PDF(Pubmed)
Abstract：
Single cell C4 (SCC4) plants, discovered around two decades ago, are promising materials for efforts for genetic engineering of C4 photosynthesis into C3 crops. Unlike C4 plants with Kranz anatomy, they exhibit a fully functional C4 photosynthesis in just a single cell and do not require mesophyll and bundle sheath cell spatial separation. Bienertia sinuspersici is one such SCC4 plant, with NAD-malic enzyme (NAD-ME) subtype C4 photosynthesis. Its chlorenchyma cell consist of two compartments, peripheral compartment (PC), analogous to mesophyll cell, and central compartment (CC), analogous to bundle sheath cell. Since oxidative stress creates an important constraint for plants under salinity and drought, we comparatively examined the response of enzymatic antioxidant system, H2O2 and TBARS contents, peroxiredoxin Q, NADPH thioredoxin reductase C, and plastid terminal oxidase protein levels of PC chloroplasts (PCC) and CC chloroplasts (CCC). Except for protein levels, these parameters were also examined on the whole leaf level, as well as catalase and NADPH oxidase activities, water status and growth parameters, and levels of C4 photosynthesis related transcripts. Many C4 photosynthesis related transcript levels were elevated, especially under drought. Activities of dehydroascorbate reductase and especially peroxidase were elevated under drought in both compartments (CCC and PCC). Even though decreases of antioxidant enzyme activities were more prevalent in PCC, and the examined redox regulating protein levels, especially of peroxiredoxin Q, were elevated in CCC under both stresses, PCC was less damaged by either stress. These suggest PCC is more tolerant and has other means of preventing or alleviating oxidative damage.
摘要：
单细胞C4（SCC4）植物，大约二十年前发现的，是将C4光合作用基因工程改造成C3作物的有前途的材料。与具有Kranz解剖结构的C4植物不同，它们仅在单个细胞中表现出功能齐全的C4光合作用，不需要叶肉和束鞘细胞空间分离。Sinsulpersici是这样一种SCC4植物，与NAD-苹果酸酶（NAD-ME）亚型C4光合作用。它的chlorenchyma细胞由两个隔室组成，外围隔间(PC)，类似于叶肉细胞，和中央隔间(CC)，类似于束鞘细胞。由于氧化应激对盐分和干旱下的植物产生了重要的约束，我们比较研究了酶促抗氧化系统的反应，H2O2和TBARS含量，过氧化物酶Q,NADPH硫氧还蛋白还原酶C,PC叶绿体（PCC）和CC叶绿体（CCC）的质体末端氧化酶蛋白水平。除了蛋白质水平,这些参数也在整个叶片水平上进行了检查，以及过氧化氢酶和NADPH氧化酶活性，水分状况和生长参数，和C4光合作用相关转录物的水平。许多C4光合作用相关的转录水平升高，尤其是在干旱的情况下。在干旱下，两个区室（CCC和PCC）的脱氢抗坏血酸还原酶，尤其是过氧化物酶的活性均升高。尽管抗氧化酶活性的降低在PCC中更为普遍，和检测的氧化还原调节蛋白水平，尤其是过氧化物酶Q,在两种应力下都在CCC中升高，PCC受到两种压力的损害较小。这些表明PCC更具耐受性，并具有其他预防或减轻氧化损伤的方法。
