Myxobacteria have potential application value in developing new antibiotics and environmental protection. In this study, in order to establish a more suitable method for diversity studies of ...myxobacteria, the effects of primers, polymerase chain reaction (PCR) approaches and sample preservation methods on the results were compared by Illumina high-throughput sequencing. The results showed that the relative abundance and operational taxonomic unit (OTU) ratio of myxobacteria amplified by the universal primers accounted for 0.91–1.85% and 2.82–4.10% of total bacteria, indicating that myxobacteria were the dominant bacteria both in population and species numbers. The relative abundance and OTU number and ratio of myxobacteria amplified by the myxobacteria semi-specific primers were significantly higher than those amplified by the universal primers, of which the primer pair W2/802R specifically amplified myxobacteria of suborder Cystobacterineae, while the primer pair W5/802R mainly amplified myxobacteria of suborder Sorangineae and also amplified more species of suborder Nannocystineae at the same time. Among three PCR approaches, the relative abundance and OTU ratio of myxobacteria amplified by the touch-down PCR were the highest. More myxobacterial OTUs were detected in most dried samples. In conclusion, the combination of the myxobacteria semi-specific primer pairs W2/802R and W5/802R, touch-down PCR, and dry preservation of samples were more conducive to diversity studies of myxobacteria.
•The order of Myxococcales was the dominant bacteria in the soil samples.•The primers had the greatest influence on diversity studies of myxobacteria.•The primers W2/802R and W5/802R were suitable for diversity studies of myxobacteria.•Touch-down PCR was conducive to diversity studies of myxobacteria.•Sample preservation by air drying was helpful to diversity studies of myxobacteria.
Myxobacteria are widely distributed in various habitats of soil and oceanic sediment. However, it is unclear whether soil-dwelling myxobacteria tolerate a saline environment. In this study, a ...salt-tolerant myxobacterium Myxococcus sp. strain MxC21 was isolated from forest soil with NaCl tolerance >2% concentration. Under 1% salt-contained condition, strain MxC21 could kill and consume bacteria prey and exhibited complex social behaviors such as S-motility, biofilm, and fruiting body formation but adopted an asocial living pattern with the presence of 1.5% NaCl. To investigate the genomic basis of stress tolerance, the complete genome of MxC21 was sequenced and analyzed. Strain MxC21 consists of a circular chromosome with a total length of 9.13 Mbp and a circular plasmid of 64.3 kb. Comparative genomic analysis revealed that the genomes of strain MxC21 and M. xanthus DK1622 share high genome synteny, while no endogenous plasmid was found in DK1622. Further analysis showed that approximately 21% of its coding genes from the genome of strain MxC21 are predominantly associated with signal transduction, transcriptional regulation, and protein folding involved in diverse niche adaptation such as salt tolerance, which enables social behavior such as gliding motility, sporulation, and predation. Meantime, a high number of genes are also found to be involved in defense against oxidative stress and production of antimicrobial compounds. All of these functional genes may be responsible for the potential salt-toleration. Otherwise, strain MxC21 is the second reported myxobacteria containing indigenous plasmid, while only a small proportion of genes was specific to the circular plasmid of strain MxC21, and most of them were annotated as hypothetical proteins, which may have a direct relationship with the habitat adaptation of strain MxC21 under saline environment. This study provides an inspiration of the adaptive evolution of salt-tolerant myxobacterium and facilitates a potential application in the improvement of saline soil in future.
Myxobacteria are famous for their capacity for social behavior and natural product biosynthesis. The unique sociality of myxobacteria is not only an intriguing scientific topic but also the main ...limiting factor for their manipulation. After more than half a century of research, a series of genetic techniques for myxobacteria have been developed, rendering these mysterious bacteria manipulable. Here, we review the advances in genetic manipulation of myxobacteria, with a particular focus on the exploitation of secondary metabolism. We emphasize the necessity and urgency of constructing the myxobacterial chassis for synthetic biology research and the exploitation of untapped secondary metabolism.
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Myxobacteria exhibit a variety of complex social behaviors that all depend on coordinated movement of cells on solid surfaces. The cooperative nature of cell movements is known as social ...(S)-motility. This system is powered by cycles of type IV pili (Tfp) extension and retraction. Exopolysaccharide (EPS) also serves as a matrix to hold cells together. Here, we characterized a new S-motility gene in
. This mutant is temperature-sensitive (Ts
) for S-motility; however, Tfp and EPS are made. A 1 bp deletion was mapped to the MXAN_4099 locus and the gene was named
. Null mutations in
exhibit a synthetic enhanced phenotype with a null
mutation, a previously characterized S-motility gene that exhibits a similar Ts
phenotype. Our results suggest that SglS and SglT contribute toward Tfp function at high temperatures in redundant pathways. However, at low temperatures only one pathway is necessary for wild-type S-motility, while in the double mutant, motility is nearly abolished at low temperatures. Interestingly, the few cells that do move do so with a high reversal frequency. We suggest SglS and SglT play conditional roles facilitating Tfp retraction and hence motility in
.
Tubulysins are a group of secondary metabolites produced by myxobacteria that inhibit the function of the eukayotic cytoskeleton. We developed a pair of PCR primers that specifically amplified ...tubulysin biosynthetic genes. Using these primers, eight out of the eighty-one strains of myxobacteria belonging to the Cystobacteraceae family that harbored putative tubulysin biosynthetic genes were screened through PCR analysis. The selected strains included two Archangium gephyra, two Stigmatella sp., two Vitiosangium cumulatum, and two unidentified myxobacteria. LC-MS analysis of the culture extracts from the selected strains revealed that A. gephyra KYC4066 produced putative tubulysin A and B.
Actinomycetes are historically important sources for secondary metabolites (SMs) with applications in human medicine, animal health, and plant crop protection. It is now clear that actinomycetes and ...other microorganisms with large genomes have the capacity to produce many more SMs than was anticipated from standard fermentation studies. Indeed ~90 % of SM gene clusters (SMGCs) predicted from genome sequencing are cryptic under conventional fermentation and analytical analyses. Previous studies have suggested that among the actinomycetes with large genomes, some have the coding capacity to produce many more SMs than others, and that strains with the largest genomes tend to be the most gifted. These contentions have been evaluated more quantitatively by antiSMASH 3.0 analyses of microbial genomes, and the results indicate that many actinomycetes with large genomes are gifted for SM production, encoding 20–50 SMGCs, and devoting 0.8–3.0 Mb of coding capacity to SM production. Several Proteobacteria and Firmacutes with large genomes encode 20–30 SMGCs and devote 0.8–1.3 Mb of DNA to SM production, whereas cultured bacteria and archaea with small genomes devote insignificant coding capacity to SM production. Fully sequenced genomes of uncultured bacteria and archaea have small genomes nearly devoid of SMGCs.
Tubulysins are a group of secondary metabolites produced by myxobacteria that inhibit the function of the eukayotic cytoskeleton. We developed a pair of PCR primers that specifically amplified ...tubulysin biosynthetic genes. Using these primers, eight out of the eighty-one strains of myxobacteria belonging to the Cystobacteraceae family that harbored putative tubulysin biosynthetic genes were screened through PCR analysis. The selected strains included two Archangium gephyra, two Stigmatella sp., two Vitiosangium cumulatum, and two unidentified myxobacteria. LC-MS analysis of the culture extracts from the selected strains revealed that A. gephyra KYC4066 produced putative tubulysin A and B. KCI Citation Count: 1
A metabolome‐guided screening approach in the novel myxobacterium Corallococcus sp. MCy9072 resulted in the isolation of the unprecedented natural product myxofacycline A, which features a rare ...isoxazole substructure. Identification and genomic investigation of additional producers alongside targeted gene inactivation experiments and heterologous expression of the corresponding biosynthetic gene cluster in the host Myxococcus xanthus DK1622 confirmed a noncanonical megaenzyme complex as the biosynthetic origin of myxofacycline A. Induced expression of the respective genes led to significantly increased production titers enabling the identification of six further members of the myxofacycline natural product family. Whereas myxofacyclines A–D display an isoxazole substructure, intriguingly myxofacyclines E and F were found to contain 4‐pyrimidinole, a heterocycle unprecedented in natural products. Lastly, myxofacycline G features another rare 1,2‐dihydropyrol‐3‐one moiety. In addition to a full structure elucidation, we report the underlying biosynthetic machinery and present a rationale for the formation of all myxofacyclines. Unexpectedly, an extraordinary polyketide synthase‐nonribosomal peptide synthetase hybrid was found to produce all three types of heterocycle in these natural products.
Discovering the natural route to “synthetic” heterocycles: Myxofacyclines are natural products isolated from myxobacteria. Myxofacyclines A–D display an isoxazole substructure, myxofacyclines E and F contain 4‐pyrimidinole, and myxofacycline G features another rare 1,2‐dihydropyrol‐3‐one moiety. The isoxazole, 4‐pyrimidinole or 1,2‐dihydropyrrol‐3‐one heterocycle in the myxofacyclines and the underlying biosynthesis are rarely described in natural products. Isolation, structure elucidation, mutagenesis of the producer strain and heterologous expression of the identified biosynthetic genes are presented.
sp. PT13 is a wild strain with multiple predatory properties that prey on multiple model microorganisms preserved in the laboratory. However, the lysis spectrum of PT13 on typical soil bacteria and ...its driving effect on soil microecosystems are still unclear.
In this study, the lawn predation method was used to determine the predation diameter of 62 typical soil bacteria by myxobacteria PT13 and analyze their lysis spectra.
The results showed that PT13 had a predation diameter greater than 15 mm against typical soil microorganisms such as
,
,
,
,
and
and had an outstanding lysis effect but a significant preference (
< 0.05). Absolute high-throughput sequencing results showed that PT13 predation drove the microcosmic system composed of 16 bacterial genera, with a significant decrease in the Shannon index by 11.8% (CK = 2.04,
= 1.80) and a significant increase in the Simpson index by 45.0% (CK = 0.20,
= 0.29). The results of principal coordinate analysis (PCoA) showed that myxobacterial addition significantly disturbed the microcosmic microbial community structure (ANOSIM,
< 0.05). LEfSe analysis showed that the relative and absolute abundances (copy numbers) of
,
,
,
and
decreased significantly very likely due to myxobacterial predation (
< 0.05). However, the predatory effect of PT13 also increased the relative or absolute abundances of some species, such as
,
,
and
. It can be concluded that PT13 has a broad-spectrum lysis spectrum but poor cleavage ability for
, and the interaction between complex microorganisms limits the predation effect of PT13 on some prey bacteria. This in turn allows some prey to coexist with myxobacteria. This paper will lay a theoretical foundation for the regulation of soil microecology dominated by myxobacteria.
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