Rapid and specific detection of Yam mosaic virus by reverse-transcription recombinase polymerase amplification

Yam
mosaic
virus
(YMV;
genus
Potyvirus
)
is
considered
to
cause
the
most
economically
important
viral
disease
of
yams
(
Dioscorea
spp.)
in
West
Africa
which
is
the
dominant
region
for
yam
production
globally.
Yams
are
a
vegetatively
propagated
crop
and
the
use
of
virus-free
planting
material
forms
an
essential
component
of
disease
control.
Current
serological
and
PCR-based
diagnostic
methods
for
YMV
are
time
consuming
involving
a
succession
of
target
detection
steps.
In
this
study,
a
novel
assay
for
specific
YMV
detection
is
described
that
is
based
on
isothermal
reverse
transcription-recombinase
polymerase
ampli-
fication
(RT-exoRPA).
This
test
has
been
shown
to
be
reproducible
and
able
to
detect
as
little
as
14
pg/

l
of
purified
RNA
obtained
from
an
YMV-infected
plant,
a
sensitivity
equivalent
to
that
obtained
with
the
reverse
transcription-polymerase
chain
reaction
(RT-PCR)
in
current
general
use.
The
RT-exoRPA
assay
has,
however,
several
advantages
over
the
RT-PCR;
positive
samples
can
be
detected
in
less
than
30
min,
and
amplification
only
requires
a
single
incubation
temperature
(optimum
37
?
C).
These
features
make
the
RT-exoRPA
assay
a
promising
candidate
for
adapting
into
a
field
test
format
to
be
used
by
yam
breeding
programmes
or
certification
laboratoriesYam
mosaic
virus
(YMV;
genus
Potyvirus
)
is
considered
to
cause
the
most
economically
important
viral
disease
of
yams
(
Dioscorea
spp.)
in
West
Africa
which
is
the
dominant
region
for
yam
production
globally.
Yams
are
a
vegetatively
propagated
crop
and
the
use
of
virus-free
planting
material
forms
an
essential
component
of
disease
control.
Current
serological
and
PCR-based
diagnostic
methods
for
YMV
are
time
consuming
involving
a
succession
of
target
detection
steps.
In
this
study,
a
novel
assay
for
specific
YMV
detection
is
described
that
is
based
on
isothermal
reverse
transcription-recombinase
polymerase
ampli-
fication
(RT-exoRPA).
This
test
has
been
shown
to
be
reproducible
and
able
to
detect
as
little
as
14
pg/

l
of
purified
RNA
obtained
from
an
YMV-infected
plant,
a
sensitivity
equivalent
to
that
obtained
with
the
reverse
transcription-polymerase
chain
reaction
(RT-PCR)
in
current
general
use.
The
RT-exoRPA
assay
has,
however,
several
advantages
over
the
RT-PCR;
positive
samples
can
be
detected
in
less
than
30
min,
and
amplification
only
requires
a
single
incubation
temperature
(optimum
37
?
C).
These
features
make
the
RT-exoRPA
assay
a
promising
candidate
for
adapting
into
a
field
test
format
to
be
used
by
yam
breeding
programmes
or
certification
laboratories