Ji Lu, Hu Ruibo, Jiang Jianxiong, Qi Guang, Yang Xuanwen, Zhu Ming, Fu Chunxiang, Zhou Gongke, Yi Zili
College of Bioscience and Biotechnology, Hunan Agricultural University, Changsha, 410128, Hunan, People's Republic of China.
Plant Cell Rep. 2014 Dec;33(12):2077-92. doi: 10.1007/s00299-014-1682-8. Epub 2014 Sep 16.
The 13 MlNAC genes could respond to various abiotic stresses, suggesting their crucial roles in stress response. Overexpression of MlNAC2 in Arabidopsis led to improved drought tolerance. NAC (NAM, ATAF1/2 and CUC2) proteins are plant-specific transcription factors that play crucial roles in plant development, growth and stress responses. In this study, 13 stress-responsive NAC genes were identified from Miscanthus lutarioriparius. Full-length cDNA sequences were obtained for 11 MlNAC genes, which were phylogenetically classified into six subfamilies. Sequence alignment revealed the highly conserved NAC domain in the N-terminus of these MlNACs, while the C-terminus was highly divergent. We performed quantitative real-time RT-PCR to examine the expression profiles of MlNAC genes in different tissues including root, rhizome, mature stem, young stem, leaf and sheath. The 13 MlNAC genes displayed distinct tissue-specific patterns in six tissues examined. To gain further insight into their roles in response to abiotic stresses, expressions of MlNAC genes were analyzed under different stresses and hormone treatments including salt, drought, cold, wounding, abscisic acid, Methyl jasmonate and salicylic acid. The 13 MlNAC genes could respond to at least five stress treatments, and over 100-fold variations in transcript levels of MlNAC1, MlNAC2, MlNAC4, and MlNAC12 were observed in salt, drought and MeJA treatments, which indicated that MlNACs play crucial roles in stress response. Crosstalk among various abiotic stress and hormone responses was also discussed based on the expression of MlNAC genes. Overexpression of MlNAC2 in Arabidopsis (Col-0) led to improved drought tolerance. The water loss rate was significantly lower, and the recovery rate after a 60-min dehydration stress treatment was significantly higher in the MlNAC2 overexpression lines than the control.
13个芒草NAC基因能够响应多种非生物胁迫，表明它们在胁迫响应中发挥着关键作用。拟南芥中MlNAC2的过表达导致耐旱性提高。NAC（NAM、ATAF1/2和CUC2）蛋白是植物特有的转录因子，在植物发育、生长和胁迫响应中起关键作用。在本研究中，从荻中鉴定出13个胁迫响应NAC基因。获得了11个MlNAC基因的全长cDNA序列，它们在系统发育上被分为6个亚家族。序列比对显示这些MlNACs的N端存在高度保守的NAC结构域，而C端则高度不同。我们进行了定量实时RT-PCR，以检测MlNAC基因在包括根、根茎、成熟茎、幼茎、叶和叶鞘在内的不同组织中的表达谱。13个MlNAC基因在所检测的6个组织中表现出明显的组织特异性模式。为了进一步深入了解它们在响应非生物胁迫中的作用，在不同胁迫和激素处理下分析了MlNAC基因的表达，包括盐、干旱、寒冷、创伤、脱落酸、茉莉酸甲酯和水杨酸。13个MlNAC基因能够响应至少5种胁迫处理，并且在盐、干旱和茉莉酸甲酯处理中观察到MlNAC1、MlNAC2、MlNAC4和MlNAC12转录水平有超过100倍的变化，这表明MlNACs在胁迫响应中起关键作用。还基于MlNAC基因的表达讨论了各种非生物胁迫和激素响应之间的相互作用。拟南芥（Col-０）中MlNAC2的过表达导致耐旱性提高。MlNAC2过表达株系的失水率显著更低，并且在60分钟脱水胁迫处理后的恢复率显著高于对照。
