Zhejiang Provincial Key Laboratory of Biometrology and Inspection and Quarantine, College of Life Science, China Jiliang University, Hangzhou 310018, China.
Department of Chemistry, Zhejiang University, Hangzhou 310027, China.
Int J Mol Sci. 2024 Mar 30;25(7):3878. doi: 10.3390/ijms25073878.
Bis (3',5')-cyclic diguanylic acid (c-di-GMP) is a ubiquitous second messenger that controls several metabolic pathways in bacteria. In , c-di-GMP is associated with morphological differentiation, which is related to secondary metabolite production. In this study, we identified and characterized a diguanylate cyclase (DGC), CdgB, from 1628, which may be involved in c-di-GMP synthesis, through genetic and biochemical analyses. To further investigate the role of CdgB, the -deleted mutant strain Δ- and the -overexpressing mutant strain O- were constructed by genetic engineering. A phenotypic analysis revealed that the O- colonies exhibited reduced mycelium formation, whereas the Δ-cdgB colonies displayed wrinkled surfaces and shriveled mycelia. Notably, O- demonstrated a significant increase in the toyocamycin (TM) yield by 47.3%, from 253 to 374 mg/L, within 10 days. This increase was accompanied by a 6.7% elevation in the intracellular concentration of c-di-GMP and a higher transcriptional level of the cluster within four days. Conversely, Δ- showed a lower c-di-GMP concentration (reduced by 6.2%) in vivo and a reduced toyocamycin production (decreased by 28.9%, from 253 to 180 mg/L) after 10 days. In addition, 1628 exhibited a slightly higher inhibitory effect against f. sp. and compared to Δ-, but a lower inhibition rate than that of O-. The results imply that CdgB provides a foundational function for metabolism and the activation of secondary metabolism in 1628.
双(3',5')-环二鸟苷酸(c-di-GMP)是一种普遍存在的第二信使，控制着细菌中的几种代谢途径。在 中，c-di-GMP 与形态分化有关，而形态分化与次生代谢产物的产生有关。在这项研究中，我们通过遗传和生化分析，从 1628 中鉴定和表征了一种双鸟苷酸环化酶(DGC)，CdgB，它可能参与 c-di-GMP 的合成。为了进一步研究 CdgB 的作用，通过遗传工程构建了 -缺失突变株 Δ-和 -过表达突变株 O-。表型分析表明，O-的菌落形成丝状菌丝的能力降低，而 Δ-cdgB 的菌落表面起皱，菌丝萎缩。值得注意的是，O-在 10 天内将 toyocamycin (TM)的产量从 253 增加到 374 mg/L，增加了 47.3%。这一增加伴随着细胞内 c-di-GMP 浓度提高了 6.7%，四天内 簇的转录水平提高了 6.7%。相反，Δ-在体内的 c-di-GMP 浓度较低(降低了 6.2%)，10 天后 toyocamycin 的产量降低(从 253 降低至 180 mg/L，降低了 28.9%)。此外，与 Δ-相比，1628 对 f. sp. 和 的抑制作用略有增强，但抑制率低于 O-。结果表明，CdgB 为 1628 中的代谢和次生代谢的激活提供了基础功能。
