated start and stop codons to intragenic recombination. A total of 51 nucleotide haplotypes encoding 38 amino acid isoforms were detected in the 96 full sequences with nucleotide diversity in the pathogen populations ranging from 0.007 to 0.023 (mean = 0.017). Although haplotype and nucleotide diversity were high, the effector gene was dominated by only three haplotypes. Evidence for a selective sweep was provided by (i) the population genetic differentiation (G ST) of haplotypes being lower than the population differentiation (F ST ) of SSR marker loci; and (ii) negative values of Tajima's D and Fu's FS. Annual mean temperature in the collection sites was negatively correlated with the frequency of the virulent form (Avr3aEM), indicating Avr3a may be regulated by temperature. These results suggest that elevated air temperature due to global warming may hamper the development of pathogenicity traits in P. infestans and further study under confined thermal regimes may be required to confirm the hypothesis.

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“…This is in contrast to some of the Mycosphaerella pathogens on agricultural crops such as wheat (Zhan et al 2003;Zhan and McDonald 2004). However, in recent years, several polymorphic markers have been developed for important Teratosphaeria spp.…”

Section: Future Prospectsmentioning

confidence: 98%

“…Here, more than 88 % of the alleles detected in the African, Pacific Islands and Latin American populations were also found in the South East Asian P. fijiensis population, indicating that South East Asia is most likely the centre of origin of the species. Zhan et al (2003) investigated the global structure of the wheat pathogen Z. tritici by employing data generated from genomic RFLPs and found that populations of the pathogen from the Middle East (Israel and Syria) exhibited higher gene diversity values than populations from America, Australia, Europe or North America. It was, therefore, suggested that Z. tritici originates from the Middle East where wheat was also first domesticated (Zhan et al 2003).…”

Section: Dna-based Techniques For Identificationmentioning

confidence: 99%

Mycosphaerella and Teratosphaeria diseases of Eucalyptus; easily confused and with serious consequences

et al. 2011

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The Mycosphaerella complex accommodates thousands of taxa. Many of these species are economically important plant pathogens, notably on native and commercially propagated Eucalyptus species where they cause a wide range of disease symptoms including leaf spot, leaf blotch, shoot blight and stem cankers. Some of these diseases represent major impediments to sustainable Eucalyptus forestry in several countries where infection by Mycosphaerella and Teratosphaeria species can result in reduction of wood volume and in severe cases tree death.Extensive research has been conducted on these disease complexes over the past 40 years. The incorporation of DNA-based molecular techniques has made it possible to define and to better understand the differences between the Mycosphaerella and Teratosphaeria species occurring on Eucalyptus. These studies have also enabled refinement of anamorph and teleomorph generic concepts for the genera and thus facilitated the more accurate identification of species. They have also promoted a more lucid understanding of the biology, life cycles, population biology and epidemiology of the most important pathogens in the group.

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The global genetic structure of the wheat pathogen Mycosphaerella graminicola is characterized by high nuclear diversity, low mitochondrial diversity, regular recombination, and gene flow

Cited by 274 publications

References 47 publications

Population genetics of fungal diseases of plants

Population genetics of fungal diseases of plants

Evidence for intragenic recombination and selective sweep in an effector gene of Phytophthora infestans

Mycosphaerella and Teratosphaeria diseases of Eucalyptus; easily confused and with serious consequences

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