Molecular analysis of ureide accumulation under drought stress in Phaseolus vulgaris L.
Molecular analysis of ureide accumulation under drought stress in Phaseolus vulgaris L.
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DOI：
10.1111/j.1365-3040.2010.02187.x
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发表时间：
2010-11-01
影响因子：
7.3
通讯作者：
Pineda, Manuel
中科院分区：
文献类型：
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作者：
Alamillo, Josefa M.;Luis Diaz-Leal, Juan;Pineda, Manuel
在水分亏缺条件下，尿素豆科植物在植物组织中积累酰脲，这种积累与固氮的抑制有关。在这项工作中，我们使用分子方法来表征干旱胁迫下菜豆酰脲积累。积累酰脲，主要是尿囊酸，被发现在根，芽和叶，但只有有限的短暂增加，观察到从干旱胁迫植物的根瘤。我们发现，酰脲积累主要是通过诱导尿囊素酶（ALN）在转录水平上进行调节，而尿囊酸酰胺水解酶（AAH），参与尿囊酸降解，略有减少，表明抑制这种酶，酰脲分解的关键在气生组织，是不是尿囊酸积累的主要原因。在这项研究中分析的酰脲代谢基因的表达诱导脱落酸（阿坝），这表明参与酰脲积累的植物激素。此外，我们观察到，增加酰脲水平的干旱胁迫组织中的P. vulgaris是相似的，在非脱水，硝酸盐喂养的植物，并在固氮条件下培养的植物。我们的研究结果表明，酰脲积累响应水分亏缺是独立的从头合成酰脲在根瘤中，因此解耦固氮。
Under water deficit, ureidic legumes accumulate ureides in plant tissues, and this accumulation has been correlated with the inhibition of nitrogen fixation. In this work we used a molecular approach to characterize ureide accumulation under drought stress in Phaseolus vulgaris. Accumulation of ureides, mainly allantoate, was found in roots, shoots and leaves, but only a limited transient increase was observed in nodules from drought-stressed plants. We show that ureide accumulation is regulated at the transcriptional level mainly through induction of allantoinase (ALN), whereas allantoate amidohydrolase (AAH), involved in allantoate degradation, was slightly reduced, indicating that inhibition of this enzyme, key in ureide breakdown in aerial tissues, is not the main cause of allantoate accumulation. Expression of the ureide metabolism genes analysed in this study was induced by abscisic acid (ABA), suggesting the involvement of this plant hormone in ureide accumulation. Moreover, we observed that increases of ureide levels in P. vulgaris drought-stressed tissues were similar in non-nodulated, nitrate-fed plants, and in plants cultured under nitrogen-fixation conditions. Our results indicate that ureide accumulation in response to water deficit is independent from de novo synthesis of ureides in nodules, and therefore uncoupled from nitrogen fixation.