Genes (DEGs) in between C. glutamicum PUT-ALE along with the wild-type strain C. glutamicum ATCC13032 in this study. The GO project supplies a controlled vocabulary to describe gene goods inside three categories: biological method, molecular function and cellular element (Boyle et al., 2004). GO enrichment evaluation has become a normally used strategy for functional studies, and the GO analysis of DEGs might help biologists greater have an understanding of the functional relevance of DEGs. In Figure 2, the results of a GO analysisof DEGs for C. glutamicum PUT-ALE vs. ATCC 13032 is presented. DEGs involved in metabolic pathways are presented in Figures 3 and four. As shown in Figure three, most of the genes (glpX, fda, gpmB, eno, pyk, aceE, prpC1, acn, kgd, sdhAB, mdh, aceAB) involved in the glycolysis and tricarboxylic acid (TCA) cycle have been drastically downregulated in C. glutamicum PUTALE in comparison to C. glutamicum ATCC13032. The low rate of growth of C. glutamicum PUT-ALE is constant together with the observed downregulated information. The pyc gene in C. glutamicum PUT-ALE was also downregulated. The pyruvate carboxylase encoded by pyc is amongst the most significant anaplerotic enzymes in C. glutamicum. Overexpression on the pyc gene can drive higher EMP flux in to the TCA cycle to strengthen it. It has been demonstrated that overexpression from the pyc gene improved L -glutamate (Shirai et al., 2007; Hasegawa et al., 2008), L -arginine (Man et al., 2016b) and putrescine (Nguyen et al., 2015a) production in C. glutamicum. Hence, we expressed pyc or its mutant pyc458 from a plasmid in C. glutamicum PUT-ALE. As shown in Table two, overexpression with the native pyc gene slightly enhanced putrescine production, when overexpression from the mutated pyc458 gene markedly improved putrescine production by 16 to 133.51 7.20 mM. It has been reported that pyc458 is really a advantageous mutation for L-lysine production (Ohnishi et al., 2002). The transcription amount of the kgd gene was also downregulated in C. glutamicum PUT-ALE. Alpha-ketoglutarate (KG) is often a key node of your TCA cycle, and -ketoglutarate decarboxylase (encoded by kgd) catalyzes the Cephalotin In Vivo oxidative decarboxylation of KG to synthesize succinyl coenzyme A. The downregulation of kgd transcription can channel improved carbon flux into the glutamate biosynthetic pathway, enhancing putrescine production. Numerous groups have reported that decreasing the Kgd activity in Corynebacterium, and even deleting kgd, enhanced the production of glutamate (Asakura et al., 2007; Kim et al., 2009), the glutamate-derived compound putrescine (Nguyen et al., 2015a), gamma-aminobutyric acid (Jorge et al., 2017) and L-arginine (Chen et al., 2015; Man et al., 2016b). It has been demonstrated that the exchanging the translational start off codon on the kgd gene from GTG to TTG reducedFrontiers in Microbiology | www.frontiersin.orgOctober 2017 | Volume 8 | ArticleLi and LiuTranscriptomic Modifications among the Putrescine-Producer and the Wild-Type StrainFIGURE 2 | Pathway gene ontology enrichment analysis. (A) The ratio on the DEGs inside the total number of genes detected. (B) The numbers of your DEGs.Frontiers in Microbiology | www.frontiersin.orgOctober 2017 | Volume eight | ArticleLi and LiuTranscriptomic Adjustments between the Putrescine-Producer and the Wild-Type StrainFIGURE 3 | Differentially expressed genes involved in glycolysis, the TCA cycle, pyruvate metabolism, amino acid biosynthesis and the putrescine biosynthetic pathway. The numbers indicate the values in the log2 rati.