Taishan Forest Ecosystem Research Station of State Forestry Administration, College of Forestry, Shandong Agricultural University, Tai'an 271018, PR China.
Institute of Mountain Hazards and Environments, Chinese Academy of Sciences, Chengdu 610041, PR China.
Sci Total Environ. 2021 Feb 20;756:143839. doi: 10.1016/j.scitotenv.2020.143839. Epub 2020 Nov 20.
Understanding the succession patterns of microbial community along root growth provides deep insights into interaction between fine roots and microbes. In the study, we investigated this issue using fine roots from poplar trees and grouped these fine roots into three growth stages: newborn white roots (WR), mature yellow roots (YR) and aging brown roots (BR). Root surface traits were observed under a scanning electron microscopy (SEM). Adhered soils on roots of the three growth stages were grouped into the three soil compartments, correspondingly. The 16S rRNA and ITS1 region were sequenced for bacteria and fungi inhabiting rhizosphere soils, respectively. Phospholipid fatty acid (PLFA) technology was employed to examine the biomass of bacterial and fungal communities. The anatomical traits of fine roots show apparent differences among the WR, YR and BR. Both bacteria and fungi have 25 dominant genera with a relative abundance over 1%, of which, four genera of the bacteria (Bacillus, Burkholderia, Ralstonia and Dyella) differ in abundance among the WR, YR and BR soil compartments and four genera of the fungi (Fusarium, Chaetomium, Penicillium and Scleroderma) differ in abundance among these soil compartments. The operational taxonomic units (OTUs) showed the highest richness in the WR soil compartment for bacteria and in the YR soil compartment for fungi, indicating a different succession pattern between the bacterial and fungal communities. Furthermore, the biomass of bacterial community is larger than the fungal community according to PLFAs, and both decreased along fine root growth. The total carbon (TC) in the soil increases along root growth while the dissolved organic carbon (DOC) decreases. Redundancy analysis (RDA) shows a close correlation between twelve dominant bacteria genera and the total organic carbon (TOC), the readily oxidizable organic carbon (ROC) and DOC and ten dominant fungi genera with the TOC and ROC. In conclusion, our results indicate that fine roots growth has shaped the composition and structure of root associated bacterial and fungal communities.
了解微生物群落沿着根系生长的演替模式可以深入了解细根与微生物之间的相互作用。在这项研究中，我们使用杨树的细根来研究这个问题，并将这些细根分为三个生长阶段：新生的白色根（WR）、成熟的黄色根（YR）和老化的棕色根（BR）。在扫描电子显微镜（SEM）下观察根表面特征。将三个生长阶段的根上附着的土壤分别归为三个土壤隔室。分别对定殖在根际土壤中的细菌和真菌的 16S rRNA 和 ITS1 区进行测序。采用磷脂脂肪酸（PLFA）技术检测细菌和真菌群落的生物量。细根的解剖学特征在 WR、YR 和 BR 之间存在明显差异。细菌和真菌都有 25 个相对丰度超过 1%的优势属，其中，细菌的 4 个属（芽孢杆菌属、伯克霍尔德氏菌属、罗尔斯通氏菌属和 Dyella 属）在 WR、YR 和 BR 土壤隔室中的丰度不同，真菌的 4 个属（镰刀菌属、毛壳菌属、青霉属和木霉属）在这些土壤隔室中的丰度不同。OTUs 在 WR 土壤隔室中细菌的丰富度最高，在 YR 土壤隔室中真菌的丰富度最高，表明细菌和真菌群落的演替模式不同。此外，根据 PLFAs，细菌群落的生物量大于真菌群落，并且随着细根生长而减少。土壤中总碳（TC）随根生长而增加，而溶解有机碳（DOC）减少。冗余分析（RDA）表明，12 个优势细菌属与总有机碳（TOC）、易氧化有机碳（ROC）和 DOC 以及 10 个优势真菌属与 TOC 和 ROC 密切相关。总之，我们的结果表明，细根的生长塑造了根相关细菌和真菌群落的组成和结构。
