Both Soil Bacteria and Soil Chemical Property Affected the Micropredator Myxobacterial Community: Evidence from Natural Forest Soil and Greenhouse Rhizosphere Soil

Abstract

Myxobacteria are abundant micropredators in soil, and are social bacteria with multicellular behavior and producers of versatile secondary metabolites. The interaction between predator and prey populations is an important component in the soil microbial food web, and this is expected to shape the composition and dynamics of microbial communities. Here we hypothesize the regulation of bacterial abundance and community composition on soil myxobacterial community. Field investigation indicated that the relative abundance of Myxococcales in subtropical and tropical forest soil from South China was 1.49−4.74% of all the 16S rRNA gene sequences, and myxobacterial community composition differed between subtropical and tropical forest. The canonical correspondence analysis and variation partitioning analysis indicated that biotic factor (bacterial community composition) showed slightly stronger explanation for variation of myxobacteria than soil properties (soil pH and soil organic matter). Based on the rhizosphere bacterial network, the greenhouse mesocosm experiment showed that most of the myxobacterial links were with Gram-negative bacteria, except that some nodes from Haliangiacea and Polyangiaceae interacted with actinomycetes and actinomycetes-like Gram-positive bacteria. We inferred that myxobacteria preferential predation on specific bacterial taxa may explain the influence of bacteria on myxobacterial community. Further study confirming the biological process of myxobacterial predation in situ is necessary to advance the understanding of the ecological role of predation behavior in the microbial world.

The soil microbial food web revisited: Predatory myxobacteria as keystone taxa?

“…In all investigated soils the myxobacteria comprised a relatively high proportion of the overall SSU rRNA transcripts. This confirms a recent PCR/16S rRNA gene based survey where myxobacteria also covered a substantial fraction (1.5–4.7%, [ 47 ]; 4.1%, [ 19 ]). On our study, they ranged from a fraction of 1.5–9.7% of all SSU rRNAs in the individual soils (4.9% of total SSU rRNAs across all datasets), which was higher than that of all other investigated bacterivores (Fig.…”

Concepts and conjectures concerning predatory performance of myxobacteria

“…Genera present in >2% of samples have only 5 sequenced representative type strains including Haliangium ochraceum DSM 14365 T (NC_013440.1), Chondromyces apiculatus DSM436 T (NZ_ASRX00000000.1), Chondromyces crocatus DSM14606 T (NZ_CP012159.1), Labilithrix luteola DSM27648 T (NZ_CP012333.1), and Sandaracinus amylolyticus DSM53668 T (NZ_CP011125.1). Similarly low abundances of myxobacteria from frequently sequenced genera have been reported from several biogeographical studies ( Brinkhoff et al, 2012 ; Li et al, 2012 ; Zhou et al, 2014 , 2020 ; Mohr et al, 2016 ; Wang W. et al, 2020 ; Petters et al, 2021 ). The discrepancy between genera of frequently sequenced myxobacteria and the geographic distribution of myxobacteria can be attributed to various challenges such as reliance on established isolation methods and underdeveloped cultivation techniques for lesser-studied genera.…”

“…Microbial community diversity is the most consistently observed environmental factor influencing myxobacteria abundance and diversity. Bacteria in ecological studies from numerous orders have Wang W. et al, 2020;Zhou et al, 2020;Dai et al, 2021). Often attributed to predatory preference of myxobacteria, connections between population-based ecological studies and predatory performance of myxobacteria remain unclear, and few environmental studies have provided genus-level correlations between myxobacteria and potential prey.…”

“…Abiotic factors such as pH and certain alkaline earth metals influence myxobacteria populations in soils and compost manure ( Zhang et al, 2013 ; Wang C. et al, 2020 ; Zhou et al, 2020 ; Dai et al, 2021 ). Increased actinorhodin production by Streptomyces coelicolor during co-culture conditions with M. xanthus has been associated with competitive acquisition of iron in soils ( Perez et al, 2011 ; Lee et al, 2020 ), and copper detoxification has been observed to improve M. xanthus predation of Sinorhizobium meliloti ( Contreras-Moreno et al, 2020 ).…”

Soil Microbial Indicators within Rotations and Tillage Systems

“…However, Myxococcales (O), the order for Archangiaceae (F), was found to be positively correlated with pH from agricultural lands, and RAs significantly increased from those under organic production [85]. Zhou et al [86] also found a positive correlation between soil pH and Myxococcales (O) from forest and greenhouse soil. Furthermore, the authors discovered that bacterial community composition was a key factor in determining Myxococcales (O) RAs since they are predatory bacteria.…”