Relatively simple eukaryotic model organisms such as the genetic model weed plant Arabidopsis thaliana possess an innate immune system that shares important similarities with its mammalian counterpart. In fact, some human pathogens infect Arabidopsis and cause overt disease with human symptomology. In such cases, decisive elements of the plant's immune system are likely to be targeted by the same microbial factors that are necessary for causing disease in humans. These similarities can be exploited to identify elementary microbial pathogenicity factors and their corresponding targets in a green host. This circumvents important cost aspects that often frustrate studies in humans or animal models and, in addition, results in facile ethical clearance.,
Drug Discovery Today
Erasmus MC: University Medical Center Rotterdam

van Baarlen, P., van Belkum, A., & Thomma, B. (2007). Disease induction by human microbial pathogens in plant-model systems: potential, problems and prospects. Drug Discovery Today (Vol. 12, pp. 167–173). doi:10.1016/j.drudis.2006.12.007