In Synechococcus sp. competition for energy between assimilation and acquisition of C and those of N only occurs when growth is light limited
In Synechococcus sp. competition for energy between assimilation and acquisition of C and those of N only occurs when growth is light limited
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在聚球藻属中。
DOI：
10.1093/jxb/erx074
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发表时间：
2017
影响因子：
6.9
通讯作者：
M. Giordano
中科院分区：
文献类型：
--
作者：
Z. Ruan;J. Raven;M. Giordano
蓝藻的碳浓缩机制 (CCM) 抵消了这些光养生物的 Rubisco 的低 CO2 亲和力和 CO2:O2 选择性以及相对较低的海洋 CO2 可用性。 CCM 的能源成本很高；如果光照有限，使用同化需要较少能量的氮源可以允许在 CCM 和无机 C (Ci) 同化中投入更多的能量。为了测试这一点，我们培养了聚球藻。 UTEX LB 2380 在氮或能量限制下，在 NO3- 或 NH4+ 存在的情况下。当生长受到能量限制时，NH4+生长的细胞的生长速率高出1.2倍，溶解无机碳（DIC）饱和光合速率高出1.3倍，线性电子转移高出19％，光合1/K1/2（DIC）高出80％，光合作用与DIC曲线的线性部分的斜率高出2.0倍，细胞内光合作用高出3.5倍 Ci 库和 Zn 配额比 NO3 生长的细胞高 2.3 倍。当能量不限制生长时，NH4+-和NO3-生长的细胞之间没有差异，除了更高的线性电子转移和更大的细胞内Ci库。我们的结论是，当能量限制生长时，使用更便宜的N源的细胞将能量从N同化转移到C获取和同化；当能量不受限制时，这种情况就不会发生。
The carbon-concentrating mechanisms (CCMs) of cyanobacteria counteract the low CO2 affinity and CO2:O2 selectivities of the Rubisco of these photolithotrophs and the relatively low oceanic CO2 availability. CCMs have a significant energy cost; if light is limiting, the use of N sources whose assimilation demands less energy could permit a greater investment of energy into CCMs and inorganic C (Ci) assimilation. To test this, we cultured Synechococcus sp. UTEX LB 2380 under either N or energy limitation, in the presence of NO3- or NH4+. When growth was energy-limited, NH4+-grown cells had a 1.2-fold higher growth rate, 1.3-fold higher dissolved inorganic carbon (DIC)-saturated photosynthetic rate, 19% higher linear electron transfer, 80% higher photosynthetic 1/K1/2(DIC), 2.0-fold greater slope of the linear part of the photosynthesis versus DIC curve, 3.5-fold larger intracellular Ci pool, and 2.3-fold higher Zn quota than NO3--grown cells. When energy was not limiting growth, there were not differences between NH4+- and NO3--grown cells, except for higher linear electron transfer and larger intracellular Ci pool.We conclude that, when energy limits growth, cells that use the cheaper N source divert energy from N assimilation to C acquisition and assimilation; this does not happen when energy is not limiting.
影响因子：
4.9
作者：
H. Mi;T. Endo;U. Schreiber;T. Ogawa;K. Asada
通讯作者：
H. Mi;T. Endo;U. Schreiber;T. Ogawa;K. Asada