Inorganic pyrophosphate content and metabolites in potato and tobacco plants expressing E. coli pyrophosphatase in their cytosol
Inorganic pyrophosphate content and metabolites in potato and tobacco plants expressing E. coli pyrophosphatase in their cytosol
复制标题
在细胞质中表达大肠杆菌焦磷酸酶的马铃薯和烟草植物中无机焦磷酸盐含量和代谢物
作者：
T. Jelitto;U. Sonnewald;L. Willmitzer;Mohammad Hajirezeai;M. Stitt
研究了烟草叶片中的代谢产物和碳水化合物含量。马铃薯（Solanum tuberosum L.）用来自大肠杆菌的焦磷酸酶转化的植物。在烟草中，叶子中含有的焦磷酸盐比对照组少两到三倍，并且相对于磷酸己糖，UDP-葡萄糖大量增加。蔗糖、己糖和淀粉的积累量较大，但可溶性糖的增加幅度大于淀粉。茎和根的生长受到抑制，淀粉、蔗糖和己糖积累。在马铃薯中，叶子中含有的焦磷酸盐减少了两到三倍，UDP-葡萄糖/己糖-磷酸盐的比例增加了。蔗糖增加，淀粉减少。这些植物产生了大量的较小的块茎，其中含有更多的蔗糖和更少的淀粉。块茎含有三倍高的UDP-葡萄糖，三倍低的己糖磷酸，甘油酸-3-磷酸和磷酸烯醇丙酮酸，和高达六倍的果糖-2，6-二磷酸酶比野生型块茎。可以得出结论，从细胞质中去除焦磷酸盐抑制植物生长。它讨论了这些结果如何提供证据表明，蔗糖动员通过蔗糖合成酶提供了一个关键的网站，焦磷酸盐是植物生长所需的，但肯定不是唯一的网站，焦磷酸盐起着至关重要的作用。
Metabolite levels and carbohydrates were investigated in the leaves of tobacco (Nicotiana tabacum L.) and leaves and tubers of potato (Solanum tuberosum L.) plants which had been transformed with pyrophosphatase from Escherichia coli. In tobacco the leaves contained two- to threefold less pyrophosphate than controls and showed a large increase in UDP-glucose, relative to hexose phosphate. There was a large accumulation of sucrose, hexoses and starch, but the soluble sugars increased more than starch. Growth of the stem and roots was inhibited and starch, sucrose and hexoses accumulated. In potato, the leaves contained two- to threefold less pyrophosphate and an increased UDP-glucose/ hexose-phosphate ratio. Sucrose increased and starch decreased. The plants produced a larger number of smaller tubers which contained more sucrose and less starch. The tubers contained threefold higher UDP-glucose, threefold lower hexose-phosphates, glycerate-3-phosphate and phosphoenolpyruvate, and up to sixfold more fructose-2,6-bisphosphatase than the wild-type tubers. It is concluded that removal of pyrophosphate from the cytosol inhibits plant growth. It is discussed how these results provide evidence that sucrose mobilisation via sucrose synthase provides one key site at which pyrophosphate is needed for plant growth, but is certainly not the only site at which pyrophosphate plays a crucial role.