Agriculture Reference
In-Depth Information
authors studied the result of elicitation on different metabolic pathways and summa-
rized that the biosynthesis of phenolics and the pathway to tryptamine are the two
important fluxes of intermediates in
C. roseus
cell cultures. There are reports which
suggest that indole alkaloids production is also affected by abiotic stresses of sorbi-
tol and mannitol (osmotic stress) whereas NaCl and KCl were employed to create
salt stress (Moreno et al.
1995
; Zhao et al.
2000b
). Zhao et al. (
2000a
) employed
metal stress with the help of vanadyl sulphate, sodium orthovanadate and some rare
earth elements whereas (Zhao et al.
2000c
;
2001c
) stimulated with various chemi-
cals. Fungal elicitors and hormones were used by (Namdeo et al.
2000
; Zhao et al.
2001d
; El-Sayed and Verpoorte
2004
). Thus elicitation of
C. roseus
cell cultures not
only enhances indole alkaloid biosynthesis in short time, but it is also responsible
for the excretion of the products into the medium (Zhao and Verpoorte
2007
).
Rijhwani and Shanks (
1998
) reported the effects of pectinase and methyl jasmo-
nate elicitor on growth and levels of several alkaloids in
C. roseus
. When pectinase
(72 units) was added about 150 % increase in tabersonine was observed whereas
due to addition of jasmonic acid (JA) a progressive increase of 60, 80, 150 and
500 % was observed respectively in serpentine, ajmalicine, lochnericine hörham-
mericine. The production of ajmalicine or catharanthine in cell suspension cultures
of
C. roseus
was enhanced by cerium (CeO
2
and CeCl
3
), yttrium (Y
2
O
3
) and neo-
dymium (NdCl
3
). The yield of ajmalicine in these treated-cultures reached 51 mg/l
(CeO
2
), 40 mg/l (CeCl
3
), 41 mg/l (Y
2
O
3
) and 49 mg/l (NdCl
3
) while catharanthine
production reached to 36 mg/l (CeO
2
) and 31 mg/l (CeCl
3
). In these treatments a
main part of improved alkaloids was released into medium (Zhao et al.
2000a
).
When 14-1 bioreactor was compared with shake flask culture of
C. roseus
cell
line a 80 % decrease in total alkaloid production was observed, but in the same cul-
ture when 1 mM trans-cinnamic acid was added the original alkaloid amounts was
restored (Godoy-Hernandez et al.
2000
). Zhao et al. (
2001b
) reported that indole
alkaloid biosynthesis in
C. roseus
cell cultures due to the action of elicitor is asso-
ciated to Ca
2
+
influx and the oxidative burst and up to some extent indole alkaloid
accumulation was inhibited by calcium channel blockers which could be improved
by re-addition of calcium chloride.
In
C. roseus
cell suspension culture Zhao et al. (
2001a
,
b
) employed biotic
elicitors derived from 12 fungi in order to test their effect on indole alkaloid pro-
duction. They reported that different indole alkaloids were stimulated by different
fungal mycelium homogenates and an improvement (2-5-fold high than control)
in alkaloid synthesis was observed. Ten Hoopen et al. (
2002
) marked the effect of
temperature on growth and ajmalicine production and reported that 27.5
0
C was
optimum temperature for biomass and secondary metabolite production. In shake
flasks and bioreactors an improved catharanthine synthesis in
C. roseus
cell cultures
was observed by combined elicitor treatment (Zhao et al.
2001a
). A combination
of fungal preparations and chemicals enhanced the alkaloid accumulation, a high-
est yield of ajmalicine with an enhanced catharanthine accumulation was observed
in a combination of tetramethyl ammonium bromide and mycelial homogenate of
Aspergillum niger
. The combination of malate and sodium alginate proved to be
beneficial for the highest yield of catharnthine with a high yield of ajmalicine pro-
Search WWH ::
Custom Search