Aspects of nitrogen-fixing<i>Actinobacteria</i>, in particular free-living and symbiotic<i>Frankia</i>

Sellstedt, Anita; Richau, Kerstin H.

doi:10.1111/1574-6968.12116

Cited by 173 publications

(84 citation statements)

References 71 publications

(112 reference statements)

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“…Interestingly, we found diverse microbes able to fix nitrogen including Frankia , Rhizobium and Bradyrhizobium (Bernhard ; Seipke et al . ; Sellstedt & Richau ). We also found high relative abundance of nitrifiers at most sampling dates, indicating the leaf litter environment to be an oligotrophic habitat in which autotrophic microbes could also survive.…”

Section: Discussionmentioning

confidence: 99%

Life in leaf litter: novel insights into community dynamics of bacteria and fungi during litter decomposition

et al. 2016

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Microorganisms play a crucial role in the biological decomposition of plant litter in terrestrial ecosystems. Due to the permanently changing litter quality during decomposition, studies of both fungi and bacteria at a fine taxonomic resolution are required during the whole process. Here we investigated microbial community succession in decomposing leaf litter of temperate beech forest using pyrotag sequencing of the bacterial 16S and the fungal internal transcribed spacer (ITS) rRNA genes. Our results reveal that both communities underwent rapid changes. Proteobacteria, Actinobacteria and Bacteroidetes dominated over the entire study period, but their taxonomic composition and abundances changed markedly among sampling dates. The fungal community also changed dynamically as decomposition progressed, with ascomycete fungi being increasingly replaced by basidiomycetes. We found a consistent and highly significant correlation between bacterial richness and fungal richness (R = 0.76, P< 0.001) and community structure (RM antel = 0.85, P < 0.001), providing evidence of coupled dynamics in the fungal and bacterial communities. A network analysis highlighted nonrandom co-occurrences among bacterial and fungal taxa as well as a shift in the cross-kingdom co-occurrence pattern of their communities from the early to the later stages of decomposition. During this process, macronutrients, micronutrients, C:N ratio and pH were significantly correlated with the fungal and bacterial communities, while bacterial richness positively correlated with three hydrolytic enzymes important for C, N and P acquisition. Overall, we provide evidence that the complex litter decay is the result of a dynamic cross-kingdom functional succession.

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Section: Discussionmentioning

confidence: 99%

Life in leaf litter: novel insights into community dynamics of bacteria and fungi during litter decomposition

et al. 2016

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“…The abundance of Blastococcus, Agromyces, Thermoleophilum, Gemmatimonas, Trichoderma and Aspergillus, significantly increased in the healthy soils when compared to the degraded soils. Blastococcus, Agromyces and Thermoleophilum belong to Actinobacteria , and some species of Agromyces are found with nitrogen-fixing capacity18. Many Actinobacteria can produce antibiotics to inhibit plant pathogens in soil.…”

Section: Discussionmentioning

confidence: 99%

Microbial taxa and functional genes shift in degraded soil with bacterial wilt

Zhang

Wang

Shu

et al. 2017

Sci Rep

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Soil degradation is a serious global problem, but little is known about how soil microbial communities respond to soil degradation as well as their feedback to ecosystem functioning. In this study, we found the microbial community composition, structure and functional potential significantly altered in the degraded soils with bacterial wilt (termed as degraded soils). Compared with healthy soils, OTU richness of beneficial microorganisms were significantly decreased, but OTU richness of pathogenic microorganisms were significantly increased in the degraded soils. Functional gene array (GeoChip 5.0) analysis showed the functional metabolic potential of genes involved in stress, virulence, sulfur cycle, metal resistance, degradation of plant cell wall was significantly increased in the degraded soils. Increased functional metabolic potential of these genes may be related to the acidification and severe plant disease of degraded soils. Biological activity of degraded soils was obviously decreased with weakened soil enzyme activities when compared to the healthy soils. Soil pH and enzyme activities were negatively correlated with the abundance of genes involved in sulfur cycle, virulence, and stress responses. This study provides new insights into our understanding of soil microbial community responses to soil degradation.

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“…Although some bacteria evolved nitrogenases for the fixation of atmospheric nitrogen (diazotrophy) into readily assimilable ammonium, the large majority of bacteria, including members of the genus Mycobacterium , can only assimilate ammonium or other nitrogenous sources such as nitrate or nitrite3. There are anecdotal reports of nitrogen-fixing mycobacteria but typical nitrogenase genes have not been detected in the genomes available45. Most mycobacteria are saprophytes with a broad spectrum of environmental adaptation but many can also opportunistically infect humans67.…”

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confidence: 99%

Mycobacterium hassiacum recovers from nitrogen starvation with up-regulation of a novel glucosylglycerate hydrolase and depletion of the accumulated glucosylglycerate

Alarico

Costa

Sousa

et al. 2014

Sci Rep

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Some microorganisms accumulate glucosylglycerate (GG) during growth under nitrogen deprivation. However, the molecular mechanisms underlying the role of GG and the regulation of its levels in the nitrogen stress response are elusive. Since GG is required for biosynthesis of mycobacterial methylglucose lipopolysaccharides (MGLP) we examined the molecular mechanisms linking replenishment of assimilable nitrogen to nitrogen-starved M. hassiacum with depletion of GG accumulated during nitrogen deficiency. To probe the involvement of a newly identified glycoside hydrolase in GG depletion, we produced the mycobacterial enzyme recombinantly and confirmed the specific hydrolysis of GG (GG hydrolase, GgH) in vitro. We have also observed a pronounced up-regulation of GgH mRNA in response to the nitrogen shock, which positively correlates with GG depletion in vivo and growth stimulation, implicating GgH in the recovery process. Since GgH orthologs seem to be absent from most slowly-growing mycobacteria including M. tuberculosis, the disclosure of the GgH function allows reconfiguration of the MGLP pathway in rapidly-growing species and accommodation of this possible regulatory step. This new link between GG metabolism, MGLP biosynthesis and recovery from nitrogen stress furthers our knowledge on the mycobacterial strategies to endure a frequent stress faced in some environments and during long-term infection.

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Aspects of nitrogen-fixingActinobacteria, in particular free-living and symbioticFrankia

Cited by 173 publications

References 71 publications

Life in leaf litter: novel insights into community dynamics of bacteria and fungi during litter decomposition

Life in leaf litter: novel insights into community dynamics of bacteria and fungi during litter decomposition

Microbial taxa and functional genes shift in degraded soil with bacterial wilt

Mycobacterium hassiacum recovers from nitrogen starvation with up-regulation of a novel glucosylglycerate hydrolase and depletion of the accumulated glucosylglycerate

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