遗传 ›› 2018, Vol. 40 ›› Issue (4): 327-338.doi: 10.16288/j.yczz.17-315

• 研究报告 • 上一篇    下一篇

谷子MYB类转录因子SiMYB42提高转基因拟南芥低氮胁迫耐性

丁庆倩1,王小婷1,2,胡利琴1,齐欣1,葛林豪1,徐伟亚1,徐兆师1,周永斌1,2,贾冠清1,刁现民1,闵东红2,马有志1,陈明1()   

  1. 1. 中国农业科学院作物科学研究所,农作物基因资源与基因改良国家重大科学工程,农业部麦类生物学与遗传育种重点实验室,北京 100081
    2. 西北农林科技大学农学院,旱区作物逆境生物学国家重点实验室,杨凌 712100
  • 收稿日期:2017-09-25 修回日期:2018-01-02 出版日期:2018-04-20 发布日期:2018-03-12
  • 通讯作者: 陈明 E-mail:chenming02@caas.cn
  • 作者简介:王小婷,在读博士研究生,专业方向：生物化学与分子生物学。E-mail: 1534270156@qq.com|丁庆倩,在读硕士研究生,专业方向：生物化学与分子生物学。E-mail: 905890270@qq.com
  • 基金资助:
    国家转基因生物新品种培育重大专项(2016ZX08002005);中国农业科学院科技创新工程项目资助

MYB-like transcription factor SiMYB42 from foxtail millet (Setaria italica L.) enhances Arabidopsis tolerance to low-nitrogen stress

Qingqian Ding1,Xiaoting Wang1,2,Liqin Hu1,Xin Qi1,Linhao Ge1,Weiya XU1,Zhaoshi Xu1,Yongbin Zhou1,2,Guanqing Jia1,Xianmin Diao1,Donghong Min2,Youzhi Ma1,Ming Chen1()   

  1. 1. National Key Facility For Crop Gene Resource and Genetic Improvement, Key Laboratory of Biology and Genetic Improvement of Triticeae Crop, Ministry of Agriculture, Institute of Crop Science, Chinese Academy of Agricultural Sciences, Beijing 100081, China
    2. State Key Laboratory of Arid Region Crop Adversity Biology, College of Agronomy, Northwest A＆F University, Yangling 712100, China
  • Received:2017-09-25 Revised:2018-01-02 Online:2018-04-20 Published:2018-03-12
  • Contact: Chen Ming E-mail:chenming02@caas.cn
  • Supported by:
    Supported by the National Majar Project for Developing New GM Crops(2016ZX08002005);the Innovation Project of Chinese Academy of Agricultural Sciences

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摘要：

Myeloblastosis (MYB)类转录因子是高等植物中最大的转录因子家族之一,在植物发育及防御反应过程中发挥重要作用,还参与植物对干旱等非生物胁迫的响应。谷子(Setaria italica L.)起源于中国,具有抗旱、耐瘠薄的特性,是研究单子叶作物非生物胁迫抗性的理想材料。本研究对耐低氮胁迫谷子品种郑204经低氮处理后进行转录组分析,鉴定出一个在低氮胁迫条件下明显上调的MYB类转录因子SiMYB42。系统发育树结果表明,SiMYB42属于R2R3-MYB亚族,具有2个MYB保守域;表达模式分析显示,SiMYB42在低氮、高盐、干旱和ABA胁迫条件下表达量显著上调;亚细胞定位、quantitative real-time PCR及转录激活活性分析结果表明,SiMYB42蛋白定位于植物的细胞核和细胞膜中,主要在谷子的叶部或根部表达,具有转录激活活性;基因功能分析结果表明,在正常条件下,转SiMYB42基因拟南芥与野生型Columbia-0拟南芥(WT)无明显差异,但在低氮条件下,转SiMYB42基因拟南芥的主根长、根系表面积及鲜重均显著高于WT,结果证明SiMYB42基因可以提高转基因植物对低氮胁迫的耐性;下游基因表达分析结果显示,在转SiMYB42基因拟南芥中,参与植物氮素转运的硝酸盐转运基因NRT2.1、NRT2.4和NRT2.5的表达水平均高于WT,启动子分析结果显示NRT2.1、NRT2.4和NRT2.5基因启动子序列中均具有MYB结合位点。以上结果证明,SiMYB42可以通过调控下游硝酸盐转运体基因的表达提高植物在低氮条件下的耐性。本研究揭示了SiMYB42基因在低氮胁迫反应途径中的作用,为进一步了解谷子低氮胁迫响应的调控网络奠定了基础。

关键词: 谷子(Setaria italica L.), MYB类转录因子, 低氮胁迫, 基因表达分析, 基因功能分析

Abstract:

Myeloblastosis (MYB) transcription factors are one of the largest families of transcription factors in higher plants. They play an important role in plant development, defense response processes, and non-biological stresses, i.e., drought stress. Foxtail millet (Setaria italica L.), originated in China, is resistant to drought and low nutrition stresses and has been regarded as an ideal material for studying abiotic stress resistance in monocotyledon. In this study, we ran a transcription profile analysis of zheng 204 under low-nitrogen conditions and identified a MYB-like transcription factor SiMYB42, which was up-regulated under low-nitrogen stress. Phylogenetic tree analysis showed that SiMYB42 belongs to R2R3-MYB subfamily and has two MYB conserved domains. Expression pattern analysis showed that SiMYB42 was significantly up-regulated under various stress conditions, including low-nitrogen stress, high salt, drought and ABA conditions. The results of subcellular localization, quantitative real-time PCR and transcriptional activation analysis indicated that SiMYB42 protein localizes to the nucleus and cell membrane of plant cells, mainly expressed in the leaf or root of foxtail millet, and has transcription activation activity. Functional analysis showed that there was no significant difference between transgenic SiMYB42 Arabidopsis and wild-type (WT) Arabidopsis under normal conditions; however, under low-nitrogen condition, the root length, surface area and seedling fresh weight in transgenic SiMYB42 Arabidopsis, were significantly higher than their counterparts in WT. These results suggest that SiMYB42 transgenic plants exhibit higher tolerance to low-nitrogen stress. Expression levels of nitrate transporters genes NRT2.1, NRT2.4 and NRT2.5, which are the transcriptional targets of SiMYB42, were higher in transgenic SiMYB42 Arabidopsis plants than those in WT; the promoter regions of NRT2.1, NRT2.4 and NRT2.5 all have MYB binding sites. These results indicate that SiMYB42 might enhance foxtail millet tolerance to low-nitrogen condition through regulating the expression of nitrate transporter genes. This study reveals the possible functions of SiMYB42 in a low-nitrogen stress response pathway, and provides a foundation for further understanding the entire regulation network of foxtail millet in response to low-nitrogen stress.

Key words: foxtail millet (Setaria italica L.), MYB-like transcription factor, low-nitrogen stress, gene expression analysis, gene function analysis