Reacción a "The Council of the EU will vote tomorrow on a proposed regulation governing the marketing of genetically modified microorganisms"

We have a better accounting of the stars in the universe than of the microbes beneath our feet. The past two decades have seen a revolution in our understanding of bacteria aided by new sequencing technologies, but this understanding is limited to detecting the presence of organisms or their genes in the environment, and their characterization is incomplete at best. The vast majority of these organisms have never been directly observed, and how their genes actually function in the environment remains largely a mystery. At the same time, it is increasingly clear that microbes exist in highly interconnected and interdependent communities, that cannot be easily taken apart in a laboratory. Consequently, most available techniques fail at predicting whether microbes will survive, establish, and interact in natural environments. Deregulating the release of GMMs and reducing monitoring against this background of unknowns is dangerous. 

The release of GMMs is an ecological issue. We still don’t understand how microbes disperse in the environment, and research continues to find the surprising mechanisms that microbes employ to move (e.g., bacteria attaching to fungal hyphae to spread). It is therefore not possible to predict how far GMMs will spread from their intended environment. All genetic modifications present risks, but the risks are not equal, and the current proposal overlooks this distinction. Modifications of mobile genetic elements (MGEs) have the potential to ‘jump’ to other microbes, but novel mechanisms for this exchange are continuously being discovered. Even if modifications are made in the microbial chromosomes, which evolve more slowly, microbial evolution can happen within days, drastically affecting the intended function of the genes. For example, ammonia oxidation (involved in nitrification, a target of current GMMs) and methane oxidation (used by methanotrophic bacteria to convert methane into carbon dioxide) share a common evolutionary origin. This means that at some point, randomly in the past, evolution drastically altered the function of these genes, with serious consequences for what those bacteria did in the environment: some fixed nitrogen, and others consumed methane. Given our current knowledge, it is not possible to guarantee that similar transitions won't happen with GMMs, especially as the genes they target have been known to evolve into other functions in the past. Considering these unknowns, the spatial and evolutionary spread of ‘intellectual property’ requires a detailed and empirically-backed regulatory framework that doesn’t yet exist.  

Soils are extremely diverse, and most of the desired genetic capacities are already present in most soils, albeit in low concentrations. This brings into question what the need for GMMs is in the first place. The deregulation of GMMs, especially for agricultural applications, overlooks existing research into microbial inoculants. (The functions of inoculated microbes rapidly plateau because the chemical reactions they are expected to carry out, such as nitrification, are energetically expensive; or because the microbes face competition and predation from local organisms.) From this perspective, the success of GMMs is unlikely. The lack of monitoring requirements in the current legislation may result in the development and sale of products whose efficiency is much lower than expected, reducing consumer protections. Alternatively, in the case that they do succeed, this would probably occur by the massive displacement of the native microbiota. The consequences of such biodiversity loss are hard to predict, especially as ecosystems face increasing compounded pressures from climate change, and here, the reduction of monitoring requirements may mask unintended environmental consequences.