Evolutionary relationships among <i>Ascochyta</i> species infecting wild and cultivated hosts in the legume tribes Cicereae and Vicieae

Peever, Tobin L.; Barve, M.P.; Stone, Linda; Kaiser, W. J.

doi:10.1080/15572536.2007.11832601

Cited by 52 publications

(69 citation statements)

References 45 publications

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“…However, the pathogen was able to infect other leguminous and non-leguminous hosts, which may increase its potential for survival and spread. Hernandez-Bello et al (2006) and Peever et al (2007) also demonstrated that interspecific crosses between closely related, but host-specific Ascochyta spp. such as A. fabae and A. pisi, were fertile but most a Dried and sterilised stem and leaf pieces were inoculated with two sexually compatible isolates of Didymella rabiei and incubated in the dark at 8°C and alternating relative humidity for 8 weeks.…”

Section: Discussionmentioning

confidence: 90%

Alternative hosts and plant tissues for the survival, sporulation and spread of the Ascochyta blight pathogen of chickpea

Trapero

Kaiser²

2009

Eur J Plant Pathol

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Various crop and weed species were infected naturally by Didymella rabiei (anamorph: Ascochyta rabiei) in blight-affected chickpea fields in the Palouse region of eastern Washington and northern Idaho, USA. The fungus was isolated from asymptomatic plants of 16 species commonly found in commercial crops in this region. Isolates of the pathogen from crop and weed species were pathogenic to chickpea and indistinguishable in cultural and morphological characteristics from isolates of D. rabiei from chickpea. Both mating types of D. rabiei were isolated from eight naturally infected plant species. Chickpeas were infected by D. rabiei when plants emerged through infested debris of seven crop and weed species. The teleomorph developed on overwintered tissues of seven plant species infected naturally by D. rabiei in a blight screening nursery and on debris of wheat, white sweet clover and pea inoculated with ascospores of D. rabiei or conidia of two compatible isolates of the pathogen. Didymella rabiei naturally infected 31 accessions of 12Cicer spp. and the teleomorph developed on the overwintered debris of all accessions, including those of three highly resistant perennial species. The fungus developed on the stem and leaf pieces of ten plant species common to southern Spain inoculated with conidia of two compatible isolates of D. rabiei, and formed pseudothecia with asci and viable ascospores on six of ten species and pycnidia with conidia on all plant species.

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Section: Discussionmentioning

confidence: 90%

Alternative hosts and plant tissues for the survival, sporulation and spread of the Ascochyta blight pathogen of chickpea

Trapero

Kaiser²

2009

Eur J Plant Pathol

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“…Steele and Wojciechowski (2003) identified two subclades within the Vicieae including Clade 1 which contained P. sativum and Clade 2 which contained L. culinaris and V. grandiflora. Although there was not complete overlap in the hosts sampled for the Steele and Wojciechowski (2003) study and our study (Peever et al 2007), there appears to be broad congruence between pathogen and host phylogenies with the Steele and Wojciechowski (2003) Clade 1 corresponding to the A. pisi/A. fabae clade in the combined analysis reported here and the Steele and Wojciechowski (2003) Clade 2 corresponding to the A. lentis clade reported here (Fig.…”

Section: Species Of Ascochytamentioning

confidence: 50%

“…Phylogenetic analyses of the combined G3PD, CHS and EF datasets using maximum likelihood methods revealed that A. rabiei, the pathogen of chickpea (C. arietinum), was distinct from the Ascochyta pathogens of pea, faba bean, wild vetches and lentil which were found in two differentiable but closely related clades ( Fig. 1, Peever et al 2007). The differentiation observed between A. rabiei and A. lentis/A.…”

Section: Species Of Ascochytamentioning

confidence: 98%

“…that cause devastating losses of these plants, little is known about the evolutionary history of either the hosts or the pathogens. Peever et al (2007) recently estimated phylogenies among the Ascochyta spp. pathogens of the cool season legumes using DNA sequence data from several regions of the genome including a glyceraldehyde-3-phosphate dehydrogenase gene (G3PD), a chitin synthase 1 gene (CHS) and translation elongation factor 1 alpha gene (EF).…”

Section: Species Of Ascochytamentioning

confidence: 99%

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Role of host specificity in the speciation of Ascochyta pathogens of cool season food legumes

Peever

2007

Eur J Plant Pathol

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Ascochyta/legume interactions are attractive systems for addressing evolutionary questions about the role of host specificity in fungal speciation because many wild and cultivated cool season food legumes are infected by Ascochyta spp. and most of these fungi have described teleomorphs (Didymella spp.) that can be induced in the laboratory. Recent multilocus phylogenetic analyses of a worldwide sample of Ascochyta fungi causing ascochyta blights of chickpea (Cicer arietinum), faba bean (Vicia faba), lentil (Lens culinaris), and pea (Pisum sativum) have revealed that fungi causing disease on each host formed a monophyletic group. Host inoculations of these fungi demonstrated that they were host-specific, causing disease only on the host species from which they were isolated. In contrast to the strict association between monophyletic group and host observed for pathogens of cultivated legumes, Ascochyta fungi causing disease on wild bigflower vetch (Vicia grandiflora) were polyphyletic. Genetic crosses between several pairs of closely related, host-specific, and phylogenetically distinct Ascochyta fungi were fully sexually compatible. Progeny from these crosses had normal cultural morphology and segregation of molecular markers indicating a lack of intrinsic, post-zygotic mating barriers between the parental taxa. However, when progeny from a cross between a faba bean-adapted isolate (A. fabae) and a pea-adapted isolate (A. pisi) were assessed for their pathogenicity to the parental hosts, almost all progeny were non-pathogenic to either faba bean or pea. These results suggest that although these fungi have retained the ability to mate and produce progeny with normal saprophytic fitness, progeny are severely compromised in parasitic fitness. The host specificity of these fungi, coupled with the inability of hybrid progeny to colonize and reproduce on a host, may constitute strong extrinsic, pre-zygotic and postzygotic mating barriers in these fungi and promote the genetic isolation and speciation of host-specific taxa. A phylogeny of the host plants is also being developed, and with more extensive sampling of pathogens and hosts from sympatric populations in the centre of origin, the hypothesis of cospeciation of pathogens and hosts will be tested. The objectives of this review are: (1) to summarize recent phylogenetic, host specificity and speciation studies of Ascochyta fungi, and (2) to suggest how current and future research using these pathosystems may lead to a better understanding of the role of host specificity in the speciation of plant-pathogenic fungi and the cospeciation of pathogens and their hosts.

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“…Molecular study of Ascochyta pathogens isolated from a number of legume species (wild and domesticated) enabled the assessment of the phylogenetic relationships among the sampled group (Barve et al 2003;Peever et al 2006). Like the host plants that undergo speciation processes on an evolutionary time scale, the pathogens are adjusting themselves to the evolutionary trends of their hosts as expected from the intimate interactions that occur through most of the life cycle of the pathogen.…”

Section: Host-pathogen Coevolutionmentioning

confidence: 99%

The sympatric Ascochyta pathosystems of Near Eastern legumes, a key for better understanding of pathogen biology

et al. 2007

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The primary and secondary centres of origin of domesticated plants are often also the places of origin of their pathogens. Therefore, the Near Eastern cradle of agriculture, where crop plants, their wild progenitors, and other congeneric taxa grow sympatrically, may hold some clues on the biology of the pathogens of the respective crops. Unlike the situation in the wellstudied Near Eastern cereals and their important diseases, hardly any data are available on basic questions regarding grain legumes. What is the role of genetic diversity at resistance loci of the wild hosts and is it greater compared with the cultigens? Are populations of Ascochyta pathogens infecting wild legumes genetically distinct from populations infecting their domesticated counterparts, and if so, is this differentiation related to differences in host specialization or to adaptation to different ecological conditions? Do isolates originating from wild taxa exhibit a similar level of aggressiveness and have different aggressiveness alleles compared with those originating from domesticated grain legumes? In this review we propose an experimental framework aimed at gaining answers to some of the above questions. The proposed approach includes comparative epidemiology of wild vs. domesticated plant communities, co-evolutionary study of pathogens and their hosts, phenotypic and genetic characterization of fungal isolates from wild and domesticated origins, and genetic analyses of pathogenicity and parasitic fitness among progeny derived from crosses between isolates from wild and domesticated hosts.

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Evolutionary relationships among Ascochyta species infecting wild and cultivated hosts in the legume tribes Cicereae and Vicieae

Cited by 52 publications

References 45 publications

Alternative hosts and plant tissues for the survival, sporulation and spread of the Ascochyta blight pathogen of chickpea

Alternative hosts and plant tissues for the survival, sporulation and spread of the Ascochyta blight pathogen of chickpea

Role of host specificity in the speciation of Ascochyta pathogens of cool season food legumes

The sympatric Ascochyta pathosystems of Near Eastern legumes, a key for better understanding of pathogen biology

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