Molecular mechanisms underlying the effects of antibiotics on the growth and development of green tide algae Ulva prolifera

Different types of algae exhibit varied sensitivities to antibiotics, influencing their growth by eradicating epiphytic bacteria. This study explored the impact of co-culturing neomycin sulfate, polymyxin B, and penicillin G on the growth and development of Ulva prolifera gametophytes. The findings revealed a significant influence of antibiotics on the morphology, growth, chlorophyll fluorescence parameters, and CAT activity of U. prolifera. The 16S rDNA sequencing revealed a significant decrease in the abundance of Maribacter spp. after antibiotic treatment of U. prolifera. Antibiotic treatment caused up-regulation of genes related to cellulose synthase, tubulin, and ribosomal protein. Conversely, key genes in the DNA replication pathway, such as mcm and Polε, were down-regulated, influencing cell division and resulting in irregular algal shapes. The up-regulation of enzyme genes in the C3 and C4 pathways, CAT, and drug metabolism genes enhanced the antioxidant and photosynthetic capacities of U. prolifera, providing a certain resilience to stress. •The physiology of U. prolifera changed after antibiotic treatment.•Antibiotics can lead to changes in the microbial community structure of algae.•Maribacter sp. can promote the growth and development of U. prolifera.•Transcriptome was used to analyze to differential genes in various forms of U. prolifera.