# The Marine Bacterial Genus _Euzebya_ Is Distributed Worldwide in Terrestrial Environments: A Review
## 3 _Euzebyales_ in Extreme Environments  
Saline and hypersaline terrestrial environments include salt mines, sediments of desiccated salt lakes, saline and alkaline soils, salt marshes, etc. These environments often have salt concentrations higher than that of seawater and support halophilic microorganisms that have adapted to deal with extreme environmental parameters (high salt concentrations, temperatures, and pH), although their community composition and structure vary depending on salinity fluctuations in the environment [39]. The occurrence of _Euzebya_ in these environments has been reported in numerous studies [40; 41; 42; 43; 44; 45; 46; 47; 48; 49; 50; 51; 52; 53; 54; 55], denoting the ability of the members of this genus to prosper in habitats with high salt concentrations (Table 2). Interestingly, the wide occurrence of _Euzebya_ and its haloulkaliphilic relatives has been registered in the drained sediments of former Mexican lakes (Texcoco and Rincon de Parangueo) [40; 45], and the Songnen Plain of Northeast China, one of the three regions with extensive saline-sodic soils in the world [50; 51; 52; 53]. The Texcoco Lake sediments are characterized by a very high pH (10) and an electric conductivity (EC) of up to 179.8 dS m\({}^{-1}\)[40; 42; 44]. There, _Euzebya_ was one of the dominant bacterial genera with relative abundances >10% [42]. It has been reported that organic carbon additions to the sediments increased _Euzebya_ abundance [42]. In the Songnen Plain of Northeast China, with very high pH (>10) and high EC, _Euzebya_ showed high relative abundance [50; 52], as well as a high sodicity/salinity niche preference, however, the genus was depleted or absent when sodicity/salinity decreased [51]. In other highly saline environments, such as salt marshes, mines, and lake soils, _Euzebya_ was detected in the rhizosphere of halophytic plants [41; 43; 47; 48; 49; 54]. [PERSON] et al. [56], using comparative genomics, investigated the salt adaptation mechanism of species within the class _Nitriliruttoria_, including _Euzebya tangerina_ and _E. rosea_. They showed that the _Nitriliruttoria_ species possess specific salt tolerance mechanisms. Deserts, covering around 33% of the planet's surface, have been explored in search of extremophilic and extremotolerant _Actinomycetota_ producing novel bioactive compounds [57; 58; 59; 60]. However, the use of molecular tools (next-generation sequencing) revealed dominant members of the extremophilic microbial communities that have not been yet isolated. They included _Euzebya_, both in cold environments (Antarctica) and hot deserts (Atacama, Sahara, Colorado Plateau, etc.) [61; 62; 63; 64; 65; 66; 67; 68; 69; 70; 71; 72] (Table 2). \begin{table}
\begin{tabular}{l l l l} \hline
**Location** & **Taxa** & **Type of Sample** & **References** \\ \hline \multicolumn{3}{l}{Saline and hypersaline environments} \\ \hline Texcoco, Mexico & _Euzebya_ & Soil & [40] \\ \hline Dafeng, Jiangsu, China & _Euzebya_ & Soil/Rhizosphere & [41] \\ \hline Texcoco, Mexico & _Euzebya_ & Soil & [42] \\ \hline Khewra salt mines, Pakistan & _Euzebya_ & Soil/Rhizosphere & [43] \\ \hline Texcoco, Mexico & _Euzebya_ & Soil & [44] \\ \hline \multicolumn{3}{l}{Rincon de Parangueo, Mexico} & _Euzebyales_ & Sediment & [45] \\ \hline \multicolumn{3}{l}{Rincon de Parangueo, Mexico} & _Euzebya_ & Sediment & [46] \\ \hline \multicolumn{3}{l}{Chaka Salt Lake, China} & _Euzebya_ & Rhizosphere & [47] \\ \hline \multicolumn{3}{l}{Jeddah, Saudi Arabia} & _Euzebya_ & Soil/Rhizosphere & [48] \\ \hline \multicolumn{3}{l}{Lebrija, Seville, Spain} & _Euzebya_ & Soil/Rhizosphere & [49] \\ \hline \multicolumn{3}{l}{Songnen Plain, Jilin, China} & _Euzebya_ & Soil & [50] \\ \hline \end{tabular}
\end{table} 
Table 2: Occurrence of _Euzebyales/Euzebyaceae/Euzebya_ in extreme environments. _Euzebya_ was one of the most frequently detected genera in Australian and Northern Antarctica soils. There, _Actinomycetota_ diversity increased with increasing pH and sodium concentration, and this applies particularly to _Euzebya_[65].