P-030 - Does PTI Hinder Agroinfiltration-Mediated Transient Expression in Different Plant Species?

Agroinfiltration, a method for transient gene expression in plants, relies on Agrobacterium tumefaciens to deliver DNA into plant cells. It is widely used in plant sciences and has been adopted as a sustainable protein production platform by the Molecular Pharming industry. Despite producing valuable protein products, agroinfiltration faces regulatory and public acceptance challenges due to its reliance on Nicotiana benthamiana, a model plant closely related to smoking tobacco. To address this, we tested agroinfiltration in several non-model species. However, agroinfiltration of many alternative species resulted in no protein production. We hypothesized that low transient expression efficiency in non-model species can be attributed to pattern-triggered immunity (PTI) mediated restriction of A. tumefaciens. We investigated this by conducting a series of assays on 15 non-model plant species. To monitor PTI activation, we conducted reactive oxygen species (ROS) assays, using boiled A. tumefaciens as the elicitor. To assess A. tumefaciens’ response to the plant immune landscape, we tracked in-planta expression of virulence genes using an Agrobacterium strain carrying a luciferase reporter driven by the virB virulence operon promoter. To evaluate the impact of PTI on transient expression efficiency, we monitored transient GFP expression upon PTI induction with the elicitor peptide flg22. Remarkably, our findings suggest that PTI is not limiting transient expression efficiency.