The plant microbiome

In this Review, Trivedi and colleagues explore the interactions between plants, their associated microbial communities and the environment, and also discuss how those interactions shape the assembly of plant-associated microbiomes and modulate their beneficial traits.

Mycorrhizas are ubiquitous mutualistic symbioses established between plant roots and soil fungi. In this Review, Bonfante and colleagues explore the origin and evolution of mycorrhizal fungi, the diversity of their interactions with host plants and the potential of application of mycorrhizal symbioses in the development of sustainable agricultural and environmental strategies.

Actinobacteria are versatile producers of bioactive natural products. In this Review, van Wezel and colleagues discuss ecological and genomic insights into the mechanisms governing natural product metabolism and how those insights can be translated into approaches for computational and experimental genome mining strategies that yield novel bioactive molecules, in particular antibiotics.

Microbiome engineering has many potential applications, ranging from agriculture to medicine. In this Review, Lawson, McMahon and colleagues guide us through the design–build–test–learn cycle that has been successful in many disciplines and explain how it applies to microbiome engineering.

The microbial majority with which we share Earth often goes unnoticed despite underlying major biogeochemical cycles and food webs, thereby taking a key role in climate change. This Consensus Statement highlights the importance of climate change microbiology and issues a call to action for all microbiologists.

Microbial communities are not only of great importance in the human gut, but also play irreplaceable roles in sustaining plant growth and functions. In this Perspective, strategies to optimize microbiome usage in agroecosystems are proposed.

This Perspective assesses the opportunities and challenges for synthetic biology in revolutionizing agriculture, and highlights the resources and approaches we need to remove the barriers and propel another Green Revolution.

This Review presents recent advances in our understanding of calcium signalling mechanisms, and how calcium channels work together to encode stimulus-specific calcium patterns, to finally elicit changes in cellular responses.

Contamination of agricultural soils by heavy metals and metalloids has severe consequences on human and ecosystem health. This Review discusses the sources of heavy metal(loid) contamination, the mechanisms by which these contaminants interact with biological and geochemical soil elements, and plant-based and microorganism-based remediation strategies.

Emerging fungal and oomycete pathogens pose a significant risk to global food security. This Review summarizes factors affecting pathogen introduction and spread and current disease control strategies, and highlights the direction that research must take to face the challenge of emerging crop pathogens.

A global assessment of the structure and function of the crop microbiome is urgently needed for the development of effective and rationally designed microbiome technologies for sustainable agriculture. Such an effort will provide new knowledge on the key ecological and evolutionary interactions between plant species and their microbiomes that can be harnessed for increasing agriculture productivity.

This month’s Genome Watch highlights efforts to engineer microorganisms and their plant hosts to address the challenges of sustainable agriculture.

In this Viewpoint article, several experts discuss the microbial contributions to climate change and consider the effects of global warming, extreme weather and other consequences of climate change on microbial communities in the ocean and soil, host–microbiota interactions and the global burden of infectious diseases and ecosystem processes, and they explore open questions and research needs.

Mutations in genes involved in immune signalling and vesicle trafficking cause defects in the leaf microbiome of Arabidopsis thaliana that result in damage to leaf tissues, suggesting mechanisms by which terrestrial plants control the level and diversity of endophytic phyllosphere microbiota.

In rhizosphere microbial communities, iron competition via secreted siderophores can be used as a predictor of commensal–pathogen interactions and plant protection against infection with the pathogen Ralstonia solanacearum.

While numerous explanations for reduced pest incidence in organic farms have been noted, plant resistance remains understudied. This article demonstrates tomato resistance to leafhoppers through soil and microbial health.

In Arabidopsis and tomato, exudation of myo-inositol by roots is epigenetically controlled by DNA demethylases and is involved in the beneficial recruitment of growth-promoting rhizobacteria.

Conducting a series of removal experiments using synthetic leaf-inhabiting bacterial communities, the authors identify several keystone strains and show that priority effects drive phyllosphere community assembly.

Quantifying bacterial load in plant leaves, the authors show that insect herbivory can cause compositional shifts in bacterial community structure, primarily by enhancing the growth of putative phytopathogens. Across a native host population, insect–bacteria co-infection load is highly clustered and associated with lower plant fitness.

Analysing soil and rhizosphere microbial communities across a latitudinal gradient from southern to central Europe, the authors show that the belowground microbiomes of range-expanding plant species become more similar the further they are from their native range.

Sampling plants and lichens from across boreal North America and Eurasia, the authors show that the composition and diversity of symbiotic fungal endophyte communities are controlled primarily by host associations, not environmental filtering.

Across large spatial scales, climate is more important than soil conditions for plant adaptation and variation in root-associated filamentous eukaryotic communities.

Tomato rhizosphere microbiome alterations that contribute to bacterial wilt resistance are detected using metagenomics.

Rice coordinates recruitment of the root microbiota to optimize nitrogen acquisition from soil.

The ecological niche of host-associated microbes is defined by both abiotic and biotic dimensions. Here the authors analyse published data on fungal and oomycete pathogens of plants, demonstrating that specialization can evolve independently on abiotic and biotic axes and that interactions with host plants reduce thermal niche breadth.

An extensive phylogenomics study based on hundreds of genomes and transcriptomes provides a new interpretation of the evolution of different types of symbiotic associations in land plants, and reveals a conserved ancestral symbiosis pathway.