Recently, a research paper entitled "Promoted Spore Formation of Bacillus amyloliquefaciens fmbJ by its Secondary Metabolite Bacillomycin D Coordinated with Mn2+" has been published online by Prof. Zhang Jin (first author), Prof. Lu Yingjian (corresponding author), and Sun Jing (corresponding author) from School of Food Science and Engineering, Nanjing University of Finance and Economics (NUFE). Bacillus amyloliquefaciens fmbJ by its Secondary Metabolite Bacillomycin D Coordinated with Mn2+".

In Bacillus, the spore formation process is associated with the synthesis and release of secondary metabolites. A large number of studies have been conducted to systematically elucidate the pathways and mechanisms of spore formation. However, there are no studies have explored the relationship between secondary metabolites and spores. In this study, we investigated the relationship between its secondary metabolite bacillomycin D (BD) and spores using the simpler dipicolonic acid fluorimetry assay for spore counting in Bacillus amyloliquefaciens fmbJ. Our results showed that BD could promote the spore formation of B. amyloliquefaciens fmbJ and had a synergistic effect with certain concentrations of Mn2+. When 15.6 mg/L of BD and 1 mM of Mn2+ were added, the number of fmbJ spores increased from 1.42 × 108 CFU/mL to 2.02 × 108 CFU/mL after 36 h of incubation. The expressions of spore formation (kinA, kinB, kinC, kinD, kinE and spo0A) and Mn-related genes (mntA, mntH, mneS, mneP) were studied by RT-PCR. The results indicated that BD and Mn2+promoted the spore formation of fmbJ by stimulating the transcription of kinB, kinD and increasing the influence of spo0F-spo0A phosphorylation transmission. This study provided a new idea to improve the spore production of B. amyloliquefaciens and laid the foundation for its industrial production.

Figure 1:Effect of BD and Mn2+ on the expression of histidine kinase genes (kinA, kinB, kinC, kinD and kinE), spore initiation genes (spo0A) and manganese transport related genes (mntA, mntH, mneS and mneP) in B. amyloliquefaciens fmbJ. At 0.05 and 0.01, * and ** were significantly different from the control.

Table 1: Interaction between different concentrations of BD and Mn2+ .

Fig. 2: Hypothesized pathways by which BD and Mn2+ promote Bacillus amyloliquefaciens fmbJ spore formation