Shibata Mari, Ohkawa Hiroshi, Katoh Hirokazu, Shimoyama Masaya, Ogawa Teruo
Bioscience Centre, Nagoya University, Chikusa, Nagoya 4648601, Japan.
Bioscience Centre, Nagoya University, Chikusa, Nagoya 4648601, Japan.Corresponding author; email:
Funct Plant Biol. 2002 Apr;29(3):123-129. doi: 10.1071/PP01188.
The cyanobacterium Synechocystis sp. strain PCC6803 possesses two CO2 uptake systems; one constitutive, dependent on NdhD3/NdhF3/CupA (Sll1734), and one low-CO2 inducible, dependent on NdhD4/NdhF4/CupB (Slr1302). Homologues of these genes are present in pairs in most cyanobacterial strains. Synechocystis PCC6803 also possesses two types of HCO3 transporters; an ATP-binding cassette (ABC)-type transporter encoded by the cmp operon, and a novel sodium-dependent transporter encoded byslr1512(sbtA) that plays a central role in HCO3 uptake. Mutants impaired for one of these four inorganic-carbon acquisition systems did not show mutant phenotype. Mutants inactivated for both CO2 uptake systems were unable to grow at pH 7.0 in air, although they grew normally at pH 9.0 in air. Additional inactivation of the SbtA-type HCO3 transporter abolished growth at pH 9.0 in air. A fragment containing the promoter region of ndhF3 fused to the coding region of luxAB was inserted into a neutral site of the ΔndhD4 mutant to construct apF3-lux/ ΔndhD4 strain. The luminescence intensity of this strain was low in high-CO2 grown cells, and was increased about 100 times after acclimation to air. Inactivation of the pF3-lux/ ΔndhD4 strain with a transposon-tagging library enabled us to isolate mutants incapable of acclimation to low CO2.
集胞藻6803株蓝细菌拥有两个二氧化碳摄取系统；一个是组成型的，依赖于NdhD3/NdhF3/CupA（Sll1734），另一个是低二氧化碳诱导型的，依赖于NdhD4/NdhF4/CupB（Slr1302）。这些基因的同源物在大多数蓝细菌菌株中以成对形式存在。集胞藻PCC6803还拥有两种类型的碳酸氢根转运体；一种由cmp操纵子编码的ATP结合盒（ABC）型转运体，以及一种由slr1512（sbtA）编码的新型钠依赖性转运体，其在碳酸氢根摄取中起核心作用。这四种无机碳获取系统之一受损的突变体未表现出突变表型。两个二氧化碳摄取系统均失活的突变体在空气中pH 7.0时无法生长，尽管它们在空气中pH 9.0时能正常生长。SbtA型碳酸氢根转运体的进一步失活消除了在空气中pH 9.0时的生长。将包含ndhF3启动子区域并与luxAB编码区域融合的片段插入ΔndhD4突变体的中性位点，构建了pF3-lux/ΔndhD4菌株。该菌株在高二氧化碳培养的细胞中发光强度较低，在适应空气后增加了约100倍。用转座子标签文库使pF3-lux/ΔndhD4菌株失活，使我们能够分离出无法适应低二氧化碳的突变体。
