The role of growth rate, redox-state of the plastoquinone pool and the trans-thylakoid ΔpH in photoacclimation of Chlorella vulgaris to growth irradiance and temperature
The role of growth rate, redox-state of the plastoquinone pool and the trans-thylakoid ΔpH in photoacclimation of Chlorella vulgaris to growth irradiance and temperature
复制标题
生长速率、质体醌库的氧化还原状态和反式类囊体 ΔpH 在小球藻光驯化生长辐照度和温度中的作用
作者：
K. Wilson;N. Huner
抽象的。研究了普通小球藻（Chlorella vulgaris Beijer，UTEX 265）在环境CO2条件下对生长光照和生长温度的长期光适应。虽然培养物在27 °C下比在5 °C下以更快的速率生长，但生长速率似乎与辐照度无关。当在稳态生长条件下估计为1−qP时，捕光多肽积累的减少、叶黄素池大小的增加和叶黄素循环色素的环氧化状态的变化与QA（光系统II的主要醌受体）的相对还原状态的增加呈线性相关。然而，我们发现，也有一个特定的温度依赖性组件，除了氧化还原状态的QA，参与调节的内容和组成的捕光复合物II的C。普通的相比之下，在5 °C下生长的细胞中，响应于1−qP增加的叶黄素池的环氧化状态的调节与在27 °C下生长的细胞中的调节是不可区分的，这表明光和温度以类似的方式相互作用来调节C中的叶黄素循环活性。普通的因为C. vulgaris在3-（3，4-二氯苯基）-1，1-二甲基脲（DCMU）存在下表现出弱光表型，而在2，5-二溴-6-异丙基-3-甲基-1，4-苯醌存在下表现出强光表型，我们认为质体醌库作为一种传感器调节光捕获多肽在C.普通的然而，非光化学荧光猝灭（qN）和叶黄素池的环氧化状态的同时测量似乎表明，除了质体醌池的氧化还原状态外，反式类囊体ΔpH也可能有助于感知辐照度和温度的变化，这将导致光合机构的过度激发。我们认为，反映在光合产物利用和细胞生长的库容量最终调节光适应在C。普通的
Abstract. The long-term photoacclimation of Chlorella vulgaris Beijer (UTEX 265) to growth irradiance and growth temperature under ambient CO2 conditions was examined. While cultures grew at a faster rate at 27 than at 5 °C, growth rates appeared to be independent of irradiance. Decreases in light-harvesting polypeptide accumulation, increases in xanthophyll pool size and changes in the epoxidation state of the xanthophyll cycle pigments were correlated linearly with increases in the relative reduction state of QA, the primary quinone receptor of photosystem II, when estimated as 1−qP under steady-state growth conditions. However, we show that there is also a specific temperature-dependent component, in addition to the redox-state of the QA, involved in regulating the content and composition of light-harvesting complex II of C. vulgaris. In contrast, modulation of the epoxidation state of the xanthophyll pool in response to increased 1−qP in cells grown at 5 °C was indistinguishable from that of cells grown at 27 °C, indicating that light and temperature interact in a similar way to regulate xanthophyll cycle activity in C. vulgaris. Because C. vulgaris exhibited a low-light phenotype in the presence of 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU), but a high-light phenotype upon addition of 2,5-dibromo-6-isopropyl-3-methyl-1,4-benzoquinone, we conclude that the plastoquinone pool acts as a sensor regulating the accumulation of light-harvesting polypeptides in C. vulgaris. However, concomitant measurements of non-photochemical fluorescence quenching (qN) and the epoxidation state of the xanthophyll pool appear to indicate that, in addition to the redox-state of the plastoquinone pool, the trans-thylakoid ΔpH may also contribute to sensing changes in irradiance and temperature that would lead to over-excitation of the photosynthetic apparatus. We suggest that sink capacity as reflected in photosynthate utilization and cell growth ultimately regulate photoacclimation in C. vulgaris.