## 3 Results
### Taxonomic Assignment Based on Gene Abundance  
As indicated earlier, gene prediction and mapping were carried for the assembled scaftigs (Table S3) and recovered ORFs (Table S4) that accommodate the QC criteria. Then, non-redundant genes were clustered, and catalogues of the initial non-redundant genes (e.g., nrGC) were constructed (Table S5). Gene abundances were then assigned to the four different taxonomic levels, e.g., domain, phylum, genus and species (Tables S6-S9). Then, we studied the relative microbial abundance of the six different metagenomes (Tables S10-S13), as well as of groups of watering time points, e.g., 0 (group A), 24 h (group B) and 48 h (group C) (Tables S14-S17) across type of soil (e.g., S and R) at different taxonomic levels. The data based on type of soil (e.g., groups S and R) and those based on watering time point (groups A, B and C) within each of the four domains are summarized in Tables S18-S21. The studied microbial non-redundant genes involved genomes of the following domains: Archaea, Bacteria, Eukaryota and Viruses (virome). As anticipated, the analysis indicated the very high abundance of bacterial genomes, and almost equally followed by Archaeal and Eukaryotic genomes, while abundance of viromes was extremely low (Figures 2 and S6). However, annotation indicated the lack of information for most taxa in the metagenomes, as gene abundance of unknown taxa was high (Figure 2). In addition, it is likely that most of the unknown genetic information reflects the high ration of low abundant unculturable microbes. At the three taxonomic levels, e.g., phylum, genus and species, we chose the top 10 most abundant taxa across soil type (e.g., S and R) and time after watering (e.g., 0, 24 and 48 h) for further analysis (Figures S4-S6 and Tables S7-S9, respectively). At the phylum level, the most abundant taxa assigned by non-redundant genes include Thaumarchaeota, Euryarchaeota and Crenarchaeota of the Archaea domain, Actinobacteria, Proteobacteria and Bacteroidetes of the Bacteria domain, and Ascomycota, Mucoromycota and Basidiomycota of the Eukaryota domain. The Viruses domain has no available classification at the phylum level (Figure S4). At genus level, the most abundant taxa assigned by non-redundant genes include Candidat  
Figure 2: Microbial abundance assigned taxonomically by non-redundant genes at domain level of metagenomes across soil type (e.g., rhizosphere and bulk) of _Dipterggium glaucum_ and time after watering (e.g., 0, 24 and 48 h). Methanosarcina of the Archaea domain, Blastococcus, Microviriga and Sphingomonas of the Bacteria domain, Rhizophagus, Sordaria and Macrophomina of the Eukaryota domain, and Phic31, Pepy6 and Badnavirus of the Viruses domain (Figure S5 and Table S8). At species level, the most abundant taxa assigned by non-redundant genes include Candidatus Nitrocosmicus oleophilus, Candidatus Nitroososphaera gargensis and marine thaumarchaeot KM3_70_D04 of the Archaea domain, Sphingomonas sp. URHD0057, Rubellmicrobium mesophilum and Blastococcus sp. DSM 46,786 of the Bacteria domain, Rhizophagus irregularities, Sordaria macrospora and Macrophomina phaseolina of the Eukaryota domain, and Ochrobactrum phage POA1180, Streptomyces phage Mildred21 and Streptomyces phage phiSAD1 of the Viruses domain (Figure S6 and Table S9). Then, we studied microbial abundance assigned taxonomically by non-redundant genes in metagenomes of the two soil types, e.g., rhizosphere (P1R1-P1R3) and bulk (P1S1-P1S3) across watering time points. This analysis was done among domains (Figure S7 and Table S10) and within the individual domains of Archaea (Figure S8 and Tables S11-S13), Bacteria (Figure S9 and Tables S11-S13), Eukaryota (Figure S10 and Tables S11-S13), and Viruses (Figure S11 and Tables S11-S13).