烟草NtFtsZ2-1基因参与叶绿体分裂和扩大的调节(英文)  

The Involvement of NtFtsZ2-1 Gene in the Regulation of Chloroplast Division and Expansion in Tobacco

作　　者：刘维仲[1] 孔冬冬[1] 王东[1] 鞠传丽[1] 胡勇[1] 刘祥林[1] 孙敬三[2] 何奕昆[1] 

机构地区：[1]首都师范大学生命科学学院 [2]中国科学院植物研究所,北京100093

出　　处：《植物生理与分子生物学学报》2007年第4期267-276,共10页Journal Of Plant Physiology and Molecular Biology

基　　金：国家自然科学基金项目(Nos.30470879和30500288);北京市自然科学基金项目(No.5032003)~~

摘　　要：叶绿体虽然是植物细胞内一种极其重要的细胞器,但其分裂的分子机制尚不很清楚。已经证明FtsZ 蛋白作为真核细胞分裂装置的一个关键成分,参与叶绿体的分裂过程。烟草的 FtsZ 基因属于 2 个不同的家族,在对 NtFtsZ1 家族成员研究的基础上,用正义和反义表达技术研究了 NtFtsZ2 家族成员NtFtsZ2-1 基因在转基因烟草中的功能。显微分析结果表明NtFtsZ2-1基因的表达水平异常增强或减弱都会严重干扰叶绿体的正常分裂过程,导致叶绿体在形态和数目上的异常(体积明显增大,数目显著减少),而单个叶肉细胞中叶绿体的总表面积在正反义转基因烟草和野生型烟草之间保持了相对稳定,没有发生明显的变化。同时还证明NtFtsZ2-1基因表达的变化对叶绿素含量和叶绿体的光合作用能力没有直接的影响。据此我们认为NtFtsZ2-1基因参与叶绿体的分裂和体积的扩大,其表达水平的波动会改变植物中叶绿体的数目和大小,而且在叶绿体的数目与体积之间可能存在一种补偿机制,保证叶绿体能最大限度地吸收光能,从而使光合作用得以正常进行。Chloroplasts are a vital group of organelles of plants, yet the molecular mechanisms associated with their division remain poorly understood. Recent studies have revealed that the FtsZ protein, known as a key component in prokaryotic cell division, is involved in chloroplast division process. The NtFtsZ2-1 gene was isolated from Nicotiana tabacum by RT-PCR, and the sense and antisense expression plasmids were used to examine the function of NtFtsZ2-1 gene in transgenic tobacco. Light and confocal observations revealed that the normal chloroplast division process was severely disrupted in transgenic plants with enhanced or reduced expression of NtFtsZ2-1 gene. These chloroplasts were abnormally larger in size and fewer in number compared with that of the wild-type tobacco. But the total chloroplast plan area per mesophyll cell was conserved in sense, antisense and wild type tobaccos. Analyses of electron micrographs and chlorophyll content of different transgenic plants showed that constitutively enhancing or inhibiting the expression of NtFtsZ2-1 gene had no direct influence on the ultrastructure and photosynthetic ability of chloroplasts. Basing on these results, we suggest that NtFtsZ2-1 gene is involved in chloroplast division and expansion; the fluctuation of NtFtsZ2-1 expression level would alter normal chloroplast number and size in plant cells. In addition, the similarities of ultrastructure and photosynthetic ability of chloroplasts among sense, antisense and wild type tobaccos implies that a special mechanism regulate the relationship between chloroplast number and size to maximize photosynthetic rate.

关 键 词：叶绿体分裂 叶绿体大小 烟草:NtFtsZ2-1 超微结构 光合作用能力 

分 类 号：Q943[生物学—植物学]