Robustness of plant quantitative disease resistance is provided by a decentralized immune network

Significance Molecular studies of plant immune responses have mainly focused on qualitative resistance, a form of immunity determined by a few large effect genes. In contrast, very limited information exists about quantitative disease resistance (QDR), although it is extensively observed in wild and crop species. We used systems biology approaches to describe this form of immunity in Arabidopsis thaliana . On the basis of gene regulation studies and search for protein–protein interactions, we report the reconstruction of a highly interconnected and distributed network, organized in five modules with differential robustness to genetic mutations. These studies revealed key functions of QDR, mainly distinct from those previously identified for plant immunity, and shed some light on the complexity of this plant immune response.