# Genome-Wide Analysis Reveals the Secondary Metabolome in _Streptomyces kanasensis_ ZX01
## 3 Results and Discussion
### Regulators for Secondary Metabolism in S. kanasensis ZX01 Genome
kanasensis_ ZX01 after \(\gamma\)-butyrolactone induction for 72 h. Ska0065, Ska1968 and Ska3482 are type-I PKS; Ska4292 is type-III PKS; Ska3506 and Ska5321 is NRPs. At least 46 two-component systems and 7 multi-component systems exist in _S. kanasensis_ ZX01 genome. Several two-component systems directly or indirectly affect antibiotics production. The two-component system PhoR-PhoP is the major signal transduction system for phosphate control in _Streptomyces_. In addition, it affects antibiotics production by influencing the transcription of biosynthesis genes, such as, _S. coelicolor_ (actinorhodin ACT and prodigiosins RED) [23], _Streptomyces griseus_ (candicidin) [24], _Streptomyces rinosus_ (oxytetracycline) [25], _Streptomyces__natalensis_ (pimaricin) [26]. Similar two-component systems, which affect antibiotic production, were predicted in genome of _S. kanasensis_ ZX01, including PhoR-P (Ska6032-6034), AfsQ1-Q2 (Ska1698-1697), RapA1-A2 (Ska2296-2297) and CutS-R (Ska4345-4346). Guanosine tetraphosphate (ppGpp) and pentaphosphate (ppGpp) activate the expression of antibiotic biosynthetic genes, when the supply of amino acids becomes rate limiting for protein synthesis. The gene of (p)ppGpp synthase enzyme _relA_ disruption mutant did not produce ACT in _S. coelicolor_[27], but, (p)ppGpp overaccumulation increased ACT and RED production [28]. Ska1310, 3074, 3731 and 3887 probably regulate secondary metabolism of _S. kanasensis_ ZX01, because they are all related to (p)ppGpp synthesis. Furthermore, GBL is a signaling molecule as well [29], GBL synthase (ScbA) and receptor (ArpA) affect antibiotic biosynthesis [4]. Ska3485, homologous gene of ScbA, has huge potential for affecting production of secondary metabolites in _S. kanasensis_ ZX01. Many putative regulators for secondary metabolism were found in _S. kanasensis_ ZX01 genome. However, most of them are unknown in the function. Hence, mining novel regulatory genes is an important work, especially global regulators, since they serve multiple purposes. Moreover, products of some gene clusters might accurately be labelled'stress metabolites', predicted to combat stresses of a physical (desiccation, low temperature), chemical (low iron) or biological (competition) nature. Therefore, searching for factors that cause the gene clusters to be silent is a focus as well. Genome sequencing of _S. kanasensis_ ZX01 revealed plenty of novel biosynthetic gene clusters, the majority of them were unexpected and excited. With this available information, there is a need for more genome-guided isolation studies of natural products. Meanwhile, our regulator analysis  
Figure 3: Differences between wild type and mutant of _S. kanasensis_ ZX01 in morphology and production of glycoprotein GP-1. (**A**) wild type strain of _S. kanasensis_ ZX01; (**B**) _nsdA_ disruption mutant in which _nsdA_ was replaced by kanamycin resistance gene (_han_); (**1**) Two strains were cultivated on the Gause-I plate medium for 5 days; (**2**) Two strains was cultivated in GCBY liquid medium for 3 days; (**3**) The differences of biomass between wild type and _ansdA_ mutant; (**4**) Determination of glycoprotein GP-1 in wild type and _ansdA_ mutant. will facilitate the process of natural product discovery and structure elucidation. Because, studies of regulator may suggest ways of increasing production levels, both at the early stages of characterizing new products and at the level of large-scale industrial production. They may also provide routes to the activation of \"silent\" gene cluster that are revealed by genome sequencing. This work was supported by the National Key Technology R&D Program of China (2014 BAD23B01), National Natural Science Foundation of China (NSFC 31201536) and Key Scientific Research Projects of Tibet (Z2016B01N01-4). And, we greatly appreciate Dr. [PERSON] (Institute of Microbiology, Chinese Academy of Sciences, China) for donating PKC1139 plasmid and _E. coli_ ET12567.