Traditional plant breeding has focused on the identification of genes of major effects that give a clear phenotype, such as race-specific disease resistances. For complex traits, such as resistance to combined abiotic stresses, that involve many genes with additive effects, classical breeding methods have shown their limitations. For such complex traits, meticulous phenotyping methods likely play a major role. One of the axes of research of EPITRANS is to develop biosensors as accurate predictors of the plant phenotype. Biosensors may involve placing a reporter gene, such as luciferase, downstream of a stress-responsive promoter. Scoring the reporter gene will permit to quantify the phenotype. We have established biosensors based phenotyping workflow, for instance to identify stress resilient mutants.