loading page

Pattern and causes of the establishment of the invasive bacterial potato pathogen Dickeya solani and of the maintenance of the resident pathogen D. dianthicola
  • +12
  • Pauline Blin,
  • Kévin Robic,
  • Slimane Khayi,
  • Jérémy Cigna,
  • Euphrasie Munier,
  • Pauline Dewaegeneire,
  • Angélique Laurent,
  • Yan Jaszczyszyn,
  • Kar-Wai Hong,
  • Kok-Gan Chan,
  • Amélie Beury,
  • sylvie Reverchon-Pescheux,
  • Tatiana Giraud,
  • Valérie Hélias,
  • Denis Faure
Pauline Blin
CNRS
Author Profile
Kévin Robic
French Federation of Seed Potato Growers
Author Profile
Slimane Khayi
CNRS
Author Profile
Jérémy Cigna
French Federation of Seed Potato Growers
Author Profile
Euphrasie Munier
French Federation of Seed Potato Growers
Author Profile
Pauline Dewaegeneire
French Federation of Seed Potato Growers
Author Profile
Angélique Laurent
French Federation of Seed Potato Growers
Author Profile
Yan Jaszczyszyn
CNRS
Author Profile
Kar-Wai Hong
Jiangsu University
Author Profile
Kok-Gan Chan
Jiangsu University
Author Profile
Amélie Beury
French Federation of Seed Potato Growers
Author Profile
sylvie Reverchon-Pescheux
INSA Lyon
Author Profile
Tatiana Giraud
Université Paris-Sud
Author Profile
Valérie Hélias
French Federation of Seed Potato Growers
Author Profile
Denis Faure
CNRS
Author Profile

Peer review status:UNDER REVIEW

22 Jun 2020Submitted to Molecular Ecology
23 Jun 2020Assigned to Editor
23 Jun 2020Submission Checks Completed
08 Jul 2020Reviewer(s) Assigned

Abstract

Invasive pathogens can be a threat when they affect human health, food production or ecosystem services, by displacing resident species, and we need to understand the cause of their establishment. We studied the patterns and causes of the establishment of the pathogen Dickeya solani that recently invaded potato agrosystems in Europe by assessing its invasion dynamics and its competitive advantages or disadvantages against the closely-related resident D.dianthicola species. Epidemiological records over one decade in France revealed the establishment of D.solani and the maintenance of the resident D.dianthicola in potato fields exhibiting blackleg symptoms. Using experimentations, we showed that D.dianthicola was more aggressive than D.solani on aerial parts, while D.solani was more aggressive on tubers. In co-infection assays, D.dianthicola outcompeted D.solani in aerial parts, while D.solani and D.dianthicola co-existed in tubers. A comparison of 76 D.solani genomes (56 of which having been sequenced here) revealed balanced frequencies of two uncharacterized alleles, VfmBPro and VfmBSer, at the vfmB virulence gene. Experimental inoculations showed that the VfmBSer population was more aggressive on tubers, while VfmBPro and VfmBSer populations exhibited a similar aggressiveness on stems. In stem co-infections, the VfmBPro population outcompeted the VfmBSer population, while they co-existed in tubers. This study thus brings novel insights allowing a better understanding of the pattern and causes of the D.solani invasion into potato production agrosystems, and the reasons why D.dianthicola nevertheless persisted. More broadly, this study contributes to our understanding the ecological determinants of pathogen invasion and of the conditions for the maintenance of endemic competitors.