Development of Arabidopsis thaliana leaves at low temperatures releases the suppression of photosynthesis and photosynthetic gene expression despite the accumulation of soluble carbohydrates.
Development of Arabidopsis thaliana leaves at low temperatures releases the suppression of photosynthesis and photosynthetic gene expression despite the accumulation of soluble carbohydrates.
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DOI：
10.1111/j.0960-7412.1997.00605.x
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发表时间：
1997
期刊：
影响因子：
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通讯作者：
Åsa Strand;V. Hurry;Petter Gustafsson;P. Gardeström
中科院分区：
文献类型：
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作者：
Åsa Strand;V. Hurry;Petter Gustafsson;P. Gardeström
拟南芥在23摄氏度的环境下生长，观察碳水化合物代谢的变化，研究了植物移入5℃后的光合作用和光合基因表达。将23℃发育后移入5℃的叶片与5℃发育后的叶片进行比较。将温暖发育的叶片移入5℃会导致光合作用受到严重抑制，这与己糖磷酸盐和可溶性糖的快速持续积累有关。与光合作用的抑制和可溶性糖的积累相关的是编码光合蛋白的基因（cab和rbc）转录量的减少。相比之下，在5℃条件下发育的叶片，光合作用和光合基因表达的控制水平均有所增加。即使在5摄氏度下发育的叶子保持了大量的可溶性糖，这种恢复也发生了。在5℃条件下发育的叶片也表现出用于可溶性糖合成的胞质途径的强烈上调，但用于淀粉合成的叶绿体途径没有上调。这表现在酶活性水平和转录物数量水平上。因此，拟南芥叶片在5℃下的发育导致代谢变化，使其能够产生和积累大量的可溶性糖池，而不会抑制光合作用或光合基因表达。这些变化也与抗冻能力增强有关。我们认为，这种与低温发育相关的碳水化合物代谢的重编程对越冬草本一年生植物的完全抗冻性发育和冬季存活至关重要。
Arabidopsis thaliana plants were grown at 23 degrees C and changes in carbohydrate metabolism, photosynthesis and photosynthetic gene expression were studied after the plants were shifted to 5 degrees C. The responses of leaves shifted to 5 degrees C after development at 23 degrees C are compared to leaves that developed at 5 degrees C. Shifting warm developed leaves to 5 degrees C lead to a severe suppression of photosynthesis that correlated with a rapid and sustained accumulation of hexose phosphates and soluble sugars. Associated with the suppression of photosynthesis and the accumulation of soluble sugars was a reduction in the amount of transcript for genes encoding photosynthetic proteins (cab and rbcS). In contrast, leaves that developed at 5 degrees C showed an increase in photosynthesis and control levels of photosynthetic gene expression. This recovery occurred even though leaves that developed at 5 degrees C maintained large pools of soluble sugars. Leaves that developed at 5 degrees C also showed a strong upregulation of the cytosolic pathway for soluble sugar synthesis but not of the chloroplastic pathway for starch synthesis. This was shown at the level of both enzyme activity and the amount of transcript. Thus, development of Arabidopsis leaves at 5 degrees C resulted in metabolic changes that enabled them to produce and accumulate large soluble sugar pools without any associated suppression of photosynthesis or photosynthetic gene expression. These changes were also associated with enhanced freezing tolerance. We suggest that this reprogramming of carbohydrate metabolism associated with development at low temperature is essential to the development of full freezing tolerance and for winter survival of over-wintering herbaceous annuals.