The Ecological Role of Volatile and Soluble Secondary Metabolites Produced by Soil Bacteria
TL;DR: This review provides an overview of the most important soluble and volatile classes of secondary metabolites produced by soil bacteria, their ecological roles, and their possible synergistic effects.
About: This article is published in Trends in Microbiology.The article was published on 2017-04-01. It has received 303 citations till now. The article focuses on the topics: Soil microbiology.
Citations
More filters
TL;DR: The fundamental role of microbe-microbe interactions (prokaryotes and micro-eukaryotes) for microbial community structure and plant health is discussed and a conceptual framework illustrating that interactions among microbiota members are critical for the establishment and the maintenance of host-microbial homeostasis is provided.
Abstract: Since the colonization of land by ancestral plant lineages 450 million years ago, plants and their associated microbes have been interacting with each other, forming an assemblage of species that is often referred to as a “holobiont.” Selective pressure acting on holobiont components has likely shaped plant-associated microbial communities and selected for host-adapted microorganisms that impact plant fitness. However, the high microbial densities detected on plant tissues, together with the fast generation time of microbes and their more ancient origin compared to their host, suggest that microbe-microbe interactions are also important selective forces sculpting complex microbial assemblages in the phyllosphere, rhizosphere, and plant endosphere compartments. Reductionist approaches conducted under laboratory conditions have been critical to decipher the strategies used by specific microbes to cooperate and compete within or outside plant tissues. Nonetheless, our understanding of these microbial interactions in shaping more complex plant-associated microbial communities, along with their relevance for host health in a more natural context, remains sparse. Using examples obtained from reductionist and community-level approaches, we discuss the fundamental role of microbe-microbe interactions (prokaryotes and micro-eukaryotes) for microbial community structure and plant health. We provide a conceptual framework illustrating that interactions among microbiota members are critical for the establishment and the maintenance of host-microbial homeostasis.
651 citations
Cites background from "The Ecological Role of Volatile and..."
...Taken together, these results suggest that VOCs produced by bacterial and fungal members of the plant microbiota act as an additional defense line against other microbes and are also likely important for long distance structuring of the microbial communities [171]....
[...]
...Soil bacteria have also been shown to produce VOCs (reviewed in [171])....
[...]
TL;DR: This article proposes a 'DefenseBiome' concept that informs the design and construction of beneficial microbial synthetic communities for improving fundamental understanding of plant-microbial interactions and the development of plant probiotics.
263 citations
TL;DR: This minireview summarizes the current knowledge on the biological functions of mV OCs with the focus on mVOCs-mediated interactions belowground, and pinpointed mVocs involved in microbe-microbe and microbe–plant interactions, and highlighted the ecological importance of microbial terpenes as a largely underexplored group of m VOCs.
Abstract: During the last decades, research on the function of volatile organic compounds focused primarily on the interactions between plants and insects. However, microorganisms can also release a plethora of volatiles and it appears that microbial volatile organic compounds (mVOCs) can play an important role in intra- and inter-kingdom interactions. So far, most studies are focused on aboveground volatile-mediated interactions and much less information is available about the function of volatiles belowground. This minireview summarizes the current knowledge on the biological functions of mVOCs with the focus on mVOCs-mediated interactions belowground. We pinpointed mVOCs involved in microbe-microbe and microbe-plant interactions, and highlighted the ecological importance of microbial terpenes as a largely underexplored group of mVOCs. We indicated challenges in studying belowground mVOCs-mediated interactions and opportunities for further studies and practical applications.
248 citations
Cites background from "The Ecological Role of Volatile and..."
...…interactions (Garbeva et al., 2014a; Schulz-Bohm et al., 2015; Tyc et al., 2015; Piechulla et al., 2017). mVOCs were often considered to be by-products of primary metabolism, but recent findings revealed that many mVOCs demonstrate biological activity (Schmidt et al., 2015; Tyc et al., 2017a)....
[...]
...While soluble metabolites are often responsible for short distance interactions, VOCs are considered to be long-distance messengers (Tyc et al., 2017b; Westhoff et al., 2017)....
[...]
TL;DR: The Streptomyces genus, which is the most abundant and arguably the most important actinomycetes, is a good source of bioactive compounds, antibiotics, and extracellular enzymes and as efficient as a biofertilizer as it is as a biocontrol.
Abstract: With the impending increase of the world population by 2050, more activities have been directed toward the improvement of crop yield and a safe environment. The need for chemical-free agricultural practices is becoming eminent due to the effects of these chemicals on the environment and human health. Actinomycetes constitute a significant percentage of the soil microbial community. The Streptomyces genus, which is the most abundant and arguably the most important actinomycetes, is a good source of bioactive compounds, antibiotics, and extracellular enzymes. These genera have shown over time great potential in improving the future of agriculture. This review highlights and buttresses the agricultural importance of Streptomyces through its biocontrol and plant growth-promoting activities. These activities are highlighted and discussed in this review. Some biocontrol products from this genus are already being marketed while work is still ongoing on this productive genus. Compared to more focus on its biocontrol ability, less work has been done on it as a biofertilizer until recently. This genus is as efficient as a biofertilizer as it is as a biocontrol.
199 citations
Cites background from "The Ecological Role of Volatile and..."
...Tyc et al. (2017), Adegboye and Babalola (2012), and other researchers have reported them to be important producers of secondary metabolites....
[...]
...Some of the bioactives include secondary metabolite production, in the form of antibiotics and extracellular enzymes not forgetting antitumor and agroactive compounds which are important in the decomposition of cellulose and chitin (Adegboye and Babalola 2012; Tyc et al. 2017)....
[...]
TL;DR: This review envisages advances in systems biology (SB), which enables the analysis of microbial behavior at a community level under different environmental stresses, and highlights the integrated SB and ME tools and techniques for bioremediation purposes.
Abstract: Today, environmental pollution is a serious problem, and bioremediation can play an important role in cleaning contaminated sites Remediation strategies, such as chemical and physical approaches, are not enough to mitigate pollution problems because of the continuous generation of novel recalcitrant pollutants due to anthropogenic activities Bioremediation using microbes is an eco-friendly and socially acceptable alternative to conventional remediation approaches Many microbes with a bioremediation potential have been isolated and characterized but, in many cases, cannot completely degrade the targeted pollutant or are ineffective in situations with mixed wastes This review envisages advances in systems biology (SB), which enables the analysis of microbial behavior at a community level under different environmental stresses By applying a SB approach, crucial preliminary information can be obtained for metabolic engineering (ME) of microbes for their enhanced bioremediation capabilities This review also highlights the integrated SB and ME tools and techniques for bioremediation purposes
167 citations
Cites background from "The Ecological Role of Volatile and..."
...The complete understanding of these metabolites gives valuable information about microbial interactions to degrade a particular pollutant [100]....
[...]
References
More filters
TL;DR: A broad, drug-like phase II metabolic response of the host to metabolites generated by the microbiome was observed, suggesting that the gut microflora has a direct impact on the drug metabolism capacity of theHost.
Abstract: Although it has long been recognized that the enteric community of bacteria that inhabit the human distal intestinal track broadly impacts human health, the biochemical details that underlie these effects remain largely undefined. Here, we report a broad MS-based metabolomics study that demonstrates a surprisingly large effect of the gut “microbiome” on mammalian blood metabolites. Plasma extracts from germ-free mice were compared with samples from conventional (conv) animals by using various MS-based methods. Hundreds of features were detected in only 1 sample set, with the majority of these being unique to the conv animals, whereas ≈10% of all features observed in both sample sets showed significant changes in their relative signal intensity. Amino acid metabolites were particularly affected. For example, the bacterial-mediated production of bioactive indole-containing metabolites derived from tryptophan such as indoxyl sulfate and the antioxidant indole-3-propionic acid (IPA) was impacted. Production of IPA was shown to be completely dependent on the presence of gut microflora and could be established by colonization with the bacterium Clostridium sporogenes. Multiple organic acids containing phenyl groups were also greatly increased in the presence of gut microbes. A broad, drug-like phase II metabolic response of the host to metabolites generated by the microbiome was observed, suggesting that the gut microflora has a direct impact on the drug metabolism capacity of the host. Together, these results suggest a significant interplay between bacterial and mammalian metabolism.
2,140 citations
"The Ecological Role of Volatile and..." refers background in this paper
...However, many non-indole producing bacteria are able to modify or to degrade indole using diverse oxygenases, such as monooxygenases, dioxygenases, and P450 family members [58]....
[...]
TL;DR: Bacteriocins are bacterially produced antimicrobial peptides with narrow or broad host ranges that can be used to confer a rudimentary form of innate immunity to foodstuffs, helping processors extend their control over the food flora long after manufacture.
Abstract: Bacteriocins are bacterially produced antimicrobial peptides with narrow or broad host ranges. Many bacteriocins are produced by food-grade lactic acid bacteria, a phenomenon which offers food scientists the possibility of directing or preventing the development of specific bacterial species in food. This can be particularly useful in preservation or food safety applications, but also has implications for the development of desirable flora in fermented food. In this sense, bacteriocins can be used to confer a rudimentary form of innate immunity to foodstuffs, helping processors extend their control over the food flora long after manufacture.
2,051 citations
"The Ecological Role of Volatile and..." refers background in this paper
...They exhibit activity against other microbes, either from the same species (narrow spectrum) or across genera (broad spectrum) [6]....
[...]
TL;DR: The main functions of rhizosphere microorganisms and how they impact on health and disease are reviewed and several strategies to redirect or reshape the rhizospheric microbiome in favor of microorganisms that are beneficial to plant growth and health are highlighted.
Abstract: Microbial communities play a pivotal role in the functioning of plants by influencing their physiology and development. While many members of the rhizosphere microbiome are beneficial to plant growth, also plant pathogenic microorganisms colonize the rhizosphere striving to break through the protective microbial shield and to overcome the innate plant defense mechanisms in order to cause disease. A third group of microorganisms that can be found in the rhizosphere are the true and opportunistic human pathogenic bacteria, which can be carried on or in plant tissue and may cause disease when introduced into debilitated humans. Although the importance of the rhizosphere microbiome for plant growth has been widely recognized, for the vast majority of rhizosphere microorganisms no knowledge exists. To enhance plant growth and health, it is essential to know which microorganism is present in the rhizosphere microbiome and what they are doing. Here, we review the main functions of rhizosphere microorganisms and how they impact on health and disease. We discuss the mechanisms involved in the multitrophic interactions and chemical dialogues that occur in the rhizosphere. Finally, we highlight several strategies to redirect or reshape the rhizosphere microbiome in favor of microorganisms that are beneficial to plant growth and health.
1,752 citations
"The Ecological Role of Volatile and..." refers background in this paper
...The rhizosphere (see Glossary), defined as the narrow region of soil attached to plant roots and influenced by plant root exudates, is a hotspot of microbial interactions and activities [1,2]....
[...]
1,474 citations
"The Ecological Role of Volatile and..." refers background in this paper
...The terminal TE domain is responsible for product release, usually under formation of a free acid or lactone [21]....
[...]
TL;DR: The demonstration that PGPR strains release different volatile blends and that plant growth is stimulated by differences in these volatile blends establishes an additional function for volatile organic compounds as signaling molecules mediating plant–microbe interactions.
Abstract: Several chemical changes in soil are associated with plant growth-promoting rhizobacteria (PGPR). Some bacterial strains directly regulate plant physiology by mimicking synthesis of plant hormones, whereas others increase mineral and nitrogen availability in the soil as a way to augment growth. Identification of bacterial chemical messengers that trigger growth promotion has been limited in part by the understanding of how plants respond to external stimuli. With an increasing appreciation of how volatile organic compounds signal plants and serve in plant defense, investigations into the role of volatile components in plant–bacterial systems now can follow. Here, we present chemical and plant-growth data showing that some PGPR release a blend of volatile components that promote growth of Arabidopsis thaliana. In particular, the volatile components 2,3-butanediol and acetoin were released exclusively from two bacterial strains that trigger the greatest level of growth promotion. Furthermore, pharmacological applications of 2,3-butanediol enhanced plant growth whereas bacterial mutants blocked in 2,3-butanediol and acetoin synthesis were devoid in this growth-promotion capacity. The demonstration that PGPR strains release different volatile blends and that plant growth is stimulated by differences in these volatile blends establishes an additional function for volatile organic compounds as signaling molecules mediating plant–microbe interactions.
1,434 citations
"The Ecological Role of Volatile and..." refers background in this paper
...For example, a range of plant growth promoting rhizobacteria (PGPR) are able to drastically alter a plant's root system development and increase plant biomass by emitting complex blends of volatiles without actual physical contact [107]....
[...]