Department of Biological Sciences, Microbiology unit, Elizade University, Ilara-Mokin, Ondo State, Nigeria.
Department of Microbiology, Lagos State University, Ojo, Lagos, Nigeria.
World J Microbiol Biotechnol. 2023 Jun 20;39(9):228. doi: 10.1007/s11274-023-03681-6.
The impacts of hexavalent chromium (Cr) contamination on the microbiome, soil physicochemistry, and heavy metal resistome of a tropical agricultural soil were evaluated for 6 weeks in field-moist microcosms consisting of a Cr-inundated agricultural soil (SL9) and an untreated control (SL7). The physicochemistry of the two microcosms revealed a diminution in the total organic matter content and a significant dip in macronutrients phosphorus, potassium, and nitrogen concentration in the SL9 microcosm. Heavy metals analysis revealed the detection of seven heavy metals (Zn, Cu, Fe, Cd, Se, Pb, Cr) in the agricultural soil (SL7), whose concentrations drastically reduced in the SL9 microcosm. Illumina shotgun sequencing of the DNA extracted from the two microcosms showed the preponderance of the phyla, classes, genera, and species of Actinobacteria (33.11%), Actinobacteria_class (38.20%), Candidatus Saccharimonas (11.67%), and Candidatus Saccharimonas aalborgensis (19.70%) in SL7, and Proteobacteria (47.52%), Betaproteobacteria (22.88%), Staphylococcus (16.18%), Staphylococcus aureus (9.76%) in SL9, respectively. Functional annotation of the two metagenomes for heavy metal resistance genes revealed diverse heavy metal resistomes involved in the uptake, transport, efflux, and detoxification of various heavy metals. It also revealed the exclusive detection in SL9 metagenome of resistance genes for chromium (chrB, chrF, chrR, nfsA, yieF), cadmium (czcB/czrB, czcD), and iron (fbpB, yqjH, rcnA, fetB, bfrA, fecE) not annotated in SL7 metagenome. The findings from this study revealed that Cr contamination induces significant shifts in the soil microbiome and heavy metal resistome, alters the soil physicochemistry, and facilitates the loss of prominent members of the microbiome not adapted to Cr stress.
研究人员在田间湿润微宇宙中评估了六价铬 (Cr) 污染对热带农业土壤微生物组、土壤理化性质和重金属抗性组的影响，该微宇宙由 Cr 污染的农业土壤 (SL9) 和未经处理的对照 (SL7) 组成，持续时间为 6 周。两个微宇宙的理化性质显示，总有机物质含量减少，SL9 微宇宙中的大量营养物磷、钾和氮浓度显著下降。重金属分析显示，农业土壤 (SL7) 中检测到七种重金属 (Zn、Cu、Fe、Cd、Se、Pb、Cr)，其浓度在 SL9 微宇宙中急剧降低。从两个微宇宙中提取的 DNA 的 Illumina shotgun 测序显示，优势菌群为放线菌门 (33.11%)、放线菌纲 (38.20%)、Candidatus Saccharimonas (11.67%)和 Candidatus Saccharimonas aalborgensis (19.70%)，分别在 SL7 中，以及变形菌门 (47.52%)、β-变形菌纲 (22.88%)、葡萄球菌 (16.18%)和金黄色葡萄球菌 (9.76%)，分别在 SL9 中。两个宏基因组对重金属抗性基因的功能注释揭示了参与各种重金属吸收、运输、外排和解毒的多样化重金属抗性组。它还揭示了仅在 SL9 宏基因组中检测到的铬抗性基因 (chrB、chrF、chrR、nfsA、yieF)、镉 (czcB/czrB、czcD) 和铁 (fbpB、yqjH、rcnA、fetB、bfrA、fecE)，而在 SL7 宏基因组中未注释。本研究结果表明，Cr 污染会导致土壤微生物组和重金属抗性组发生显著变化，改变土壤理化性质，并促进不适应 Cr 胁迫的微生物组主要成员的损失。
