The growth defect of a Bacillus subtilis mutant lacking the glucose-6-phosphate-dehydrogenase

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K05375
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 38020:Applied microbiology-related
• Research Institution: National Agriculture and Food Research Organization
• Principal Investigator: Inaoka Takashi 国立研究開発法人農業・食品産業技術総合研究機構, 食品研究部門, グループ長補佐 (40391205)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: グルコース6リン酸デヒドロゲナーゼ / NADPH / 増殖 / 菌密度 / サプレッサー変異 / 枯草菌

Outline of Final Research Achievements

The disruption of zwf gene encoding glucose-6-phosphate dehydrogenase causes a significant decrease in the intracellular NADPH pool. In B. subtilis, a zwf mutant showed inoculum-dose-dependent growth. To investigate the correlation between intracellular NADPH and cell growth, I isolated the spontaneous suppressor mutants from a zwf mutant. Then, seven mutations were found in adeR, relA, yqeZ, lysP, ccpA, trmF, or thrS gene. Transformation analysis revealed that these mutations except for adeR mutation can restore the growth of zwf mutant. Therefore, six mutations were identified as the suppressor mutation that can restore the growth of zwf mutant. Among them, three mutations (lysP6, ccpA107, and trmF528) effectively suppressed the growth of zwf mutant. In these mutants, the intracellular levels of nicotinic acid and pantothenic acid were restored to the wild-type levels.

Free Research Field

応用微生物学

Academic Significance and Societal Importance of the Research Achievements

ペントースリン酸経路の最初の酵素であるG6PDは真核生物も含めて普遍的に存在する重要な酵素である。本研究では枯草菌G6PD欠損株におこる低菌密度からの増殖不全を回復する変異を同定し、これら変異が細胞内のニコチン酸やパントテン酸量を回復させることを明らかにした。これらの結果は、G6PDによるNADPHの低下がこれらビタミンの細胞内濃度を低下させ、低菌密度からの増殖不全を引き起こしていることを示唆しており、新薬開発や新しい微生物制御法の開発に繋がると期待できる。