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草业学报 ›› 2019, Vol. 28 ›› Issue (8): 200-208.DOI: 10.11686/cyxb2019145

• 研究论文 • 上一篇    下一篇

蒺藜苜蓿MtNSN1的克隆与功能分析

张智琦, 王珍, 张铁军, 龙瑞才, 杨青川, 康俊梅*   

  1. 中国农业科学院北京畜牧兽医研究所,北京100193
  • 收稿日期:2019-03-05 出版日期:2019-08-20 发布日期:2019-08-20
  • 通讯作者: *,E-mail: kangjunmei@caas.cn
  • 作者简介:张智琦(1993-),女,内蒙古包头人,硕士。E-mail: suixi_suibuxi@126.com
  • 基金资助:
    国家科技部中欧政府间科技合作重点专项“牧草和豆类作物育种以提高欧盟和中国蛋白质自给”(2017YFE0111000)和中国农业科学院北京畜牧兽医研究所科技创新工程特设项目(ASTIP-IAS-TS-14)资助

Cloning and functional analysis of the MtNSN1 gene in Medicago truncatula

ZHANG Zhi-qi, WANG Zhen, ZHANG Tie-jun, LONG Rui-cai, YANG Qing-chuan, KANG Jun-mei*   

  1. Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing 100193, China
  • Received:2019-03-05 Online:2019-08-20 Published:2019-08-20
  • Contact: *,E-mail: kangjunmei@caas.cn

摘要: 核干因子(NS)是一类广泛存在于动物细胞核中的GTP结合蛋白,主要参与胚的形成和细胞增殖,对维持细胞周期具有重要作用。本研究旨在初探蒺藜苜蓿MtNSN1的表达模式及其对生长发育的调控功能。克隆获得蒺藜苜蓿MtNSN1基因cDNA全长2193 bp,其中开放阅读框为1800 bp,编码599个氨基酸,蛋白分子量133.7 kDa。进化树分析显示MtNSN1与大豆NSN1的氨基酸同源性为66.67%。组织器官表达分析表明,MtNSN1在蒺藜苜蓿花中表达量最高,根次之,叶中表达量最低。RNA原位杂交的结果显示该基因主要在蒺藜苜蓿生长发育活跃的茎尖分生组织及其周围的幼嫩叶中表达。MtNSN1转化野生型拟南芥得到超表达植株,通过统计分析表明超表达植株的主根长度和叶片数量都明显优于野生型。在超表达植株中5个细胞周期标记基因的表达水平均比野生型拟南芥显著上调;利用DNA化学诱变剂博来霉素对植株进行处理,发现超表达植株的根系受抑制程度小于野生型。以上结果表明,MtNSN1与蒺藜苜蓿茎尖分生组织的维持及地上、地下器官的发育有关,同时异源表达MtNSN1在转录水平上影响拟南芥细胞周期的表达。

关键词: 蒺藜苜蓿, MtNSN1, 分生组织, 细胞周期

Abstract: Nucleostemin (NS), a nucleolar GTP-binding protein widely present in animals, is involved in embryogenesis and cell proliferation, which are heavily dependent on cell cycling. This research investigated the expression pattern of MtNSN1 and the function in plant growth and development in Medicago truncatula. The full-length cDNA of MtNSN1 (2193 bp) was cloned revealing an open reading frame of 1800 bp encoding 599 amino acids of molecular weight 133.7 kDa. Phylogenetic analysis showed that MtNSN1 is related to NSN1 in Glycine max with a homology of 66.67%. The highest transcript level of MtNSN1 was detected in flowers, followed by roots, and the lowest in leaves. In situ hybridization showed that was mainly expressed in the shoot apical meristem and the nearby leaf primordia and emerging leaves. Transgenic plants overexpressing MtNSN1 had longer primary roots, and the transgenic plants possessed more leaves than the non-transgenic ones. Real-time quantitative PCR analysis indicated that five cell cycling marker genes were significantly up-regulated in plants overexpressing MtNSN1. Treatment with the genotoxic agent bleomycin demonstrated that the length of the primary roots of plants overexpressing MtNSN1 was longer than that of the non-transgenic control plants. These findings suggest that MtNSN1 may be involved in the maintenance of the shoot of Medicago truncatula, which is crucial for the development of both underground and aerial organs. In addition, ectopic expression of MtNSN1 altered the transcriptional level of the cell cycling genes.

Key words: Medicago truncatula, MtNSN1, meristem, cell cycle