Zhang Yan, Li Zhou, Peng Yan, Wang Xiaojuan, Peng Dandan, Li Yaping, He Xiaoshuang, Zhang Xinquan, Ma Xiao, Huang Linkai, Yan Yanhong
College of Animal Science and Technology, Sichuan Agricultural University, Chengdu 611130, China.
Molecules. 2015 Nov 24;20(11):20939-54. doi: 10.3390/molecules201119741.
Increased transcriptional levels of genes encoding antioxidant enzymes play important protective roles in coping with excessive accumulation of reactive oxygen species (ROS) in plants exposed to various abiotic stresses. To fully elucidate different evolutions and functions of ROS-scavenging enzymatic genes, we isolated iron superoxide dismutase (FeSOD), dehydroascorbate reductase (DHAR) and monodehydroascorbate reductase (MDHAR) from white clover for the first time and subsequently tested dynamic expression profiles of these genes together with previously identified other antioxidant enzyme genes including copper zinc superoxide dismutase (Cu/ZnSOD), manganese superoxide dismutase (MnSOD), glutathione reductase (GR), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX) in response to cold, drought, salinity, cadmium stress and exogenous abscisic acid (ABA) or spermidine (Spd) treatment. The cloned fragments of FeSOD, DHAR and MDHAR genes were 630, 471 and 669 bp nucleotide sequences encoding 210, 157 and 223 amino acids, respectively. Phylogenetic analysis indicated that both amino acid and nucleotide sequences of these three genes are highly conservative. In addition, the analysis of genes expression showed the transcription of GR, POD, MDHAR, DHAR and Cu/ZnSOD were rapidly activated with relatively high abundance during cold stress. Differently, CAT, APX, FeSOD, Cu/ZnSOD and MnSOD exhibited more abundant transcripts compared to others under drought stress. Under salt stress, CAT was induced preferentially (3-12 h) compared to GR which was induced later (12-72 h). Cadmium stress mainly up-regulated Cu/ZnSOD, DHAR and MDHAR. Interestingly, most of genes expression induced by ABA or Spd happened prior to various abiotic stresses. The particular expression patterns and different response time of these genes indicated that white clover differentially activates genes encoding antioxidant enzymes to mitigate the damage of ROS during various environmental stresses.
编码抗氧化酶的基因转录水平升高，在应对暴露于各种非生物胁迫的植物中活性氧（ROS）的过度积累方面发挥着重要的保护作用。为了全面阐明ROS清除酶基因的不同进化和功能，我们首次从白三叶中分离出铁超氧化物歧化酶（FeSOD）、脱氢抗坏血酸还原酶（DHAR）和单脱氢抗坏血酸还原酶（MDHAR），随后测试了这些基因与先前鉴定的其他抗氧化酶基因（包括铜锌超氧化物歧化酶（Cu/ZnSOD）、锰超氧化物歧化酶（MnSOD）、谷胱甘肽还原酶（GR）、过氧化物酶（POD）、过氧化氢酶（CAT）和抗坏血酸过氧化物酶（APX））在响应冷、干旱、盐度、镉胁迫以及外源脱落酸（ABA）或亚精胺（Spd）处理时的动态表达谱。FeSOD、DHAR和MDHAR基因的克隆片段分别为630、471和669 bp的核苷酸序列，分别编码210、157和223个氨基酸。系统发育分析表明，这三个基因的氨基酸和核苷酸序列都高度保守。此外，基因表达分析表明，在冷胁迫期间，GR、POD、MDHAR、DHAR和Cu/ZnSOD的转录被迅速激活，且丰度相对较高。不同的是，在干旱胁迫下，CAT、APX、FeSOD、Cu/ZnSOD和MnSOD的转录本比其他基因更丰富。在盐胁迫下，与GR（在12 - 72小时后被诱导）相比，CAT优先被诱导（3 - 12小时）。镉胁迫主要上调Cu/ZnSOD、DHAR和MDHAR。有趣的是，ABA或Spd诱导的大多数基因表达发生在各种非生物胁迫之前。这些基因的特定表达模式和不同的响应时间表明，白三叶在各种环境胁迫期间差异激活编码抗氧化酶的基因，以减轻ROS的损伤。
