Wang Fubiao, Liu Jianchao, Zhou Lujian, Pan Gang, Li Zhaowei, Zaidi Syed-Hassan-Raza, Cheng Fangmin
Institute of Crop Science, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, 310058, China; Jiangsu Collaborative Innovation Center for Modern Crop Production, Nanjing, China.
Institute of Crop Science, College of Agriculture and Biotechnology, Zhejiang University, Hangzhou, 310058, China.
Plant Physiol Biochem. 2016 Dec;109:248-261. doi: 10.1016/j.plaphy.2016.10.005. Epub 2016 Oct 11.
To clarify the interaction between different antioxidant enzymes for monitoring oxidative stress and ROS burst in rice senescent leaves, we investigated the genotype-dependent alteration in temporal patterns of the O production rate, HO content, and ROS-scavenging enzyme activities during leaf senescence in two rice genotypes, namely, the premature senescence of flag leaf (psf) mutant and its wild type. Results showed that the psf mutant differed obviously from its wild type in leaf O generation rate and HO content accumulation, and the decreased activities of SOD, CAT, and APX in the psf leaves were strongly responsible for the increased ROS level and the accelerated leaf senescence. By contrast, the increase in POD activity was positively correlated with the senescence-related enhancement in O generation in rice leaves. Among various SOD isoforms, Mn-SOD responded sensitively to the increasing O generation rate, whereas Cu/Zn-SOD remained stable with the progression of leaf senescence. These findings suggest that the senescence-related decline in total SOD activity was mostly attributable to the downregulation of both the translation and transcription of Mn-SOD isoform. This occurrence finally resulted in the collapse of SOD defense system and accelerated leaf senescence for the psf mutant. Furthermore, we presented the possible contribution of several Cu/Zn-SOD expression patterns to the senescence-related O detoxification in different cell compartments.
为了阐明不同抗氧化酶之间的相互作用，以监测水稻衰老叶片中的氧化应激和活性氧爆发，我们研究了两种水稻基因型（即旗叶早衰（psf）突变体及其野生型）在叶片衰老过程中O产生速率、HO含量和活性氧清除酶活性的时间模式的基因型依赖性变化。结果表明，psf突变体在叶片O生成速率和HO含量积累方面与野生型明显不同，psf叶片中SOD、CAT和APX活性的降低是导致活性氧水平升高和叶片衰老加速的主要原因。相比之下，POD活性的增加与水稻叶片中与衰老相关的O生成增强呈正相关。在各种SOD同工型中，Mn-SOD对O生成速率的增加反应敏感，而Cu/Zn-SOD随着叶片衰老的进展保持稳定。这些发现表明，与衰老相关的总SOD活性下降主要归因于Mn-SOD同工型的翻译和转录下调。这种情况最终导致psf突变体的SOD防御系统崩溃和叶片衰老加速。此外，我们还展示了几种Cu/Zn-SOD表达模式对不同细胞区室中与衰老相关的O解毒的可能贡献。
