Myxobacterial community is a predominant and highly diverse bacterial group in soil niches

Abstract

Although many molecular ecological surveys have been conducted, there is little concerning the details of specific bacterial groups, resulting in an incomplete understanding of the microorganismal composition and community structures in the environment. Myxobacteria are micropredators that are metabolically active in the soil microbial food web and have typically been considered minority components of soil bacterial communities. In this study, we surveyed the percentage of myxobacteria in a single soil sample via pyrosequencing on combined universal libraries of the V3-V4 and V6-V8 hypervariable regions of the 16S rRNA gene. Surprisingly, myxobacteria accounted for 4.10% of the bacterial community and 7.5% of the total operational taxonomic units at the 3% similarity level in the soil, containing almost all of the cultivated myxobacterial families or genera. To testify the appearance of myxobacteria in soil niches, we retrieved myxobacteria-related 16S rRNA gene sequences of 103 high-throughput sequencing data sets obtained from public databases. The results indicated that myxobacteria-related sequences were among the predominant groups in these data sets accounting for 0.4-4.5% of bacterial communities. The abundance of myxobacterial communities were correlated with site temperature, carbon-to-nitrogen ratio and pH values. Based on these results, we discussed the survival strategies of myxobacterial community in soil.

Minimization of nitrous oxide emission in a pilot-scale oxidation ditch: Generation, spatial variation and microbial interpretation

“…The relatively higher abundance probably resulted from the low organic carbon stress and moderate oxygenation levels in the oxidation ditch that favored their growth (Zhou et al, 2014). Besides the well-known formation of fruiting bodies and production of secondary metabolites, Myxococcales was also reported to be a dominant and active denitrifying bacterial group responsible for dissimilatory nitrate reduction and N 2 O consumption (Manucharova et al, 2000;Zhou et al, 2014).…”

Current trends in myxobacteria research

“…The myxobacteria seem to be a ubiquitous group of microorganisms that can inhabit very diverse habitats, including desert crust soils (Powell et al 2015), the surface of the older leaves in grain crops, as well as the surface of wheat and barley seeds (Leontievskaya and Dobrovol'skaya 2014), the fruiting bodies and hyphosphere of several basidiomycetes (Zagriadskaia et al 2014) and sewage sludge (Zhou et al 2014a). Myxobacteria were dominant on the older leaves of grain crops and in grain of wheat and barley ears; species composition and structure of epiphytic bacterial communities in the grain cereal crops changed in the course of vegetation (Leontievskaya and Dobrovol'skaya 2014).…”

How Myxobacteria Cooperate

“…It is also striking that these are the only known groups of organisms to share this strategy of building multicellular structures by gathering cells from the environment, which in both cases results in fruiting body formation. Given their evolutionary success [3], the ability to transition from unicellular to multicellular life (fruiting bodies) on a temporal basis offers important fitness advantages for these organisms.…”

“…1). As individual cells, myxobacteria are thought to struggle to survive [8], but as a collective they are very successful and even a dominant species [3], as evident by their great abundance in a wide range of soil and water habitats [8; 9; 10]. Their two gliding motility engines and molecular arsenal of exoenzymes and secondary metabolites make them mobile predators.…”

“…That is, in spite of mechanisms to maintain genetic relatedness within a group, cell diversity nevertheless exists within myxobacterial populations [16]. Moreover, within some microenvironments genetic diversity can vary and be extremely high [3; 17], as spores are stable to environmental stresses and readily disperse by wind and water, creating a global microbial melting pot of species and sub-species. In other cases, heterogeneous nutrient availability in soil limits clonal expansion, and thus islands of separate populations can develop and change, and groups that are compatible may eventually merge (Fig.…”