We can't find the internet
Attempting to reconnect
Something went wrong!
Hang in there while we get back on track
Stress-induced enrichment of Pseudomonas sp. stimulates the adaptive response of Auxenochlorella pyrenoidosa and antibiotic-resistant proliferation
Summary
Co-culturing the microalga Auxenochlorella pyrenoidosa with bacteria under polylactic acid microplastic and antibiotic stress revealed that PLA microplastics promoted algal growth while selectively enriching antibiotic-resistant Pseudomonas bacteria, with horizontal gene transfer playing a lesser role than niche-based selective pressure in spreading antibiotic resistance genes. This demonstrates that microplastics can act as selective pressure hotspots for antibiotic resistance proliferation in aquatic microbial communities, with implications for environmental health beyond the plastics themselves.
Abstract Background The phycosphere is an important ecological niche for bacteria and antibiotic resistance genes (ARGs). However, whether and how the interaction between microalgae and bacteria changed, and its further effect on the transmission of ARGs under pollutant stress remains enigmatic. Here, Auxenochlorella pyrenoidosa was co-cultured with bacteria screened from lake water to explore the algal–bacteria interaction and ARGs’ transmission in the presence of florfenicol (FF) and polylactic acid microplastics (PLA MPs). Results Our study demonstrated that the growth and metabolism of A. pyrenoidosa were promoted under FF treatment or co-treatment with PLA MPs, validated by phenotypic, transcriptome, and metabolome analyses. In contrast, the abundance of phycospheric bacteria was decreased as a result of niche competition. Nonetheless, the transmission of ARGs in the phycosphere was promoted due to the enrichment of antibiotic-resistant bacteria, especially Pseudomonas, rather than horizontal gene transfer. The algal-bacteria co-culture experiment further suggested that vitamin B6 secreted by Pseudomonas sp. likely contributes to underpinning A. pyrenoidosa’ survival under FF and PLA MPs stress. Conclusions These findings underscore the dynamic interplay and co-evolution between algae and bacteria under pollutant exposure, and reveal a potential mechanism of vitamin B6-mediated mutualism. This study provides new insights into the assembly of phycospheric bacterial communities and the adaptive strategies of microalgae in contaminated aquatic environments. Video Abstract