Seasonal succession of bacterial communities in cultured Caulerpa lentillifera detected by high-throughput sequencing

Abstract

An increasing number of microorganisms are being identified as pathogens for diseases in macroalgae, but the species composition of bacteria related to Caulerpa lentillifera, fresh edible green macroalgae worldwide, remains largely unclear. The bacterial communities associated with C. lentillifera were investigated by high-throughput 16S rDNA sequencing, and the bacterial diversities in washed and control groups were compared in this study. A total of 4,388 operational taxonomic units were obtained from all the samples, and the predominant prokaryotic phyla were Proteobacteria, Bacteroidetes, Planctomycetes, Cyanobacteria, Actinobacteria, Verrucomicrobia, Chloroflexi, and Acidobacteria in C. lentillifera. The bacterial diversity changed with seasons and showed an increasing trend of diversity with the rising temperature in C. lentillifera. There were slight reductions in the abundance and diversity of bacteria after washing with tap water for 2 h, indicating that only parts of the bacterial groups could be washed out, and hidden dangers in C. lentillifera still exist. Although the reduction in the abundance of some bacteria revealed a positive significance of washing C. lentillifera with tap water on food safety, more effective cleaning methods still need to be explored.