An official website of the United States government
Since the invention of the microscope, scientists have described microbial communities on living and non-living matter. In terms of human-associated microbes, scientists have documented the beneficial effects of the microbiota for many decades. Prophylactic effects include protection from pathogens, digestion potential, and the production of essential vitamins. However, recent high-throughput methodologies and analytical advances have accelerated microbiome science and our understanding of microbial diversity in living organisms. The microbiome denotes the complex network of all the microorganisms and microbial genes located in specific biotic or abiotic environments. We now realize the enormous diversity and functionality of the microbiota in humans and the endless benefits to health and disease. Dysbiosis facilitates the manufacture of various proinflammatory mediators, biochemical imbalances, and colonization of microbes associated with disease outcomes. Additional work is necessary to determine whether changes in the human microbiome are due to anthropogenic, genetic, or environmental variations. This review will present microbiome research studies focusing on human disease. The findings documented in this article offer optimism on the profound role microorganisms play in supporting human health and how pharmaceutical interactions targeting specific microbes can decrease the incidence of human disease caused by the ecological disturbance of the normal microbiota.
more »
« less
Maintaining Symbiotic Homeostasis: How Do Plants Engage With Beneficial Microorganisms While at the Same Time Restricting Pathogens?
This article is part of the Top 10 Unanswered Questions in MPMI invited review series. That plants recruit beneficial microbes while simultaneously restricting pathogens is critical to their survival. Plants must exclude pathogens; however, most land plants are able to form mutualistic symbioses with arbuscular mycorrhizal fungi. Plants also associate with the complex microbial communities that form the microbiome. The outcome of each symbiotic interaction—whether a specific microbe is pathogenic, commensal, or mutualistic—relies on the specific interplay of host and microbial genetics and the environment. Here, we discuss how plants use metabolites as a gate to select which microbes can be symbiotic. Once present, we discuss how plants integrate multiple inputs to initiate programs of immunity or mutualistic symbiosis and how this paradigm may be expanded to the microbiome. Finally, we discuss how environmental signals are integrated with immunity to fine-tune a thermostat that determines whether a plant engages in mutualism, resistance to pathogens, and shapes associations with the microbiome. Collectively, we propose that the plant immune thermostat is set to select for and tolerate a largely nonharmful microbiome while receptor-mediated decision making allows plants to detect and dynamically respond to the presence of potential pathogens or mutualists. [Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .
more »
« less
- Award ID(s):
- 2010946
- PAR ID:
- 10392539
- Date Published:
- Journal Name:
- Molecular Plant-Microbe Interactions®
- Volume:
- 34
- Issue:
- 5
- ISSN:
- 0894-0282
- Page Range / eLocation ID:
- 462 to 469
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
Unlike animals, plants do not have specialized immune cells and lack an adaptive immune system. Instead, plant cells rely on their unique innate immune system to defend against pathogens and coordinate beneficial interactions with commensal and symbiotic microbes. One of the major convergent points for plant immune signaling is the nucleus, where transcriptome reprogramming is initiated to orchestrate defense responses. Mechanisms that regulate selective transport of nuclear signaling cargo and chromatin activity at the nuclear boundary play a pivotal role in immune activation. This review summarizes the current knowledge of how nuclear membrane-associated core protein and protein complexes, including the nuclear pore complex, nuclear transport receptors, and the nucleoskeleton participate in plant innate immune activation and pathogen resistance. We also discuss the role of their functional counterparts in regulating innate immunity in animals and highlight potential common mechanisms that contribute to nuclear membrane-centered immune regulation in higher eukaryotes.more » « less
-
The sustainability of plant life is intimately connected to its evolution with microbial life. Based on experimental evidence, microbial assemblages benefit plants on molecular, cellular, and ecological levels. The plant microbiome or phytomicrobiome are the microbes closely associated with a particular plant species. Distinct plant microbial ecosystems are in the phyllosphere, rhizosphere, soil, and endosphere. Plant-associated microbes affect plants in numerous ways and participate in various physiological functions essential for the plant, including nutrient recycling, the breakdown and synthesis of critical molecules, and other phytoprotective functions. While studying plant-microbe interactions is not new, recent developments in metagenomic sequencing and high-throughput pathway identification techniques have allowed scientists to explore unculturable microbes associated with plants. This review primarily focuses on the significant role of the phytomicrobiome and describes the prevalent taxonomic units found in association with plants. Plants are suitable tractable model systems to study plant-microbe interactions and can be grown under different experimental conditions to examine other characteristics of the phytomicrobiome. This article also provides a systematic review of the current research on the phytomicrobiome. It explores the extent to which the phytomicrobiome participates in an essential process that promotes plant fitness and sustainabilityand reviews research that focuses on microbiome community shifts in response to abiotic and biotic stress. Genetic engineering of plant-associated microbes to enhance plant growth and protection is addressed. The use of nanofertilizers and phytomicrobiome transplantation to restore plant health and improve the success of agriculturally beneficial crops is also discussed.more » « less
-
While a plant's microbiome can facilitate adaptive phenotypes, the plant's role in selecting for these microbes is unclear. Do plants actively recruit microbes beneficial to their current environment, or are beneficial microbes only an incidental by-product of microbial adaptation? We addressed these questions through a multigeneration greenhouse experiment, selecting for either dry- or wet-adapted soil microbial communities, either with or without plants. After three plant generations, we conducted a full reciprocal transplant of each soil community onto wet- and dry-treated plants. We found that plants generally benefited from soil microbes, and this benefit was greater whenever their current watering conditions matched the microbes' historical watering conditions. Principally, the plant's presence was not necessary in the historical treatments for this environmental matching benefit to emerge. Moreover, we found microbes from droughted soils could better tolerate drought stress. Taken together, these results suggest that the moisture environment selects for microbes that benefit plants under those specific moisture conditions, and that these beneficial properties arise as a by-product of microbial adaptation to the watering environment and not as a co-adapting plant–microbe system. This work highlights that understanding the selective agents on these plant-associated microbes will lead to a better understanding of plant adaptation.more » « less
-
Abstract The rhizosphere has been called “one of the most complex ecosystems on earth” because it is a hotspot for interactions among millions of microbial cells. Many of these are microbes are also participating in a dynamic interplay with host plant tissues, signaling pathways, and metabolites. Historically, breeders have employed aplant‐centric perspective when trying to harness the potential of microbiome‐derived benefits to improve productivity and resilience of economically important plants. This is potentially problematic because: (i) the evolution of the microbes themselves is often ignored, and (ii) it assumes that the fitness of interacting plants and microbes is strictly aligned. In contrast, amicrobe‐centric perspective recognizes that putatively beneficial microbes are still under selection to increase their own fitness, even if there are costs to the host. This can lead to the evolution of sophisticated, potentially subtle, ways for microbes to manipulate the phenotype of their hosts, as well as other microbes in the rhizosphere. We illustrate this idea with a review of cases where rhizosphere microbes have been demonstrated to directly manipulate host root growth, architecture and exudation, host nutrient uptake systems, and host immunity and defense. We also discuss indirect effects, whereby fitness outcomes for the plant are a consequence of ecological interactions between rhizosphere microbes. If these consequences are positive for the plant, they can potentially be misconstrued as traits that have evolved to promote host growth, even if they are a result of selection for unrelated functions. The ubiquity of both direct microbial manipulation of hosts and context‐dependent, variable indirect effects leads us to argue that an evolutionary perspective on rhizosphere microbial ecology will become increasingly important as we continue to engineer microbial communities for crop production.more » « less
- Free Publicly Accessible Full Text
-
Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1094/MPMI-11-20-0318-FI
