Diversity and growth promotion of nitrogen-fixing bacteria isolated from the offshore of Donghai Island in the South China Sea

Abstract:

[Objective] We studied the diversity and crop-growth promotion of marine nitrogen-fixing bacteria and screened for excellent plant rhizosphere-promoting strains. [Methods] We identified the representative strains by morphological, physiological and biochemical characteristics, and 16S rRNA gene sequence alignment analysis. We used strains with excellent properties as the combined bacterial liquids in the pot-planting test. [Results] We isolated a total of 18 nitrogen-fixing bacteria from the offshore of Donghai Island in the South China Sea, which were classified into 9 species of 6 genera, belonging to 4 strains of the genus Acinetabacter, 1 strain of the genus Pseudoalteromonas, 8 strains of the genus Bacillus, 1 strain of the genus Psyctrobacter, 1 strain of the genus Oceanimonas and 3 strains of the genus Alteromonas. The seedlings of Chinese flowering cabbage were irrigated by combined microbial agents. Among them, the strains of the genera Bacillus and Acinetobacter had a key promoting effect in the growth process of Chinese flowering cabbage, and showed the best growth promoting effect on Chinese flowering cabbage. [Conclusion] This study provides an important basis for the targeted utilization of marine microbial resources and the pollution-free production of vegetables.