Molecular characterization of novel TaNAC genes in wheat and overexpression of TaNAC2a confers drought tolerance in tobacco.
Molecular characterization of novel TaNAC genes in wheat and overexpression of TaNAC2a confers drought tolerance in tobacco.
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DOI：
10.1111/j.1399-3054.2011.01539.x
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发表时间：
2012-03
影响因子：
6.4
通讯作者：
Yimiao Tang;Mei-ying Liu;Shi-Qing Gao;Zhao Zhang;Xin Zhao;Changping Zhao;Feng-ting Zhang;Xue-ping Chen
中科院分区：
文献类型：
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作者：
Yimiao Tang;Mei-ying Liu;Shi-Qing Gao;Zhao Zhang;Xin Zhao;Changping Zhao;Feng-ting Zhang;Xue-ping Chen
植物特异性NAC （NAM/ATAF/CUC）转录因子（TFs）已被报道在多种胁迫反应和发育过程中发挥作用。作者在小麦（Triticum aestivum）中发现了6个编码NAC TFs的新基因（分别命名为TaNAC2a、TaNAC4a、TaNAC6、TaNAC7、TaNAC13和TaNTL5），并通过系统发育分析将其分为应激相关NACs、发育相关NACs和属于NAC的膜相关TFs 3类。所有的TaNACs均受到脱水、盐度和低温等一种或几种胁迫处理的诱导，但不同基因的表达水平不同。这些TaNACs除TaNAC7外，均在酵母菌AH109中具有转录激活活性。此外，亚细胞定位分析显示，4个TaNAC:GFP（绿色荧光蛋白）融合蛋白定位于细胞核，TaNAC2a:GFP主要定位于细胞核和质膜，TaNTL5:GFP与膜相关，而截断的TaNTL5（ΔTM）：GFP（缺乏跨膜基序）仅在细胞核中检测到。半定量反转录聚合酶链反应分析表明，5个基因表现出器官特异性表达。在干旱条件下，过表达TaNAC2a的转基因烟草鲜重和干重均高于非转基因烟草，表明转基因烟草提高了烟草的抗旱能力。总之，这些结果提供了六种TaNACs的初步特征，这些TaNACs具有提高小麦抗逆性和调节发育的潜在作用，并表明TaNAC2a在工程抗旱植物中具有潜在的用途。
Plant-specific NAC (NAM/ATAF/CUC) transcription factors (TFs) have been reported to play a role in diverse stress responses and developmental processes. We show here that six new genes encoding NAC TFs in wheat (Triticum aestivum) were identified (named as TaNAC2a, TaNAC4a, TaNAC6, TaNAC7, TaNAC13 and TaNTL5, respectively), and we classified them into three groups: stress-related NACs, development-related NACs and NTLs (membrane-associated TFs belonging to NAC) by phylogenetic analysis. All TaNACs were induced by one or several kinds of stress treatments including dehydration, salinity and low temperature, whereas different genes showed different expression levels. All these TaNACs, except TaNAC7, were proven to have transcriptional activation activity in the yeast strain AH109 by transactivation analysis. Furthermore, subcellular localization analysis revealed that four TaNAC:GFP (green fluorescent protein) fusion proteins were localized in the nucleus, TaNAC2a:GFP mainly located in the nucleus and the plasma membrane, TaNTL5:GFP was associated with the membrane, while truncated TaNTL5(ΔTM):GFP (lacking the transmembrane motif) was detected exclusively in the nucleus. Semi-quantitative reverse transcription polymerase chain reaction analysis demonstrated that five genes exhibited organ-specific expression. Transgenic tobacco plants overexpressing TaNAC2a showed higher fresh weight and dry weight than non-transgenic plants under drought condition, which indicated that the transgene improved tobacco tolerance to drought treatment. Together, these results provided a preliminary characterization of six TaNACs, which possessed a potential role in improving stress tolerance and the regulation of development in wheat, and suggested that TaNAC2a was potentially useful for engineering drought tolerant plants.