RiZeSisT · Discovering susceptibility genes to Rhizoctonia solani in rice as breeding targets for sheath blight disease resistance

Discovering susceptibility genes to Rhizoctonia solani in rice as breeding targets for sheath blight disease resistance

Conclusion of the action: In “RiZeSisT” to breed for broad-spectrum resistance in rice to the sheath blight disease (ShBD), caused by the soil-borne fungus Rhizoctonia solani AG1-IA, we proposed to employ altered susceptibility genes (S genes). The molecular mechanisms underlying susceptibility to R. solani are largely unknown. Therefore, throughout this MSCA-IF, these mechanisms were dissected by using an -omics tool box. 21 candidate S genes were identified and the majority where functionally validated for their response to R. solani. The most promising genes may become the next targets to generate rice varieties with improved resistance to ShBD. Summary: Rice (Oryza sativa L.) is the second most grown cereal worldwide. However, its production is largely affected by the sheath blight disease (ShBD) caused by the soil-borne fungus Rhizoctonia solani Kühn, AG1-IA. To date, some level of partial resistance in rice has been identified, expressed by a number of QTLs, but germplasm with complete resistance is not available. This pathogen survives by forming sclerotia or dormant mycelia, infects rice during flooding and causes necrotic lesions on leaf sheaths and blades that lead to a strong yield reduction. Recently, the incidence and severity of ShBD in rice has increased due to the large-scale deployment of semi-dwarf varieties, high plant densities and the intensified application of nitrogen fertilizers. To date, control of ShBD is achieved by extensive use of fungicides. Therefore, it is essential to develop resistant varieties as an alternative to the use of chemical control. To breed for broad-spectrum resistance in rice we proposed to employ altered susceptibility genes (S genes). A S gene describes any plant gene that makes them vulnerable to infection by supporting a compatible interaction with the pathogen enabling it to grow and infect. The ultimate goal is to disable susceptibility gene function to limit the interaction with the attacker and disrupt the ability of the pathogen to induce disease. The molecular mechanisms underlying susceptibility to R. solani are largely unknown and therefore, “RiZeSisT” -Rice RhiZoctonia reSisTance-, aimed to identify essential rice candidate S genes required for R. solani infection (discovery) and to test whether mutations in these genes provide resistance to sheath blight disease (functional validation). The selected genes will become the next targets to generate rice varieties with improved resistance to ShBD.

Текст от CORDIS, на английски · Данни: CORDIS, © Европейски съюз