Characterizing bacterial communities in Phragmites australis rhizosphere and non-rhizosphere sediments under pressure of antibiotics in a shallow lake

Abstract

IntroductionAntibiotics are ubiquitous pollutants and widely found in aquatic ecosystems, which of rhizosphere sediment and rhizosphere bacterial communities had certain correlation. However, the response of bacterial communities in Phragmites australis rhizosphere and non-rhizosphere sediments to antibiotics stress is still poorly understood.MethodsTo address this knowledge gap, the samples of rhizosphere (R) and non-rhizosphere (NR) sediments of P. australis were collected to investigate the differences of bacterial communities under the influence of antibiotics and key bacterial species and dominate environmental factors in Baiyangdian (BYD) Lake.ResultsThe results showed that the contents of norfloxacin (NOR), ciprofloxacin (CIP) and total antibiotics in rhizosphere sediments were significantly higher than that in non-rhizosphere sediments, meanwhile, bacterial communities in non-rhizosphere sediments had significantly higher diversity (Sobs, Shannon, Simpsoneven and PD) than those in rhizosphere sediments. Furthermore, total antibiotics and CIP were found to be the most important factors in bacterial diversity. The majority of the phyla in rhizosphere sediments were Firmicutes, Proteobacteria and Campilobacterota, while Proteobacteria, Chloroflexi was the most abundant phyla followed by Bacteroidota, Actinobacteriota in non-rhizosphere sediments. The dominate factors of shaping the bacterial communities in rhizosphere were total antibiotics, pH, sediment organic matter (SOM), and NH4-N, while dissolved organic carbon (DOC), NO3-N, pH, and water contents (WC) in non-rhizosphere sediments.DiscussionIt is suggested that antibiotics may have a substantial effect on bacterial communities in P. australis rhizosphere sediment, which showed potential risk for ARGs selection pressure and dissemination in shallow lake ecosystems.

Antibiotics affected the bacterial community structure and diversity in pore water and sediments with cultivated Phragmites australis in a typical Chinese shallow lake

“…Moreover, there was no significant difference in the bacterial community structure in pore water between the wild and cultivated P. australis regions under the same antibiotics stress. The possible explanation was no significant difference in the total antibiotics in pore water between both regions ( Zhang et al, 2022a , b ), What is more, the similar bacterial community in sediments between both regions might be explained by the fact that the two P. australis regions were connected by inflow rivers, and the bacterial communities may coalesced between pore water and sediments ( Ren et al, 2017 ; Gao et al, 2021 ). It is different from the previous research that the bacterial community in pore water in different types of wetlands can be distinguished ( Wang et al, 2018 ).…”

“…The toxicological effects ( Välitalo et al, 2017 ) and the pressure selection ( Zhu et al, 2019 ; Sun et al, 2021 ) of antibiotics on bacterial communities ultimately change the bacteria populations, which could affect the migration of bacterial communities and the balance of the ecosystem. However, the distribution of antibiotics in aquatic environments was different, such as in pore water and sediments ( Xu et al, 2014 ; Zhang et al, 2022a , b ). Keshri et al (2018) found that pore water and sediment share 6.7–20.3% of operational taxonomic units (OTUs), which indicated a link between sediment bacterial communities and pore water bacterial communities.…”

“…Aquatic plants were one of the important components of the lake ecosystem and play an important role in the fate of pollutants and bacterial communities in lakes ( Perez-Jaramillo et al, 2018 ; Zhang et al, 2022a , b ). Plants accumulated antibiotics ( Zhang et al, 2022a , b ) and transfer their metabolites to the bacterial community in the form of root exudates, thereby affecting the changes in the bacterial community ( Huang et al, 2020 ). However, there is evidence that cultivated and wild plants respond differently to environmental stress.…”

“…Similarly, wild and cultivated P. australis also show different responses to antibiotics. Compared to wild Phragmites australis ( P. australis ), cultivated P. australis had a developed root system, high plant height, and large stem and leaf area, which lead to more antibiotics accumulation from sediments and pore water ( Zhang et al, 2022a , b ) and bacteria enrichment ( Pantigoso et al, 2020 ). Similarity, the bacterial community has received much influence due to their associations with plant growth and environmental pollution in lake ecosystems ( Marschner et al, 2004 ).…”

“…Generally, compared with the wild P. australis region, total antibiotics in sediments of the cultivated P. australis region was higher, while no significant difference was observed in the pore water in our previous study. What is more, wild and cultivated P. australis had different antibiotic accumulation abilities ( Zhang et al, 2022a , b ). However, antibiotics will produce selection pressure on the bacterial community, and the bacterial community affects the growth and development of plants.…”