Molecular bases of the insensitivity of bacteria to the carriage of various plasmids

2020 Fiscal Year Final Research Report

• Project/Area Number: 18H02121
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 38020:Applied microbiology-related
• Research Institution: The University of Tokyo
• Principal Investigator: Nojiri Hideaki 東京大学, 農学生命科学研究科, 教授 (90272468)
• Project Period (FY): 2018-04-01 – 2021-03-31
• Keywords: 細菌 / プラスミド / 遺伝子 / 水平伝播 / fitness / 淘汰

Outline of Final Research Achievements

Pseudomonas resinovorans CA10dm4 exhibits the novel property, named “plasmid insensitivity”, by which, even when carrying various plasmids, the bacterial strain is not out-competed during competitive culture with plasmid-free strain. In this study, we clarified that the transcriptional activation of the regulon of CysB, which was conventionally known as the master transcription regulator of the sulfur metabolism in Gram-negative bacteria, is important for the expression of this novel phenotype. The TCA cycle and energy metabolism system are located downstream of this metabolic control system, strongly suggesting that the regulation of intracellular metabolism is the key to plasmid insensitivity.

Free Research Field

環境微生物学

Academic Significance and Societal Importance of the Research Achievements

プラスミド非感受性は、一部の細菌だけが示す他に報告がない形質であり、その発現機構の解明はそれ自体が重要な科学的成果である。また、この現象の発現に、硫黄代謝系を中心とする代謝調節が重要である点は、プラスミドの負荷という言葉で言い表されてきた現象の実体が代謝の乱れにあったことを実験的に証明する意味で非常に意義深い。また、この機構が明らかになったことで、物質生産などに利用される汎用宿主をプラスミドベクター（さらには外来遺伝子）に対して非感受性化できる可能性も示され、産業応用等の観点からも重要である。