Distribution Of Cell Size Of Environmental Bacteria And Its Implication With Phylogeny And Ecological Significances

Cell size is one of the most important and basic characteristics of microorganisms,it can reflect the strategy of resources distribution,the community structure of ecosystems and the structure of food webs,at the same time,it can also provide theoretical foundation about understanding the biomass,the energy flow,the circulation of materials and the function of the ecosystem.At present,a majority of studies about molecular ecology of environmental microbial are confined to the analysis about the relative abundance or the absolute abundance such as cells' number,but they were always lost sight of the ecological significance of cell size.In this study,the distribution of cell size of environmental bacteria and its implication with phylogeny and ecological significances are being analyzed by synthesizing the microbial cell size,the phylogenetic relationship,the abundance in the environment,the growth rate and the metabolic activity using size-fraction and the high-throughput sequencing.And the five kinds of environmental bacteria were from sludge and effluent in sewage treatment plant,the bioreactor in laboratory and seawater,and sludge samples were studied mainly.The results show that(1)the closer relative relationship,especially the same genus or species,between different bacteria,the greater likelihood of the similar cell size.But the chances of dissimilarity in cell size of bacteria those have close relative relationship are greater than 50%,this means that there are cell size diversity in bacterial.which are the same genus or species;(2)Most of the higher relative abundance microorganisms are main functional taxa,so do some of the lower abundance,which have bigger cell size,and the influence of the latter on environment should be focus on;(3)most of the microorganisms having the highest metabolic activity are possessing the cell size in 0.6-2.7?m,and there is no microbe groups having high expression of 16S rRNA gene were being found in the microorganisms having smaller cell size.And most of the microorganisms having high abundance,metabolic activity and growth rate are possessing cell size in 0.4-2.0?m.