Wang F., Smith A. G., Brenner M. L.
Departments of Horticultural Science (F.W., A.G.S., M.L.B) and Plant Biology (M.L.B), University of Minnesota, St. Paul, Minnesota 55108.
Plant Physiol. 1994 Feb;104(2):535-540. doi: 10.1104/pp.104.2.535.
Sucrose synthase is proposed to play an important role in the early stages of tomato fruit (Lycopersicon esculentum Mill.) growth. In this work, the temporal and spatial expression patterns of sucrose synthase during tomato fruit development were investigated. Fruit contained the majority of the sucrose synthase protein and mRNA relative to other organs. Only trace levels of sucrose synthase protein and mRNA were detected in the stem, petiole, and roots. Sucrose synthase mRNA was detected in pistils prior to anthesis, reached peak levels in fruit 5 to 7 d after anthesis (DAA), and was not detectable after 35 DAA. Sucrose synthase protein levels reached a maximum at 20 to 25 DAA and then declined to nondetectable levels after 45 DAA. The lack of coordination between protein and mRNA levels suggests that sucrose synthase expression may be controlled at the levels of both transcription and translation. Sucrose synthase mRNA was differentially localized in the fruit, being most abundant in the mesocarp cells adjacent to the placenta, the columella, and the cells surrounding the vascular bundle. Except around the vascular tissue, the localization of sucrose synthase mRNA positively correlates with starch granule accumulation at the cellular level.
蔗糖合酶被认为在番茄果实（番茄）生长的早期阶段发挥重要作用。在这项工作中，研究了番茄果实发育过程中蔗糖合酶的时空表达模式。相对于其他器官，果实中含有大部分的蔗糖合酶蛋白和mRNA。在茎、叶柄和根中仅检测到痕量水平的蔗糖合酶蛋白和mRNA。在开花前的雌蕊中检测到蔗糖合酶mRNA，在开花后5至7天（DAA）的果实中达到峰值水平，在35 DAA后无法检测到。蔗糖合酶蛋白水平在20至25 DAA时达到最大值，然后在45 DAA后下降到无法检测的水平。蛋白质和mRNA水平之间缺乏协调性表明蔗糖合酶的表达可能在转录和翻译水平上受到控制。蔗糖合酶mRNA在果实中呈差异定位，在与胎座、小柱以及维管束周围细胞相邻的中果皮细胞中最为丰富。除了维管组织周围，蔗糖合酶mRNA的定位在细胞水平上与淀粉颗粒积累呈正相关。
