Insights into the effects of drying treatments on cultivable microbial diversity of marine sediments.

Microbes are widespread in the sea that covers more than two-thirds of the earth's surface and most microorganisms living in the marine environment have yet to be cultured. Previous studies showed that drying treatment, a strategy of sample pre-treatment widely applied in microbial isolation and incubation, may alter the cultivable microbial diversity, such as Actinomycetota, essential for exploring novel secondary metabolites from the marine environment, isolated from drying-treated samples. However, whether drying treatments actually can change microbial community diversity and how the drying treatments of samples influence the cultivable microbial diversity of marine samples have not yet adequately been evaluated. Here, three marine sediment samples were dried and incubated at 28 ºC, 37 ºC, and 45 ºC, and the microbial diversity was assessed with high-throughput sequencing. Our results suggested that drying treatments had different effects on different genera and some potential novel species could be cultured only from drying-treated samples, including the novel members from the families Paenibacillaceae and Thermoactinomycetaceae. Non-metric multidimensional scaling analysis showed that the treated samples were clustered according to the cultivation temperatures rather than the drying conditions at high cultivation temperatures. However, at the cultivation temperatures of 28 ºC, drying treatments were the larger separation between cultivable microbial communities in the process of microbial isolation. These results showed that the drying treatments influenced the cultivated microbes in a taxon-specific pattern and extended potential novel taxa. Combining high-throughput sequencing to various drying conditions and incubation temperatures, this study provides new insight into the effects of drying treatment on the cultivable microbial diversity of marine sediments.