Centre for Plant Sciences, Faculty of Biology, University of Leeds, Leeds, UK.
Philos Trans R Soc Lond B Biol Sci. 2012 Dec 19;367(1608):3475-85. doi: 10.1098/rstb.2012.0068.
Redox chemistry and redox regulation are central to the operation of photosynthesis and respiration. However, the roles of different oxidants and antioxidants in the regulation of photosynthetic or respiratory gene expression remain poorly understood. Leaf transcriptome profiles of a range of Arabidopsis thaliana genotypes that are deficient in either hydrogen peroxide processing enzymes or in low molecular weight antioxidant were therefore compared to determine how different antioxidant systems that process hydrogen peroxide influence transcripts encoding proteins targeted to the chloroplasts or mitochondria. Less than 10 per cent overlap was observed in the transcriptome patterns of leaves that are deficient in either photorespiratory (catalase (cat)2) or chloroplastic (thylakoid ascorbate peroxidase (tapx)) hydrogen peroxide processing. Transcripts encoding photosystem II (PSII) repair cycle components were lower in glutathione-deficient leaves, as were the thylakoid NAD(P)H (nicotinamide adenine dinucleotide (phosphate)) dehydrogenases (NDH) mRNAs. Some thylakoid NDH mRNAs were also less abundant in tAPX-deficient and ascorbate-deficient leaves. Transcripts encoding the external and internal respiratory NDHs were increased by low glutathione and low ascorbate. Regulation of transcripts encoding specific components of the photosynthetic and respiratory electron transport chains by hydrogen peroxide, ascorbate and glutathione may serve to balance non-cyclic and cyclic electron flow pathways in relation to oxidant production and reductant availability.
氧化还原化学和氧化还原调节是光合作用和呼吸作用的核心。然而，不同氧化剂和抗氧化剂在调节光合作用或呼吸作用基因表达中的作用仍知之甚少。因此，比较了一系列拟南芥基因型的叶片转录组谱，这些基因型缺乏过氧化氢处理酶或小分子抗氧化剂，以确定不同的抗氧化系统如何处理过氧化氢影响编码靶向叶绿体或线粒体的蛋白质的转录物。在缺乏光呼吸（过氧化氢处理的过氧化氢酶 (cat)2）或质体（类囊体抗坏血酸过氧化物酶 (tapx)）的叶片的转录组模式中，观察到小于 10%的重叠。谷胱甘肽缺乏的叶片中光合作用 II (PSII) 修复循环组件的转录物较低，类囊体 NAD(P)H（烟酰胺腺嘌呤二核苷酸 (磷酸)）脱氢酶 (NDH) mRNAs 也是如此。在 tAPX 缺乏和抗坏血酸缺乏的叶片中，一些类囊体 NDH mRNAs 的丰度也较低。外部和内部呼吸 NDH 的转录物编码物被低谷胱甘肽和低抗坏血酸增加。过氧化氢、抗坏血酸和谷胱甘肽对光合作用和呼吸电子传递链特定成分的转录物的调节可能有助于平衡非循环和循环电子流动途径与氧化剂产生和还原剂可用性的关系。
