Characterization of an ammonium transporter in the oleaginous alga Chlorella protothecoides
Characterization of an ammonium transporter in the oleaginous alga Chlorella protothecoides
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DOI：
10.1007/s00253-012-4534-x
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发表时间：
2012-11
影响因子：
5
通讯作者：
D. Yan;Junbiao Dai;Qingyu Wu
中科院分区：
文献类型：
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作者：
D. Yan;Junbiao Dai;Qingyu Wu
利用抑制性消减杂交基因文库筛选小球藻原生质体培养过程中光合作用-发酵途径(PFA)差异表达(上调)基因。共获得87个克隆并测序，其中78个克隆与数据库中的已知基因同源。其中，对氨基转运蛋白基因(CpAMT1)进行了详细的分析。实时荧光定量聚合酶链式反应显示，PFA显著诱导CpAMT1的表达，且CpAMT1的表达与脂质蓄积有关。谷氨酰胺抑制CpAMT1的上调，同时也抑制脂质的生物合成。进一步的分析表明，CpAMT1的表达与谷氨酰胺合成酶活性相关，这表明CpAMT1与谷氨酰胺合成酶/谷氨酸合成酶一起可能参与了原盖刺蛾对氮素的感知。综上所述，这些结果表明，氨转运蛋白CpAMT1可能是缺氮的初始感受器，并将过剩的碳引导到脂质的生物合成中。
A suppression subtractive hybridization cDNA library was used to screen the differently expressed (up-regulated) genes in the photosynthesis–fermentation approach (PFA) ofChlorella protothecoidescultivation. A total of 87 clones were obtained and sequenced, in which 78 clones were homologous to known genes in databases. Among them, the ammonium transporter gene (CpAMT1) was characterized in detail. Quantitative real-time PCR showed that the expression ofCpAMT1was significantly induced by PFA and correlated with lipid accumulation. The up-regulation ofCpAMT1was suppressed by glutamine, while the lipid biosynthesis was also inhibited. Further analysis showed that the expression ofCpAMT1was correlated with glutamine synthetase activity, suggesting thatCpAMT1, along with glutamine synthetase/glutamate synthase, may be responsible for nitrogen sensing inC.protothecoides. Together, these results imply that the ammonium transporterCpAMT1could be the initial sensor of nitrogen deficiency and channels the carbon excess toward lipid biosynthesis.