Evidence for homoploid speciation in Phytophthora alni supports taxonomic reclassification in this species complex - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Fungal Genetics and Biology Année : 2015

Evidence for homoploid speciation in Phytophthora alni supports taxonomic reclassification in this species complex

Claude Husson
  • Fonction : Auteur
  • PersonId : 951865
Jaime Aguayo
Cécile Revellin
Pascal Frey
Renaud Ioos
Benoit Marçais

Résumé

Alder decline has been a problem along European watercourses since the early 1990's. Hybridization was identified as the main cause of this emerging disease. Indeed, the causal agent, a soil-borne pathogen named [i]Phytophthora alni[/i] subsp. [i]alni[/i][i] (Paa)[/i] is the result of interspecific hybridization between two taxa, Phytophthora alni subsp. multiformis [i](Pam)[/i] and [i]Phytophthora alni[/i] subsp.[i] uniformis[/i] [i](Pau)[/i], initially identified as subspecies of[i] Paa[/i]. The aim of this work was to characterize the ploidy level within the [i]P. alni[/i] complex that is presently poorly understood. For that, we used two complementary approaches for a set of 31 isolates of [i]Paa, Pam[/i] and[i] Pau[/i]: i) quantification of allele copy number of three single-copy nuclear genes using allele-specific real-time PCR and ii) comparison of the genome size estimated by flow cytometry. Relative quantification of alleles of the three single-copy genes showed that the copy number of a given allele in [i]Paa[/i] was systematically half that of its parents [i]Pau[/i] or [i]Pam[/i]. Moreover, DNA content estimated by flow cytometry in [i]Paa[/i] was equal to half the sum of those in [i]Pam[/i] and [i]Pau[/i]. Our results therefore suggest that the hybrid [i]Paa[/i] is an allotriploid species, containing half of the genome of each of its parents [i]Pam[/i] and [i]Pau[/i], which in turn are considered to be allotetraploid and diploid, respectively. [i]Paa[/i] thus results from a homoploid speciation process. Based on published data and on results from this study, a new formal taxonomic name is proposed for the three taxa [i]Paa[/i], [i]Pam[/i] and [i]Pau[/i] which are raised to species status and renamed [i]P. ×alni, P. ×multiformis[/i] and[i] P. uniformis[/i], respectively.
Fichier principal
Vignette du fichier
2015-FGB-Husson&al.pdf (688.2 Ko) Télécharger le fichier
Origine : Fichiers produits par l'(les) auteur(s)
Loading...

Dates et versions

hal-01269090 , version 1 (05-04-2019)

Identifiants

Citer

Claude Husson, Jaime Aguayo, Cécile Revellin, Pascal Frey, Renaud Ioos, et al.. Evidence for homoploid speciation in Phytophthora alni supports taxonomic reclassification in this species complex. Fungal Genetics and Biology, 2015, 77, pp.12-21. ⟨10.1016/j.fgb.2015.02.013⟩. ⟨hal-01269090⟩
229 Consultations
210 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More