5 the state of science in south africa
B I O L O G I C A L S C I E N C E S
lower seed bank via containment, rehabili- abounds. Much effort goes into validation
tation and restoration. of medicinal efficacy of both newly-discov-
ered compounds, and established herbal
5.2.4 Resurrection plants
remedies.
Sugar industry
S
outh Africa is the main home of a
group of extraordinary plants, able to
Knowledge of the identity of genes partici-
withstand extreme tissue desiccation.
pating in the delivery of important traits or
Collectively called resurrection plants, these
displaying tissue- or organ-specific expres-
species tolerate desiccation by entraining
sion is advantageous in the development of
particular mechanisms, only to regain full
rational molecular breeding strategies for
metabolic potential when water is again
crop improvement. Over the past 15 years,
available. In-depth systems-based research
the South African Sugarcane Research In-
to understand desiccation tolerance (which
stitute (SASRI) has enjoyed considerable
is the reverse side of the coin of desiccation
success in the discovery of such genes in lo-
sensitivity) is conducted at the University
cally-bred sugarcane varieties, which have
of Cape Town (UCT). The research covers
been used within marker-assisted breeding
and genetic engineering strategies. Using a
the spectrum from gene transcription and
linkage disequilibrium mapping approach,
regulation, through characterisation of
identified genes have facilitated the devel-
the proteins produced and their regula-
opment of genetic markers depicting resist-
tion, examination of putatively protective
ance or susceptibility to the sugarcane stalk
metabolites produced, to the whole-plant
borer, Eldana saccharina, and to sugarcane
ecophysiological level. The phenomenon of
smut disease caused by Ustilago scitaminea
‘shutting down’ metabolism when dry, and
infection. The success of this approach re-
its resumption on rehydration is also stud-
sulted in the South African sugar industry
ied on lichens and mosses at UKZN-Pieter-
being the first to apply marker-assisted
maritzburg.
sugarcane breeding within a commercial
context.
5.2.5 Biotechnology
Recombinant DNA and in vitro culture
P
lant-based biotechnology comes into technologies have been used in concert at
so many programmes at universities SASRI to genetically engineer sugarcane.
and research institutes in South Africa The purpose of such research has been
that it makes it impossible to survey the field two-fold, viz. to establish proof-of-princi-
in detail in this chapter. Hence, information ple regarding the delivery of novel input
is provided on a few institutional endea- and resistance traits to sugarcane and to
vours. Research in many centres is focused investigate the genetic basis of sucrose ac-
on drug discovery from the wide range of cumulation. Underpinning these goals has
biodiversity afforded by the South African been the in-house development of essen-
flora and the indigenous knowledge which tial genetic resources, including the isola-
140
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