Background and Aims
Soil microorganisms play a crucial role in promoting growth and development, nutrient absorption, and disease resistance in poplar plantations. Long-term planting decays soil ...nutrient contents and changes the microfloral structure, and pathogenic microorganisms accumulate. It is of great significance to clarify the distribution and synergistic relationships between beneficial and pathogenic microorganisms in plantation soil for solving the long-term planting obstacles of poplar plantation.
Methods
High-throughput sequencing, culture, pure bacterial identification, functional verification, and bioinformatics methods were used to explore the population and functional characteristics of the soil microorganisms in the perennial poplar forest, identify the main pathogenic and beneficial microorganisms in the soil, and investigate the synergistic relationships among the microorganisms in the system.
Results
An evaluation of soil from a perennial poplar plantation revealed the presence of many beneficial microbes, such as
Bacillus, Sphingomonas
,
Variovorax
, and
Streptomyces
, as well as pathogenic microorganisms, including
Fusarium
and
Alternaria
. Most of these microorganisms were enriched in the rhizosphere soil. The study found that phosphorus was the driving factor affecting soil microorganisms, with available phosphorus (K = 0.189) and pH value (K = 0.113) significantly affecting fungal phylogeny. Bacterial community assembly processes were deterministic (βNTI < − 2), while those of fungi were stochastic (− 1 > βNTI > − 2). The microbial network in the rhizosphere was more stable than that in the bulk soil. This study expands our knowledge of the functional microbial germplasm resources of forest plantations and provides a theoretical basis for soil remediation in perennial poplar plantations.
Summary
Fine roots, and their functional traits, influence associated rhizosphere microorganisms via root exudation and root litter quality. However, little information is known about their ...relationship with rhizosphere microbial taxa and functional guilds.
We investigated the relationships of 11 fine root traits of 20 sub‐arctic tundra meadow plant species and soil microbial community composition, using phospholipid fatty acids (PLFAs) and high‐throughput sequencing. We primarily focused on the root economics spectrum, as it provides a useful framework to examine plant strategies by integrating the co‐ordination of belowground root traits along a resource acquisition–conservation trade‐off axis.
We found that the chemical axis of the fine root economics spectrum was positively related to fungal to bacterial ratios, but negatively to Gram‐positive to Gram‐negative bacterial ratios. However, this spectrum was unrelated to the relative abundance of functional guilds of soil fungi. Nevertheless, the relative abundance of arbuscular mycorrhizal fungi was positively correlated to root carbon content, but negatively to the numbers of root forks per root length.
Our results suggest that the fine root economics spectrum is important for predicting broader groups of soil microorganisms (i.e. fungi and bacteria), while individual root traits may be more important for predicting soil microbial taxa and functional guilds.
As one of the largest biotechnological applications, activated sludge (AS) systems in wastewater treatment plants (WWTPs) harbor enormous viruses, with 10-1,000-fold higher concentrations than in ...natural environments. However, the compositional variation and host-connections of AS viruses remain poorly explored. Here, we report a catalogue of ~50,000 prokaryotic viruses from six WWTPs, increasing the number of described viral species of AS by 23-fold, and showing the very high viral diversity which is largely unknown (98.4-99.6% of total viral contigs). Most viral genera are represented in more than one AS system with 53 identified across all. Viral infection widely spans 8 archaeal and 58 bacterial phyla, linking viruses with aerobic/anaerobic heterotrophs, and other functional microorganisms controlling nitrogen/phosphorous removal. Notably, Mycobacterium, notorious for causing AS foaming, is associated with 402 viral genera. Our findings expand the current AS virus catalogue and provide reference for the phage treatment to control undesired microorganisms in WWTPs.
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