Dipartimento di Produzione Vegetale, Università degli Studi di Milano, Via Celoria 2, 20133 Milano, Italy.
BMC Plant Biol. 2010 Dec 1;10:268. doi: 10.1186/1471-2229-10-268.
Iron deficiency induces in Strategy I plants physiological, biochemical and molecular modifications capable to increase iron uptake from the rhizosphere. This effort needs a reorganization of metabolic pathways to efficiently sustain activities linked to the acquisition of iron; in fact, carbohydrates and the energetic metabolism has been shown to be involved in these responses. The aim of this work was to find both a confirmation of the already expected change in the enzyme concentrations induced in cucumber root tissue in response to iron deficiency as well as to find new insights on the involvement of other pathways.
The proteome pattern of soluble cytosolic proteins extracted from roots was obtained by 2-DE. Of about two thousand spots found, only those showing at least a two-fold increase or decrease in the concentration were considered for subsequent identification by mass spectrometry. Fifty-seven proteins showed significant changes, and 44 of them were identified. Twenty-one of them were increased in quantity, whereas 23 were decreased in quantity. Most of the increased proteins belong to glycolysis and nitrogen metabolism in agreement with the biochemical evidence. On the other hand, the proteins being decreased belong to the metabolism of sucrose and complex structural carbohydrates and to structural proteins.
The new available techniques allow to cast new light on the mechanisms involved in the changes occurring in plants under iron deficiency. The data obtained from this proteomic study confirm the metabolic changes occurring in cucumber as a response to Fe deficiency. Two main conclusions may be drawn. The first one is the confirmation of the increase in the glycolytic flux and in the anaerobic metabolism to sustain the energetic effort the Fe-deficient plants must undertake. The second conclusion is, on one hand, the decrease in the amount of enzymes linked to the biosynthesis of complex carbohydrates of the cell wall, and, on the other hand, the increase in enzymes linked to the turnover of proteins.
缺铁会诱导策略 I 植物发生生理、生化和分子修饰，从而增加从根际吸收铁的能力。这一努力需要对代谢途径进行重组，以有效地维持与铁获取相关的活动；事实上，碳水化合物和能量代谢已被证明与这些反应有关。本工作的目的是不仅确认已经预期的黄瓜根组织中缺铁诱导的酶浓度变化，而且还要找到新的见解，了解其他途径的参与。
通过 2-DE 获得了从根组织中提取的可溶性胞质蛋白的蛋白质组图谱。在所发现的大约两千个斑点中，只有那些浓度至少增加或减少两倍的斑点才被认为是随后通过质谱鉴定的。有 57 种蛋白质显示出显著变化，其中 44 种被鉴定。其中 21 种蛋白的含量增加，而 23 种蛋白的含量减少。大多数增加的蛋白质属于糖酵解和氮代谢，与生化证据一致。另一方面，减少的蛋白质属于蔗糖和复杂结构碳水化合物以及结构蛋白的代谢。
新的可用技术可以为铁缺乏条件下植物发生的变化所涉及的机制提供新的认识。这项蛋白质组学研究获得的数据证实了黄瓜在缺铁条件下发生的代谢变化。可以得出两个主要结论。第一个结论是，确认了糖酵解通量的增加和无氧代谢的增加，以维持缺铁植物必须进行的能量消耗。第二个结论是，一方面，与细胞壁复杂碳水化合物生物合成相关的酶的含量减少，另一方面，与蛋白质周转相关的酶的含量增加。
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