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SUMMARY:Vitamin B₁₂ Accumulation in Duckweed Emerges from a Cooperativ
 e\, Environmentally Responsive Microbiome
DTSTART;VALUE=DATE-TIME:20260930T071500Z
DTEND;VALUE=DATE-TIME:20260930T073000Z
DTSTAMP;VALUE=DATE-TIME:20260916T020036Z
UID:indico-contribution-2911@cern.ch
DESCRIPTION:Speakers: Osnat Gillor (Ben Gurion University of the Negev)\nV
 itamin B₁₂ is synthesized exclusively by bacteria and archaea\, yet du
 ckweeds accumulate bioavailable B₁₂ despite lacking the capacity to pr
 oduce or use it. We asked how this function is organized within the duckwe
 ed microbiome\, and whether cultivation conditions could enhance it.\nBioa
 vailable B₁₂ was detected across rooted and rootless duckweed genera\,
  and in additional aquatic plants. Among 16 B₁₂-containing duckweed ha
 plotypes spanning seven species\, endophyte composition varied markedly\, 
 but neither community structure nor predicted B₁₂-biosynthesis potenti
 al tracked host taxonomy\; distinct microbiomes converged on the same func
 tion. In the rootless species Wolffia globosa\, the endosphere formed a ho
 st-filtered community in which a subset of bacteria encoded complete or ne
 ar-complete cobalamin pathways\; most co-occurring taxa instead carried pa
 rtial 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 produ
 ction. Experimental manipulation confirmed that B₁₂ production is a co
 mmunity-level trait. Epiphytic Rhizobium and Caulobacter isolates produced
  B₁₂ in culture\, but co-cultivation with duckweed did not increase pl
 ant B₁₂ and instead disrupted plant–microbiome performance. Cobalt s
 upplementation\, by contrast\, increased bioavailable B₁₂ up to fivefo
 ld without cost to growth\, and reshaped endophyte composition\, diversity
 \, and core-community membership in species-specific ways.\nOur results sh
 ow that B₁₂ accumulation in duckweed is an emergent property of a coop
 erative\, environmentally responsive microbiome\, not the output of a sing
 le producer. This positions duckweed as a tractable model for cobamide-med
 iated microbial interactions and a promising platform for microbiome-guide
 d B₁₂ biofortification.\n\nhttps://indico.unina.it/event/117/contribut
 ions/2911/
LOCATION:Department of Agricultural Sciences of the University of Napoli F
 ederico II\, Portici\, Italy Sala Cinese
URL:https://indico.unina.it/event/117/contributions/2911/
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