Agrobacteria - stowaways in transgenic plants?

Agrobacteria are a genus of Gram-negative, sporeless, aerobic, and motile rods within the family Rhizobiaceae , which are found worldwide, primarily in the rhizosphere of plants. After infecting a plant, Agrobacteria transfer tumor-inducing genes into the plant genome and trigger the formation of tumors. In green biotechnology, Agrobacteria that no longer possess tumor-inducing properties are routinely used to transform crops in order to transfer a transgene into the plant genome. It is often mistakenly assumed that the endobiotic relationship between Agrobacteria and the host plant is transient and short-lived, and that after the initial selection steps, no Agrobacteria are present. However, it has been known for many years that Agrobacteria can be isolated from transformed plants months after infection. Various studies with different plant species have demonstrated that Agrobacteria can survive under different environmental conditions in various plant organs and are thus persistent. Furthermore, they possess the ability to move within the plant in the intercellular space or in the conducting tissues, such as the phloem. The successful detection of Agrobacteria in the seeds of transgenic plants is of particular importance. Contrary to previous assumptions, it is now known that Agrobacteria can also be passed on intergenerationally via the seeds to plant offspring. Despite the incomplete data, it is currently assumed that up to three generations of transgenic plants could be affected after transformation. Consequently, the persistence of Agrobacteria plays an important role in the identity and purity of the transgenic plants and thus in the reliability of research results. But does it also have implications for organizational and personal protective measures ? Adapting personal protective equipment (PPE) along with additional hygiene and disinfection measures within the STOP principle (see AGCT-Gentechnik. report) PPE is always removed (from January 2022 and June 2024 ) when the risk assessment warrants it. PPE is considered appropriate if it is capable of reducing the risk to the user to an acceptable level. We will address the question of how Agrobacteria should be classified and which criteria should generally be applied for classifying plant pathogens as donor and recipient organisms for genetic engineering work in the coming issues of the AGCT- Gentechnik.reports .