Analyse du transcriptome des interactions entre le blé et le champignon pathogène Septoria tritici (Mycosphaerella graminicola) – TWIST

Wheat is the most widely grown and consumed food crop in the world. It is the staple food of nearly 35% of the world population, and demand for wheat is expected to grow faster than for any other major crop. Fungal diseases are a major concern for wheat production. Among them, Septoria tritici (syn. Mycosphaerella graminicola) is responsible of one of the most important foliar diseases of wheat (blotch, STB). This disease has a significant incidence on wheat yield in Europe. Up to now, protection of wheat against STB has mainly relied on fungicide treatments. However, the chemical control of STB is not fully effective. Indeed, since 2003, this strategy has been undermined by the rapid emergence of STB isolates highly resistant to fungicides from the strobilurin family, and the decreased susceptibility of STB populations to triazoles, the remaining family of effective fungicides (Maufras et al., 2006). In light of the reduced efficiency of STB control by fungicides, there is a clear requirement for the development of alternative control strategies. Additionally, forthcoming European directives are planning to reduce the use of pesticides in agriculture (50% in 2012). These evolutions have increased the interest in growing wheat cultivars resistant to STB as a cost-effective method to control this disease. However, most actual wheat cultivars are susceptible or only moderately resistant to STB (Bernicot, 2006). In view of this particular situation, European wheat breeders consider STB as one of the major targets for disease resistance breeding. An important investment is therefore needed to better understand this disease (this project) and to develop methods for the evaluation of wheat resistance to STB (ex FSOV 2006 projects and FSOV 2008 proposed project). These initial studies are needed to support genetic studies aiming at identifying wheat genes/QTL controlling resistance to STB to be integrated in breeding programs.

The proposed project aims at increasing our basic knowledge of this plant fungal interaction using a large scale transcriptomic analysis of STB infected wheat tissues. This analysis will provide large datasets of wheat and fungal genes differentially expressed during resistant or susceptible interactions. The wheat genes will be integrated in networks of candidates genes likely involved in resistance or susceptibility to STB that will be used for further projects on the genetic of resistance to this disease (markers for evaluating resistance, candidate genes for transgenics, and linkage to resistance QTLs). The fungal genes will be integrated in networks of candidates genes either likely manipulating the host plants (effectors, susceptible interaction) or needed for the adaptation of the fungus to plant defences (resistant interaction) allowing the monitoring of host resistance through the fungal response.