Institut des Sciences du Végétal (ISV), UPR2355, CNRS, Saclay Plant Sciences, Avenue de la Terrasse, Gif-sur-Yvette, 91198, France.
Mol Ecol. 2014 Oct;23(19):4846-61. doi: 10.1111/mec.12890.
To investigate how exudation shapes root-associated bacterial populations, transgenic Arabidopsis thaliana plants that exuded the xenotopic compound octopine at low and high rates were grown in a nonsterile soil. Enumerations of both cultivable and octopine-degrading bacteria demonstrated that the ratios of octopine degraders increased along with octopine concentration. An artificial exudation system was also set up in which octopine was brought at four ratios. The density of octopine-degrading bacteria directly correlated with the input of octopine. Bacterial diversity was analysed by rrs amplicon pyrosequencing. Ensifer and Pseudomonas were significantly more frequently detected in soil amended with artificial exudates. However, the density of Pseudomonas increased as a response to carbon supplementation while that of Ensifer only correlated with octopine concentrations possibly in relation to two opposed colonization strategies of rhizosphere bacteria, that is, copiotrophy and oligotrophy.
为了研究渗出物如何塑造根相关细菌种群，我们在非无菌土壤中种植了能够以低浓度和高浓度分泌异源化合物章鱼碱的转基因拟南芥植物。可培养和降解章鱼碱的细菌的计数表明，随着章鱼碱浓度的增加，章鱼碱降解菌的比例也增加。我们还建立了一个人工渗出系统，以四种比例输入章鱼碱。章鱼碱降解菌的密度与章鱼碱的输入直接相关。通过 rrs 扩增子焦磷酸测序分析了细菌多样性。在添加人工渗出物的土壤中，固氮螺菌和假单胞菌的检测频率明显更高。然而，假单胞菌的密度随着碳源的补充而增加，而固氮螺菌的密度仅与章鱼碱浓度相关，这可能与根际细菌的两种相反的定殖策略有关，即富营养型和寡营养型。
