Lang Ming, Bei Shuikuan, Li Xia, Kuyper Thomas W, Zhang Junling
College of Resources and Environment, Southwest University, Chongqing, China.
Centre for Resources, Environment and Food Security, College of Resources and Environmental Sciences, China Agricultural University, Beijing, China.
Front Microbiol. 2019 Dec 10;10:2856. doi: 10.3389/fmicb.2019.02856. eCollection 2019.
Much effort has been directed toward increasing the availability of soil residual phosphorus (P). However, little information is available for the P fertilization-induced biotic P legacy and its mediation of plant P uptake. We collected microbial inocula from a monoculture maize field site with a 10-year P-fertilization history. A greenhouse experiment was conducted to investigate whether bacterial communities, as a result of different P-fertilization history (nil P, 33 and/or 131 kg P kg ha yr), affected the growth of a conspecific (maize) or heterospecific (clover) plant, at two levels of current P application (5 and 30 mg P kg soil; P and P). Deep amplicon sequencing (16S rRNA) was used to determine the maize and clover root-associated bacterial microbiome in different rhizocompartments (rhizoplane, rhizosphere, bulk soil). For both maize and clover, rhizocompartment and host identity were the dominant factors shaping bacterial assemblages, followed by P supply level and the inoculum effect was smallest. Bacterial operational taxonomic unit (OTU) numbers decreased from bulk soil to rhizoplane, whilst specific OTUs were enriched from bulk soil to rhizoplane. A clear hierarchical habitat filtering of bacterial communities was observed in the rhizoplane of the two plant species. The functional prediction of dominant bacterial taxa in the rhizoplane differed between clover and maize, and clover microbiota were more closely associated with P metabolism and maize with carbon cycling. More connected and complex interactions were observed in the clover rhizoplane compared to maize. The microbial legacy effect caused by long-term P fertilization is overridden by host identity and rhizocompartment. Our results highlight the importance of crop diversification in improving P efficiency. The fine-tuning of rhizosphere microbiome in host metabolism indicates that the functions of microbial communities should be integrated into P management to increase P use efficiency and sustainable food production.
人们已付出诸多努力来提高土壤残留磷（P）的有效性。然而，关于磷肥诱导的生物磷遗产及其对植物磷吸收的调节作用，目前所知甚少。我们从一个有10年磷肥施用历史的单作玉米田采集了微生物接种物。进行了一项温室实验，以研究不同磷肥施用历史（不施磷、33和/或131千克磷公顷年）导致的细菌群落是否会在两个当前施磷水平（5和30毫克磷千克土壤；低磷和高磷）下影响同种（玉米）或异种（三叶草）植物的生长。利用深度扩增子测序（16S rRNA）来确定不同根际隔室（根面、根际、土体）中玉米和三叶草根际相关细菌微生物组。对于玉米和三叶草而言，根际隔室和宿主身份是塑造细菌群落的主要因素，其次是磷供应水平，而接种物效应最小。细菌操作分类单元（OTU）数量从土体到根面减少，而特定OTU则从土体到根面富集。在两种植物的根面观察到了明显的细菌群落分层生境过滤。三叶草和玉米根面优势细菌类群的功能预测不同，三叶草微生物群与磷代谢的关联更紧密，而玉米与碳循环的关联更紧密。与玉米相比，在三叶草根面观察到了更多相互连接且复杂的相互作用。长期施磷引起的微生物遗产效应被宿主身份和根际隔室所掩盖。我们的结果突出了作物多样化在提高磷效率方面的重要性。根际微生物组在宿主代谢中的微调表明，应将微生物群落的功能整合到磷管理中，以提高磷利用效率和可持续粮食生产。
