The color of biodegradable mulch films is associated with differences in peanut yield and bacterial communities.

Biodegradable mulch films (BDMs) are increasingly used in agricultural production as desirable alternatives to the current widespread use of polyethylene (PE) mulch films in China. However, potential effects of different colors of BDMs on field crop production and microbiomes remain unexplored. Here, the differences in bacterial communities of peanut rhizosphere soil (RS) and bulk soil (BS) under non-mulching (CK), PE, and three different colors of BDMs were studied. The results indicated that all treatments could increase the soil temperature, which positively affected the growth of the peanut plants. Moreover, mulching affected the bacterial community structure in RS and BS compared to CK. Furthermore, certain BDM treatments significantly enriched N-fixing bacteria (Bradyrhizobium and Mesorhizobium) and functional groups, increased the closeness of bacterial networks, and harbored more beneficial bacteria as keystone taxa in the RS. This in turn facilitated the growth and development of the peanut plants under field conditions. Our study provides new insights into the micro-ecological effects of mulch films, which can be affected by both the mulch type and color. The observed effects are likely caused by temperature and prevalence of specific microbial functions under the employed films and could guide the development of optimized mulching materials.

Toxicity evaluation of polycyclic aromatic hydrocarbons (PAHs) in soils of coal chemical industry areas, North China.

Objectives of this study were to investigate the concentrations, distributions, toxicities, and risk assessment of 16 polycyclic aromatic hydrocarbons in surface soils surrounding a coal chemical industrial zone in the southeast of Shanxi province, China. A total of 52 topsoil samples were collected from different land-use areas: cereal agriculture, roadsides, and parkland. Results show that the total PAHs (∑16PAHs) ranged from 3.87 × 103 to 116 × 103 µg kg-1 and that the total carcinogenicity PAHs (∑BPAHs) ranged from 3.11 × 103 to 94.2 × 103 µg kg-1, with the highest concentration of ∑16PAHs noted in the RS samples, followed by PS and AS. The entire risk quotient of all PAH maximum permissible concentrations (RQ∑PAHMPCi) was greater than 1.0, and the minimum concentration entire risk quotient (RQ∑PAHNCi) of 84.3% of all samples was higher than 800. The value of the total toxicity equivalent concentration of PAH (PAHBapeq) for areas surrounding the coal chemical industrial zone was higher than the value of the standard level, and the incremental lifetime cancer risk (ILCR) far exceeds the U.S. EPA's risk standard. The toxic properties of PAHs indicated that the soils in the survey areas have a high risk to human health and the environment.

Effects of di-n-butyl phthalate on aerobic composting process of agricultural waste: Mainly based on bacterial biomass and community dynamics analysis.

Phthalic acid esters (PAEs) pollution has become a major environmental problem in agricultural waste composting. However, little information was available about the how the PAEs alter microbial processes during composting. This study investigated the effects of di-n-butyl phthalate (DBP) on bacterial biomass and community dynamics during composting. The results showed that a decreasing of DBP was observed from thermophilic phase and 43.26% of DBP was degraded after composting. The bacterial biomass and diversity during composting were reduced under DBP stress, so delaying the decomposition of organic matter. Moreover, the changes in bacterial community were observed since the thermophilic phase of DBP-contaminated composting. KEGG pathway analysis indicated that DBP stress decreased the relative abundance of the main metabolic pathways and inhibited compost maturation. Moreover, DBP stress had more significant correlation with the dominant bacteria. This work will expand the understanding of PAEs-contaminated organic waste composting and further control of PAEs pollutants.

Implications of environmentally shaped microbial communities for insecticide resistance in Sitobion miscanthi.

Insect-associated bacteria play an important role in the resistance to pesticides, yet bacterial community compositions in wild insect host populations and the environmental factors that shape them are mostly elusive. In this study, Sitobion miscanthi (Takahashi) populations were collected from major wheat growing regions in China. Following high-throughput sequencing of 16S rRNA gene fragments, association analyses were performed within the bacterial community associated with S. miscanthi, as well as with population resistance levels to four commonly used pesticides and different environmental factors. We found that bacterial community structures differed in various regions, and that the abundances of dominant bacteria such as Buchnera, Candidatus Regiella, Candidatus Hamiltonella showed high variations. The resistance of S. miscanthi to avermectin and bifenthrin was shown to decline with increasing bacterial diversity. Meanwhile, with the increase of bacterial network modularity, the resistance of S. miscanthi populations to imidacloprid, avermectin and bifenthrin also increased correspondingly. In addition, correlation analysis indicated that altitude and air pressure had the strongest impact on bacterial community diversity and relative abundance, followed by humidity, rainfall and temperature. Overall, insights into such complex interactions between bacteria and their insect hosts offer new directions for biological pest control.

Sulfobacillus harzensis sp. nov., an acidophilic bacterium inhabiting mine tailings from a polymetallic mine.

A mixotrophic and acidophilic bacterial strain BGR 140T was isolated from mine tailings in the Harz Mountains near Goslar, Germany. Cells of BGR 140T were Gram-stain-positive, endospore-forming, motile and rod-shaped. BGR 140T grew aerobically at 25-55 °C (optimum 45 °C) and at pH 1.5-5.0 (optimum pH 3.0). The results of analysis of the 16S rRNA gene sequences indicated that BGR 140T was phylogenetically related to different members of the genus Sulfobacillus, and the sequence identities to Sulfobacillus acidophilus DSM 10332T, Sulfobacillus thermotolerans DSM 17362T, and Sulfobacillus benefaciens DSM 19468T were 94.8, 91.8 and 91.6 %, respectively. Its cell wall peptidoglycan is A1γ, composed of meso-diaminopimelic acid. The respiratory quinone is DMK-6. The major polar lipids were determined to be glycolipid, phospholipid and phosphatidylglycerol. The predominant fatty acid is 11-cycloheptanoyl-undecanoate. The genomic DNA G+C content is 58.2 mol%. On the basis of the results of phenotypic and genomic analyses, it is concluded that strain BGR 140T represents a novel species of the genus Sulfobacillus, for which the name Sulfobacillus harzensis sp. nov. is proposed because of its origin. Its type strain is BGR 140T (=DSM 109850T=JCM 39070T).

Diversity of bacteria and archaea in the groundwater contaminated by chlorinated solvents undergoing natural attenuation.

Chlorinated solvents (CS)-contaminated groundwater poses serious risks to the environment and public health. Microorganisms play a vital role in efficient remediation of CS. In this study, the microbial community (bacterial and archaeal) composition of three CS-contaminated groundwater wells located at an abandoned chemical factory which covers three orders of magnitude in concentration (0.02-16.15 mg/L) were investigated via 16S rRNA gene high-throughput sequencing. The results indicated that Proteobacteria and Thaumarchaeota were the most abundant bacterial and archaeal groups at the phylum level in groundwater, respectively. The major bacterial genera (Flavobacterium sp., Mycobacterium sp. and unclassified Parcubacteria taxa, etc.) and archaeal genera (Thaumarchaeota Group C3, Miscellaneous Crenarchaeotic Group and Miscellaneous Euryarchaeotic Group, etc.) might be involved in the dechlorination processes. In addition, Pearson's correlation analyses showed that alpha diversity of the bacterial community was not significantly correlated with CS concentration, while alpha diversity of archaeal community greatly decreased with the increased contamination of CS. Moreover, partial Mantel test indicated that oxidation-reduction potential, dissolved oxygen, temperature and methane concentration were major drivers of bacterial and archaeal community composition, whereas CS concentration had no significant impact, indicating that both indigenous bacterial and archaeal community compositions are capable of withstanding elevated CS contamination. This study improves our understanding of how the natural microbial community responds to high CS-contaminated groundwater.

Euonymus japonicus phyllosphere microbiome is significantly changed by powdery mildew.

Euonymus japonicus Thunb. is a woody and ornamental plant popular in China, Europe and North America. Powdery mildew is one of the most serious diseases that affect E. japonicus growth. In this study, the diseased and apparently healthy leaves were collected from E. japonicus planted in a greenbelt in Beijing, and the effect of powdery mildew on the epiphytic microbial community was investigated by using Illumina sequencing. The results showed that the healthy leaves (HL) harbored greater bacterial and fungal diversity than diseased leaves (DL). Furthermore, both bacterial and fungal communities in DL exhibited significantly different structures from those in HL. The relative abundance of several bacterial phyla (Proteobacteria and Firmicutes) and fungal phyla (Ascomycota and Basidiomycota) were altered by powdery mildew. At the genus level, most genera decreased as powdery mildew pathogen Erysiphe increased, while the genera Kocuria and Exiguobacterium markedly increased. Leaf properties, especially protein content was found to significantly affect beta-diversity of the bacterial and fungal community. Network analysis revealed that positive bacterial interactions in DL were stronger than those in HL samples. Insights into the underlying the indigenous microbial phyllosphere populations of E. japonicus response to powdery mildew will help in the development of methods for controlling plant diseases.

Developmental stage has a greater effect than Cry1Ac expression in transgenic cotton on the phyllosphere mycobiome.

Transgenic Bt cotton is widely cultivated, yet its impact on the phyllosphere mycobiome is poorly understood. Hence, the objective of this study was to investigate the effects resulting from the planting of Bt cotton on fungal diversity composition. The α diversity for the Bt cotton line SGK321 was lower than that of control plants at the budding stage and the blossoming and boll-forming stage, while an obvious increase in diversity for Bt cotton XP188 was observed at the same stage. The Cry1Ac levels were higher at the seedling stage than at the budding stage and the blossoming and boll-forming stage. There was no direct relationship between the expression of the Bt protein and variation in the fungal community for Bt cotton. However, PCoA and PCA results indicated that community structure differed among developmental stages. These results indicated that developmental stage rather than Cry1Ac expression was the key factor shaping the phyllosphere mycobiome in transgenic cotton.

Genetic diversity of diazotrophs and total bacteria in the phyllosphere of Pyrus serotina, Prunus armeniaca, Prunus avium, and Vitis vinifera.

The phyllosphere, which supports a large number of microorganisms, represents the interface between the aboveground parts of plants and air. In this study, four nifH clone libraries were constructed from the phyllosphere of Pyrus serotina (L), Vitis vinifera (P), Prunus armeniaca (X), and Prunus avium (Y). Clones related to Skermanella (L, 12.1%; X, 15.6%; Y, 62.5%; P 70.8%), Bradyrhizobium (X, 2.1%; P, 15.1%; L, 63.7%), Erwinia (X, 68.8%), Pseudomonas (L, 3.3%; P, 7.6%), and Chroococcidiopsis (P, 0.9%; L, 4.4%, X; 5.2%, Y; 19.6%) were present at high percentages, highlighting their critical role in contributing nitrogen to the phyllosphere ecosystem. The 16S rDNA sequence analysis suggested that phyllosphere-associated bacteria were affiliated with a wide range of taxa, encompassing members from Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, Deltaproteobacteria, Actinobacteria, Bacteroidetes, Firmicutes, Cyanobacteria, Tenericutes, and Deinococcus-Thermus. Additionally, the abundance of the nifH gene and 16S rDNA was assessed with quantitative PCR. The number of copies of nifH and 16S rDNA ranged from 1.14 × 103 to 1.49 × 104 and from 3.72 × 106 to 7.02 × 107 copies/g fresh leaf sample, respectively. In conclusion, our work sheds light on the microbial communities of the phyllosphere that are important for plant growth. Moreover, we observed a unique composition of nitrogen-fixing bacteria in each phyllosphere sample, suggesting the existence of specific interactions between these functional microorganism and plants, which may provide information or be a reference for the development of bacterial fertilizers.

The phyllosphere indigenous microbiota of Brassica campestris L. change its diversity in responding to di-n-butyl phthalate pollution.

In this study, the effects of di-n-butyl phthalate (DBP) on the phyllosphere bacterial community of field mustard (Brassica campestris L.) at the five-leaf stage were investigated. The indigenous alpha-diversity of the phyllosphere bacteria was altered after spraying with different concentrations of DBP. Shannon diversity indices were significantly changed on day 5 after treatment at DBP concentrations > 400 mg L-1 (P > 0.05). Nevertheless, the difference between treatment and control was not significant on day 9 after DBP treatment (P > 0.05). Exposure to DBP resulted in a decrease in Proteobacteria and Firmicutes, and an increase in Actinobacteria at all sampling intervals. These changes included significant increases in the relative abundance of Paracoccus and Rhodococcus, and significant decreases in that of Pseudomonas, Exiguobacterium, an unclassified genus of Pseudomonadaceae, and an unclassified genus of Enterobacteriaceae. This study provides new evidence for the possibility of using phyllosphere microbiota to remediate DBP contamination.

Divergent Responses of Forest Soil Microbial Communities under Elevated CO2 in Different Depths of Upper Soil Layers.

Numerous studies have shown that the continuous increase of atmosphere CO2 concentrations may have profound effects on the forest ecosystem and its functions. However, little is known about the response of belowground soil microbial communities under elevated atmospheric CO2 (eCO2) at different soil depth profiles in forest ecosystems. Here, we examined soil microbial communities at two soil depths (0 to 5 cm and 5 to 15 cm) after a 10-year eCO2 exposure using a high-throughput functional gene microarray (GeoChip). The results showed that eCO2 significantly shifted the compositions, including phylogenetic and functional gene structures, of soil microbial communities at both soil depths. Key functional genes, including those involved in carbon degradation and fixation, methane metabolism, denitrification, ammonification, and nitrogen fixation, were stimulated under eCO2 at both soil depths, although the stimulation effect of eCO2 on these functional markers was greater at the soil depth of 0 to 5 cm than of 5 to 15 cm. Moreover, a canonical correspondence analysis suggested that NO3-N, total nitrogen (TN), total carbon (TC), and leaf litter were significantly correlated with the composition of the whole microbial community. This study revealed a positive feedback of eCO2 in forest soil microbial communities, which may provide new insight for a further understanding of forest ecosystem responses to global CO2 increases.IMPORTANCE The concentration of atmospheric carbon dioxide (CO2) has continuously been increasing since the industrial revolution. Understanding the response of soil microbial communities to elevated atmospheric CO2 (eCO2) is important for predicting the contribution of the forest ecosystem to global atmospheric change. This study analyzed the effect of eCO2 on microbial communities at two soil depths (0 to 5 cm and 5 to 15 cm) in a forest ecosystem. Our findings suggest that the compositional and functional structures of microbial communities shifted under eCO2 at both soil depths. More functional genes involved in carbon, nitrogen, and phosphorus cycling were stimulated under eCO2 at the soil depth of 0 to 5 cm than at the depth of 5 to 15 cm.

Chitinophaga caeni sp. nov., isolated from activated sludge.

A novel Gram-stain-negative, non-motile, non-spore-forming, rod-shaped, strictly aerobic bacterium, designated strain 13T, was isolated from an activated sludge wastewater treatment plant in Beijing, China. 16S rRNA gene sequence analysis placed this organism within the genus Chitinophaga of the class Bacteroidetes, with Chitinophaga skermanii CC-SG1B (92.4 % gene sequence similarity) and Chitinophaga rupis CS5-B1 (91.2 %) as its closest relatives. This isolate contained meso-diaminopimelic acid as the diagnostic diamino acid and the whole-cell hydrolysate was ribose. Phosphatidylethanolamine was the predominant polar lipid. The major cellular fatty acids were iso-C15 : 0, C16 : 1ω5c and iso-C17 : 0 3-OH. Menaquinone-7 was the only isoprenoid quinone present. The complete genome of the novel strain was sequenced; the size of the genome was 5.28 Mb and the genomic DNA G+C content was 42.5 mol%. The phenotypic, chemotaxonomic and phylogenetic data showed that strain 13T represents a novel species of the genus Chitinophaga, for which the name Chitinophaga caeni sp. nov. is proposed. The type strain is 13T (=CICC 24262T=KCTC 62265T).

Investigating the bacterial community and amoebae population in rural domestic wastewater reclamation for irrigation.

Reclamation of domestic wastewater for agricultural irrigation is viewed as a sustainable option to create an alternative water source and address water scarcity. Free-living amoebae (FLA), which are amphizoic protozoa, are widely distributed in various environmental sources. The FLA could cause considerable environmental and health risks. However, little information is available on the risk of these protozoa. In this study, we evaluated the feasibility using rural domestic wastewater for agricultural irrigation, and analyzed dynamic changes of the microbial community structure and FLA populations in raw and treated wastewater, as well as the phyllosphere and rhizosphere of lettuce production sites that were irrigated with different water sources. The bacterial community dynamics were analyzed by terminal restriction fragment length polymorphism (T-RFLP). The bacterial community structures in the influent were similar to that in the effluent, while in some cases relative abundances varied significantly. The populations of Acanthamoeba spp. and Hartmannella vermiformis in the anaerobically treated wastewater were significantly higher than in the raw wastewater. The vegetables could harbor diverse amoebae, and the abundances of Acanthamoeba spp. and H. vermiformis in the rhizosphere were significantly higher than in the phyllosphere. Accordingly, our studies show insight into the distribution and dissemination of amoebae in wastewater treatment and irrigation practices.

Gordonia phthalatica sp. nov., a di-n-butyl phthalate-degrading bacterium isolated from activated sludge.

A phthalate esters-degrading bacterial strain, designated QH-11T, was isolated from an activated sludge wastewater treatment plant in Beijing, PR China. The cells were aerobic, Gram-stain-positive, non-motile, catalase-positive, oxidase-negative, short rods and formed white colonies on trypticase soy agar. This isolate contained meso-diaminopimelic acid as the diagnostic diamino acid and whole-cell hydrolysates contained arabinose and ribose. Diphosphatidylglycerol and phosphatidylethanolamine were the predominant polar lipids. According to the results of full-length of 16S rRNA gene sequence analysis, QH-11T represented a member of the genus Gordonia and showed the highest sequence similarity to Gordonia hydrophobica DSM 44015T (99.2 %), but was distinguishable by a low level of DNA-DNA relatedness (37.8 %). Genome-based comparisons indicated a clear distinction from the top ten most similar type strains (16S rRNA gene sequence) with pairwise average nucleotide identities (ANI) between 74.6 and 83.4 %. The predominant respiratory quinone was MK-9(H2), the mycolic acids present had 56 to 62 carbon atoms, and the major fatty acids were C16 : 0 (33.3 %), C17 : 1ω8c (23.4 %) and C18 : 1ω9c (17.9 %). The DNA G+C content was 68.0 mol%. On the basis of the results of DNA-DNA hybridization, ANI and physiological and biochemical tests, it is proposed that QH-11T represents a novel species of the genus Gordonia, for which the name Gordonia phthalatica sp. nov. is proposed. The type strain is QH-11T (CICC 24107T =KCTC 39933T).

Patulibacter brassicae sp. nov., isolated from rhizosphere soil of Chinese cabbage (Brassica campestris).

A novel actinobacterial strain, designated SDT, was isolated from rhizosphere soil of Chinese cabbage in Shandong province, China. The cells were aerobic, Gram-staining-positive, oxidase- and catalase-positive, short rods and formed white colonies on trypticase soy agar. The cell-wall peptidoglycan contained meso-diaminopimelic acid as the diagnostic diamino acid and alanine, glutamic acid and leucine. Diphosphatidylglycerol was the predominant polar lipid. The predominant cellular fatty acid was C18 : 1ω9c; minor components were anteiso-C15 : 0 and anteiso-C17 : 0. The only isoprenoid quinone was demethylmenaquinone 7 (DMK-7), and the DNA G+C content was 72.7 mol%. Based on the full-length 16S rRNA gene sequence analysis, the closest phylogenetic neighbours of strain SDT were Patulibacter medicamentivorans DSM 25962T (96.9 %), Patulibacter minatonensis DSM 18081T (96.7 %), Patulibacter americanus DSM 16676T (96.2 %) and Patulibacter ginsengiterrae DSM 25990T (95.9 %). Considering combined phenotypic and genotypic characteristics, it is proposed that strain SDT represents a novel species of the genus Patulibacter, for which the name Patulibacter brassicae sp. nov. is proposed. The type strain is SDT (=CICC 24108T=KCTC 39817T).

Characterization and Genomic Analysis of a Highly Efficient Dibutyl Phthalate-Degrading Bacterium Gordonia sp. Strain QH-12.

A bacterial strain QH-12 isolated from activated sludge was identified as Gordonia sp. based on analysis of 16S rRNA gene sequence and was found to be capable of utilizing dibutyl phthalate (DBP) and other common phthalate esters (PAEs) as the sole carbon and energy source. The degradation kinetics of DBP under different concentrations by the strain QH-12 fit well with the modified Gompertz model (R² > 0.98). However, strain QH-12 could not utilize the major intermediate product phthalate (phthalic acid; PA) as the sole carbon and energy source, and only a little amount of PA was detected. The QH-12 genome analysis revealed the presence of putative hydrolase/esterase genes involved in PAEs-degradation but no phthalic acid catabolic gene cluster was found, suggesting that a novel degradation pathway of PAEs was present in Gordonia sp. QH-12. This information will be valuable for obtaining a more holistic understanding on diverse genetic mechanisms of PAEs-degrading Gordonia sp. strains.

Response patterns of the microbiome during hexavalent chromium remediation by Tagetes erecta L.

Chromium pollution, particularly hexavalent chromium [Cr(VI)], may threaten the environment and human health. This study investigated the potential of Tagetes erecta L. (Aztec marigold) for phytoremediation of soil contaminated with Cr(VI), and focused on the effects of varying concentrations of Cr(VI) on both the physicochemical properties of soil and microbiome of Tagetes erecta L. We observed that Tagetes erecta L. showed tolerance to Cr(VI) stress and maintained normal growth under these conditions, as indicated by bioconcentration factors of 0.33-0.53 in shoots and 0.39-0.70 in roots. Meanwhile, the structure and diversity of bacterial communities were significantly affected by Cr(VI) pollution. Specifically, Cr(VI) had a more significant effect on the microbial community structure in the endophytic of Tagetes erecta L. than in the rhizosphere (p < 0.05). The genera Devosia and Methylobacillus were positively correlated with Cr(VI) concentrations. Biomarkers such as Bacilli and Pseudonocardia were identified under the different Cr(VI)-contaminated treatments using LEfSe. In addition, the interaction and stability of the endophytic microbiome were enhanced under Cr(VI) stress. This study explored the interactions between heavy metals, microorganisms, and plants, providing valuable insights for developing in situ bioremediation of Cr(VI)-contaminated soils.

Terrimonas pekingensis sp. nov., isolated from bulking sludge, and emended descriptions of the genus Terrimonas, Terrimonas ferruginea, Terrimonas lutea and Terrimonas aquatica.

A Gram-negative, strictly aerobic, non-motile and non-spore-forming rod that produced white, viscous colonies, designated QH(T), was isolated from bulking sludge collected from a municipal wastewater treatment plant in Beijing, China. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain QH(T) belonged to the genus Terrimonas and shared 96.3 % sequence similarity with Terrimonas lutea DY(T), 94.1 % with Terrimonas ferruginea ATCC 13524(T) and 93.8 % with Terrimonas aquatica RIB1-6(T). Strain QH(T) contained iso-C15 : 0, summed feature 3 (comprising one or more of C16 : 1ω7c, C16 : 1ω6c and iso-C15 : 0 2-OH) and iso-C15 : 1 G as the predominant fatty acids. The predominant polar lipid of strain QH(T) and members of the genus Terrimonas was phosphatidylethanolamine. The major isoprenoid quinone of strain QH(T) was MK-7 and the DNA G+C content was 41.0 mol%. DNA-DNA relatedness between strain QH(T) and T. lutea BCRC 17944(T), T. ferruginea BCRC 17943(T) and T. aquatica BCRC 17941(T) was 32, 23 and 22 %, respectively. On the basis of phylogenetic inference, differential phenotypic data and low DNA-DNA relatedness with members of the genus Terrimonas, strain QH(T) represents a novel species, for which the name Terrimonas pekingensis sp. nov. is proposed. The type strain is QH(T) ( = CICC 10452(T)  = NCCB 100397(T)). The descriptions of the genus Terrimonas and T. ferruginea, T. lutea and T. aquatica are also emended.

Biodegradation of di-n-butyl phthalate by a newly isolated halotolerant Sphingobium sp.

A Gram-negative strain (TJ) capable of growing aerobically on mixed phthalate esters (PAEs) as the sole carbon and energy source was isolated from the Haihe estuary, Tianjin, China. It was identified as belonging to the Sphingobium genus on the basis of morphological and physiological characteristics and 16S rRNA and gyrb gene sequencing. The batch tests for biodegradation of di-n-butyl phthalate (DBP) by the Sphingobium sp. TJ showed that the optimum conditions were 30 °C, pH 7.0, and the absence of NaCl. Stain TJ could tolerate up to 4% NaCl in minimal salt medium supplemented with DBP, although the DBP degradation rates slowed as NaCl concentration increased. In addition, substrate tests showed that strain TJ could utilize shorter side-chained PAEs, such as dimethyl phthalate and diethyl phthalate, but could not metabolize long-chained PAEs, such as di-n-octyl phthalate, diisooctyl phthalate, and di-(2-ethyl-hexyl) phthalate. To our knowledge, this is the first report on the biodegradation characteristics of DBP by a member of the Sphingobium genus.

Native fungal community remains resilient during bioremediation of DBP pollution by exogenous Gordonia phthalatica QH-11T.

Microbial bioremediation is a highly effective method to degrade phthalates in the environment. However, the response of native microbial communities to the exogenously introduced microorganism remains unknown. In this study, the native fungal community was monitored by amplicon sequencing of the fungal ITS region during the restoration process of the di-n-butyl phthalate (DBP)-contaminated soils with Gordonia phthalatica QH-11T. Our results showed that the diversity, composition, and structure of the fungal community in the bioremediation treatment did not differ from the control, and no significant correlations were found between number of Gordonia and variation of fungal community. It was also observed that DBP pollution initially increased the relative abundance of plant pathogens and soil saprotrophs first, but their proportions returned to the initial level. Molecular ecological network analysis showed that DBP pollution increased the network complexity, while the network was not significantly altered by bioremediation. Overall, the introduction of Gordonia was shown to not have a long-term impact on the native soil fungal community. Therefore, this restoration method can be considered safe in terms of soil ecosystem stability. The present study provides a deeper insight into the effect of bioremediation on fungal communities and provides an extended basis to further explore the ecological risks of introducing exogenous microorganisms.