【土壤细菌和古菌类群的尺寸分布】Maria C. Portillo^a Jonathan W. Leff^ab Christian L. Lauber^a and Noah Fierer^ab. Cell Size Distributions of Soil Bacterial and Archaeal Taxa. Appl. Environ. Microbiol. December 2013 vol. 79 no. 24 7610-7617

Abstract

Cell size is a key ecological trait of soil microorganisms that determines a wide range of life history attributes including the efficiency of nutrient acquisition. However because of the methodological issues associated with determining cell sizes in situ we have a limited understanding of how cell abundances vary across cell size fractions and whether certain microbial taxa have consistently smaller cells than other taxa. In this study we extracted cells from three distinct soils and fractionated them into seven size ranges (5 μm to 0.2 μm) by filtration. Cell abundances in each size fraction were determined by direct microscopy with the taxonomic composition of each size fraction determined by high-throughput sequencing of the 16S rRNA gene. Most of the cells were smaller than cells typically grown in culture with 59 to 67% of cells <1.2 μm in diameter. Furthermore each size fraction harbored distinct bacterial and archaeal communities in each of the three soils and many of the taxa exhibited distinct size distribution patterns with the smaller size fractions having higher relative abundances of taxa that are rare or poorly characterized (including Acidobacteria Gemmatimonadetes Crenarchaeota Verrucomicrobia and Elusimicrobia). In general there was a direct relationship between average cell size and culturability with those soil