Interdepartmental Microbiology Graduate Program, Iowa State University, Ames, IA, United States of America.
Department of Animal Science, Iowa State University, Ames, IA, United States of America.
PLoS One. 2020 Jul 23;15(7):e0233945. doi: 10.1371/journal.pone.0233945. eCollection 2020.
The survival of Listeria (L.) monocytogenes in foods and food production environments (FPE) is dependent on several genes that increase tolerance to stressors; this includes competing with intrinsic bacteria. We aimed to uncover genes that are differentially expressed (DE) in L. monocytogenes sequence type (ST) 121 strain 6179 when co-cultured with cheese rind bacteria. L. monocytogenes was cultivated in broth or on plates with either a Psychrobacter or Brevibacterium isolate from cheese rinds. RNA was extracted from co-cultures in broth after two or 12 hours and from plates after 24 and 72 hours. Broth co-cultivations with Brevibacterium or Psychrobacter yielded up to 392 and 601 DE genes, while plate co-cultivations significantly affected the expression of up to 190 and 485 L. monocytogenes genes, respectively. Notably, the transcription of virulence genes encoding the Listeria adhesion protein and Listeriolysin O were induced during plate and broth co-cultivations. The expression of several systems under the control of the global stress gene regulator, σB, increased during co-cultivation. A cobalamin-dependent gene cluster, responsible for the catabolism of ethanolamine and 1,2-propanediol, was upregulated in both broth and plate co-cultures conditions. Finally, a small non-coding (nc)RNA, Rli47, was induced after 72 hours of co-cultivation on plates and accounted for 50-90% of the total reads mapped to L. monocytogenes. A recent study has shown that Rli47 may contribute to L. monocytogenes stress survival by slowing growth during stress conditions through the suppression of branch-chained amino acid biosynthesis. We hypothesize that Rli47 may have an impactful role in the response of L. monocytogenes to co-cultivation by regulating a complex network of metabolic and virulence mechanisms.
李斯特菌（Listeria）在食品和食品生产环境（FPE）中的存活取决于一些增加其对压力耐受的基因；这包括与固有细菌竞争。我们旨在揭示当李斯特菌 121 型 6179 株与奶酪皮细菌共培养时差异表达（DE）的基因。李斯特菌在肉汤或平板中与来自奶酪皮的 Psychrobacter 或 Brevibacterium 分离株一起培养。在共培养 2 或 12 小时后从肉汤中提取 RNA，并在 24 和 72 小时后从平板中提取 RNA。与 Brevibacterium 或 Psychrobacter 的肉汤共培养产生了多达 392 和 601 个 DE 基因，而平板共培养分别显著影响了多达 190 和 485 个李斯特菌基因的表达。值得注意的是，在平板和肉汤共培养过程中，编码李斯特菌黏附蛋白和李斯特菌溶素 O 的毒力基因的转录被诱导。在共培养过程中，受全局应激基因调控因子 σB 控制的几个系统的表达增加。一个依赖钴胺素的基因簇，负责乙醇胺和 1,2-丙二醇的分解代谢，在肉汤和平板共培养条件下均上调。最后，一种小的非编码（nc）RNA，Rli47，在平板共培养 72 小时后被诱导，并占映射到李斯特菌的总读数的 50-90%。最近的一项研究表明，Rli47 可能通过在应激条件下通过抑制支链氨基酸生物合成来减缓生长，从而有助于李斯特菌的应激存活。我们假设 Rli47 通过调节代谢和毒力机制的复杂网络，可能在李斯特菌对共培养的反应中发挥重要作用。
