CORRELATION BETWEEN ARRESTED SECONDARY PLASMODESMAL DEVELOPMENT AND ONSET OF ACCELERATED LEAF SENESCENCE IN YEAST ACID INVERTASE TRANSGENIC TOBACCO PLANTS
CORRELATION BETWEEN ARRESTED SECONDARY PLASMODESMAL DEVELOPMENT AND ONSET OF ACCELERATED LEAF SENESCENCE IN YEAST ACID INVERTASE TRANSGENIC TOBACCO PLANTS
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DOI：
10.1046/j.1365-313x.1993.04010179.x
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发表时间：
1993-07-01
期刊：
影响因子：
7.2
通讯作者：
LUCAS, WJ
中科院分区：
文献类型：
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作者：
DING, B;HAUDENSHIELD, JS;LUCAS, WJ
组成型表达酵母来源酸性转化酶基因的转基因烟草植株（烟草，沙姆逊变种，A41 - 10品系）的成熟叶片出现症状，其特征为同一叶片上存在黄绿色和绿色区域，以及叶片早衰的发生。先前的研究表明，黄绿色区域的转化酶活性比绿色区域高两到三倍。我们的结构分析显示，在黄绿色区域，叶肉细胞之间通过对现有初生胞间连丝的修饰而形成次生胞间连丝的过程受到严重抑制，而在绿色区域仅受到轻微抑制。相反，通过结构和染料偶联研究确定，在相同的有症状区域，初生胞间连丝的结构和功能保持不变。据推测，次生胞间连丝与初生胞间连丝不同，它具有传递信息分子以协调叶片发育和生理功能的特殊能力。转基因烟草叶片中高转化酶活性抑制次生胞间连丝的发育可能阻止了这种信息传递，从而导致叶片早衰。研究结果还表明，表达酵母酸性转化酶的烟草可能为调节次生胞间连丝的发育、功能以及可能的周转的细胞机制的分子特性研究提供一个有效的实验系统。
Mature leaves of a transgenic tobacco plant (Nicotiana tabacum L. var. Samsun, line A41-10) that constitutively express a yeast-derived acid invertase gene develop symptoms which are characterized by the presence of greenish-yellow and green sectors in the same leaf, and onset of early leaf senescence. Previous studies indicated that invertase activity was two- to threefold higher in the greenish-yellow sectors than in the green sectors. Our structural analyses revealed that development of secondary plasmodesmata, via modification of existing primary plasmodesmata, between mesophyll cells was inhibited severely in the greenish-yellow sectors, but only marginally in the green sectors. In contrast, the structure and function of primary plasmodesmata in the same symptomatic sectors remained unaltered as determined by structural and dye coupling studies. It is hypothesized that secondary plasmodesmata differ from primary plasmodesmata in having special abilities to traffic information molecules to coordinate leaf development and physiological function(s). Arrest of secondary plasmodesmal development by high invertase activity in the transgenic tobacco leaf may have prevented this type of trafficking and hence resulted in early leaf senescence. The results also indicate that the yeast acid invertase-expressing tobacco may provide an effective experimental system for the molecular characterization of cellular mechanisms that regulate the development, function, and possible turnover of secondary plasmodesmata.