Shi Zurong, Liang Zhibin, Yang Qian, Zhang Lian-Hui, Wang Qingwei
School of Biological Engineering, HuaiNan Normal University, Huainan, China.
Guangdong Laboratory for Lingnan Modern Agriculture, Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou, China.
mSphere. 2025 Apr 29;10(4):e0068224. doi: 10.1128/msphere.00682-24. Epub 2025 Mar 20.
Putrescine is an important interspecies and interkingdom communication signal, modulating the bacterial motility, biofilm formation, and virulence of . The understanding of the regulation of putrescine biosynthesis and transport in is limited. In this study, we report that alarmone ppGpp hierarchically modulates putrescine biosynthesis and transport and synergistically cooperates with putrescine to regulate virulence traits and the virulence of . We found that the alarmone ppGpp synthesized by RelA regulated putrescine biosynthesis through modulating expression, and the product putrescine would thus inhibit the expression of and . Remarkably, we unveiled the synergistic effect of alarmone ppGpp and putrescine on the modulation of swimming motility and zeamine production. Compared with the single deletion of either or , the double deletion of and could decrease the expression of RNA chaperone encoded gene and the production of phytotoxin zeamine, which further attenuated the capability of EC1 in inhibition of rice seed germination. Collectively, the findings from this study depict alarmone ppGpp regulation on putrescine biosynthesis and transport and present the cooperation of regulation of alarmone ppGpp and putrescine in the virulence of .IMPORTANCE is the causal agent of rice root rot disease. Bacterial motility and phytotoxic zeamines are characterized as two major virulent factors during infecting rice seed. Putrescine, as an interspecies and interkingdom communication signal for the infections of , has been previously demonstrated to be involved in the modulation of bacterial motility. Here we report the novel synergistic effect of putrescine signal and alarmone ppGpp on the regulation of both zeamine production and bacterial motility via modulating the expression of RNA chaperone-encoded gene . In addition, we also showed that alarmone ppGpp hierarchically modulates putrescine biosynthesis and transport. Therefore, the findings of this study unveil the previously undetermined contribution of putrescine in the modulation of virulence determinants, and the regulatory mechanism of putrescine biosynthesis and transport in .
腐胺是一种重要的种间和跨界通讯信号，可调节细菌的运动性、生物膜形成及[具体细菌名称]的毒力。目前对[具体细菌名称]中腐胺生物合成和转运调控的了解有限。在本研究中，我们报道警报素ppGpp分级调节腐胺的生物合成和转运，并与腐胺协同作用以调节[具体细菌名称]的毒力特征和毒力。我们发现由RelA合成的警报素ppGpp通过调节[具体基因名称]的表达来调控腐胺的生物合成，而产物腐胺会抑制[具体基因名称]和[具体基因名称]的表达。值得注意的是，我们揭示了警报素ppGpp和腐胺在调节游动性和玉米赤霉烯酮产生方面的协同作用。与单独缺失[具体基因名称]或[具体基因名称]相比，同时缺失[具体基因名称]和[具体基因名称]会降低RNA伴侣编码基因[具体基因名称]的表达以及植物毒素玉米赤霉烯酮的产生，这进一步削弱了[具体细菌名称]EC1抑制水稻种子萌发的能力。总的来说，本研究的结果描述了警报素ppGpp对腐胺生物合成和转运的调控，并展示了警报素ppGpp和腐胺在[具体细菌名称]毒力调控中的协同作用。重要性[具体细菌名称]是水稻根腐病的病原体。细菌运动性和植物毒性玉米赤霉烯酮是[具体细菌名称]感染水稻种子期间的两个主要致病因素。腐胺作为[具体细菌名称]感染的种间和跨界通讯信号，先前已被证明参与细菌运动性的调节。在此我们报道腐胺信号和警报素ppGpp通过调节RNA伴侣编码基因[具体基因名称]的表达对玉米赤霉烯酮产生和细菌运动性的调控具有新的协同作用。此外，我们还表明警报素ppGpp分级调节腐胺的生物合成和转运。因此，本研究的结果揭示了腐胺在毒力决定因素调节中先前未确定的作用，以及[具体细菌名称]中腐胺生物合成和转运的调控机制。
