## 3 Results
### Microbial Community Structure Analysis
#### 3.2.2 Relative Abundance
\begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Taxon**} & \multicolumn{2}{c}{**Burgos**} & \multicolumn{2}{c}{**Tabasco**} \\ \cline{2-5}  & **SB.R1 (\%)** & **SB.R2 (\%)** & **ST.R1 (\%)** & **ST.R2 (\%)** \\ \hline Phyla & & & & \\ Proteobacteria & 93 & 85.3 & 93.9 & 89.5 \\ Actinobacteria & 3.2 & 5.8 & 3.5 & 2.0 \\ Firmicutes & 0.8 & 2.7 & 1.6 & 3.6 \\ Cyanobacteria & 1.9 & 3.0 & 0.5 & 0.6 \\ Families & & & & \\ Rhodospirillaceae & 64.2 & 43.8 & 5.3 & 6.6 \\ Sphingomonadaceae & 6.0 & 6.8 & 32.3 & 24.3 \\ Kilonielaceae & 0.015 & 0.03 & 28.3 & 22.3 \\ Unclassified member of the Alphaproteobacteria & 0.5 & 0.7 & 9.6 & 11.0 \\ Families with abundances between 2 and 7\% & & & & \\ Acetobacteraceae & 5.9 & 7.0 & 0.1 & 0.4 \\ Rhodobacteraceae & 5.3 & 5.8 & 3.3 & 4.6 \\ Bradyrhizobiaceae & 5.2 & 6.5 & 0.1 & 0.04 \\ Unclassified derived from Sphingomonadales order & 0.04 & 0.1 & 5.2 & 3.9 \\ Unclassified derived from the order Rhizobiales & 2.5 & 3.1 & 2.8 & 4.7 \\ Microbacteriaceae & 0.1 & 0.2 & 0 & 1.6 \\ Phylobacteriaceae & 0.1 & 0.1 & 1.8 & 2.6 \\ Oxalobacteraceae & 0.4 & 3.6 & 0 & 0.004 \\ Genera & & & & \\ _Skermmella_ & 35 & 22.8 & 0.3 & 0.5 \\ _Azospirillum_ & 15.9 & 10.4 & 0.3 & 0.3 \\ Unclassified genus derived from Rhodospirillaceae & 10.8 & 9.2 & 3.9 & 4.6 \\ _Thalassospira_ & 0.02 & 0.04 & 28.3 & 22.3 \\ Unclassified genus derived from Sphingomonadaceae family & 5.1 & 5.8 & 19.7 & 14.6 \\ Unclassified genus derived from Alphaproteobacteria & 0.5 & 0.7 & 9.6 & 11 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Relative abundance. The plotted heatmap represents the relative percentage of each bacterial genera within each sample as clustered in four samples to form two main clades or groups (Figure 5). We used the plotted heatmap to compare the similarity patterns between the samples for each region. Therefore, the heatmap shows the highest degree of similarity among samples of the same region. The bioinformatics analysis at the genus level showed that the sequencing reads could be assigned to 408 taxons, of which 20 were common in both soil samples. In Figure 5, the red color scale indicates a major percentage (highest abundance) and yellow a minor percentage (lowest abundance) of the identified phyla. Some genera in the Tabasco soils clearly differed from those in the Burgos region; for example, the color of _Azospirillum_ was red in Burgos samples in comparison with yellow in Tabasco samples. In soil samples from Burgos (Tamaulipas) _Skermanella_ (SB.R1 = 35.0%, SB.R2 = 22.8%, ST.R1 = 0.3%, ST.R2 = 0.5%), _Azospirillum_ (SB.R1 = 15.9%, SB.R2 = 10.4%, ST.R1 = 0.3%, ST.R2 = 0.3%) and Unclassified genus derived from Rhodospirillaceae(SB.R1 = 10.8%, SB.R2 = 9.2%, ST.R1 = 3.9%, ST.R2 = 4.6%), were the main genera. On the other hand, in soil samples from Tabasco, the predominant genera were _Thalassospira_ (SB.R1 = 0.02%, SB.R2 = 0.04%, ST.R1 = 28.3%, ST.R2 = 22.3%), unclassified genus derived from Sphingomonadaceae family (SB.R1 = 5.1%, SB.R2 = 5.8%, ST.R1 = 19.7%, ST.R2 = 14.6%) and Unclassified genus derived from Alphaproteobacteria(SB.R1 = 0.5%, SB.R2 = 0.7%, ST.R1 = 9.6%, ST.R2 = 11%).