Transposable Element-assisted evolution and adaptation to host plant within the Leptosphaeria maculans-Leptosphaeria biglobosa species complex of fungal pathogens Academic Article uri icon

abstract

  • Background: Many plant-pathogenic fungi have a tendency towards genome size expansion, 51 mostly driven by increasing content of transposable elements (TEs). Through comparative and 52 evolutionary genomics, five members of the Leptosphaeria maculans-Leptosphaeria biglobosa 53 species complex (class Dothideomycetes, order Pleosporales), having different host ranges and 54 pathogenic abilities towards cruciferous plants, were studied to infer the role of TEs on genome 55 shaping, speciation, and on the rise of better adapted pathogens. 56 Results: L. maculans ‘brassicae’, the most damaging species on oilseed rape, is the only member of 57 the species complex to have a TE-invaded genome (32.5%) compared to the other members 58 genomes (<4%). These TEs had an impact at the structural level by creating large TE-rich regions 59 and also through chromosomal rearrangements possibly leading to speciation. TEs, associated with 60 species-specific genes involved in disease process, also had an incidence on evolution of 61 pathogenicity by being responsible of translocations of effector genes to highly dynamic regions 62 and thus tuning the regulation of effector gene expression in planta. 63 Conclusions: Invasion of L. maculans ’brassicae’ genome by TEs followed by bursts of TE activity 64 allowed this species to evolve and to better adapt to its host, making this genome species a 65 peculiarity within its own species complex as well as in the Pleosporales lineage. 66 67

authors

  • Grandaubert, J
  • Lowe, RGT
  • Soyer, JL
  • Schoch, CL
  • Fudal, I
  • Robbertse, B
  • Lapalu, N
  • Links, MG
  • Linglin, J

publication date

  • 2014