School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China; Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China.
School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China.
Sci Total Environ. 2018 Dec 10;644:1591-1601. doi: 10.1016/j.scitotenv.2018.07.095. Epub 2018 Jul 23.
Successful in situ phytoremediation depends on beneficial interactions between roots and microbes. However, the assembly strategies of root-associated microbiome during phytoremediation are not well known. Here we investigated the assembly patterns of root-associated microbiomes during phytoremediation as well as its regulation by both plants and heavy metals. Plant cultivation and soil amendment increased microbial diversity and restructured microbial communities. Rhizo-compartmentalization was the largest source of variation in root-associated microbiomes, with endosphere being the most independent and exclusive compartment. Soil type explained a larger amount of microbiomes variation in bulk soil and rhizosphere than that in endosphere. A specific core root microbiome was likely to be selected by the metal-tolerant plant H. cannabinus, with Enterobacteriaceae, Pseudomonadaceae and Comamonadaceae which contain a large number of metal-tolerant and plant growth-promoting bacteria (PGPB) being the most abundant families. The root-associated microbial community tended to proceed a niche-assembled patterns and formed a smaller bacterial pool dominant by Proteobacteria, Actinobacteria and Chloroflexi under metal-contaminated conditions. Among these genera, potential metal-tolerant PGPB species have taken up the keystone positions in the microbial co-occurrence networks, revealing their key roles in metal-contaminated environment due to niche selection. We also detected a keystone functional group reducing metal bioavailability which might work as vanguards and devote to maintaining the structure and function of the whole microbial community. In conclusion, this study suggested a specific assembly pattern of root-associated microbiomes of the metal-tolerant plant H. cannabinus during phytoremediation, showing the directional selections of the associated microbiomes by both the plant and metal-contaminated conditions in such a system.
成功的原位植物修复依赖于根系和微生物之间的有益相互作用。然而，植物修复过程中根相关微生物组的组装策略尚不清楚。在这里，我们研究了植物修复过程中根相关微生物组的组装模式及其受植物和重金属的调节。植物栽培和土壤改良增加了微生物的多样性，并重构了微生物群落。根共生体的区室化是根相关微生物组变异的最大来源，其中内共生体是最独立和排他的区室。与根际和内共生体相比，土壤类型解释了更多的土壤微生物组变异。一种特定的核心根微生物组可能被耐金属植物大麻选择，其中肠杆菌科、假单胞菌科和丛毛单胞菌科含有大量耐金属和促进植物生长的细菌（PGPB），是最丰富的科。在受金属污染的条件下，根相关微生物群落倾向于进行生态位组装模式，并形成一个由变形菌门、放线菌门和绿弯菌门主导的较小细菌池。在这些属中，具有潜在耐金属特性的 PGPB 物种在微生物共生网络中占据关键位置，由于生态位选择，它们在金属污染环境中发挥着关键作用。我们还检测到一个降低金属生物有效性的关键功能群，它可能作为先锋，致力于维持整个微生物群落的结构和功能。总之，本研究提出了一种耐金属植物大麻在植物修复过程中根相关微生物组的特定组装模式，表明了植物和受金属污染的条件对相关微生物组的定向选择。
