# Potential of Halophytes-Associated Microbes for the Phytoremediation of Metal-Polluted Saline Soils
## 7 Perspectives and Conclusions  
The selection of microbial candidates based on their production of phytohormones, antioxidant enzymes, siderophores, or exopolysaccharide depends on the chosen phytoremediation strategy. Screening PGP microbes in in vitro conditions is the main method used to select relevant candidates but does not guarantee the proper establishment and persistence of inoculants in the field. Greenhouse and field trials highlighted the downsides of such approaches because indigenous microbial communities and fluctuant edaphic and environmental conditions interfere with root colonization of microbial inoculants and their efficiency [163]. As underlined by [PERSON] et al. [188], these techniques can increase the complexity of the phytoremediation with many unpredictable effects and thus require multiple studies to prevent any long-term adverse effects in an ecosystem that is already weakened by metal contaminations. Moreover, phytoremediation, even in combination with microbes, is a slow process that is not adequate for urgent and rapid decontamination [24]. The complexity of interactions between microbes-plant-soil and metals and the prior studies that must be achieved before a concrete application daunt remediation workers, as the process is often considered to be a series of time-consuming tasks with no guarantee of success [21]. Moreover, phytoremediation can sometimes be unsuitable when the contaminants are at a depth that the plant roots cannot reach, or when the pollution needs to be immediately remediated, as this technique requires repeated plantations [23; 189]. However, in a lot of cases, microbes-assisted phytoremediation could be relevant, all the more so because most of the studies presented here have shown encouraging results, which should lead to an increase of the number of field studies in the near future and thus an improvement of the efficiency of biological techniques. The combination of several microbes has also been tested and could, in some cases, improve the application of these techniques. Moreover, bacteria and fungi can have synergic effects that can facilitate the establishment of each other while helping plants to stabilize or extract metals. Hence, field experiments with halophytes associated with microbes for the metal phytoremediation of saline soils should now increase to assess the applicability of large-scale projects. The reason why such techniques take time to emerge could be related to the duration of field studies to assess their applicability and efficiency at the large scale of the inoculants, considering particularly the diversity of the environments and the stressful conditions. Moreover, even if the applicability is assessed, these biological solutions are still new and can also arouse suspicion for people according to the employed technique (metals stabilization that leaves contaminants in situ, suspicion of use of genetically modified microbes or plants, etc.) [190]. According to [PERSON] and [PERSON] [190], \"remediation decision making is a social process informed by scientific and technical information, rather than a science- or technology-driven process\". The implementation of such a project requires population acceptance, which varies among cultures and individuals and depends on the perception of risks and values of the techniques [191]. [PERSON] and [PERSON] [191] measured the acceptability of people regarding phytoremediation of polycyclic aromatic hydrocarbons on 114 visitors of a park from a metropolitan area in the Pacific Northwest and found a high level of social acceptability of phytoremediation. Moreover, there is a lack of transfer of information and education to decontamination workers between the scientific and professional fields. A survey of [PERSON] and [PERSON] [192; 193] was conducted on 100 decontamination experts in Quebec, Canada, to evaluate the level of knowledge on biological decontamination technologies.