INTRODUCTION
Tissue
culture
is
one
of
the
most
widely
used
biotechnologies
in
African
agricultural
improvement.
When
coupled
with
various
therapies
it
can
be
used
for
elimina;on
of
viruses
from
plants.
The
known
therapies
include:
1.
Thermotherapy
2.
Chemotherapy
and
3.
Electrotherapy.
Thermotherapy
combined
with
meristem
;p
culture
has
proven
to
be
successful.
However,
the
rate
of
success
can
be
improved
by
combining
two
or
more
different
treatments.
The
Swedish
government,
through
SIDA,
is
suppor;ng
;ssue
culture
and
diagnos;cs
research
of
the
following
crops:
Taro,
Yam,
Garlic
and
Passion
fruit
from
different
regions
within
eastern
and
central
Africa.
The
aims
of
this
work
are
to
(1)
Iden;fy
the
viruses
present
in
the
plants
(2)
Produce
clean
plan;ng
materials
through
;ssue
culture
using
one
or
more
of
the
above
men;oned
cleaning
methods,
(3)
pass
clean
plantlets
to
partners
for
mul;plica;on
and
subsequent
distribu;on.
However,
the
above
cleaning
methods
can
be
used
for
other
clonally
propagated
crops.
Pictures
DELIVERING
SCIENCE
AND
DEVELOPING
CAPACITY
Ø
Virus-­‐free
plan;ng
materials
can
be
obtained
using
one
or
a
combina;on
of
the
known
cleaning
therapies.
Ø
Famers
will
have
access
to
disease
-­‐free
plan;ng
materials,
leading
to
increased
crop
yields.
Ø
Diagnos;c
technologies
will
be
transferred
to
na;onal
as
well
as
regional
partners
hence
building
capacity.
CONCLUSION
The
results
of
this
study
demonstrate:
Ø
Successful
elimina;on
of
badnavirus
from
taro
using
thermotherapy
combined
with
meristem
;p
culture.
Ø
Thermotherapy
combined
with
chemotherapy
yielded
beRer
results
hence
the
need
to
combine
cleaning
therapies
for
higher
success
rates.
Dec
2012
METHODOLOGY
Tissue
culture
and
virus
indexing
for
the
producFon
of
clean
planFng
materials
P. ASAMI1; C. TOO1; M. MACHARIA1; P. NIYONZIMA2 ; D. BIGIRIMANA3; G. NDARUBAYEMWO3;
D. BEYENE4; J. HARVEY1 and T.A. HOLTON1
1Biosciences eastern and central Africa-International Livestock Research Institute, Nairobi, Kenya (BecA-ILRI);
2Institut des Sciences Agronomiques du Burundi (ISABU); 3University of Burundi, Faculty of Agronomy; 4 Ethiopian Institute of
Agricultural Research (EIAR)
RESULTS
(TARO
CASE
STUDY)
Samples
collec;on
and
ini;a;on
in
vitro
(before
thermotherapy
treatment)
Serological
test
(ELISA)
Molecular
diagnos;cs
(PCR
and
RT-­‐PCR)
Thermotherapy
treatment
of
all
posi;ves
in
vitro
plantlets
for
20
days
:
§
daily
temperature
:
38°C
§
photoperiod:
16
hours
§
dark
period:
8
hours
at
28°C
§
intensity
con;nued
light:
5000
lux
§
70%
rela;ve
humidity.
Molecular
diagnos;cs
(PCR
and
RT-­‐PCR)
a^er
thermotherapy
and
meristem
;p
culture
Sequencing
and
data
analysis
Excising
and
culturing
of
meristem
PCR
for
badna
virus
using
universal
badna
primers.
Badna
amplified:
280bp.
M
12
13
14
15
16
17
18
19
W
20
21
22
M
12
13
14
15
16
17
18
W
19
20
21
22
Badna
PCR
a^er
thermotherapy
and
meristem
;p
culture
using
universal
badna
primers
Virus-­‐free
in
vitro
plantlets
In
vitro
plantlets
a^er
combined
thermotherapy
and
meristem
;p
culture
Plant
with
viral
symptoms
collected
from
a
taro-­‐growing
field
in
Burundi.
BEFORE
TREATMENT
AFTER
TREATMENT
§ Badnavirus
was
detected
in
diseased
plants
prior
to
;ssue
culture.
§ 60
in
vitro
plantlets
tested
posi;ve
for
badnavirus:
DNA
sequencing
iden;fied
a
new
suspected
taro
virus
(Dioscorea
bacilliform
virus)
that
has
previously
been
reported
in
yam.
§ Thermotherapy
combined
with
chemotherapy
was
able
to
produce
clean
plants,
confirmed
a^er
PCR
and
RT-­‐PCR
diagnos;cs.
Unlocking livestock development potential through science, influence and capacity development
ILRI APM, Addis Ababa, 15-17 May 2013