Transcriptional profile of genes involved in ascorbate glutathione cycle in senescing leaves for an early senescence leaf (esl) rice mutant
Transcriptional profile of genes involved in ascorbate glutathione cycle in senescing leaves for an early senescence leaf (esl) rice mutant
复制标题
早期衰老叶（ESL）水稻突变体衰老叶中参与抗坏血酸谷胱甘肽循环的基因的转录谱
DOI：
10.1016/j.jplph.2014.09.020
复制
发表时间：
2015-03-15
影响因子：
4.3
通讯作者：
Cheng, Fangmin
中科院分区：
文献类型：
--
作者：
Li, Zhaowei;Su, Da;Cheng, Fangmin
为了阐明抗坏血酸-谷胱甘肽（AsA-GSH）循环与H2O2诱导的叶片衰老之间的复杂关系，利用两种水稻基因型（即早期衰老叶片（esl）突变体及其野生型）研究了一些衰老相关生理参数的基因型依赖性差异以及叶片衰老过程中参与AsA-GSH循环的基因的转录水平和时间模式。同时，利用离体叶片检测了外源H2O2对OsAPX基因表达的触发作用。结果表明，esl突变体在叶片衰老初期比野生型具有更高的H2O2水平。在转录水平上，参与 AsA-GSH 循环的各种基因的表达与叶片衰老的关联是异构体依赖性的。对于 OsAPX，两个胞质 OsAPX 基因（OsAPX1 和 OsAPX2）、类囊体结合的 OsAPX8、叶绿体 OsAPX7 和过氧化物酶体 OsAPX4 的转录本在叶片衰老过程中的表达水平和时间模式上表现出显着的基因型依赖性变化，OsAXP1 和 OsAPX7 的转录本显着增加，OsAPX7 的转录本严重抑制 OsAPX4 和 OsAPX8 用于 esl 水稻在叶子初始衰老时的情况。相比之下，OsAPX8 的抑制转录本对衰老水稻叶片中 H2O2 水平的增加高度敏感，而较高的 H2O2 浓度导致两个胞质 OsAPX 基因的转录本增强，OsAPX7 转录本随 H2O2 浓度和孵育时间的不同而变化很大，表明不同的 OsAPXs 亚型在感知和感知方面发挥着互补作用。 清除叶片衰老过程中不同 H2O2 浓度下的 H2O2 积累。 esl突变体叶片中较高的H2O2水平、较高的AsA水平、较高的APX和谷胱甘肽还原酶(GR)活性以及在整个采样期间相对稳定的GSH含量表明水稻叶片衰老过程中AsA水平与APX活性之间存在密切的相互关系。尽管两种水稻基因型之间的 GR 活性存在与衰老相关的变化，但水稻叶片中的 GSH 供应并不是有效维持 AsA-GSH 循环的限制因素。 (C) 2014 年爱思唯尔有限公司。版权所有。
To clarify the complex relationship between ascorbate-glutathione (AsA-GSH) cycle and H2O2-induced leaf senescence, the genotype-dependent difference in some senescence-related physiological parameters and the transcript levels and the temporal patterns of genes involved in the AsA-GSH cycle during leaf senescence were investigated using two rice genotypes, namely, the early senescence leaf (esl) mutant and its wild type. Meanwhile, the triggering effect of exogenous H2O2 on the expression of OsAPX genes was examined using detached leaves. The results showed that the esl mutant had higher H2O2 level than its wild type at the initial stage of leaf senescence. At transcriptional level, the association of expression of various genes involved in the AsA-GSH cycle with leaf senescence was isoform dependent. For OsAPXs, the transcripts of two cytosolic OsAPX genes (OsAPX1 and OsAPX2), thylakoid-bound OsAPX8, chloroplastic OsAPX7 and peroxisomal OsAPX4 exhibited remarkable genotype-dependent variation in their expression levels and temporal patterns during leaf senescence, there were significantly increasing transcripts of OsAXP1 and OsAPX7, severely repressed transcripts of OsAPX4 and OsAPX8 for the esl rice at the initial leaf senescence. In contrast, the repressing transcript of OsAPX8 was highly sensitive to the increasing H2O2 level in the senescing rice leaves, while higher H2O2 concentration resulted in the enhancing transcripts of two cytosolic OsAPX genes, OsAPX7 transcript was greatly variable with different H2O2 concentrations and incubating duration, suggesting that the different OsAPXs isoforms played a complementary role in perceiving and scavenging H2O2 accumulation at various H2O2 concentrations during leaf senescence. Higher H2O2 level, increased AsA level, higher activities of APX and glutathione reductase (GR), and relatively stable GSH content during the entire sampling period in the leaves of esl mutant implied that a close interrelationship existed between AsA level and APX activity in the ongoing senescence of rice leaves. The GSH supply in rice leaves was not the limiting factor for the efficient maintenance of AsA-GSH cycle, despite the senescence-related change in GR activity between the two rice genotypes. (C) 2014 Elsevier GmbH. All rights reserved.