Deep sequencing of microbes living on grassland plant surfaces identified 885,396 potential antimicrobial peptides, with over 99% previously unknown, and all 13 synthesized candidates showed real antimicrobial activity.
885,396 potential AMPsNearly 900,000 candidate antimicrobial peptides were identified from grassland plant surface microbiomes, with 99.76% being completely new to science.
What the researchers found
From over 68 million non-redundant gene sequences obtained through ultra-deep metagenomic sequencing of grassland plant phyllosphere microbiomes, researchers identified 885,396 potential antimicrobial peptides (AMPs). Of these, 99.76% were previously uncharacterized.
The researchers reconstructed hundreds of near-complete bacterial genomes, with 32.61% representing unclassified species. Of the biosynthetic gene clusters (BGCs) found in these genomes, 91.97% were also previously unknown.
Host plant family significantly influenced microbial biosynthetic capacity. Pseudomonas genomes associated with grasses (Poaceae) contained an average of 28 BGCs, significantly more than those associated with daisy-family plants (Asteraceae, mean = 14.76, p = 0.033).
Critically, all 13 AMPs synthesized via solid-phase peptide synthesis demonstrated real antimicrobial activity, each inhibiting at least one tested bacterial strain.
Why it matters
With antibiotic resistance rising globally, finding new sources of antimicrobial compounds is urgent. This study reveals that the microbes living on ordinary grassland plants represent a vast, largely untapped reservoir of potential new antibiotics. The fact that all tested candidates showed real activity suggests this isn't just a theoretical resource — it could yield practical new antimicrobial drugs.
How the study worked
Researchers collected 221 grassland plant samples spanning 45 plant families and performed ultra-deep metagenomic sequencing to characterize the microbial communities on plant surfaces (phyllosphere). They used computational analysis to identify biosynthetic gene clusters and potential antimicrobial peptides, reconstructed near-complete bacterial genomes from the metagenomic data, and performed host phylogenetic analysis. To validate their findings, they chemically synthesized 13 candidate AMPs and tested them against bacterial strains in bioactivity assays.
What this study cannot tell us
Only 13 of the 885,396 identified peptide candidates were actually synthesized and tested, leaving the vast majority unvalidated. The antimicrobial testing was limited to a few bacterial strains and did not assess toxicity, stability, or efficacy in living organisms. The study focused on grassland ecosystems, and findings may not generalize to other environments. Computational predictions of AMPs may include false positives.
How to read the evidence
This is a large-scale metagenomic discovery study with experimental validation of 13 candidate peptides. While the computational identification is robust and the validation is promising, only a tiny fraction of candidates were tested, and no in vivo or clinical data exist yet.
When this study was published
Published in 2025, this is a very recent study representing cutting-edge metagenomics and antimicrobial peptide discovery approaches.
The bigger picture
Most antimicrobial peptides discovered to date come from a small number of well-studied organisms. This study dramatically expands the known AMP landscape by tapping into plant-associated microbial communities that have been largely ignored. As traditional antibiotic pipelines struggle against resistance, bioprospecting approaches like this — combining metagenomics with peptide synthesis — could accelerate the discovery of next-generation antimicrobial agents.
Questions still open
- How many of the nearly 900,000 predicted AMPs will prove effective and safe enough for therapeutic development?
- Do these plant-surface-derived peptides have different mechanisms of action than existing antibiotics, potentially overcoming current resistance patterns?
- Could similar bioprospecting approaches in other ecosystems yield equally rich antimicrobial peptide reservoirs?
Common questions
What are antimicrobial peptides and why are they important?
Could these grassland-derived peptides become new antibiotics?
Read the original research
Phyllosphere microbiomes in grassland plants harbor a vast reservoir of novel antimicrobial peptides and biosynthetic diversity.
Journal of advanced research
Citation
Zhou, Hongzhang; Gao, Yu; Wu, Baiyila; Xu, Gang; Tian, Limei; Sun, Yunlei; Yang, Fuyu; Ni, Kuikui. (2025). Phyllosphere microbiomes in grassland plants harbor a vast reservoir of novel antimicrobial peptides and biosynthetic diversity.. Journal of advanced research. https://doi.org/10.1016/j.jare.2025.12.017