Speaker
Description
Vitamin B₁₂ is synthesized exclusively by bacteria and archaea, yet duckweeds accumulate bioavailable B₁₂ despite lacking the capacity to produce or use it. We asked how this function is organized within the duckweed microbiome, and whether cultivation conditions could enhance it.
Bioavailable B₁₂ was detected across rooted and rootless duckweed genera, and in additional aquatic plants. Among 16 B₁₂-containing duckweed haplotypes spanning seven species, endophyte composition varied markedly, but neither community structure nor predicted B₁₂-biosynthesis potential tracked host taxonomy; distinct microbiomes converged on the same function. In the rootless species Wolffia globosa, the endosphere formed a host-filtered community in which a subset of bacteria encoded complete or near-complete cobalamin pathways; most co-occurring taxa instead carried partial pathways, precursor-salvage genes, or cobamide-remodeling capacity. Network analysis linked putative producers to salvagers, and endophytic genomes carried fewer biosynthetic genes than related planktonic strains, suggesting adaptation to metabolic interdependence over autonomous production. Experimental manipulation confirmed that B₁₂ production is a community-level trait. Epiphytic Rhizobium and Caulobacter isolates produced B₁₂ in culture, but co-cultivation with duckweed did not increase plant B₁₂ and instead disrupted plant–microbiome performance. Cobalt supplementation, by contrast, increased bioavailable B₁₂ up to fivefold without cost to growth, and reshaped endophyte composition, diversity, and core-community membership in species-specific ways.
Our results show that B₁₂ accumulation in duckweed is an emergent property of a cooperative, environmentally responsive microbiome, not the output of a single producer. This positions duckweed as a tractable model for cobamide-mediated microbial interactions and a promising platform for microbiome-guided B₁₂ biofortification.
Keywords
B₁₂ biosynthesis
Metabolic interdependence
Endophytes
References
Dutta R., Obayomi O., Freidjung Yosef A., Ghazaryan L., Chalifa-Caspi V., Lapidot M., Gillor O. 2026. A cooperative cobalamide biosynthesis guild in the endosphere of the edible aquatic plant Wolffia globosa Mankai. Enviornmental Microbiome. https://doi.org/10.1186/s40793-026-00917-4
Friedjung Yosef A, Ghazaryan L, Klamann L, Kaufman KS, Baubin C, Poodiack B, Ran N, Gabay T, Didi-Cohen S, Bog M, Khozin-Goldberg I, Gillor O. 2022. Diversity and Differentiation of Duckweed Species from Israel. Plants-Basel 11 (23): 3326. https://doi.org/10.3390/plants11233326
| Corresponding author email | gilloro@bgu.ac.il |
|---|---|
| Scientific Session | Microbiome & Interactions |
