Bacteria are everywhere: they live in the soil, in the air, in water and colonise other organisms, for example, the roots of maize plants. Bacteria only produce nitrogen compounds to promote plant growth under certain conditions. (Top left) The soil bacteria in the example given above have been genetically engineered to continuously produce nitrogen compounds. (A) After being spread on the field, the genetically modified bacteria colonise the roots of maize plants and ideally stimulate root growth. The bacteria and their genetic material multiply en masse. (B) However, frequent cell divisions can change the genetic material and (C) the bacteria can exchange genes, thus possibly causing the genetic modification to become unstable; it may also be passed on to other bacterial species. (D) At present, it is unclear whether the genetically engineered bacteria can also spread beyond the fields. Their use has already been authorised in the USA, but it is not known whether environmental risks have been tested.
References and further reading:
Wen et al. 2021: https://pubs.acs.org/doi/10.1021/acssynbio.1c00049