Medicago truncatula increases its iron-uptake mechanisms in response to volatile organic compounds produced by Sinorhizobium meliloti
Medicago truncatula increases its iron-uptake mechanisms in response to volatile organic compounds produced by Sinorhizobium meliloti
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DOI：
10.1007/s12223-013-0243-9
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发表时间：
2013-11-01
影响因子：
2.6
通讯作者：
Valencia-Cantero, Eduardo
中科院分区：
文献类型：
--
作者：
del Carmen Orozco-Mosqueda, Ma;Macias-Rodriguez, Lourdes I.;Valencia-Cantero, Eduardo
苜蓿是了解豆科植物与细菌相互作用的一种模式植物。根与固氮细菌Sinorhizobium meliloti形成一种特殊的根瘤共生关系。共生固氮对细菌的氮酶、全酶和植物的豆红蛋白产生高铁需求。豆科植物通过“策略1”获得铁，其中包括根际酸化和铁还原酶活性增强等机制。本研究主要分析了富铁和缺铁条件下甜槠幼苗挥发性有机物（VOCs）对其铁吸收机制的影响。无菌培养表明，植物和细菌在各自的共生伙伴存在的情况下都能改变VOC的合成。重要的是，在富铁和缺铁实验中，细菌VOCs增加了植物生物量的产生、根际酸化、铁还原酶活性和叶绿素含量。基于我们的研究结果，我们提出M. truncatula通过VOC排放感知其共生体，并相应地增加铁吸收机制以促进共生。
Medicago truncatula represents a model plant species for understanding legume-bacteria interactions. M. truncatula roots form a specific root-nodule symbiosis with the nitrogen-fixing bacterium Sinorhizobium meliloti. Symbiotic nitrogen fixation generates high iron (Fe) demands for bacterial nitrogenase holoenzyme and plant leghemoglobin proteins. Leguminous plants acquire Fe via "Strategy I," which includes mechanisms such as rhizosphere acidification and enhanced ferric reductase activity. In the present work, we analyzed the effect of S. meliloti volatile organic compounds (VOCs) on the Fe-uptake mechanisms of M. truncatula seedlings under Fe-deficient and Fe-rich conditions. Axenic cultures showed that both plant and bacterium modified VOC synthesis in the presence of the respective symbiotic partner. Importantly, in both Fe-rich and -deficient experiments, bacterial VOCs increased the generation of plant biomass, rhizosphere acidification, ferric reductase activity, and chlorophyll content in plants. On the basis of our results, we propose that M. truncatula perceives its symbiont through VOC emissions, and in response, increases Fe-uptake mechanisms to facilitate symbiosis.