The Miscanthus NAC transcription factor MlNAC9 enhances abiotic stress tolerance in transgenic Arabidopsis
The Miscanthus NAC transcription factor MlNAC9 enhances abiotic stress tolerance in transgenic Arabidopsis
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芒草 NAC 转录因子 MlNAC9 增强转基因拟南芥的非生物胁迫耐受性
DOI：
10.1016/j.gene.2016.04.028
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发表时间：
2016
期刊：
影响因子：
3.5
通讯作者：
Gongke Zhou
中科院分区：
文献类型：
--
作者：
Xun Zhao;Xuanwen Yang;Shengqiang Pei;Guo He;Xiaoyu Wang;Qi Tang;Chunlin Jia;Ying Lu;Ruibo Hu;Gongke Zhou
NAC （NAM、ATAF1/2和CUC2）转录因子在植物对非生物胁迫的响应中起重要作用。目前，关于NAC基因在芒草（miscanthus lutarioriparius）中抗逆性中的功能作用的信息很少，芒草是一种有前途的纤维素乙醇生产生物能源植物。在本研究中，我们对mlnac9在非生物胁迫中的功能进行了表征。MlNAC9被证明是一个核局部转录激活子，其激活域位于其c端。mlnac9在拟南芥中的过表达导致了种子萌发和根伸长阶段对脱落酸（ABA）的超敏感性。此外，在盐（NaCl）处理下，mlnac9过表达导致种子发芽率和根系生长增加。同时，转基因拟南芥过表达基因mlnac9对干旱和寒冷胁迫的耐受性增强。在ABA、干旱、盐和冷胁迫下，与WT相比，mlnac9过表达系的应激响应标记基因的表达显著增加。干旱和盐胁迫下，mlnac9过表达系抗氧化酶超氧化物歧化酶（SOD）、过氧化物酶（POD）和过氧化氢酶（CAT）活性显著升高，丙二醛（MDA）含量显著降低。这些结果表明，过表达mlnac9通过aba依赖途径提高了转基因植株对非生物胁迫的耐受性，转基因植株的耐受性增强主要归因于胁迫应答基因的表达增加和活性氧（ROS）的清除能力增强。
NAC (NAM, ATAF1/2, and CUC2) transcription factors are known to play important roles in responses to abiotic stresses in plants. Currently, little information regarding the functional roles of NAC genes in stress tolerance is available inMiscanthus lutarioriparius, a promising bioenergy plant for cellulosic ethanol production. In this study, we carried out the functional characterization ofMlNAC9in abiotic stresses. MlNAC9 was shown to act as a nuclear localized transcription activator with the activation domain in its C-terminus. The overexpression ofMlNAC9in Arabidopsis conferred hypersensitivity to abscisic acid (ABA) at seed germination and root elongation stages. In addition, the overexpression ofMlNAC9led to increased seed germination rate and root growth under salt (NaCl) treatment. Meanwhile, the transgenicArabidopsisoverexpressingMlNAC9showed enhanced tolerance to drought and cold stresses. The expression of stress-responsive marker genes was significantly increased inMlNAC9overexpression lines compared to that of WT under ABA, drought, salt, and cold stresses. Correspondingly, the activities of antioxidant enzymes superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) were significantly increased and the malondialdehyde (MDA) content was lower accumulated inMlNAC9overexpression lines under drought and salt treatments. These results indicated that the overexpression ofMlNAC9improved the tolerance to abiotic stresses via an ABA-dependent pathway, and the enhanced tolerance of transgenic plants was mainly attributed to the increased expression of stress-responsive genes and the enhanced scavenging capability of reactive oxygen species (ROS).