Biofuels Institute, School of Environment & Safety Engineering, Jiangsu University, Zhenjiang 212013, China.
Biofuels Institute, School of Environment & Safety Engineering, Jiangsu University, Zhenjiang 212013, China; School of Life Sciences, Jiangsu University, Zhenjiang 212013, China; Department of Zoology & Environmental Biology, University of Nigeria, Nsukka 410001, Nigeria.
Sci Total Environ. 2024 Sep 10;942:173775. doi: 10.1016/j.scitotenv.2024.173775. Epub 2024 Jun 4.
The rhizosphere environment of plants, which harbors halophilic bacterial communities, faces significant challenges in coping with environmental stressors, particularly saline soil properties. This study utilizes a high-throughput 16S rRNA gene-based amplicon sequencing to investigate the variations in bacterial community dynamics in rhizosphere soil (RH), root surface soil (RS), root endophytic bacteria (PE) compartments of Suaeda salsa roots, and adjoining soils (CK) across six locations along the eastern coast of China: Nantong (NT), Yancheng (YC), Dalian (DL), Tianjin (TJ), Dongying (DY), and Qingdao (QD), all characterized by chloride-type saline soil. Variations in the physicochemical properties of the RH compartment were also evaluated. The results revealed significant changes in pH, electrical conductivity, total salt content, and ion concentrations in RH samples from different locations. Notably, the NT location exhibited the highest alkalinity and nitrogen availability. The pH variations were linked to HCO accumulation in S. salsa roots, while salinity stress influenced soil pH through H discharge. Despite salinity stress, enzymatic activities such as catalase and urease were higher in soils from various locations. The diversity and richness of bacterial communities were higher in specific locations, with Proteobacteria dominating PE samples from the DL location. Additionally, Vibrio and Marinobacter were prevalent in RH samples. Significant correlations were found between soil pH, salinity, nutrient content, and the abundance and diversity of bacterial taxa in RH samples. Bioinformatics analysis revealed the prevalence of halophilic bacteria, such as Bacillus, Halomonas, and Streptomyces, with diverse metabolic functions, including amino acid and carbohydrate metabolisms. Essential genes, such as auxin response factor (ARF) and GTPase-encoding genes, were abundant in RH samples, suggesting adaptive strategies for harsh environments. Likewise, proline/betaine transport protein genes were enriched, indicating potential bioremediation mechanisms against high salt stress. These findings provide insight into the metabolic adaptations facilitating resilience in saline ecosystems and contribute to understanding the complex interplay between soil conditions, bacterial communities, and plant adaptation.
植物的根际环境中栖息着嗜盐细菌群落，它们面临着应对环境胁迫的巨大挑战，特别是盐渍土壤的特性。本研究利用高通量 16S rRNA 基因扩增子测序技术，调查了中国东部沿海六个地点（南通、盐城、大连、天津、东营和青岛）盐生植物海蓬子根际土壤（RH）、根表土（RS）、根内生细菌（PE）和相邻土壤（CK）中细菌群落动态的变化，这些地点的土壤均为氯化物型盐渍土。还评估了 RH 区物理化学性质的变化。结果表明，不同地点 RH 样本的 pH 值、电导率、总盐含量和离子浓度均发生显著变化。值得注意的是，南通地区的碱性和氮素有效性最高。pH 值的变化与海蓬子根中 HCO3-的积累有关，而土壤 pH 值则受到盐胁迫下 H+的释放影响。尽管受到盐胁迫，各种地点的土壤中过氧化氢酶和脲酶等酶活性仍较高。在特定地点，细菌群落的多样性和丰富度较高，DL 地区的 PE 样本中优势菌为变形菌门。此外，弧菌属和海洋杆菌属在 RH 样本中较为常见。在 RH 样本中，土壤 pH 值、盐度、养分含量与细菌分类群的丰度和多样性之间存在显著相关性。生物信息学分析表明，耐盐细菌如芽孢杆菌属、盐单胞菌属和链霉菌属普遍存在，具有丰富的代谢功能，包括氨基酸和碳水化合物代谢。在 RH 样本中，生长素反应因子（ARF）和 GTP 酶编码基因等必需基因丰富，表明它们对恶劣环境有适应策略。脯氨酸/甜菜碱转运蛋白基因也得到了富集，表明它们可能具有针对高盐胁迫的生物修复机制。这些发现深入了解了促进盐生生态系统恢复力的代谢适应机制，并有助于理解土壤条件、细菌群落和植物适应之间的复杂相互作用。
