水稻矮杆突变体的细胞学特征及基因定位研究  

Cytological Characteristics and Gene Location of a Rice Dwarf Mutant

作　　者：郝小花 向玉婷[2] 曾孟 杨友伟 谢鹏 李密 李东屏 田连福[2] HAO Xiao-hua;XIANG Yu-ting;ZENG Meng;YANG You-wei;XIE Peng;LI Mi;LI Dong-ping;TIAN Lian-fu(College of Life and Environmental Sciences,Hunan University of Arts and Science,Changde 415000,Hunan,China;Hunan Province Key Laboratory of Crop Sterile Germplasm Resource Innovation and Application,College of Life Sciences,Hunan Normal University,Changsha 410081,Hunan,China)

机构地区：[1]湖南文理学院生命与环境科学学院,中国湖南常德415000 [2]湖南师范大学生命科学学院作物不育资源创新与利用湖南省重点实验室,中国湖南长沙410081

出　　处：《生命科学研究》2021年第1期39-47,共9页Life Science Research

基　　金：国家自然科学基金资助项目(31570316,32071930);湖南省教育厅项目(17C0974);湖南省研究生创新性项目(CX2017B230,CX2018B300);湖南省生物发育工程及新产品研发协同创新中心项目(20134486)。

摘　　要：赤霉素合成基因在植物的生长发育中起着重要的作用。甲基磺酸乙酯(ethyl methane sulfonate, EMS)诱变的超矮杆突变株水稻ag1 (ai-gan1)表现出明显的节间和叶片伸长缺陷,成熟期株高仅为野生型的34.81%,穗长以及各节间长度占整株高度的比例发生明显变化,其中倒二节间和倒三节间所占比例显著降低。MBS(mapping-by-sequencing)基因定位及CRISPR-Cas9基因敲除验证显示,该突变基因为赤霉素-3β羟化酶2 (gibberellin 3-beta-hydroxylase 2, GA3ox2)编码基因D18的等位基因。细胞的形态分析显示,突变体倒二节间的细胞长度显著变短,纵向细胞数量显著减少,而节间中横向薄壁细胞层数显著增加;突变体剑叶中横向小叶脉的数量显著增加,但维管束周围的纵向薄壁细胞数目显著减少。同时,部分与细胞分裂和伸长相关基因的表达量在突变体中都显著降低。上述结果说明GA3ox2在水稻中严重影响地上节间细胞的伸长及节间和剑叶中细胞的分裂活性,从而导致水稻地上部分的形态出现异常。Gibberellin synthesis genes play an important role in plant growth and development.The super dwarf mutant ai-gan1(ag1)induced by ethyl methane sulfonate(EMS)showed obvious defects in internode and leaf elongation.The plant height at mature stage reached only 34.81%of the wild-type(WT)height.The panicle length and the ratio of internode length to the whole plant height changed significantly.The propor-tion of the last second and third internodes had a significant decrease in the total length.Mapping-by-se-quencing(MBS)and CRISPR-Cas9 mediated gene knockout confirmed that the mutant gene was an allele encoding gibberellin 3-beta-hydroxylase 2(GA3ox2).Morphological analysis showed that the length of internode cells in the penultimate internode of the mutants was significantly shorter,and the number of longitu-dinal cells was significantly reduced.The number of transverse parenchyma cells in internodes increased significantly,and the number of transverse venules in flag leaves of the mutants increased significantly,but the number of longitudinal parenchyma cells around vascular bundles decreased significantly.At the same time,the expression levels of some genes related to cell division and elongation were significantly decreased in the mutants.The results showed that GA3ox2 in rice seriously affected the elongation of aboveground internode cells and the cell division activity in internodes and flag leaves,which led to the abnormal morphology of the aboveground part of rice.

关 键 词：水稻 赤霉素(GA) 细胞分裂 CRISPR-Cas9技术 矮杆突变体 

分 类 号：Q946[生物学—植物学]