乳品发酵中噬菌体的持续挑战需要开发具有增强的噬菌体抗性的发酵剂培养物。最近,三个质粒编码的乳球菌抗噬菌体系统,名叫Rhea,Aristaios,和Kamadhenu,被发现了。发现这些系统赋予对各种Skunavirus成员的高水平抗性。在本研究中,它们对抗噬菌体感染的有效性在牛奶培养基中得到证实,从而验证他们的潜力,以确保可靠的乳制品发酵。我们进一步证明Rhea和Kamadhenu不会直接阻碍噬菌体基因组复制,转录,或相关翻译。相反,发现Aristaios干扰噬菌体转录。两个抗噬菌体系统在pMRC01样共轭质粒上编码,编码Kamadhenu的质粒通过接合成功转移到三个乳球菌菌株上,每个都获得了针对Skunavirus成员的显著增强的噬菌体抗性。我们对乳球菌噬菌体抗性组的认识的这种进步以及动员这些保护功能以增强敏感菌株中的噬菌体保护的可能性,为工业食品发酵中持续存在的噬菌体问题提供了实用的解决方案。重要在当前的研究中,我们表征和评估了最近描述的三种机制的多样性,质粒编码的乳球菌抗噬菌体系统。发现这些系统对最普遍和有问题的乳球菌噬菌体属的许多成员具有高抗性,使它们对乳制品行业特别感兴趣,持续的噬菌体挑战需要开发具有增强的噬菌体抗性特性的发酵剂培养物。我们获得的知识突出表明,加强对乳球菌噬菌体抗性系统及其编码质粒的了解可以为乳制品发酵设施中噬菌体感染的持久问题提供合理有效的解决方案。
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 Skunavirus 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 Skunavirus 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.