含有高密度植物生长促进细菌的生物肥料作为解决富营养化引起的环境问题的可持续解决方案而受到关注。然而,由于当前调查技术的局限性,选择的微生物并不总是被寄主植物所偏好,防止招募到本地微生物群或未能诱导植物生长促进作用。为了解决这个问题,选择了以前从水山药(DioscoreaalataL.)植物中分离出的五种固氮菌,并在水山药微生物群中显示出1%或更多的优势丰度,以分析其用作植物的植物生长促进活性。合成细菌接种剂。水山药简历。在温室条件下种植后10周和12周将A-19植物接种两次。根中的细菌群落,根际,和散装土壤样品使用高通量16SrRNA扩增子测序进行表征。与未接种的植物相比,接种后,所有细菌群落都发生了显著变化,主要在属水平。在种植后16周时,在根系群落中明显发现了接种效果,与对照样品相比,所有接种的属均显示出优势(在前35个属中)。然而,在处理之间没有观察到任何生长参数或氮含量的显着差异。种植后20周,在接种的根中,寡养单胞菌的优势下降,表明接种效果下降。有趣的是,在所有样品中,只有变种根瘤菌-新根瘤菌-对根瘤菌-根瘤菌进化枝占优势(>1%相对丰度),表明与该进化枝相关的细菌是水山药生长的关键核心细菌。这是关于在山药植物中添加合成固氮细菌群落的第一份报告,表明本地细菌群落可以被合成细菌群落取代,接种后几周,寡养单胞菌对改良群落的影响下降。
Biofertilizers containing high-density plant growth-promoting bacteria are gaining interest as a sustainable solution to environmental problems caused by eutrophication. However, owing to the limitations of current investigative techniques, the selected microorganisms are not always preferred by the host plant, preventing recruitment into the native microbiota or failing to induce plant growth-promoting effects. To address this, five nitrogen-fixing bacteria previously isolated from water yam (Dioscorea alata L.) plants and showing dominant abundance of 1% or more in the water yam microbiota were selected for analysis of their plant growth-promoting activities when used as a synthetic bacterial inoculant. Water yam cv. A-19 plants were inoculated twice at 10 and 12 weeks after planting under greenhouse conditions. Bacterial communities in root, rhizosphere, and bulk soil samples were characterized using high-throughput 16S rRNA amplicon sequencing. Compared with non-inoculated plants, all bacterial communities were significantly altered by inoculation, mainly at the genus level. The inoculation effects were apparently found in the root communities at 16 weeks after planting, with all inoculated genera showing dominance (in the top 35 genera) compared with the control samples. However, no significant differences in any of the growth parameters or nitrogen contents were observed between treatments. At 20 weeks after planting, the dominance of Stenotrophomonas in the inoculated roots decreased, indicating a decline in the inoculation effects. Interestingly, only the Allorhizobium-Neorhizobium-Pararhizobium-Rhizobium clade was dominant (>1% relative abundance) across all samples, suggesting that bacteria related to this clade are essential core bacteria for water yam growth. This is the first report on addition of a synthetic nitrogen-fixing bacterial community in water yam plants showing that native bacterial communities can be replaced by a synthetic bacterial community, with declining in the effects of Stenotrophomonas on the modified communities several weeks after inoculation.