采用GUS标记技术研究钙调素在转基因烟草中的分布

为了监测钙调素 (Ca M)在植物细胞内的分布并探索其生物学功能 ,将水稻 Ca M和 GU S融合基因 (cam.gus)分别置于 35 S启动子和花粉特异启动子 L AT5 2 - 7控制下 ,构建出载体 p MD/ Ca M.GU S和 p BI/ L AT.Ca M.GU S,转化烟草 (N icotiana tobacum cv.SR ) ,GU S染色结果显示 ,Ca M.GU S融合蛋白广泛分布于植物根、茎、叶等组织 ,根尖生长点细胞、根毛细胞、表皮毛细胞、气孔保卫细胞、维管束细胞的细胞质中融合蛋白含量较多。花粉粒中也分布着 Ca M,并在萌发沟处表现出较高的浓度。保卫细胞和表皮毛细胞中 Ca M分布在相邻细胞连接处细胞模内侧 ,呈现出极性分布。研究结果表明 ,细胞内 Ca M的不均匀分布可能与细胞功能相关。     

钙调素依赖型蛋白激酶在植物开花调控中的作用

钙调素依赖型蛋白激酶已被证明在诸多信号传导过程中起重要作用.研究了这一类激酶在植物开花调控中的可能作用.将分离自玉米的钙调素依赖型蛋白激酶(maize calmodulin-dependent protein kinase 1,MCK1),经过基因羧基末端(此羧基末端含有该基因的钙调素结合区)缺失突变成为MCKt,该基因的表达不再受钙调素的调控,通过农杆菌转化法获得转基因烟草植株.结果表明,MCKt的表达显著影响烟草的开花发育程序, 导致植物主枝的花原基败育以及侧枝营养生长期的延长.败育过程首先开始于正在发育的花药,然后是整个花的衰老.侧芽营养生长期的延长表征为产生成簇的伸长、窄小而扭曲的非典型叶片.这些结果显示,钙调素依赖型蛋白激酶同源物在开花调控中起着重要作用.     

Mediation of flowering by a calmodulin-dependent protein kinase

A calmodulin-dependent protein kinase (MCK1) appeared important in regulating flowering in tobacco. The expression of modifiedMCK1 that lacks the C-terminal including calmodulin-binding domain upsets the flowering developmental program, leading to the abortion of flower primordia initiated on the main axis of the plant and, as well, caused the prolongation of the vegetative phase in axillary buds. The abortion process of flowers began first in the developing anthers and subsequently the entire flower senesces. In axillary buds the prolonged vegetative phase was characterized by atypical elongated, narrow, twisted leaves. These results suggested a role for calmodulin-dependent protein kinase homologs in mediating flowering.     

钙调素激酶在玉米体内的免疫组织化学定位

应用免疫组织化学定位方法研究了玉米体内钙调素激酶(CaM kinase,CaMK)的表达模式。结果表明CaMK广泛分布于玉米体内,但表达水平存在着明显时空差异。在营养器官中钙调素激酶主要分布于叶的维管束鞘细胞、侧根原基和根尖等部位,而其它部位没有检测到明显的分布。在生殖器官中,有大量钙调素激酶分布于幼胚及花药小孢子母细胞、四分体及绒毡层细胞中;在成熟胚囊的卵细胞、中央细胞以及二者的分界面上也有少量分布。这些结果为进一步探索钙调素激酶在植物体内的生理功能提供了重要线索。     

Mediation of flowering by a calmodulin-dependent protein kinase

A calmodulin-dependent protein kinase (MCK1) appeared important in regulating flowering in tobacco. The expression of modified MCK1 that lacks the C-terminal including calmodulin-binding domain upsets the flowering developmental program, leading to the abortion of flower primordia initiated on the main axis of the plant and, as well, caused the prolongation of the vegetative phase in axillary buds. The abortion process of flowers began first in the developing anthers and subsequently the entire flower senesces. In axillary buds the prolonged vegetative phase was characterized by atypical elongated, narrow, twisted leaves. These results suggested a role for calmodulin-dependent protein kinase homologs in mediating flowering.     

烟草幼苗两种钙调素结合蛋白激酶的活性调节及基因表达

在体外条件下,烟草两种钙调素结合蛋白激酶(NtCBK1与NtCBK2)自磷酸化活性的最适pH分别是7.5和8;Mg2 离子浓度对两种激酶自磷酸化活性影响比Na 离子大.Northern杂交结果显示:两基因在花和叶中都有大量表达,但在根和茎中NtCBKl的表达量明显多于NtCBK2;高盐处理会引起NtCBKl基因表达量升高,而高温、低温和干旱处理对该基因表达没有影响,说明NtCBKl参与植物体内盐诱导的信号转导.