Grafakou Andriana, Mosterd Cas, de Waal Paul P, van Rijswijck Irma M H, van Peij Noël N M E, Mahony Jennifer, van Sinderen Douwe
School of Microbiology & APC Microbiome Ireland, University College Cork, Cork, Ireland.
dsm-firmenich, Taste, Texture & Health, Center for Food Innovation, Delft, the Netherlands.
Appl Environ Microbiol. 2024 Sep 18;90(9):e0112024. doi: 10.1128/aem.01120-24. Epub 2024 Aug 13.
The persistent challenge of phages in dairy fermentations requires the development of starter cultures with enhanced phage resistance. Recently, three plasmid-encoded lactococcal antiphage systems, named Rhea, Aristaios, and Kamadhenu, were discovered. These systems were found to confer high levels of resistance against various members. In the present study, their effectiveness against phage infection was confirmed in milk-based medium, thus validating their potential to ensure reliable dairy fermentations. We furthermore demonstrated that Rhea and Kamadhenu do not directly hinder phage genome replication, transcription, or associated translation. Conversely, Aristaios was found to interfere with phage transcription. Two of the antiphage systems are encoded on pMRC01-like conjugative plasmids, and the Kamadhenu-encoding plasmid was successfully transferred by conjugation to three lactococcal strains, each of which acquired substantially enhanced phage resistance against members. Such advances in our knowledge of the lactococcal phage resistome and the possibility of mobilizing these protective functions to bolster phage protection in sensitive strains provide practical solutions to the ongoing phage problem in industrial food fermentations.IMPORTANCEIn the current study, we characterized and evaluated the mechanistic diversity of three recently described, plasmid-encoded lactococcal antiphage systems. These systems were found to confer high resistance against many members of the most prevalent and problematic lactococcal phage genus, rendering them of particular interest to the dairy industry, where persistent phage challenge requires the development of starter cultures with enhanced phage resistance characteristics. Our acquired knowledge highlights that enhanced understanding of lactococcal phage resistance systems and their encoding plasmids can provide rational and effective solutions to the enduring issue of phage infections in dairy fermentation facilities.
噬菌体在乳制品发酵过程中持续存在的挑战，要求开发具有增强噬菌体抗性的发酵剂培养物。最近，发现了三种由质粒编码的乳球菌抗噬菌体系统，分别命名为瑞亚（Rhea）、阿里斯泰俄斯（Aristaios）和卡玛德胡努（Kamadhenu）。这些系统被发现对各种噬菌体具有高水平的抗性。在本研究中，它们在基于牛奶的培养基中对噬菌体感染的有效性得到了证实，从而验证了它们确保可靠乳制品发酵的潜力。我们还证明，瑞亚和卡玛德胡努系统不会直接阻碍噬菌体基因组的复制、转录或相关的翻译过程。相反，发现阿里斯泰俄斯系统会干扰噬菌体转录。其中两种抗噬菌体系统由类似pMRC01的接合性质粒编码，并且编码卡玛德胡努系统的质粒通过接合成功转移到三株乳球菌菌株中，每株菌株对多种噬菌体的抗性都得到了显著增强。我们对乳球菌噬菌体抗性组的认识取得了这些进展，以及将这些保护功能转移到敏感菌株中以增强噬菌体保护的可能性，为解决工业食品发酵中持续存在的噬菌体问题提供了切实可行的解决方案。重要性在当前的研究中，我们对最近描述的三种由质粒编码的乳球菌抗噬菌体系统的机制多样性进行了表征和评估。这些系统被发现对最普遍且最具问题的乳球菌噬菌体属的许多成员具有高度抗性,这使得它们对乳制品行业特别有吸引力，因为在乳制品行业中，噬菌体的持续挑战要求开发具有增强噬菌体抗性特征的发酵剂培养物。我们所获得的知识强调，对乳球菌噬菌体抗性系统及其编码质粒的深入了解，可以为乳制品发酵设施中噬菌体感染这一长期问题提供合理有效的解决方案。
