Analysis of Proteome Dynamics in Early-Stage Sporulation-Inhibited Variants of Parageobacillus thermoglucosidasius

<i>Parageobacillus thermoglucosidasius</i> is a thermophilic Gram-positive that is emerging as a platform for bioproduction. However, one potential limitation of <i>P. thermoglucosidasius</i> is its natural tendency to sporulate. As a non-model organism, the complex regulatory system that governs sporulation in <i>P. thermoglucosidasius</i> remains poorly characterised. To advance current understanding, this study presents a comparative characterisation and proteomic analysis of the <i>P. thermoglucosidasius</i> wildtype strain alongside four early-stage sporulation-inhibited variants. To inhibit sporulation, the genes <i>spo0A</i>, <i>spo0B</i>, <i>spo0F</i>, and <i>sigF</i> were targeted for deletion, as based on their crucial regulatory roles in the sporulation pathway of <i>Bacillus subtilis</i>. Microscopic analysis indicated that the Δ<i>spo0A</i>, Δ<i>spo0F</i>, and Δ<i>sigF</i> strains were sporulation-suppressed while the Δ<i>spo0B</i> strain sporulated at low levels. Proteomics data were obtained from four different growth stages and the resulting expression profiles were compared. Consistent with the regulatory network of <i>B. subtilis</i>, the Δ<i>spo0A</i>, Δ<i>spo0B</i>, and Δ<i>spo0F</i> strains exhibited largely inactive sporulation pathways, while the Δ<i>sigF</i> strain retained some early regulatory functions. Additionally, two co-expression modules comprising approximately 300 genes were identified and linked to the <i>P. thermoglucosidasius</i> sporulation pathway. Overall, these results expand the understanding of the sporulation network of <i>P. thermoglucosidasius</i> and provide a foundation for future engineering of non-sporulating variants.