Growth and nodulation of symbiotic Medicago truncatula at different levels of phosphorus availability.
Growth and nodulation of symbiotic Medicago truncatula at different levels of phosphorus availability.
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DOI：
10.1093/jxb/ert122
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发表时间：
2013-07
影响因子：
6.9
通讯作者：
Tran LS
中科院分区：
文献类型：
--
作者：
Sulieman S;Ha CV;Schulze J;Tran LS
苜蓿是豆科植物生理和分子水平上研究缺磷的重要模式植物。优化该植物的生长与磷供应是阐明磷在结瘤调节中的作用的第一步。因此，本研究对不同磷水平下水培短尾草的生长规律进行了研究。结果表明，短尾草的磷区较窄，其最佳磷浓度为12 μM P，较接近引起磷中毒的浓度。干物质累积磷浓度（2.7 mg g-1）在其他作物和豆科植物中是正常的，但对短尾草的生长有不利影响。在缺磷条件下，与S. meliloti 102F51相比，截尾草与Sinorhizobium meliloti 2011表现出更高的共生效率，部分原因是电子分配给N2比H+更高。磷剥夺显著影响了韧皮部游离氨基酸的总组成。这种模式几乎完全是天冬酰胺水平升高的结果，表明天冬酰胺可能是芽源信号，转运到根瘤中，对氮酶活性施加下调作用。此外，缺磷对根瘤碳代谢产物的含量有较大影响。虽然蔗糖和琥珀酸盐的水平趋于下降，但观察到苹果酸盐的积累较高。这些发现证明了M. truncatula的固氮是通过与根瘤碳代谢密切相关的N反馈机制介导的。
Medicago truncatula is an important model plant for characterization of P deficiency on leguminous plants at the physiological and molecular levels. Growth optimization of this plant with regard to P supply is the first essential step for elucidation of the role of P in regulation of nodulation. Hence, a study was carried out to address the growth pattern of M. truncatula hydroponically grown at different gradual increases in P levels. The findings revealed that M. truncatula had a narrow P regime, with an optimum P level (12 μM P) which is relatively close to the concentration that induces P toxicity. The accumulated P concentration (2.7 mg g–1 dry matter), which is normal for other crops and legumes, adversely affected the growth of M. truncatula plants. Under P deficiency, M. truncatula showed a higher symbiotic efficiency with Sinorhizobium meliloti 2011 in comparison with S. meliloti 102F51, partially as a result of higher electron allocation to N2 versus H+. The total composition of free amino acids in the phloem was significantly affected by P deprivation. This pattern was found to be almost exclusively the result of the increase in the asparagine level, suggesting that asparagine might be the shoot-derived signal that translocates to the nodules and exerts the down-regulation of nitrogenase activity. Additionally, P deprivation was found to have a strong influence on the contents of the nodule carbon metabolites. While levels of sucrose and succinate tended to decrease, a higher accumulation of malate was observed. These findings have provided evidence that N2 fixation of M. truncatula is mediated through an N feedback mechanism which is closely related to nodule carbon metabolism.
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影响因子：
6.4
作者：
Bacanamwo, M;Harper, JE
通讯作者：
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影响因子：
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作者：
Fischinger, Stephanie A.;Drevon, Jean-Jacques;Schulze, Joachim
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DOI：
10.1002/9780470168035.ch7
发表时间：
2007-01-01
期刊：
Plant Breeding Reviews
影响因子：
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作者：
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作者：
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作者：
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通讯作者：
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