摘要

重金属会对土壤造成严重污染，特别是在矿区。详细了解重金属对植物和根系相关微生物群落的影响可能有助于改善植物修复系统。在这项研究中，将有或无根瘤菌接种的刺槐（刺槐）幼苗种植在受不同重金属污染的土壤中。使用Illumina MiSeq平台上的16S rRNA基因测序和Illumina HiSeq平台上的鸟枪宏基因组测序分析根际和大块土壤样品中的细菌群落。土壤细菌群落根据土壤污染程度而显着变化，种植也有一定影响。尽管接种Mesorhizobium loti HZ76（刺槐属的天然微孢子虫）是一个相对较小的因素，但确实影响了土壤细菌群落。在选择压力下，与未接种对照相比，接种后根际中与植物生长促进有关的生物标志物增加，尤其是与Mesorhizobium，Variovorax，Streptomyces和Rhodococcus属相关的对照。与硫/氮代谢有关的基因相比，编码ATP结合盒转运蛋白的基因在接种后在根际中上调。这些结果提供了深入的土壤细菌群落及其在根瘤菌接种和重金属污染反应中在刺槐根际中的功能。这些知识可能对改善金属污染土壤的植物修复有用。

Heavy metals can cause serious contamination of soils, especially in mining regions. A detailed understanding of the effects of heavy metals on plants and root-associatedmicrobial communities could help to improve phytoremediation systems. In this study, black locust (Robinia pseudoacacia) seedlings with or without rhizobial inoculation were planted in soils contaminated with different levels of heavy metals. Bacterial communities in rhizosphere and bulk soil samples were analyzed using 16S rRNA gene sequencing on the Illumina MiSeq platform and shotgun metagenome sequencing on the Illumina HiSeq platform. Soil bacterial communities varied significantly depending on the level of soil contamination, and planting also had some influence. Although inoculation ofMesorhizobium loti HZ76 (a natural microsymbiont of R. pseudoacacia) was a relatively minor factor, it did influence the soil bacterial community. Under the selective pressure, plant growth promotion-related biomarkers in the rhizosphere increased after inoculation compared with non-inoculated controls, especially those associated with Mesorhizobium, Variovorax, Streptomyces, and Rhodococcus genera. Genes encoding ATP-binding cassette transporters were up-regulated in the rhizosphere after inoculation compared with genes related to sulfur/nitrogen metabolism. These results provide insight into soil bacterial communities and their functions in the R. pseudoacacia rhizosphere in response to rhizobial inoculation and heavy metal contamination. This knowledge may prove useful for improving phytoremediation of metal-contaminated soils.

https://www.sciencedirect.com/science/article/pii/S004565351830119X