AtTGA4, a bZIP transcription factor, confers drought resistance by enhancing nitrate transport and assimilation in Arabidopsis thaliana.
AtTGA4, a bZIP transcription factor, confers drought resistance by enhancing nitrate transport and assimilation in Arabidopsis thaliana.
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DOI：
10.1016/j.bbrc.2015.01.009
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发表时间：
2015-02
影响因子：
3.1
通讯作者：
Li Zhong;Dandan Chen;Dong-hong Min;Weiwei Li;Zhaoshi Xu;Yongbin Zhou;Lian-cheng Li;Ming Chen
中科院分区：
文献类型：
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作者：
Li Zhong;Dandan Chen;Dong-hong Min;Weiwei Li;Zhaoshi Xu;Yongbin Zhou;Lian-cheng Li;Ming Chen
为了应对全球气候变化和过量施氮造成的环境压力，提高作物水和氮的利用效率非常重要。据报道，较高的氮吸收量可以减轻干旱胁迫的破坏性影响。然而，没有足够的证据来解释氮吸收如何影响抗旱性。在这项研究中，我们观察到bZIP转录因子AtTGA4（TGACG基序结合因子4）是由干旱和低氮胁迫诱导的，并且AtTGA4的过度表达同时提高了拟南芥的抗旱性并减少了氮饥饿。干旱胁迫后，转基因AtTGA4植物中的氮和脯氨酸含量高于野生型对照，并且参与硝酸盐同化过程的关键酶亚硝酸还原酶(NIR)的活性也更高。转基因植株中高亲和力硝酸盐转运蛋白基因NRT2.1和NRT2.2以及硝酸盐还原酶基因NIA1和NIA2的表达量均高于野生型，表明较高水平的硝酸盐转运和同化活性有助于AtTGA4转基因植株的抗旱性增强。因此，AtTGA4的遗传转化可能提供一种同时提高作物对干旱和低氮胁迫的耐受性的新方法。
To cope with environmental stress caused by global climate change and excessive nitrogen application, it is important to improve water and nitrogen use efficiencies in crop plants. It has been reported that higher nitrogen uptake could alleviate the damaging impact of drought stress. However, there is scant evidence to explain how nitrogen uptake affects drought resistance. In this study we observed that bZIP transcription factorAtTGA4(TGACG motif-binding factor 4) was induced by both drought and low nitrogen stresses, and that overexpression ofAtTGA4simultaneously improved drought resistance and reduced nitrogen starvation inArabidopsis. Following drought stress there were higher nitrogen and proline contents in transgenicAtTGA4plants than in wild type controls, and activity of the key enzyme nitrite reductase (NIR) involved in nitrate assimilation processes was also higher. Expressions of the high-affinity nitrate transporter genesNRT2.1andNRT2.2and nitrate reductase genesNIA1andNIA2in transgenic plants were all higher than in wild type indicating that higher levels of nitrate transport and assimilation activity contributed to enhanced drought resistance ofAtTGA4transgenic plants. Thus genetic transformation withAtTGA4may provide a new approach to simultaneously improve crop tolerance to drought and low nitrogen stresses.