Partner choice in Medicago Truncatula-Sinorhizobium symbiosis
Partner choice in Medicago Truncatula-Sinorhizobium symbiosis
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DOI：
10.1098/rspb.2009.2072
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发表时间：
2010-07-07
影响因子：
4.7
通讯作者：
Bena, Gilles
中科院分区：
文献类型：
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作者：
Gubry-Rangin, Cecile;Garcia, Marjorie;Bena, Gilles
在固氮共生中，植物对无效细菌的制裁已经在先前对大豆和黄矮羽扇豆进行的研究中得到证实，两者都与慢生根瘤菌菌株一起形成有限根瘤。在这项研究中，我们集中在广泛研究的共生协会蒺藜苜蓿中华根瘤菌meliloti，形成不确定的结节。使用两个菌株从同一土壤中分离，并显示不同的固氮表型在同一个固定的植物线，我们分析了存在的合作伙伴的选择和植物制裁进行分根实验。通过对根瘤数、根瘤生物量和根瘤菌活菌数等参数的测定，表明M.在固氮步骤之前和之后，蒺藜能够基于识别信号选择根瘤菌。然而，没有制裁机制，描述为减少根瘤内的根瘤菌健身，检测。因此，即使合作伙伴的选择似乎是普遍的豆类，制裁无效根瘤菌可能不是普遍的。
In nitrogen-fixing symbiosis, plant sanctions against ineffective bacteria have been demonstrated in previous studies performed on soybean and yellow bush lupin, both developing determinate nodules with Bradyrhizobium sp. strains. In this study, we focused on the widely studied symbiotic association Medicago truncatula-Sinorhizobium meliloti, which forms indeterminate nodules. Using two strains isolated from the same soil and displaying different nitrogen fixation phenotypes on the same fixed plant line, we analysed the existence of both partner choice and plant sanctions by performing split-root experiments. By measuring different parameters such as the nodule number, the nodule biomass per nodule and the number of viable rhizobia per nodule, we showed that M. truncatula is able to select rhizobia based on recognition signals, both before and after the nitrogen fixation step. However, no sanction mechanism, described as a decrease in rhizobia fitness inside the nodules, was detected. Consequently, even if partner choice seems to be widespread among legumes, sanction of non-effective rhizobia might not be universal.