# Genome-Wide Analysis Reveals the Secondary Metabolome in _Streptomyces kanasensis_ ZX01
## 3 Results and Discussion
### Gene Clusters for Secondary Metabolites  
The genome of _S. kanasensis_ ZX01 was mined using bioinformatics tools, namely antiSMASH 4.0, for identifying the gene clusters that are involved in secondary metabolism. Twenty-one biosynthetic gene clusters for secondary metabolic (siderophores, terpen, phenazine, phosphonate, bacteriocin, ectoine, lassopeptide, thiopeptide, polykiteide, nonribosomal peptide, and so on.) were identified by antiSMASH (Table 1). The total length of these gene clusters was almost 535 kb. This analysis told us that 7.61% of the _S. kanasensis_ ZX01 genome is occupied by genes related to the biosynthesis of secondary metabolites. Some clusters for the metabolite biosynthesis are conserved in most _Streptomyces_ species (e.g., desferrioxamines, isorenieratene, ectoine gene clusters). In these cases, the percent of this genes conserved when compared with known clusters is close to 100%. However, some other gene clusters showed a low conservation (e.g., cluster 11, 12, 14, 15, 16 and 19). Moreover, 40 unclassified putative clusters were identified by antiSMASH (Data not shown). Therefore, the secondary metabolic capability of _S. kanasensis_ ZX01 is powerful. Further works would be focused on the function and products of these gene clusters. \begin{table}
\begin{tabular}{c c c c c c c} \hline \multirow{2}{*}{**Cluster**} & \multirow{2}{*}{**Type**} & \multirow{2}{*}{**GenBank ID**} & \multicolumn{2}{c}{**Location**} & \multicolumn{2}{c}{**Most Similar Known**} & \multirow{2}{*}{**Similarity (\%) \(\ast\)**} \\ \cline{3-4}  & & & **From** & & & **To** & & **Biosynthetic Gene Cluster** \\ \hline
1 & Siderophore & LNSV01000002 & 180883 & 189602 & Macroletrolide & 33 \\
2 & Siderophore & LNSV01000023 & 1 & 11484 & Desferrioxamine B & 100 \\
3 & Siderophore & LNSV01000114 & 10308 & 18860 & - & - \\
4 & Tepene & LNSV0100004 & 55721 & 76761 & - & - \\
5 & Tepene & LNSV01000004 & 119146 & 140210 & - & - \\
6 & Tepene & LNSV01000006 & 39446 & 61665 & - & - \\
7 & Tepene & LNSV0100031 & 32044 & 58653 & Hogene & 61 \\
8 & Tepene & LNSV01000035 & 41851 & 62261 & - & - \\
9 & Tepene & LNSV01000039 & 39913 & 59882 & Isoorientatene & 85 \\
10 & Phenazine & LNSV01000013 & 37297 & 57785 & Marinophenazines & 30 \\ \hline \end{tabular}
\end{table} 
Table 1: Putative gene clusters for secondary metabolite in _S. kanasensis_ ZX01. Six putative polyketide synthase (PKS) or nonribosomal peptide synthetase (NRPs) clusters harbored in the genome of _S. kanasensis_ ZX01. Two clusters (cluster 16 and 19) contain typical PKS genes (1 type-I and 1 type-III), one cluster (cluster 21) contains NRPs genes, and three complex clusters (cluster 17, 18 and 20) contain PKS or NRPs (Figure 1). We identified a biosynthetic cluster (cluster 18) showing 100% similarity with known micromonolactam (ML) biosynthetic cluster (BGC0000095_c5), which consists of malonyl CoA-acyl carrier protein transacylasse (mmolK) and long chain fatty acid CoA ligase (mmolJ). However, the cluster (BGC0000095_c5) depositing in BGC database was a part of whole gene cluster for ML biosynthesis in _Micromonspora_ sp. CMS I2-32 [16]. The ML biosynthesis gene cluster was split on 15 different contigs (Accession no. : KC608848-608862). There were some differences between cluster 18 and ML biosynthesis gene cluster on PKS or NRPs domains of other genes. Therefore, a low quality sequencing data will influences the analysis result of gene clusters. The butvrolactone synthetase gene divided cluster 18 into type-I PKS domains and NRPs domains (Figure 1). \(\gamma\)-Butyrolactone (GBL) autoregulators are regarded as microbial hormones that trigger secondary metabolism and morphogenesis in _Streptomyces_[17; 18; 19]. We found chemical GBL could induce expression of some PKS or NRPs gene. The expression of Ska1968, 3482, 3506 and 4292 increased dramatically under induction condition of chemical GBL (Figure 2).