Spatio‐temporal Variations in the Molecular Diversity of Microeukaryotes in Particular Ciliates in Soil of the Yellow River Delta, China

Abstract

The Yellow River delta in China is one of the most active regions of land-ocean interaction. It has suffered serious salinization due to drying-up of the Yellow River, rising sea level, and seashore erosion, and thus represents a special and extreme environment. We evaluated the microeukaryotic molecular diversity and its response to change of seasons and environmental variables, in particular salinity in the soil of the Yellow River delta, by denaturing gradient gel electrophoresis (DGGE) and gene sequencing. The sequencing of the microeukaryotic DGGE bands revealed the presence of diverse groups dominated by protists in particular ciliates. We further recovered a high diversity of marine and soil ciliates inhabiting in coastal soil using the ciliate-specific DGGE. The neighbor-joining tree indicated that the ciliate 18S rDNA sequences from high-salinity soil were affiliated to Colpodea, Spirotrichea, Litostomatea, and Oligohymenophorea, while all the sequences unique to the low-salinity soil were affiliated to Colpodea. Statistical analysis indicated that the microeukaryotic molecular diversity was significantly different among sites, while statistically indistinguishable among seasons. Soil salinity might be the main factor regulating the distribution of microeukaryotes in the soil from the Yellow River delta.