在光合作用过程中,形成活性氧(ROS),包括过氧化氢(H2O2)和单线态氧(1O2),它们在信号中具有推定的作用,但它们在光合适应中的参与尚不清楚。由于极端的反应性和短暂的寿命,1O2信号通过其反应产物发生,例如类囊体膜中的氧化多不饱和脂肪酸。所得的脂质过氧化物衰变为各种醛和反应性亲电物质(RES)。这里,我们研究了ROS在强光(HL)信号转导中的作用,专注于光合生物特有的GreenCut2基因。使用RNAseq。数据,将莱茵衣藻对2hHL的转录反应与弱光下对外源RES(丙烯醛;4-羟基壬烯醛)的反应进行了比较,β-环二尖瓣,β-胡萝卜素氧化产物,以及玫瑰孟加拉,产生1O2的光敏剂,和H2O2。HL诱导108和23个GreenCut2基因显著(p<0.05)上调和下调,分别。在所有HL上调基因中,超过一半的人也被RES上调,包括RBCS1(核糖二磷酸羧化酶小亚基),与NPQ相关的PSBS1和LHCSR1。此外,96%的基因下调HL也下调1O2或RES,包括CAO1(叶绿素-α氧合酶),MDH2(NADP-苹果酸脱氢酶)和PGM4(磷酸甘油酸变位酶)用于糖酵解。相比之下,只有0-4%的HL影响的GreenCut2基因受到H2O2或β-cycitral的类似影响。总的来说,通过上调光保护和碳同化以及下调特定的主要代谢途径,1O2在莱茵衣原体对HL的初始适应过程中在信号传导中起着重要作用。我们的数据支持该途径涉及RES。
During photosynthesis, reactive oxygen species (ROS) are formed, including hydrogen peroxide (H2O2) and singlet oxygen (1O2), which have putative roles in signalling, but their involvement in photosynthetic acclimation is unclear. Due to extreme reactivity and a short lifetime, 1O2 signalling occurs via its reaction products, such as oxidised poly-unsaturated fatty acids in thylakoid membranes. The resulting lipid peroxides decay to various aldehydes and reactive electrophile species (RES). Here, we investigated the role of ROS in the signal transduction of high light (HL), focusing on GreenCut2 genes unique to photosynthetic organisms. Using RNA seq. data, the transcriptional responses of Chlamydomonas reinhardtii to 2 h HL were compared with responses under low light to exogenous RES (acrolein; 4-hydroxynonenal), β-cyclocitral, a β-carotene oxidation product, as well as Rose Bengal, a 1O2-producing photosensitiser, and H2O2. HL induced significant (p < 0.05) up- and down-regulation of 108 and 23 GreenCut2 genes, respectively. Of all HL up-regulated genes, over half were also up-regulated by RES, including RBCS1 (ribulose bisphosphate carboxylase small subunit), NPQ-related PSBS1 and LHCSR1. Furthermore, 96% of the genes down-regulated by HL were also down-regulated by 1O2 or RES, including CAO1 (chlorophyllide-a oxygnease), MDH2 (NADP-malate dehydrogenase) and PGM4 (phosphoglycerate mutase) for glycolysis. In comparison, only 0-4% of HL-affected GreenCut2 genes were similarly affected by H2O2 or β-cyclocitral. Overall, 1O2 plays a significant role in signalling during the initial acclimation of C. reinhardtii to HL by up-regulating photo-protection and carbon assimilation and down-regulating specific primary metabolic pathways. Our data support that this pathway involves RES.