Genome Statistics

Scaffolds

3,569

Contigs >= 100bp

555,289

Contigs >= 500bp

103,796

Contigs N50

3,449

Annotated genes

49, 294

introduction

Erysiphe alphitoides (Griffon & Maubl.) U. Braun & S. Takam., one of the species responsible of the oak powdery mildew disease, infects the leaves of a large variety of oak species in Europe and Asia (Takamatsu 2007,2015). In Europe, it was at the origin of a major outbreak at the beginning of the 20th century, likely associated with an introduction from Asia, its putative native area (Desprez-Loustau et al. 2011, Takamatsu 2015). Oak mortality and very severe damage were reported in the first decades after the outbreak.

Today, the disease is widespread in Europe but its impact on European oak populations has strongly decreased, although it can still cause high mortalities on young seedlings in forests. Therefore, it may act as an important selective agent for oak populations at this early stage (Marcais and Desprez-Loustau 2014).

Beyond oak species, E. alphitoides also infects a large host range from different families (Fagaceae, Anacardiaceae, Paeoniaceae, Euphorbiaceae,...; Takamatsu 2007, 2015). This wide host range, quite unfrequent among all powdery mildew species, raises the question of which molecular mechanisms may allow by-passing of the defenses of these various host plants. A large diversity of fungal effectors, i.e. the small secreted proteins involved in the success of infection (Schulze-Lefert and Panstruga 2011, Spanu et al. 2012) could be a key factor to explain this large host range.


Very heavy powdery mildew infection on the second flush of young oak seedlings (mature and immature chasmothecia visible as black and orange dots, respectively - photo ML Desprez-Loustau - © INRAE)

  • Desprez-Loustau M-L, Feau N, Mougou-Hamdane A, Dutech C (2011) Interspecific and intraspecific diversity in oak powdery mildews in Europe: coevolution history and adaptation to their hosts. Mycoscience 52:165-173.
  • Marçais B & Desprez-Loustau M-L (2014). European oak powdery mildew: impact on trees, effects of environmental factors, and potential effects of climate change. Annals of Forest Science 71: 633-642.
  • Takamatsu S, Braun U, Limkaisang S, et al (2007) Phylogeny and taxonomy of the oak powdery mildew Erysiphe alphitoides sensu lato. Mycological research 111:809-826.
  • Takamatsu S, Ito H, Shiroya Y, Kiss L, & Heluta V. (2015). First comprehensive phylogenetic analysis of the genus Erysiphe (Erysiphales, Erysiphaceae) I. The Microsphaera lineage. Mycologia: 15-007.
  • Schulze-Lefert P & Panstruga R (2011). A molecular evolutionary concept connecting nonhost resistance, pathogen host range, and pathogen speciation. Trends in plant science, 16: 117-125.
  • Spanu PD, Abboyy JC, Amselem J et al. (2010) Genome expansion and gene loss in powdery mildew fungi reveal tradeoffs in extreme parasitisme. Science 330: 1543-1546

Data availability

Data resulting from this work has been deposited in Data INRAE portal, DOI : 10.15454/UGMTBK. Please see details in the DATA tab