Discovery of a High-Efficient Algicidal Bacterium against Based on Examinations toward Culture Strains and Natural Bloom Samples.

Harmful cyanobacterial blooms occur worldwide and pose a great threat to aquatic ecosystems and public health. The application of algicidal bacteria represents an eco-friendly strategy for controlling harmful cyanobacterial blooms; thus, searching for a high efficiency of algicidal bacteria has been becoming an important and continuous task in science. Herein, we identified a bacterial strain coded sp. HY with a highly algicidal activity, and investigated its algicidal efficiency and mechanism against . The strain HY displayed high algicidal activity toward cells, with a removal rate of 93.04% within 2 days via indirect attack. sp. HY also showed the ability to lyse several genera of cyanobacterial strains, including , , , and , whereas it showed a minor impact on the green alga , demonstrating its selectivity specially for targeting cyanobacteria. Its algicidal mechanism involved damages to the photosynthesis system, morphological injury of algal cells, oxidative stress, and dysfunction of the DNA repair system. Furthermore, HY treatment reduced the expression levels of genes ( and ) related to microcystin biosynthesis and decreased the total content of microcystin-leucine-arginine by 79.18%. Collectively, these findings suggested that the algicidal bacteria HY is a promising candidate for harmful cyanobacterial bloom control.