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CBN-V Video Archives - S7-14
Tryptophan and Tryptamine, two Precursors of Indole-3-Acetic Acid,
Improve Formation of Friable Embryogenic Callus in Cassava
Kokora R.N.N.1,
N.J. Taylor1, A. Sangaré2 and C.M. Fauquet1
1. International Laboratory for Tropical Agricultural Biotechnology
(ILTAB), Danforth Plant Science Center, 975 Warson Road, St Louis,
MO 63132
iltab@danforthcenter.org
2. Centre National de Recherche Agronomique, 01 BP 1740 Abidjan 01,
Côte d’Ivoire
Totipotent, friable embryogenic callus (FEC), is an ideal target
tissue for transgene insertion in cassava. FEC is induced from
organized embryogenic structures (OES) by culture of the latter on
Gresshoff and Doy (GD) basal medium containing the auxin picloram.
Increasing the efficiency of FEC production is required before the
benefits of transgenic technologies can be applied to agronomically
important cassava cultivars. Tryptophan and tryptamine, natural
precursors of endogenous indole-3-acetic acid (IAA), were
investigated for their effects on somatic embryogenesis in the three
West African cultivars TMS 60444, Bonoua Rouge and Kataoli. Addition
of tryptophan to the culture medium was found to have no effect on
induction of OES from leaf lobe explants while the addition of
exogenous IAA at 50
mM
was detrimental to this process. Conversely, inclusion of tryptophan
to GD medium at 125 mM shortened the time required for conversion of
OES to FEC and increased formation of FEC by 160% in cv. TMS 60444.
Addition of tryptamine at 25 and 50 mM was also found to
significantly elevate the formation of FEC in TMS 60444. Cassava
plants have been regenerated from tryptohan-induced FEC and are
being assessed in the greenhouse. Further experiments are in
progress to study the effect of tryptophan, tryptamine and related
compounds in additional cassava cultivars.
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Donald Danforth Plant Science Center All rights reserved.
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