Shi Baihui, Hou Kaixuan, Cheng Chao, Bai Yao, Liu Changrui, Du Zhongkun, Wang Jinhua, Wang Jun, Li Bing, Zhu Lusheng
College of Resources and Environment, Shandong Agricultural University, Key Laboratory of Agricultural Environment in Universities of Shandong, 61 Daizong Road, Taian, 271018, PR China.
College of Resources and Environment, Shandong Agricultural University, Key Laboratory of Agricultural Environment in Universities of Shandong, 61 Daizong Road, Taian, 271018, PR China; College of Biological and Environmental Engineering, Binzhou University, Binzhou, 256603, PR China.
Environ Res. 2023 Dec 15;239(Pt 2):117379. doi: 10.1016/j.envres.2023.117379. Epub 2023 Oct 11.
Soil ecosystems are being more contaminated with polyhalogenated carbazoles (PHCZs), which raising much attention about their impact on soil microorganisms. 3-Bromocarbazole (3-BCZ) and 1,3,6,8-tetrabromocarbazole (1,3,6,8-TBCZ) are two typical PHCZs with high detection rates in the soil environment. However, ecological risk research on these two PHCZs in soil is still lacking. In the present study, after 80 days of exposure, the ecological influence of 3-BCZ and 1,3,6,8-TBCZ was investigated based on 16S rDNA sequencing, ITS sequencing, gene (16S rDNA, ITS, amoA, nifH, narG and cbbL) abundance and soil enzyme activity. The results showed that the bacterial 16S rDNA gene abundance significantly decreased under 3-BCZ and 1,3,6,8-TBCZ exposure after 80 days of incubation. The fungal ITS gene abundance significantly decreased under 1,3,6,8-TBCZ (10 mg/kg) exposure. PHCZs contributed to the alteration of bacteria and fungi community abundance. Bacteria Sphingomonas, RB41 and fungus Mortierella, Cercophora were identified as the most dominant genera. The two PHCZs consistently decreased the relative abundance of Sphingomonas, Lysobacter, Dokdonella, Mortierella and Cercophora etc at 80th day. These keystone taxa are related to the degradation of organic compounds, carbon metabolism, and nitrogen metabolism and may thus have influence on soil ecological functions. Bacterial and fungal functions were estimated using functional annotation of prokaryotic taxa (FAPROTAX) and fungi functional guild (FUNGuild), respectively. The nitrogen and carbon metabolism pathway were affected by 3-BCZ and 1,3,6,8-TBCZ. The soil nitrogen-related functions of aerobic ammonia oxidation were decreased but the soil carbon-related functions of methanol oxidation, fermentation, and hydrocarbon degradation were increased at 80th day. The effects of 3-BCZ and 1,3,6,8-TBCZ on the abundances of the amoA, nifH, narG, and cbbL genes showed a negative trend. These results elucidate the ecological effects of PHCZs and extend our knowledge on the structure and function of soil microorganisms in PHCZ-contaminated ecosystems.
土壤生态系统正受到多卤代咔唑（PHCZs）的污染，这引发了人们对其对土壤微生物影响的高度关注。3-溴咔唑（3-BCZ）和1,3,6,8-四溴咔唑（1,3,6,8-TBCZ）是土壤环境中检测率较高的两种典型PHCZs。然而，关于这两种PHCZs在土壤中的生态风险研究仍然缺乏。在本研究中，经过80天的暴露后，基于16S rDNA测序、ITS测序、基因（16S rDNA、ITS、amoA、nifH、narG和cbbL）丰度以及土壤酶活性，研究了3-BCZ和1,3,6,8-TBCZ的生态影响。结果表明，在培养80天后，3-BCZ和1,3,6,8-TBCZ暴露下细菌16S rDNA基因丰度显著下降。在1,3,6,8-TBCZ（10 mg/kg）暴露下真菌ITS基因丰度显著下降。PHCZs导致了细菌和真菌群落丰度的改变。细菌鞘氨醇单胞菌属、RB41属以及真菌被孢霉属、尾孢菌属被确定为最优势的属。在第80天时，这两种PHCZs持续降低了鞘氨醇单胞菌属、溶杆菌属、独岛菌属、被孢霉属和尾孢菌属等的相对丰度。这些关键类群与有机化合物的降解、碳代谢和氮代谢有关，因此可能对土壤生态功能产生影响。分别使用原核生物分类群功能注释（FAPROTAX）和真菌功能类群（FUNGuild）来评估细菌和真菌的功能。3-BCZ和1,3,6,8-TBCZ影响了氮和碳代谢途径。在第80天时，土壤中与氮相关的好氧氨氧化功能下降，但与碳相关的甲醇氧化、发酵和烃类降解功能增加。3-BCZ和1,3,6,8-TBCZ对amoA、nifH、narG和cbbL基因丰度的影响呈负趋势。这些结果阐明了PHCZs的生态效应，并扩展了我们对受PHCZs污染生态系统中土壤微生物结构和功能的认识。
