Abstract.
Methylmercury
(MeHg),
accumulated
in
rice
grain,
is
highly
toxic
for
human.
Its
production
largely
driven
by
microbial
methylation
paddy
soils;
however,
dissolved
organic
matter
(DOM)
represents
a
hotspot
soil
biogeochemistry,
resulting
MeHg
production,
remain
poorly
understood.
Here,
we
conducted
hgcA
gene
sequencing
and
genome-resolved
metagenomic
analysis
to
identify
core
Hg-methylating
microbiome
investigate
the
effect
of
DOM
on
soils
across
Hg
contamination
gradient.
In
general,
communities
varied
with
degree
soils.
Surprisingly,
was
identified
exclusively
associated
concentration.
The
partial
Mantel
test
revealed
strong
linkages
among
composition,
Structural
equation
model
further
indicated
that
composition
significantly
impacted
concentration
(accounting
89
%);
while
crucial
determining
(65
%).
These
results
suggested
regulates
altering
microbiome.
presence
various
genes
carbon
metabolism
metagenome-assembled
genome
microorganisms
suggests
different
DOMs
stimulate
activity
methylate
Hg,
which
confirmed
pure
incubation
experiment
Geobacter
sulfurreducens
PCA
(core
microorganism)
amended
natural
solution
extracted
from
investigated
Overall,
simultaneously
changes
functional
thus
enhances
Photo-,
microbial,
and
abiotic
dark
reduction
of
soil
mercury
(Hg)
may
all
lead
to
elemental
(Hg(0))
emissions.
Utilizing
lab
incubations,
isotope
signatures
Hg(0)
emitted
from
mining
soils
were
characterized
quantify
the
interplay
contributions
various
Hg
pathways,
which
have
been
scarcely
studied.
At
15
°C,
microbial
reduced
showed
a
negative
mass-dependent
fractionation
(MDF)
(δ
Abstract.
Methylmercury
(MeHg),
accumulated
in
rice
grain,
is
highly
toxic
for
human.
Its
production
largely
driven
by
microbial
methylation
paddy
soils;
however,
dissolved
organic
matter
(DOM)
represents
a
hotspot
soil
biogeochemistry,
resulting
MeHg
production,
remain
poorly
understood.
Here,
we
conducted
hgcA
gene
sequencing
and
genome-resolved
metagenomic
analysis
to
identify
core
Hg-methylating
microbiome
investigate
the
effect
of
DOM
on
soils
across
Hg
contamination
gradient.
In
general,
communities
varied
with
degree
soils.
Surprisingly,
was
identified
exclusively
associated
concentration.
The
partial
Mantel
test
revealed
strong
linkages
among
composition,
Structural
equation
model
further
indicated
that
composition
significantly
impacted
concentration
(accounting
89
%);
while
crucial
determining
(65
%).
These
results
suggested
regulates
altering
microbiome.
presence
various
genes
carbon
metabolism
metagenome-assembled
genome
microorganisms
suggests
different
DOMs
stimulate
activity
methylate
Hg,
which
confirmed
pure
incubation
experiment
Geobacter
sulfurreducens
PCA
(core
microorganism)
amended
natural
solution
extracted
from
investigated
Overall,
simultaneously
changes
functional
thus
enhances
