Caractérisation génétique de Phytophthora alni Brasier & S.A. Kirk, hybride interspécifique agent du dépérissement de l'aulne en Europe

Abstract : An emergent disease of alder is caused by a complex of three taxa belonging to the genus Phytophthora (Oomycetes): P. alni subsp. alni (Paa), P. alni subsp. multiformis (Pam) and P. alni subsp. uniformis (Pau). The first part of this study focused on the development of specific detection tools for these three taxa. Based on SCARs generated with RAPD, we designed three PCR primer pairs which can be combined to specifically detect and identify Paa, Pam and Pau in different substrates (plant tissue, water, soil). Second, we studied the occurrence and the allelic distribution for several nuclear single-copy genes containing introns on a wide collection of P. alni and close species. Mitochondrial DNA was also studied through RFLP and gene sequencing. We demonstrated that i) Pau may not result from a hybridization event, ii) two divergent alleles for each of the nuclear genes are observed in Pam, which suggests this taxon may have been generated by a reticulation or by autopolyploidisation, iii) Paa combines the alleles observed in Pam and Pau and was probably generated by hybridization between Pam and Pau or Pam- and Pau-like taxa. In addition, we studied the expression of elicitin genes, a multigenic family specific to the genus Phytophthora. The cumulative patterns of Pau and Pam in regard with Paa confirmed our first results. Last, in order to study the genetic variability of the different taxa, microsatellite markers were isolated in Paa and characterized. The genotypes we resolved demonstrate a low level of variability for the three taxa. They confirm our hypotheses in regard with Paa origin and suggest that Pam is also an allopolyploid taxon.
Document type :
Theses
Complete list of metadatas

https://hal.univ-lorraine.fr/tel-01754315
Contributor : Thèses Ul <>
Submitted on : Friday, March 30, 2018 - 9:44:39 AM
Last modification on : Tuesday, April 10, 2018 - 1:31:25 AM

File

SCD_T_2006_0105_IOOS.pdf
Files produced by the author(s)

Identifiers

  • HAL Id : tel-01754315, version 1

Collections

Citation

Renaud Ioos. Caractérisation génétique de Phytophthora alni Brasier & S.A. Kirk, hybride interspécifique agent du dépérissement de l'aulne en Europe. Sciences de la Terre. Université Henri Poincaré - Nancy 1, 2006. Français. ⟨NNT : 2006NAN10105⟩. ⟨tel-01754315⟩

Share

Metrics

Record views

31

Files downloads

59