## 3 Results
### Rhizosphere and Endosphere Bacterial Isolates
Figure 1: Distribution by genera of the 120 bacterial isolates retrieved from the rhizosphere and root endosphere of _Salicornia nanosissima_, in the subsets corresponding to 5 sampling sites: Av1, Av2, Av3—Ria de Aveiro; Tg—Tagus estuary; Al—Almargem (Algarve). Cluster analysis based on a heatmap of OTU abundances (Figure 2) indicated a closer clustering of Av1, Al and Tg subsets. Although one OTU (OTU 8), identified as _Bacillus australimaris_, was found in all sampling sites, most of the OTUs were unevenly represented in the different sampling sites, and most of them were restricted to one particular sampling site (Figure 2; Appendix A, Figure A4). _Kocuria_ sp. (OTU 12), _Virgibacillus dokonensis_ (OTU 22), _V. halodenitrificans_ (OTU 40) and _Pseudomonas juntedi_ (OTU 17) were represented only in the Av1 subset. Genera _Exiguobacterium_ (_E. mexicanum_; OTU 25), _Kushneria_ (_K. phylosphapareae_; OTU 26), _Idionarina_ (_I. loiliensis_; OTU 28) _Gracibacillus_ (_G. massiliensis_; OTU 29), _Halomonas titanicae_ (OTU 27) and _B. licheniformis_ (OTU 36) were represented only in the Av2 subset. Isolates identified as _Thalassospira lohafexi_ (OTU 4), _Brevibacterium casei_ (OTU 6), _Providencia rettgeri_ (OTU 7), _Sporosarcina luteola_ (OTU 11), _Bacillus intantis_ (OTU 41), _Bacillus simplex_ (OTU 37), _Halomonas taenensis_ (OTU 5) and _Staphylococcus xylosus_ (OTU 9) were found only in the Av3 subset. The species _Altererytrhobacter indicus_ (OTU 24) and _Blargavaea ginseng_ (OTU 34) were found exclusively in site Tg, and OTU 33, identified as _Lysinobacillus variants_, was exclusive to Al. \begin{table}
\begin{tabular}{l c c c c c} \hline \hline \multirow{2}{*}{**Sites**} & **Number of** & **Average 16 SrRNA** & **Number** & **Average** & **Average Pielou’s** \\  & **Isolates** & **Sequence Length (bp)** & **of OTUs a** & **Shannon’s H’** & **Evenness** \\ \hline Av1 & 21 & 889 & 17 & 2.71 & 0.95 \\ Av2 & 26 & 884 & 15 & 2.55 & 0.94 \\ Av3 & 25 & 905 & 13 & 2.34 & 0.91 \\ Tg & 28 & 929 & 13 & 2.31 & 0.90 \\ Al & 20 & 940 & 9 & 1.98 & 0.90 \\ \hline \hline \end{tabular}  
* OTU Operational Taxonomic Unit.  
\end{table} 
Table 2: Diversity of the subsets of isolates, based on the analysis of 16S rRNA gene partial sequences. Figure 2: Heatmap showing relative abundance of OTUs in the subsets corresponding to each sampling. Dendrograms show hierarchical clustering between OTUs and sampling sites. The ordination analysis relating the composition of the subsets of isolates with the physico-chemical descriptors of sediment and pore water properties in each site is represented in Figure 3. Sediment pH is related more with the composition of the Av1 and Tg subsets. The pH of pore water and the concentration of Ca\({}^{2+}\) are related with the Al subset, and SOM is related more with Av3. Descriptors of sediment and pore water salinity (SAR, ESP) and concentration of the cations (Mg\({}^{2+}\), K\({}^{+}\) and Na\({}^{+}\)) are the parameters most related with the composition of the subset of isolates from site Av2. Salinity Tolerance, Extracellular Enzymatic Activity and Plant-Growth Promoting Traits of Bacterial Isolates  
Most of the isolates (69%) were able to grow at the highest tested salinity (100 g L\({}^{-1}\)), 28% tolerated up to 50 g L\({}^{-1}\) and only 3% were unable to grow with salinity >25 g L\({}^{-1}\) (Figure 4). Isolates growing at the highest salinity were recovered from all the sampling sites; however, the less salt-tolerant isolates (RA2, EA4A, SB78) were found in the lesser saline places (Av3 and Al), except for one isolate (SF91), which was cultivated from the rhizosphere of the saltier local, Av2 (Appendix A, Table A1). Maximum tolerance (growth at 100 g L\({}^{-1}\) NaCl) was found for rhizosphere and endophytic isolates in similar proportion: 46% and 54%, respectively.