## 5 Discussion: Can Microl plastics and Microbioplastics Act as Vectors of Pathogens? After reviewing current literature, the main findings relevant to our topic can be summarized as follows:  
* Microplastics (MPs) in soil undergo complex transformation processes that enhance their interaction with soil constituents. Microbial bioplastics (MBPs) are particularly prone to these processes. * MPs can adsorb contaminants such as metal ions and organic pollutants from the soil, acting as vectors for these substances. MBPs are more effective at adsorbing polar compounds/particles, and aging increases this capability for both MPs and MBPs. * The mobility of MBPs within the soil matrix is higher than that of MPs, likely because MBPs are more polar and less likely to be trapped within the soil structure. * MPs create environments favorable for the growth of pathogenic bacteria and fungi. MBPs are especially susceptible to microbial biofilm formation over a shorter time-frame. Additionally, MPs negatively impact the soil microbiome by increasing the prevalence of antibiotic-resistant genes and virulence factors, with more pronounced effects observed in MBPs. * While not conclusively proven, current theories suggest that microplastic particles may serve as carriers of pathogenic microorganisms, with bioplastics potentially being more effective carriers when not inhibited by interactions with bulk soil. The introduction of biodegradable plastics as an alternative to conventional plastics aims to balance the benefits of plastic use, such as durability, flexibility, and cost-effectiveness, with the need to protect the environment and reduce the ecological footprint of human activities. However, this effort requires robust data support to prevent future problems. Currently, biodegradable plastics represent one potential solution to mitigate plastic pollution and the persistence of resistant plastics in environmental compartments. Yet, as this work shows, an increasing number of studies on the interactions between soil and other environmental compartments with bioplastics indicate emerging issues, such as nutrient imbalances [14], shifts in microbial communities [25], and a priming effect [15], which appear to intensify with the rate of bioplastics' biodegradation. This work aimed to draw public attention to other potential threats, such as the support and spread of pathogenic organisms within and beyond the soil matrix by MPs and MBPs. The increasing frequency and severity of pathogen-induced plant disease outbreaks pose substantial threats to primary productivity, global food security, and biodiversity. These outbreaks lead to significant crop yield losses, estimated to cost around 220 billion USD annually, impacting food security, regional economic stability, and related socio-economic factors [130]. In untouched soils, the spread of pathogenic microorganisms is facilitated by several factors and vectors, among the most important belong water, rainfall, and runoff that can mobilize pathogens, leaching them deeper into the soil and affecting groundwater quality or spreading them across landscapes, into surface water bodies [131]. The second factor is wind [130], which can carry soil particles along with attached microorganisms over various distances, depending on the wind speed and soil particle size. This is particularly significant in arid and semi-arid regions where wind erosion is prevalent. The third factor is animals, which can spread soil pathogens through their movement and excrete and during soil disturbance [132]. Earthworms, insects, birds, and mammals can transport pathogens on their bodies or internally and deposit them in new locations. Anthropogenic activities have increased the natural spread of pathogens. Agricultural practices, like irrigation, digging, the use of contaminated machinery, tools, and footwear, can mechanically spread pathogens from one field to another. Furthermore, the transportation and application of contaminated manure, compost, or soil amendments can introduce pathogens into the soil.