Jasmonic acid and salicylic acid transcriptionally regulate in cultivated tomato to activate resistance to parasitization by dodder .

The parasitic dodder (, Convolvulaceae) species have wide ranges of hosts. However, some plants, including the cultivated tomato (), have different degrees of resistance to . The cultivated tomato plants activate a strong hypersensitive response (HR) where haustoria penetrate stems of cultivated tomato, but the underlying mechanisms by which the cultivated tomato perceives and activates resistance remain unclear. In this study, we show that the phytohormones jasmonic acid (JA) and salicylic acid (SA) in cultivated tomato stems were highly induced by parasitization. Genetic analyses and experiments of supplementation of JA or SA indicated that the JA and SA pathway not only are both required for activation of HR against parasitization but also function in non-HR-based resistance. The Cuscuta Receptor 1 (CuRe1), which is a leucine-rich repeat receptor-like protein, and suppressor of BAK1-interacting receptor kinase (SOBIR1) and SOBIR1-like, two adaptor kinases, are also important for HR-based and non-HR-based resistance. Importantly, we found that the JA and SA pathway both transcriptionally regulate . However, in the mutants, JA and SA levels were still normally induced by parasitization. We propose a linear model that an unknown receptor perceives parasitization and thus triggers accumulation of JA and SA, which in turn induce the transcription of , and CuRe1 and SOBIR1/SOBIR1-like thereby activate HR-based and non-HR-based resistance to . This study underscores the important roles of hormone signaling and () genes in host plant-parasitic plant interactions.