Collectively, FMT fungi illustrate how divergent ecological strategies can emerge through differential modification and regulatory deployment of a shared hypocrealean genomic toolkit.
Abstract
SUMMARY Fungi in the genera Fusarium, Metarhizium, and Trichoderma (FMT) are traditionally defined by their roles as plant pathogens, insect pathogens, and mycoparasites, respectively. However, these classifications obscure both their shared hypocrealean ancestry and the remarkable ecological plasticity that characterizes all three genera. Across these lineages, plant endophytism appears to represent the predominant ecological state, with frequent transitions among saprotrophy, symbiosis, pathogenicity, and antagonism. Comparative genomics reveals that FMT fungi possess two-speed genomes comprising conserved core chromosomes and dynamic accessory regions enriched in host-interaction and secondary metabolism genes. These architectures support a shared hypocrealean genomic toolkit that has been differentially modified across lineages. In Fusarium, transitions along the mutualism-to-pathogenicity continuum appear to be driven primarily by regulatory plasticity rather than by major changes in gene content. By contrast, Metarhizium and Trichoderma expanded from ancestral pathogenic states toward broader plant associations through horizontal gene transfer, gene duplication, and diversification of host-recognition, signaling, and metabolite-production pathways. Reproductive strategies similarly reflect ecological divergence. Generalist lineages are predominantly clonal, whereas specialists more frequently retain sexual reproduction, facilitating adaptation to predictable hosts and environments. Ecologically, FMT fungi occupy overlapping but distinct niches: Trichoderma dominates stable environments through mycoparasitism and competitive exclusion; Fusarium thrives in disturbed habitats through rapid colonization of stressed plants; and Metarhizium bridges soil, plant, and insect environments through combined root association and insect pathogenicity. Collectively, FMT fungi illustrate how divergent ecological strategies can emerge through differential modification and regulatory deployment of a shared hypocrealean genomic toolkit.
Conordance of codon usage and functional gene abundance with phylogeny is revealed, along with diverse host- and lifestyle-associated adaptive strategies in this important group of plant pathogens.
Jian-Xin Shen, M. Qiao, Jiahao Hong et al.· IMA Fungus· 0 citations
The first comprehensive species-wide pangenomic and systems-level analyses of B. sorokiniana are presented, providing vital insights into the evolutionary architecture of pathogenicity, adaptation, and genome diversification and providing a valuable genomic resource for disease surveillance and functional characterization of virulence determinants.
Anand Kumar Shukla, Narendra Y. Kadoo· bioRxiv· 0 citations
Rhizobiaceae serve as classical models for elucidating mutualistic plant-microbe interactions yet they represent a narrow phylogenetic subgroup of Alphaproteobacteria. Studying additional lineages of Rhizobiaceae, we observed broad associations with oxygenic phototrophs beyond land plants, including early branching clades of submerged plants, multicellular and unicellular algae, as well as cyanobacteria. In particular, bacteria of the genus Hoeflea were often affiliated with cyanobacteria or microbial algae, whereas Peteryoungia spp. colonized roots of submerged plants. While both genera were originally described as nonpigmented heterotrophs, our detailed genomic, biochemical and physiological analyses revealed that most strains actually contained genes for anoxygenic photosynthesis. Under oligotrophic, oxic growth conditions, each characterized representative expressed bacteriochlorophyll a-containing functional photosynthetic complexes. Photosynthesis genes shared the highest homology among phylogenetically closest relatives, displaying topologies congruent to cognate house-keeping gene phylogenies, and maintained highly conserved gene synteny across the chromosomes of different species. Together, this indicated a vertical inheritance and long ancestral history of aerobic anoxygenic photosynthesis in Rhizobiaceae rather than multiple recent horizontal transfers. Subsequent time-scale phylogenetic analysis suggested that the last common ancestor of Rhizobiaceae was an aquatic phototroph, with different lineages of Rhizobiaceae consecutively evolving in association with algae, land plants, then later legumes. While aquatic lineages maintained photosynthetic machinery till today, Rhizobia which developed symbioses with land plants either as mutualistic endosymbiosis within root nodules or as plant pathogens, concomitantly lost photosynthetic capability. Based on our results, multiple biotic interactions with diverse oxygenic phototrophs drove the early evolution of Rhizobiaceae.
Steven B. Kuzyk, Philipp Halama, M. Saini et al.· bioRxiv· 0 citations
The genus Bacillus, particularly endophytic species, has been widely studied as a source of plant growth-promoting bacteria in agricultural systems. These microorganisms contribute to plant performance through nutrient acquisition, phytohormone production, pathogen suppression, microbiome modulation, and enhanced tolerance to biotic and abiotic stresses. However, their ecological roles, functional plasticity, and genomic diversity remain poorly integrated into conceptual frameworks that extend beyond crop-based applications. Functional plasticity is reflected in their ability to colonize diverse plant hosts and tissues and to promote similar plant responses through distinct molecular mechanisms. Likewise, genomic diversity is evidenced by variation in accessory genomes, biosynthetic gene clusters, and regulatory networks that shape ecological functions and metabolite production. This review examines endophytic Bacillus as a model for understanding how metabolically versatile and genomically plastic bacteria establish functional, but context-dependent, associations with plants. Drawing on evidence from functional genomics, pangenomics, metabolomics, and microbial ecology, we discuss mechanisms associated with plant growth promotion and emphasize their dependence on host identity, environmental conditions, and microbial interactions. We address functional convergence arising from distinct genetic and metabolic routes, the contribution of accessory genomes and regulatory variation, and the ecological consequences of microbial inoculation in resident plant-associated microbiomes. We also highlight the limitations of in vitro screening approaches and the need for experimental validation across multiple biological scales to establish robust genotype-phenotype relationships. Finally, we extend the discussion beyond agricultural systems to consider the use of endophytic Bacillus in wild plant systems and ecological restoration, emphasizing the importance of evaluating both functional outcomes and ecological impacts.
Jefferson Brendon Almeida dos Reis· Folia Microbiologica (Prague...· 0 citations
Abstract Zygnematophytes emerged as the unexpected closest algal relatives of land plants despite their simple body plans, raising questions about the morphogenetic toolkit present in the last common ancestor of land plants and algae. Genomic analyses have revealed that zygnematophytes are cellular giants, sharing homologous frameworks for several phytohormones, secondary metabolites, and key morphogenetic and transcriptional regulatory processes. Zygnematophytes fall into 5 orders, each of which has charted its own evolutionary path. Here, we have sequenced a contiguous genome of Spirogyra pratensis, the eponymous representative of Spirogyrales and a classical model system for evolutionary cell biology in the green lineage. Building on this genome, we transcriptionally profiled the tractable life cycle of Spirogyra and its responses to a bifactorial gradient of light and temperature. Our data highlight the activation of quiescence and homeostatic programs. Yet what stands out most in Spirogyra is its spiral chloroplast—undulating intracellularly and abscising during mixed phragmoplast formation and furrowing. Leveraging the genome in tandem with co-expression network analyses, we describe the molecular underpinnings of the unique cytokinetic processes that govern both cell and plastid division. We find that Spirogyra deploys a molecular program characteristic of Phragmoplastophyta yet lacks the deeply conserved plastid division machinery found in other archaeplastid plastids.
Elisa S. Goldbecker, Deepti Varshney, A. Holzhausen et al.· The Plant Cell· 1 citation
Marine and coastal fungi experience intense environmental variability, yet the genomic features associated with tolerance to such conditions remain unclear. From 56 fungal isolates collected along the Lailai rocky shore in northern Taiwan, we selected the coastal isolate Annulohypoxylon annulatoides RYS0019 for phenotypic and genomic investigation because of its prevalence and distinctive stress-response profile. Compared with five bark-derived conspecific strains, RYS0019 showed distinct growth and recovery dynamics under salinity, temperature, and UV-associated stress treatments. We generated a high-quality 41.8 Mbp de novo genome assembly with 11,523 predicted proteins and compared it with 15 other Hypoxylaceae genomes. Across Annulohypoxylon genomes, we identified variably sized and dispersed AT-rich isochores that are repeat-enriched and gene-poor. Despite variation in AT content, core gene content and Pfam domain profiles remained broadly conserved. Most AT-rich isochores were embedded within syntenically conserved regions and showed limited positional conservation across species, supporting recurrent, lineage-specific formation or expansion after species divergence. These regions also exhibit several sequence and structural features consistent with scaffold/matrix attachment regions (S/MARs), raising the possibility that they influence higher-order genome organisation or context-dependent regulation. Together, our findings identify repeat-rich genome architecture as a dynamic feature of Annulohypoxylon genome evolution and provide a framework for testing how such regions may contribute to fungal environmental flexibility.
C. Kuo, Yu-Ching Liu, Cheng-Ju Yang et al.· G3· 0 citations