Evidence for high degrees of specialisation, evolutionary diversity, and morphological distinctiveness in the genus Bremia

Young Joon Choi, Marco Thines, Fabian Runge, Seung Beom Hong, Sabine Telle, Hyeon-Dong Shin

Research output: Contribution to journalArticle

26 Citations (Scopus)

Abstract

Bremia lactucae is one of the most important pathogens in lettuce production. Recent molecular studies revealed considerable genetic variation in this species complex. However, only few accessions from the same host have been examined for most species and no study investigating the morphological distinctiveness of phylogenetic lineages of Bremia has so far been reported. Thus it is believed that morphological species delimitation in Bremia is not feasible. In the present study, multiple accessions of neglected species, which had been described decades ago, but have not been widely accepted, were investigated, considering both multi-gene phylogenies and morphological characters. All previously described species from host genera other than Lactuca investigated, Bremia microspora, Bremia ovata, Bremia saussureae, and Bremia sonchicola, could be confirmed as distinct, host-specific entities. Also, morphological characteristics of their conidiophores and conidia allowed delimitation of these species. Therefore, not only the wide species concept to merge all Bremia species on the Asteraceae under B. lactucae is inappropriate but also their delimitation on the basis of morphological characters seems feasible. In addition, it has been shown that Bremia elliptica is phylogenetically distinct from the other species infecting the genus Lactuca, B. lactucae. It is therefore concluded that B. lactucae is most likely limited to Lactuca sativa and closely-related species, and that most species of Bremia are highly host specific. This finding might stimulate the search for durable resistance genes in genera closely related to the genus Lactuca and in divergent species of the genus itself.

Original languageEnglish
Pages (from-to)102-111
Number of pages10
JournalFungal Biology
Volume115
Issue number2
DOIs
Publication statusPublished - 2011 Feb 1

Fingerprint

Bremia
Lettuce
Microsporidia
Bremia lactucae
Asteraceae
Fungal Spores
Phylogeny
Genes
Lactuca
Microsporum
conidiophores
species concept
phylogeny
Lactuca sativa
gene
species complex
lettuce
conidia
genes
genetic variation

Keywords

  • Conidial morphology
  • Host specificity
  • Multi-gene genealogy
  • Peronosporaceae
  • Species delimitation

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Plant Science
  • Genetics
  • Infectious Diseases

Cite this

Evidence for high degrees of specialisation, evolutionary diversity, and morphological distinctiveness in the genus Bremia. / Choi, Young Joon; Thines, Marco; Runge, Fabian; Hong, Seung Beom; Telle, Sabine; Shin, Hyeon-Dong.

In: Fungal Biology, Vol. 115, No. 2, 01.02.2011, p. 102-111.

Research output: Contribution to journalArticle

Choi, Young Joon ; Thines, Marco ; Runge, Fabian ; Hong, Seung Beom ; Telle, Sabine ; Shin, Hyeon-Dong. / Evidence for high degrees of specialisation, evolutionary diversity, and morphological distinctiveness in the genus Bremia. In: Fungal Biology. 2011 ; Vol. 115, No. 2. pp. 102-111.
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